Outwith the spraying season, concentrations for chlorpyrifos were the same as those within spraying season backgrounds, but for chlormequat, lower concentrations were observed outwith the spraying season Overall, study observed no evidence indicative of additional urinary pesticide biomarker excretion as a result of spray events, suggesting that sources other than local spraying are responsible for the relatively low urinary pesticide biomarkers detected in the study population. J Expo Sci Environ Epidemiol. The aim of this study was to evaluate the exposure of rural residents control group and occupational exposed population group of sprayers to organophosphorus pesticides OPs by measuring their non-specific dialkylphosphate metabolites DAPs in hair and in urine samples.
Data analysis revealed significantly higher sumDAPs levels in urine of sprayers than in the urine of control group and this is justified since sampling occurred during spraying periods. SumDAPs levels in hair samples of the sprayers were also significantly higher than in the hair of control group, confirming the long-term exposure to OPs. SumDAPs found levels in urine and hair samples of subjects were significantly correlated. Study confirmed the elevated levels of DAPs in hair and urine samples in occupationally exposed group of sprayers in comparison to control group, even detected levels were similar in logarithmic scale.
Ongoing pesticide exposure has to be monitored in the study of long term outcome of pesticide adverse effects since changes in the type and amount of exposure can influence outcome. The aim of this paper is to describe the trend in long term pesticide exposure in children through the analysis of pesticides in their hair. As part of an NIH study on the long term effects of pesticide exposure in young children, ongoing exposure to pesticides was determined by the analysis of children's hair for propoxur and pyrethroids at 2, 4 and 6 years of age.
There were significant changes in the prevalence and concentration of propoxur and pyrethroids in children's hair at 2, 4 and 6 years of age. At ages 2 and 4 years, the prevalence of propoxur exposure increased from For bioallethrin, the prevalence of exposure steadily increased from 2 years to 4 years and to 6 years. Exposure to transfluthrin significantly increased from 4 years to 6 years. Between 4 and 6 years, there was a higher median concentration of propoxur at 4 compared to 6 years and for transfluthrin and bioallethrin, at 6 compared to 4 years.
Changes in the prevalence and concentration of exposure to propoxur and pyrethroids in children at 2, 4 and 6 years of age are related to the progress in ambulation of young children and to changes in the formulation of home spray pesticides. Thus, periodic monitoring of pesticide exposure is necessary when studying the long term effects of pesticide exposure in the neurodevelopment of young children. Wearing of permethrin treated clothing usually implicates an uptake of permethrin by the user.
Aim of study was to examine the kinetics of internal permethrin exposure in volunteers during and after a single 8h-use of treated clothing as well as factors potentially influencing permethrin uptake. The clothing was worn for 8h, simulating differing external conditions, including comfort conditions as well as conditions of increased temperature and humidity without and with additional physical workload. Internal permethrin exposure was monitored by determination of permethrin metabolites DCCA and 3-PBA in a set of 12 urine samples, covering a period of h from the beginning of the wearing interval.
Time-concentration curves showed an increase of internal exposure associated with wearing of the clothing individual maximum: Metabolite excretion was affected by the make of clothing, which could be explained by differing permethrin contents of the garment. Assuming dermal uptake of permethrin, this may be ascribed to an alteration of the barrier function of the skin. Toxicol Lett. Data for chemical analytes in 12 chemical classes for subsamples of pregnant women from NHANES , a nationally representative sample of the U.
The percent of pregnant women with detectable levels of an individual chemical ranged from 0 to percent. The median number of detected chemicals by chemical class ranged from 4 out of 12 PFCs to 9 out of 13 phthalates. Across chemical classes, median number ranged from 8 out of 17 chemical analytes to 50 out of 71 chemical analytes. Generally, levels in pregnant women were similar or lower than levels in non-pregnant women, adjustment for covariates tended to increase levels in pregnant women compared to non-pregnant women.
Authors conlude, pregnant women in the U. Further efforts are warranted to understand sources of exposure and implications for policy-making. Plasma samples and interview data on sources of potential endocrine disruptors were collected from men with different exposures profiles. Occupational exposure to pesticides, disinfectants, and exhaust fumes seemed to be associated with increased plasma EEQs: 1.
Although the results are not yet readily interpretable, they indicate that these measurements can be valuable for epidemiologic studies on endocrine disruptors and give direction for further research. Females had significantly greater concentrations of acenaphthylene female: Positive correlations were found between concentrations of each class of pollutant, with respect to seafood diet habit, Body Mass Index BMI , and age. Concentrations of HCHs and DDTs in blood plasma of healthy Hong Kong residents were greater than those of other countries, and it was found that smoking, consumption of a seafood diet, BMI, and age could influence concentrations in human blood.
Environ Sci Technol. At three months and at 6 to 11 years of age the children underwent a clinical examination and blood sampling for analysis. Body fat percentage was also calculated. Compared to unexposed children birth weight and weight for gestational age were lower in the highly exposed children and medium exposed children. Exposed children had significantly larger increase in BMI Z-score from birth to school age and highly exposed children had If prenatally exposed to both pesticides and maternal smoking, the sum of four skin folds was Main, I.
Schmidt, M. Boas, T. Jensen, P. Grandjean, et al. A 4-month-old girl presented with sexual development, including breast enlargement, menstruation, uterine length of 69mm at ultrasonography, and dramatically high estrogen bioactivity, but no growth acceleration, pubic hair, pelvis masses or adrenal tumors. Gas chromatography with an electron capture detector and mass spectrometry detected pesticides p,p-DDD, p,p-DDT, lindane and endosulfan sulpfate in plasma from the infant, the mother, and the year-old father, who reported a dramatic decrease in libido, and in soil samples from their farm.
The precocious sexual development was probably caused by the estrogen activity of the environmental contamination by tons of pesticides stored in the family farm. Gynecol Endocrinol. Study compared creatinine-adjusted OP pesticide metabolite concentrations, as well as plasma pesticide concentrations, with other populations of pregnant women.
Creatinine-adjusted total dimethyl DM metabolite concentrations were between 4 and 6 times higher in this population compared to other populations of pregnant women in the United States while total diethyl DE metabolite concentrations were lower. Mean plasma concentrations of bendiocarb and chlorpyrifos in our sample were 4. Women with a graduate degree had significantly higher geometric mean concentrations of total urinary DM metabolite concentrations compared to other women. It is unclear why total DM metabolites concentrations were much higher in this population compared to other populations of pregnant women in the United States and Netherlands.
Individual or composite food items were analyzed for organophosphate OP and pyrethroid insecticide residues. The frequent consumption of food commodities with episodic presence of pesticide residues that are suspected to cause developmental and neurological effects in young children supports the need for further mitigation. Biomonitoring data from these studies indicate that current exposures to 2,4-D are below applicable exposure guidance values.
This review demonstrates the value of biomonitoring data in assessing population exposures in the context of existing risk assessments using the BE approach. Risk managers can use this approach to integrate the available biomonitoring data into an overall assessment of current risk management practices for 2,4-D.
Authors evaluated the following pesticide compounds in both maternal and umbilical cord sera: chlorpyrifos, diazinon, carbofuran, chlorothalonil, dacthal, metolachlor, trifluralin and diethyl-m-toluamide DEET. Of these compounds, chlorpyrifos, carbofuran, chlorothalonil, trifluralin, metolachlor and DEET were the pesticides most frequently detected in the serum samples.
An increase in abdominal circumference with increasing cord dichloran concentrations was also observed. These observations suggest that in utero exposures to certain pesticides may alter birth outcomes. Sci Total Environ. In a case-control study nested within the Nurses' Health Study, a prospective cohort of U. We also evaluated these associations for major histologic subtypes of NHL.
Cancer Epidemiol Biomarkers Prev. Non-Hispanic blacks had significantly higher 3PBA concentrations than did non-Hispanic whites and Mexican Americans in the survey period and in the combined 4-year survey periods but not in the survey period. Cis- and trans- 2,2-dichlorovinyl -2,2-dimethylcyclopropanecarboxylic acid were highly correlated with each other and with 3PBA, suggesting that urinary 3PBA was derived primarily from exposure to permethrin, cypermethrin, or their degradates.
Study concludes pyrethroid insecticide exposure in the U. However, to date there has been little published on ways to evaluate the relative public health significance of biomonitoring data for different chemicals and even less on cumulative assessment of multiple chemicals. The objectives of this study were to develop a methodology for a health risk interpretation of biomonitoring data and to apply it using NHANES body burden data fororganophosphorus OP pesticides.
Study back-calculates OP pesticide exposures from urinary metabolite data and compares cumulative dose estimates with available toxicity information for a common mechanism of action brain cholinesterase inhibition using data from U. Limitations include uncertainty related to assumptions about likely precursor pesticide compounds of the urinary metabolites, sources of exposure, and intraindividual and temporal variability.
The effect was detected through the sister chromatid exchanges SCE in lymphocytes of peripheral blood and micronuclei MN and other nuclear anomalies NA in buccal exfoliated cells. Also, the influence on cellular proliferation kinetics CPK was studied by means of the replication index RI and the cytotoxic effect was examined with the mitotic index MI. The non-exposed group consisted of 70 other persons, 21 women and 47 men from the city of Los Mochis, Sinaloa, Mexico.
Analysis of variance revealed that age, gender, smoking and alcohol consumption did not have a significant effect on genetic damage. However, there was a correlation between exposure time to pesticides and SCE frequency. These results could have been due to the exposure of workers to pesticides containing different chemical compounds. This study afforded valuable data to estimate the possible risk to health associated with pesticide exposure. Environ Int;35 8 ] Organochlorine and heavy metals in newborns: results from the Flemish Environment and Health Survey FLEHS To collect regional information on internal levels of pollutants in humans in Flanders, mother-child pairs were systematically recruited in via 25 maternities across Flanders.
Age and smoking habits of the mothers, did not influence the cord blood Pb and Cd levels. Mothers had 2. Season of delivery, breastfeeding previous children or consumption of local dairy products, were minor determinants. It was concluded that the place of birth in Flanders is an important determinant of the load of pollutants measured at the start of life.
This underlines the validity of human biomonitoring on relatively small geographical scale. The pesticides assessed include the banned organochlorine pesticides, the more modern organophosphorus, carbamate, and pyrethroid insecticides along with a variety of herbicides including phenoxyacetic acids and triazines. These methods are capable of detecting concentrations in biological samples resulting from occupational exposures to pesticides, and in some instances, general background exposures from residential or dietary exposures.
These data have been used for a variety of applications. They have documented the pervasiveness of pesticide exposures, have allowed us to determine the primary predictors of exposure in certain populations, have helped us to identify the most important pathways of exposure, and have helped us to better understand any potential risks associated with exposures.
In addition, these methods have helped us to document poisoning cases and identify etiologic agents in crisis situations. This review discusses the methods that have been employed over the last 40 years and how these methods have addressed critical public health questions.
Twenty-three children years of age who consumed only conventional diets were recruited for this 1-year study conducted in Children switched to organic diets for 5 consecutive days in the summer and fall sampling seasons. Study measured specific urinary metabolites for malathion, chlorpyrifos, and other OP pesticides in urine samples collected twice daily for a period of 7, 12, or 15 consecutive days during each of the four seasons. By substituting organic fresh fruits and vegetables for corresponding conventional food items, the median urinary metabolite concentrations were reduced to nondetected or close to non-detected levels for malathion and chlorpyrifos at the end of the 5-day organic diet intervention period in both summer and fall seasons.
Study also observed a seasonal effect on the OP urinary metabolite concentrations, and this seasonality corresponds to the consumption of fresh produce throughout the year. The findings from this study demonstrate that dietary intake of OP pesticides represents the major source of exposure in young children. Biomonitoring, the measurement of chemicals in blood, urine, and other tissues or fluids, is becoming an increasingly common tool in the study of human exposure to environmental chemicals and the potential health effects of those chemicals.
The NHANES databases provide valuable information for deriving reference ranges and trend information and can be used for hypothesis-generating analyses, but they cannot be used to establish causal relationships between environmental chemicals and health effects. This commentary examines issues unique to the use of such databases and the interpretation of biomonitoring-based epidemiological studies. J Environ Health ;70 9 ] The influence of age and gender on triclosan concentrations in Australian human blood serum. Recent in vitro and in vivo studies indicate that triclosan might exert adverse effects in humans.
In this study authors investigated the influence of age, gender, and the region of residence on triclosan concentrations in pooled samples of Australian human blood serum.
The results showed no influence of region of residence on the concentrations of triclosan. There was a small but significant influence of age and gender on the serum triclosan concentrations, which were higher in males than in females, and highest in the group of year old males and females. However, overall there was a lack of pronounced differences in the triclosan concentrations within the dataset, which suggests that the exposure to triclosan among different groups of the Australian population is relatively homogenous.
A selection of the dataset was compared with previous measurements of triclosan concentrations in human plasma from Sweden, where the use of triclosan is expected to be low due to consumer advisories. The triclosan concentrations were a factor of 2 higher in Australian serum than in Swedish plasma. Study analyzed 2, urine samples and detected concentrations of total free plus conjugated triclosan in Concentrations of triclosan were higher in people in the high household income than in people in low and medium income categories. In about three-quarters of urine samples analyzed as part of NHANES , we detected concentrations of triclosan.
Specifically, the concentrations of triclosan appeared to be highest during the third decade of life and among people with the highest household incomes. Environ Health Perspect ; 3 ] Agreement of pesticide biomarkers between morning void and h urine samples from farmers and their children In pesticide biomonitoring studies, researchers typically collect either single voids or daily h urine samples.
Collection of h urine samples is considered the "gold-standard", but this method places a high burden on study volunteers, requires greater resources, and may result in misclassification of exposure or underestimation of dose due to noncompliance with urine collection protocols. To evaluate the potential measurement error introduced by single void samples, we present an analysis of exposure and dose for two commonly used pesticides based on single morning void MV and h urine collections in farmers and farm children.
The agreement between the MV concentration and its corresponding h concentration was analyzed using simple graphical and statistical techniques and risk assessment methodology. A consistent bias towards overprediction of pesticide concentration was found among the MVs, likely in large part due to the pharmacokinetic time course of the analytes in urine. These results suggest that the use of single voids can either over- or under-estimate daily exposure if recent pesticide applications have occurred.
This held true for both farmers as well as farm children, who were not directly exposed to the applications. As a result, single void samples influenced the number of children exposed to chlorpyrifos whose daily dose estimates were above levels of toxicologic significance. In populations where fluctuations in pesticide exposure are expected e.
Study uses model estimates of organophosphate OP intake and urinary dialkylphosphate DAP metabolite excretion to develop premises about relative contributions from different exposure sources and pathways. This comparison supports the premise that diet is the common and dominant exposure pathway in both populations. Authors attribute the magnitude and small variance of this intake to residential nondietary exposures from local agricultural OP uses.
These results show that mass-balance models can estimate exposures for OP pesticides within the range measured by biological monitoring. Parental occupational exposure to pesticides is also a concern because exposures occurring during pregnancy and carry-home residues also contribute to children's cumulative burden. A number of epidemiological studies consistently reported increased risks between pesticide exposures and childhood leukemia, brain cancer, neuroblastoma, non-Hodgkin's lymphoma, Wilms' tumor, and Ewing's sarcoma.
Fifteen case-control studies, 4 cohort studies, and 2 ecological studies have been published since this review, and 15 of these 21 studies reported statistically significant increased risks between either childhood pesticide exposure or parental occupational exposure and childhood cancer. Therefore, one can confidently state that there is at least some association between pesticide exposure and childhood cancer.
However, an unambiguous mechanistic cause-and-effect relationship between pesticide exposure and childhood cancer was not demonstrated in these studies, and modifying factors such as genetic predisposition, rarely considered in the reviewed studies, likely play an important role. Most of the children's conventional diets were substituted with organic food items for 5 consecutive days and two daily spot urine samples wrer collected, throughout the day study period.
Yrine samples for five common pyrethroid metabolites were analyzed. Authors found an association between the parents' self-reported pyrethroid use in the residential environment and elevated pyrethroid metabolite levels found in their children's urine. Children were also exposed to pyrethroids through their conventional diets, although the magnitude was smaller than for the residential exposure. Children's ages appear to be significantly associated with pyrethroids exposure, which is likely attributed to the use of pyrethroids around the premises or in the facilities where older children engaged in the outdoor activities.
Study concludes that residential pesticide use represents the most important risk factor for children's exposure to pyrethroid insecticides. Because of the wide use of pyrethroids in the United States, the findings of this study are important for both children's pesticide exposure assessment and environmental public health. Peaches containing added residues of chlorpyrifos-methyl, fenitrothion, procymidone and vinclozolin were used for simulated industrial processing in the manufacture of baby food puree.
Residues were determined in raw material, in intermediate products at crucial steps of the processing procedure and in final products. The results of the study were interpreted with respect to enforcement of the stringent Maximum Residue Limit MRL of 0. Peeling was identified as the most effective procedure in reducing residues. Thermal treatment concentration and sterilisation substantially reduced organophosphate chlorpyrifos-methyl, fenitrothion residues, whereas procymidone and vinclozolin residue levels were increased in peach puree.
Food Addit Contam. For biomonitoring of exposure, chlorpyrifos and malathion have been measured in blood, but most typically their urinary metabolites have been measured. Although many biologic monitoring data have been generated and published on these chemicals, their interpretation is not straightforward. For example, exposure to environmental degradates of chlorpyrifos and malathion may potentially increase f urinary metabolite levels, thus leading to overestimation of exposure.
Also, the temporal nature of the exposures makes the evaluation of both exposure and effects difficult. Authors present an overview of the current biomonitoring and other relevant data available on exposure to chlorpyrifos and malathion and the use of these data in various environmental public health applications. Environ Health Perspect; 11 : —] Reference values for metabolites of pyrethroid and organophosphorous insecticides in urine for human biomonitoring in environmental medicine With reliable and sensitive analytical methods for detecting metabolites of organophosphorous and pyrethroid insecticides in urinary specimens of the general population several studies have been published on internal exposure to these insecticides of the population in Germany.
In Germany, reference values for environmental pollutants related to the population are established continuously by the Human Biomonitoring Commission of the German Federal Environmental Agency, preferably based on data gained by representative studies. Since there is a need for reference values to characterise the population's exposure to organophosphates and pyrethroids, and since there are different studies available from Germany that agree quite well with data from other industrialised countries, the Commission has derived reference values from the available data, though none of the studies had fulfilled criteria on representativity.
As the volume-related concentrations of organophosphate and pyrethroid metabolites show no significant age-dependence, the reference values derived are not age-stratified. Though based merely on statistical and not on toxicological data, levels analysed above the reference levels, when reliably measured verified several times , should prompt environmental health practitioners to search for sources, within the bounds of proportionality.
In addition to accidental poisoning, possible sources include indoor contamination following improper pest control operations in homes as well as in pets and food products contaminated by these pesticides. International Journal of Hygiene and Environmental Health, 3 ] Triclosan in plasma and milk from Swedish nursing mothers and their exposure via personal care products In this study, plasma and milk were sampled from 36 mothers and analyzed for triclosan.
Scrutinization of the women's personal care products revealed that nine of the mothers used toothpaste, deodorant or soap containing triclosan. The concentrations were higher in both plasma and milk from the mothers who used personal care products containing triclosan than in the mothers who did not. This demonstrated that personal care products containing triclosan were the dominant, but not the only, source of systemic exposure to triclosan. The concentrations were significantly higher in plasma than in milk, indicating that infant exposure to triclosan via breast milk is much less than the dose in the mother.
Biomonitoring is the study of the presence and concentration of chemicals in humans usually by the measurement of blood, urine or breath exhaled air. Properly conducted, these data provide a picture of the amount of a chemical or agent actually absorbed into the body for a specific period of time. This review provides a history of biomonitoring, as well as the limitations and potential benefits of these studies. Examples of the proper and possibly improper use of biomonitoring and the impact made on our society are provided.
Reasons for having comprehensive national biomonitoring programs are summarized, along with the societal benefits and risks. By , it has been predicted that the Centers for Disease Control CDC will be monitoring nearly chemicals in persons from all regions of the nation. The measurement of chemicals and biomarkers has revolutionized the field of exposure assessment. Overall, we recommend an approach of careful interpretation, understanding that the data obtained are useful for establishing baseline information about exposure, rather than equating detection with risk.
We present suggestions for contextualizing biomonitoring results in order to provide the public with the tools to distinguish genuine health risks from trivial ones. Glyphosate is the active ingredient in Roundup agricultural herbicides and other herbicide formulations that are widely used for agricultural, forestry, and residential weed control. As part of the Farm Family Exposure Study, we evaluated urinary glyphosate concentrations for 48 farmers, their spouses, and their 79 children years of age.
We evaluated hr composite urine samples for each family member the day before, the day of, and for 3 days after a glyphosate application. Sixty percent of farmers had detectable levels of glyphosate in their urine on the day of application. The geometric mean GM concentration was 3 ppb, the maximum value was ppb, and the highest estimated systemic dose was 0. Farmers who did not use rubber gloves had higher GM urinary concentrations than did other farmers 10 ppb vs. Their maximum value was 3 ppb. All but one of the children with detectable concentrations had helped with the application or were present during herbicide mixing, loading, or application.
None of the systemic doses estimated in this study approached the U. Nonetheless, it is advisable to minimize exposure to pesticides, and this study did identify specific practices that could be modified to reduce the potential for exposure. Environ Health Perspect; 3 : —] Genotoxicity of pesticides: a review of human biomonitoring studies Pesticides have been considered potential chemical mutagens: experimental data revealed that various agrochemical ingredients possess mutagenic properties inducing mutations, chromosomal alterations or DNA damage.
Biological monitoring provides a useful tool to estimate the genetic risk deriving from an integrated exposure to a complex mixture of chemicals. Studies available in scientific literature have essentially focused on cytogenetic end-points to evaluate the potential genotoxicity of pesticides in occupationally exposed populations, including pesticide manufacturing workers, pesticide applicators, floriculturists and farm workers.
A positive association between occupational exposure to complex pesticide mixtures and the presence of chromosomal aberrations CA , sister-chromatid exchanges SCE and micronuclei MN has been detected in the majority of the studies, although a number of these failed to detect cytogenetic damage. Conflicting results from cytogenetic studies reflect the heterogeneity of the groups studied with regard to chemicals used and exposure conditions.
Genetic damage associated with pesticides occurs in human populations subject to high exposure levels due to intensive use, misuse or failure of control measures. The majority of studies on cytogenetic biomarkers in pesticide-exposed workers have indicated some dose-dependent effects, with increasing duration or intensity of exposure. Chromosomal damage induced by pesticides appears to have been transient in acute or discontinuous exposure, but cumulative in continuous exposure to complex agrochemical mixtures.
Authors collected amniotic fluid samples slated for disposal and evaluated analytical methods to measure organophosphate and carbamate pesticides and metabolites, synthetic pyrethroid metabolites, herbicides, and chlorinated phenolic compounds. These levels are low compared with levels reported in urine, blood, and meconium in other studies, but indicate direct exposures to the young fetus, possibly during critical periods of development.
Results of this pilot study suggest that amniotic fluid offers a unique opportunity to investigate fetal exposures and health risks. Study assessed organophosphorus OP pesticide exposure from diet by biological monitoring among Seattle, Washington, preschool children. Parents kept food diaries for 3 days before urine collection, and they distinguished organic and conventional foods based on label information.
Children were then classified as having consumed either organic or conventional diets based on analysis of the diary data. Residential pesticide use was also recorded for each home. Results found significantly higher median concentrations of total dimethyl alkylphosphate metabolites than total diethyl alkylphosphate metabolites. The median total dimethyl metabolite concentration was approximately six times higher for children with conventional diets than for children with organic diets.
The dose estimates suggest that consumption of organic fruits, vegetables, and juice can reduce children's exposure levels from above to below the U. Environmental Protection Agency's current guidelines, thereby shifting exposures from a range of uncertain risk to a range of negligible risk. Consumption of organic produce appears to provide a relatively simple way for parents to reduce their children's exposure to OP pesticides. Levels of POPs and metals in populations in the Faeroe Islands and the Scandinavian countries are already reasonably low and are only likely to decline marginally by To improve understanding of the health effects associated with exposure to contaminants in the Arctic, authors recommend that circumpolar epidemiological studies should be implemented on a larger scale.
MeHg- and POPs-related effects are still the key issues. However, the role of newly discovered contaminants, such as PBDEs polybrominated diphenyl ethers and PCNs polychlorinated naphthalenes , should be investigated, as well as a more nuanced view on human dietary exposure to xenobiotics. Acta Paediatr ;92 11 ] Analytical methods for biological monitoring of exposure to pesticides: a review Synthetic pesticides have been used since in the early to mid twentieth century. In the US alone, over pesticide active ingredients are formulated in about 21 different commercial products.
Although many public health benefits have been realized by the use of pesticides, their potential impact on the environment and public health is substantial. For risk assessment studies, exposure assessment is an integral component, which has unfortunately, often been weak or missing. In the past several decades, researchers have proposed to fill these missing data gaps using biological monitoring of specific markers related to exposures. In this paper, authors present a review of existing analytical methodology for the biological monitoring of exposure to pesticides.
They also present a critical assessment of the existing methodology and explore areas in which more research is needed. Journal of Chromatography B ; ] Biomonitoring of persons exposed to insecticides used in residences Pesticides used indoors inevitably result in some unintentional and unavoidable exposures of residents. Measured dosages of residents are well below toxic levels. Exposures are substantially less and occur over a longer time than suggested by unvalidated estimates derived from previous extreme, conservative default assumptions based solely on environmental residues.
Human chlorpyrifos exposures were monitored following three different types of applications: fogger, broadcast, and crack-and-crevice. Persistence of total residue on carpet was substantially greater than the persistence of transferable residue. Low-level exposures of family members persisted for periods of weeks to a month after pesticide use.
Although few children who resided with their parents in pest-protected homes have been monitored, they eliminated more biomarker than their parents on a kg body weight-day basis when absorbed dosages were derived from spot urine specimens corrected for volume by an age-specific creatinine correction. Ultimately environmental residues may become useful elements of predictive residential exposure models, but their potential contribution to indirect exposure assessments must include careful determination of residue availability for contact transfer to clothing or skin and biological validation.
Experimental and situational monitoring of exposed persons is essential for meaningful and responsible predictive resident exposure model building. Ann Occup Hyg, 45 suppl 1 : SS S] Measurement of organophosphate metabolites in postpartum meconium as a potential biomarker of prenatal exposure: a validation study. Experimental data have linked exposure to prenatal organophosphates to adverse neurocognitive sequalae. However, epidemiologic research has been hampered by lack of reliable dosimeters. Existing biomarkers reflect short-term exposure only.
Measurements of pesticides in postpartum meconium may yield a longer-term dosimeter of prenatal exposure. Levels were similar to those seen in adult urine in population-based research. Results indicate that measurements of organophosphate metabolites in meconium have promise as biomarkers of prenatal exposure. Further research is needed to determine the time frame of exposure represented by pesticide levels in meconium and to evaluate the dose-response relationship.
The current study was conducted in two apartments and examines the accumulation of the pesticide chlorpyrifos in childrens' toys after the time suggested for reentry after application. It has been established for the first time that a semivolatile pesticide will accumulate on and in toys and other sorbant surfaces in a home via a two-phase physical process that continues for at least 2 weeks postapplication. The above information should be used to determine if current procedures for postapplication reentry are sufficient and to evaluate the need for procedures to store frequently used household toys, pillows, and other sorbant objects during insecticidal application.
Robson, N. Freeman, B. Buckley, A. Environ Health Perspec. Detection of these compounds in the body indicates that an exposure has occurred; that the pesticide is bioavailable, having been absorbed; and that a dose to critical tissues may have been incurred. Biomarker methods such as for adducted proteins or nucleic acids are being investigated for some pesticides. Methods are becoming more sensitive as advances are made in analytical instrumentation systems. Immunochemical methods are being developed and emphasized for screening purposes, as well as for an enhanced sensitivity and the potential to detect parent compound and multiple metabolites through selective cross-reactivity.
When initiating the biomonitoring component of an exposure assessment for pesticides an array of decisions must be made, primarily based on what is known about the metabolism of the pesticide of interest. Detectability of pesticide exposure depends upon selecting the most appropriate biological matrix, the dominant analyte s in that matrix, and the timing of sample collection relative to exposure. Useful analytical results are dependent on proper handling and storage of biological samples, as well as the availability of sensitive analytical methods.
These factors, currently known biomonitoring approaches, and the results of selected recent biomonitoring studies are presented. Specifically, the committee was asked to examine the adequacy of current risk assessment policies and methods; to assess information on the dietary intakes of infants and children; to evaluate data on pesticide residues in the food supply; to identify toxicological issues of greatest concern; and to develop relevant research priorities.
The committee considered the development of children from the beginning of the last trimester of pregnancy 26 weeks through 18 years of age, the point when all biological systems have essentially matured. The committee found both quantitative and occasionally qualitative differences in toxicity of pesticides between children and adults; that quantitative differences in toxicity between children and adults are usually less than a factor of approximately fold; and that infants and children differ both qualitatively and quantitatively from adults in their exposure to pesticide residues in foods.
Washington, D. Air and surface chlorpyrifos residues were measured for 24 hours following a 0. Two of the three treated rooms were ventilated following application. Maximum air concentrations were measured hours post-application. Surface residues available through wipe sampling were 0.
Estimated total absorbed doses for infants were 0. These doses are 1. Exposures to cholinesterase inhibiting compounds following properly conducted broadcast applications could result in doses at or above the threshold of toxicological response in infants, and should be minimized through appropriate regulatory policy and public education. Black, K. Elkner, L. Chorng-Li, M. Methner and R. Am J Pub Health. Longitudinal assessment of occupational determinants of chlorpyrifos exposure in adolescent pesticide workers in Egypt.
This study aims to determine the concentrations of commonly used pesticides azoxystrobin, buprofezin, chlorantraniliprole, difenoconazole, fipronil, imidacloprid, isoprothiolane, pretilachlor, propiconazole, pymetrozine, tebuconazole, tricyclazole, and trifloxystrobin in personal air samples and their associated health risks among paddy farmers. Eighty-three farmers from Tangjung Karang, Selangor were involved in this study. A solid sorbent tube was attached to the farmer's breathing zone with a clip, and an air pump was fastened to the belt to collect personal air samples.
The target compounds were detected with a maximum concentration reaching up to The hazard quotient HQ was less than 1 and the hazard index HI value was 3. The results reported in this study can be beneficial in terms of risk management within the agricultural community. The purpose of this study was to assess the knowledge and beliefs of 72 Latino farmworkers in North Carolina about the threat of health effects of pesticides, including cancer.
It sought to explore relationships between threat perceptions and pesticide protective behaviors observed in the field. Utilizing stepwise multiple regression, the authors found that years worked in agriculture in the United States was associated with decreased use of protective clothing. Pesticide protective behaviors in the field may be improved by utilizing moderately experienced farmworkers less 10 years as lay advisors to reinforce training.
J Agromedicine. Prostate cancer is one of the most frequent cancers among men worldwide. Its etiology is largely unknown, but an increased risk has been repeatedly observed among farmers. Data on lifetime agricultural exposures type of crops, livestock and tasks including pesticide use, re-entry and harvesting were collected from the enrolment questionnaire.
During the period from enrolment to 31 December , incident prostate cancers were identified. We found an increased risk for cattle breeders using insecticides [HR 1. A dose-response relationship was also observed with the number of hogs P for trend 0. We found an excess of prostate cancer risk among people involved in grassland activities, mainly in haymaking HR 1. Pesticide use and harvesting among fruit growers were associated with an elevated prostate cancer risk, with a two-fold increased risk for the largest area.
For potato and tobacco producers, an elevated prostate cancer risk was observed for almost all tasks, suggesting a link with pesticide exposure since all of them potentially involved pesticide exposure. Our analysis suggests that the risk of prostate cancer is increased in several farming activities cattle and hog breeding, grassland and fruit-growing and for some tasks including pesticide use. Scand J Work Environ Health. The results of this exploratory ethnographic research among children of farmworkers in California dramatically suggest otherwise.
Little work has been reported employing photovoice, a community-based participatory research method, to study childhood exposure to pesticides. A rich narrative about perceptions of pesticide exposure emerged from the ethnographic interviews.
Thematic analysis yielded beliefs about the relationship between air quality and childhood asthma. The findings suggest that childhood asthma should be reviewed within the context of local levels of environmental exposure and the principles of environmental justice. Health Place. This review considers the proposed revisions' likelihood of addressing historical gaps in farmworker protection. The proposal was compared to the existing Worker Protection Standard, and key aspects were analyzed in relation to existing science on farm labor hazards, as well as historic occupational health, labor and immigration policy.
US law historically has left farm workers largely unprotected. These exclusions and delays have been tolerated in part thanks to the myth of the independent family farmer, but more significant is the stingy nativism that presumes to benefit from immigrant labor without assuming any responsibility to protect the humans who provide it. Key aspects of the proposed revision include stronger protections against drift and re-entry exposures, better information provision and training, and increased protections for workers under 16 years.
The proposed changes represent an improvement over existing legislation, but do not go far enough. The revision should be strengthened along lines suggested by farm workers themselves, and other labor laws must also be amended to give the men, women, and children who work in the fields of this country full rights and protections. Int J Occup Environ Health. Farmworkers in the United States occupy a range of housing, including both on- and off-farm family and communal dwellings.
As the farmworker population is becoming more settled, housing needs are changing. Existing regulations designed originally for grower-supplied migrant housing may need to be expanded. Much of farmworker housing is in poor condition, and likely linked to negative mental and physical health outcomes of residents because of exposures to crowding; mold, mildew, and other allergens; pesticides; and structural deficiencies. The existing research literature, both on housing conditions and their associations with farmworker health, is sparse, and large areas of the country and significant domains of health are omitted.
This paper reviews this literature and formulates research and policy recommendations for addressing these deficiencies. New Solut. Median child urinary dialkyl phosphate DAP metabolite levels were slightly lower among the intervention group children at follow-up compared with baseline, albeit nonsignificantly. DAP metabolite levels in the control group children were markedly higher at follow-up compared with baseline. Carbaryl, chlorpyrifos, cypermethrin, dacthal, diazinon, malathion, and trans-permethrin were commonly detected in the floor wipes. In summary, intervention group children had slightly reduced pesticide exposures, whereas child exposures were higher among the control group.
Additional intervention studies evaluating methods to reduce pesticide exposures to farmworker families and children are needed. This study used qualitative descriptive data and directed content analysis to analyse semi-structured interviews and photographs that were data elements of a larger community-based participatory research study designed to document housing quality and health among North Carolina farmworkers.
Specific problems described by the participants include exposure to pesticides, safety issues, pests, water supply and air quality, temperature and moisture. This study describes migrant farmworkers' perceptions of housing quality and numerous potential impacts on health and safety.
Research, social policy and practice-based implications derived from this research could serve to improve the health status of these individuals and their families. This study suggests there is much room for sustained advocacy and action, given that many of the farmworkers' descriptions and photographs depicted housing conditions below accepted standards of living. Access to adequate and safe employer-provided housing for migrant farmworkers should be considered a basic human right.
Rural Remote Health. The goal of this preliminary study was to test evaluation items for measuring knowledge increases among farmworkers and to assess the effectiveness of the Toolkit in improving farmworkers' knowledge of key WPS and risk communication concepts when the Toolkit lesson was delivered by trained trainers in the field. After receiving training on the curriculum, four participating trainers provided lessons using the Toolkit as part of their regular training responsibilities and orally administered a pre- and post-lesson evaluation instrument to 20 farmworker volunteers who were generally representative of the national farmworker population.
Farmworker knowledge of pesticide safety messages significantly increased after participation in the lesson. Further, items with visual alternatives were found to be most useful in discriminating between more and less knowledgeable farmworkers. The pilot study suggests that the Pesticides and Farmworker Health Toolkit is an effective, research-based pesticide safety and health intervention for the at-risk farmworker population and identifies a testing format appropriate for evaluating the Toolkit and other similar interventions for farmworkers in the field. This analysis documents lifetime and current pesticide exposure of North Carolina Latino migrant farmworkers, with comparison to non-farmworker Latino immigrants.
During May to October , Latino farmworkers and Latino non-farmworkers completed interviews with items to construct measures of lifetime, current residential and occupational pesticide exposure. Farmworkers experience levels of lifetime and residential pesticide exposure that are consistently greater than among non-farmworkers. Farmworkers report a large number of occupational pesticide exposures. Lifetime exposure and current residential pesticide exposure are related to social determinants. Education is inversely related to lifetime pesticide exposure for farmworkers and non-farmworkers; farmworkers with H-2A visas report greater residential pesticide exposure than those without H-2A visas.
Occupational safety policy needs to consider these patterns of lifetime exposure when setting standards. Health care providers should be aware of the lifetime and current exposure of this vulnerable population. Am J Ind Med. Using data from the Community Based Participatory Research Study for Healthy Kids, study compared activity patterns recorded over 7 days during two agricultural seasons pre thinning and thinning between farmworker and non-farmworker children aged years old living in Eastern Washington State.
Study observed substantial differences in child activity patterns between the two seasons. The children in this sample spent more time outdoors and were more likely to engage in behaviors, such as playing in the fields and accompanying their parents to work in the fields during the high-spray thinning season.
- Investigations of Pesticide Contamination in Varied Pesticide-Use Settings?
- Henry VI, Part I.
- Toxics Program Bibliography - Pesticides in the Environment.
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There were some differences in activities and behaviors between farmworker and non-farmworker children during the thinning season. The purpose of this paper is to present and evaluate descriptively bivariate associations between urinary metabolites of pesticides and herbicides and migrant camp conditions, violations, and personal worker behaviors at home for farmworkers who do not apply pesticides. Authors studied migrant farmworker camps in eastern North Carolina in Changing and storing clothing and shoes in sleeping rooms increased the number of detects for the diazinon metabolite.
Farmworkers had exposures to multiple chemicals. No single housing domain was identified as critical to mitigating housing-related exposure; specific attention should be paid to changing and storing soiled clothing in sleeping rooms, and insect infestations. In , migrant farmworkers camps in NC were recruited and pesticide wipe samples for houses were analyzed.
OPs were found in of houses average of 2. The number of different OPs detected in each camp and concentrations of these OPs were not associated with camp and housing characteristics. The number of different pyrethroids detected in each camp and concentrations of these pyrethroids were associated with camps having residents with H2-A visas, a posted North Carolina Department of Labor Certificate of Inspection, no barracks, fewer residents, no bedroom weather protection or floor violations, and no roaches. Farmworkers are exposed to pesticides where they live.
Policy on removing pesticides from farmworker houses is needed. Reducing pesticides in farmworker houses will reduce one health risk confronted by this vulnerable population. The primary aim for this analysis is to describe the personal characteristics, work characteristics, occupational safety behaviors, and occupational injuries of North Carolina youth farmworkers. Participants included males The majority Most worked in tobacco Three quarters wore a hat, and Five 5.
Biopesticides fall into three major classes:. They can control many different kinds of pests, although each with separate active ingredient that is relatively specific for its target pest s. Biopesticides are environmentally safe and non toxic to plants and animals. However, their use is limited due to 1 less social awareness, 2 comparatively lower crop yields, 3 need for frequent applications, 4 less worked research area. On the contrary, application of chemical pesticides has proved to be economically beneficial and hence their use has increased globally especially after the advent of "Green Revolution".
The productivity of crop has been increased by use of suitable pesticide. They protect the crop from disease causing organisms, from plant pathogens and also from vector borne diseases. Another important advantage is reduction in cost of labor. Even though pesticides play significant role in agriculture they are the most important environmental pollutants. This is due to their wide spread presence in water, soil, atmosphere and agricultural products.
Currently it poses major threat not only to living organisms but also to environment specially ground and surface water. Synthetic pesticides affect the growth of plants. Chemical compounds in the pesticides are not biodegradable. This causes their sedimentation near plant roots making the supply of essential NPK inefficient. This inefficiency hinders growth of crops and their resistance to other harmful microbes. Pesticides percolate into the soil and get mixed with ground water. This causes draining of pesticides into the nearby stream or lake. This in turn adversely disturbs the aquatic eco system.
Soil is another. Pesticides hamper the fertility of soil by inhibiting the storage of nitrogen and other essentials in soil. Light and toxic compounds are suspended in air by pesticide spray. This causes air borne diseases and nasal infections. Besides all the environmental hazards; pesticides pose serious risk to mankind. Health hazards caused by some of the pesticides are summarized in Table 1.
The Toxicity of pesticides, made it essential to have accurate and reliable methods of monitoring their levels for safety purposes. They were sensitive and reliable. However, they had limitations like 1 complex procedure, 2 time consuming sample treatments, 3 need of highly trained technicians, 4 inability to perform on site detection etc. To improve these methods newer techniques are being developed. The new techniques use more sensitive devices like chromatographic techniques with various detection methods, electro analytical techniques, chemical and biosensors, spectroscopic techniques and flow injection analysis FIA.
Sometimes a combination of one or more methods proved successful in detecting a particular class of pesticide. This article presents an all embracing survey of the classical methods along with update knowledge of recent advances in the techniques. This was a widely used method for the detection of pesticide residues from environmental samples. Organophosphates Adversely affects nerve functioning, direct exposure can cause eye problems like blurring of vision, reddening, retardation in fetal growth etc. Chlorides Disruption of dopamine transport in the brain, increased risk of lung and pancreatic cancer, neutrophil inflammation etc.
Fungicides like atrazines, amides, etc. Irritation of skin and eyes, slowing of heart beats, weakness of muscles, central nervous system disorders etc. Rhodenticides like Strychnine Sodium monofluoroacetate Thallium, etc. Complete loss of hair, paresthesias, nausea, vomiting and abdominal pain, pulmonary oedema bronchopneumonia, diaphoresis, blurred vision and severe symmetric extensor muscle spasms .
The technique is based on two properties of light: 1 particle nature of light and 2 wave nature of light. The former gives rise to photoelectric effect and the latter results in formation of visible spectrum of light. Normally white or UV light is used as a source of light. The beam of light splits into its component wavelengths after passing through the prism.
Light of different wavelengths is absorbed by different analyte solutions to different extent depending on analyte concentration. The analyte particles absorb photons and then the unabsorbed photons are converted into electrical signal by the phototube. The detection unit then records the difference in the intensity of light. The difference in the intensities of source beam and the beam coming out of the analyte determines the concentration of the analyte. The components of a spectrophotometer are 1 source of light, 2 cell containing analyte solution, 3 phototube, and 4 detection unit.
The authors reported detection limits LOD of 0. Moreover spectropho-tometric detection methods were also found suitable for detection of organopesticides such as malathion, phorate and dimethoate from food samples. The procedure was based on oxidation of organophosphoours pesticides with slight excess of N-bromosuccinimide. The unconsumed N-bromosuccinimide was then reacted with rhodamine B which was followed by spectrophotometric estimation of decrease in color at nm.
Even with limited success in these methods, some drawbacks were evident. They were 1 extensive sample preparation, 2 relatively slow and 3 could not be used for real time estimation. Hence these days spectropho-tometric methods are used only for detection of limited number of pesticides. Sometimes they are coupled with other systems as terminal detection devices to detect pesticides.
Electroanalytical techniques have gained importance for analysis of environmental samples. Their main advantages are simplicity in operation, sensitivity, selectivity, portability and so on. Commonly used electroanalytical techniques are: potentiometry, conductometry, voltametry, amperometry etc . The basic principles of these techniques are discussed below. Potentiometry measures the potential of electrochemical cells. A potentiometric cell is composed of i reference electrode ii salt bridge iii analyte solution and iv indicator electrode. The indicator electrodes can be either metallic or ion selective.
The salt bridge acts as a barrier between the standard electrode and the analyte solution. Potentiometric methods are governed by Nernst equation. The potential E is calculated as 1 [16,17]. It is based on the property of electrolyte solutions to dissociate into ions. It measures the change in electrical resistance of a solution. A conductometric cell consists of 1 two electrodes: Anode positively charged and cathode negatively charged 2 an electrolyte solution and 3 battery current reading detection unit. The number of ions determines the amount of current generated which indicates the concentration of electrolytes.
The electrolytic properties of a conductor are described by Ohm's law 2 and the conductance is given by 3 [18, 19]. It measures the change in the current—potential characteristics of an electrochemical cell. This change is directly proportional to the concentration of the analyte. The current—potential relationship is dependent on the mass transfer rate.
It is the rate at which the electroactive species generated due to oxidation reduction reactions reach the electrode. This mass transfer can be due 1 ionic migration formed due electrochemical gradient 2 diffusion under a chemical potential difference or 3 bulk transfer. In voltametry the potential applied is usually varied as a function of time. Based on this voltametry is grouped into A linear voltametry and B cyclic Volta-metry. In former the potential applied to the electrochemical cell is gradually increased.
In latter, the potential is varied between a fixed lower and upper value [20, 21]. Amperometry can be considered as a sub-class of volta-metry since both the procedures depend on the same principal. The only difference in voltametry and am-perometry is that in amperometry the potential applied across the cell is constant. It measures the current generated due to the oxidation-reduction reactions taking place in the analyte solutions. The electroanalytical techniques are described in detail by Bard et al. Many variations in these techniques have been reported in literature.
For instance amperometry and potentiometry are coupled together for quantify-cation of analytes. One or more of these techniques are combined with other methods like chromatography, biosensors, flow injection analysis etc. Applications of these techniques are discussed below.
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Chromatographic techniques are among the first few techniques that were put to use for pesticide detection. As technology developed various modifications have been made in basic chromatography. However all forms of chromatography utilize the property of the analyte to distribute itself between two immiscible phases X and Y.
This co-efficient of distribution remains constant at a particular temperature and is given by 4. Every chromatographic system consists of two phases viz. While performing the method the analytes continuously move between the two phases.
They get separated from each other because of the difference in their distribution co-efficient. A typical chromatographic unit is made of stationary phase, mobile phase, a column, injector system, a detector, chart recorder and fraction collector. The performance of the system depends mainly on three factors; 1 Retention time T 5 2 retention factor which is the time taken by the analyte bound to the stationary phase to elute from the column relative to the time taken by the free analyte and 3 column height and resolution.
Chromatographic analysis requires sample preparation. This makes the technique more time consuming. The main steps of sample preparation are: 1 solvent extraction for example by acetone or acetonitrile or solid phase extraction, 2 column switching beneficial for HPLC: here the analyte is adsorbed on a suitable ad-sorbtant. The impurities are washed and then the analyte is eluted with an appropriate organic solvent. After a pesticide has been extracted and isolated from the sample, it is further separated from other coex-tractives.
It makes use of gas chromatography or liquid chromatography or, less frequently thin layer chroma-tography . In TLC the stationary phase is bound to a glass or a metal plate. The sample is spot inoculated or applied as a thin band near the end of the plate. The mobile phase flows over the stationary phase by capillary action. Separation of analytes takes place by adsorption or partition or ion exchange or molecular exclusion depending on the type of stationary phase.
The movement of the analyte depends on the retardation factor 6. TLC is usually followed by detection of compounds by i examining the plate under UV, ii spraying the plate with reagent which reacts with the compound to form coloured products, iii use of fluorescent dye iv by radio labeling the analytes and observing them by radiography. The separated compounds can be quantified with a precision densitometer. A number of modifications in TLC technique are used to detect pesticides. They are listed below.
This technique described by N. Ardikaran et al. Here the presence of pesticide is confirmed by absence of fungal growth around the sample spot . Due to automation it is possible to attain precision in the sample size and also the position at which the sample is applied on the TLC plate. This advancement rules out the possibility of variation in results due to human error. High performance thin layer chromatography HPTLC with use of automated multiple developments AMD makes use of gradient to separate pesticide compounds.
The gradient is formed by running a single or multiple mobile phases over the TLC plate. This method has been used for screening of a variety of pesticides including organophosphates, urea, tri-azines etc. HPTLC with diode array scanning was used to detect atrazine, clofentezine, chlorfenvinphos, hexaflumuron, terbuthylazine, lenacyl, neburon, bitertanol, and metami-tron from water samples.
Here samples were extracted by solid phase extraction on octadecyl silane. Dichloro-methane was used as an eluent and LOD was 0. HPTLC combined with different detectors like con-ductometry , multi enzyme assay  have been used for pesticide analysis. Advances in TLC are reviewed by Sherma . Gas Chromatography GC is based on difference in partition coefficients between a liquid stationary phase si-licone grease or wax and a gaseous mobile phase inert carrier gas like nitrogen. This method is applicable only. The partition coefficients are inversely proportional to the rate of volatilization of the compound.
Gas Chromatography GC is routinely used for qualitative and quantitative analysis of pesticides. The main components of a GC unit are represented in Figure 1. The detection unit is an important part of a GC unit from the analytical point of view. The same unit can be employed for detection of variety of compounds by varying the type of detector. The use of these detectors for pesticide detection is summarized in Table 2. Simple liquid chromatography consists of a column with a narrow bottom containing the stationary phase. The column is a made of glass and its length and diameter depend on the compound to be separated.
The optimum working of LC depends on the matrix on which the stationary phase is immobilized. The matrix used should have high mechanical and chemical stability to ensure optimum flow rate. The matrix is made up of inert materials like agarose, cellulose, dextran, polyacrylamide, silica, polysterene etc.
The stationary phase is always in equilibrium with a solvent. The sample is loaded onto the top of the column by i direct application, ii using sucrose gradient or iii with the help of a peristaltic pump along with solvent. The different components in the sample mixture pass through the column at different rates. This is due to differences in their partitioning coefficients between the mobile liquid phase and the station-. Types: 1. Packed conventional 2. Wall coated open tubular b. Support coated open.
The compounds are separated by collecting aliquots of the column eluent at different time intervals . This chromatography is widely used in combination with MS for pesticide quantification . This technique has been successfully been applied for detection of organophosphates, organochlorines etc. However certain modifications in the LC are essential. This is because many a time pesticides cannot be detected in one run due to interference of groups present in the pesticides.
In order to overcome these problems dual LC-MS systems have been developed. In such a unit two types of experimental conditions can be simultaneously applied for effective separation. This type of chromatography has a better edge over other types of chromatography. The reason behind is the materials used for making the column can withstand high pressure and flow rates. Here usually the columns are long 3 - 50 cm in length and 1 - 4 mm in diameter. The HPLC unit consists of 1 stationary phase which is either in microporous, pellicular or bonded form, 2 mobile phase, 3 pumps for delivering the eluent and 4 detectors.
The detectors used are: Variable wavelength length detectors, Scanning wavelength detectors fluorescence detectors, electrochemical detectors, mass spectrometer, NMR spectrometer, refractive index detector and evaporative light scattering detectors and so on. Vodeb et al. HPLC combined with supercritical fluid extraction has been used to detect multiple pesticide residues from food samples in the method described by Kaihara et al. The authors have reported LOD of 0. Application of re-. Biosensors have been described as analytical machines coupled with bio recognition elements with various detection techniques.
The biological components include enzymes, antibodies, microorganisms or DNA. The immobilized biocatalyst incorporated into the sensor allows continuous utilization of substrate. These methods have been reviewed extensively by Theveno et al. With the help of biosensors, on site analysis can be performed to understand the extent of pollution almost immediately . The advantages of using biosensors are: 1 disposable, selective, reliable and economical 2 they can be produced in large quantities and can be miniaturized for efficient use for onsite detection, 3 require less sample size and 4 easy to operate even by non skilled personnel .
In spite of their clear advantages, they have certain limitations. However, these drawbacks can be minimized by proper designing of the biosensor. For convenient use, biosensors are usually coupled with an electrochemical sensor. The sensors are potentiometer, amperometer, voltameter, conductimeter etc.
This coupling gives the data in readable form. A number of electrochemical sensors are available commercially. Certain characters like selectivity, response time, and linear range, limit of detection, reproducibility, stability and lifetime of biosensors are compared with standard IUPAC protocols for their per-. Different types of biosensors coupled with electrochemical devices are briefly described below.
They make use of living microorganisms such as algae, bacteria, yeast and fungi as bio-catalytic elements. Their main advantage is that they are easy to develop and there is no need for isolating sub-cellular components like enzymes, antibodies, antigens etc to detect pesticides. Various examples reported in literature are summarized in Table 3.
These biosensors measure the activity of the enzyme or enzymes used in the system. The activity of the enzyme depends on the various factors. They are amount of substrate, time of incubation, presence of inhibitors, reactions conditions like pH, temperature etc.
To make the system more cost effective, enzymes are immobilized using various methods . Mostly such biosensors are based either on enzyme activity or enzyme inhibiton. Example of former is organophosphorus hydrolase OPH with broad substrate specificity. Biosensors of second type often make use of Choline estarese CE , acid phos-phatase, tyrosinase, ascorbate oxidase, acetolactate syn-thase, aldehyde dehydrogenase etc. In such systems, acetylcholine esterase ACE immobilized on activated silica gel is most commonly used. The method is based on enzyme inhibition since carbamate and organophosphte pesticides inhibit the activity of ACE.
ACE primarily hydrolyses neurotransmitters producing choline and acetic acid. This can be easily monitored using spec-trophotometer  fluorescence indicator , potentiometer  or direct measurement by pH meter using glass electrode or change in conductance of medium. Research on enzyme based methods for detection is extensively discussed in review by Van Dyk et al. Examples of both the types enzyme based sensors are summarized in Table 4. These biosensors are based on the property of specific binding of two immunological molecules viz.
They are characterized by sensitivity, rapidity, specificity, low cost and ability to analyse large number of samples. Here pesticide specific antigen-antibody reactions are employed for their detection.
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For quantification purposes the antigen-antibody reactions are coupled with enzyme labels. Immunosensors are of two types: i labeled type and ii label free type. The first type makes use of different enzymes like glucose oxidase, horse raddish peroxidase, alkaline phosphatse etc.
Two different methods viz: sandwhich assay and competitive assay are used with labeled type. Similarly labeled free types of sensors are grouped into direct and indirect types. The applications of immunoassay as pesticide detection method have been reviewed in many papers . Commercial immunoassay kits are also available in the market. In immunosensors, sensing element can be either an antibody Ab or an antigen Ag which is immobilized on a transducer.
If Ab is immobilized, the binding of analyte can be measured directly. If Ag is immobilized, the detection is based on the competition between immobilized Ag, the analyte, and a fixed amount of Ab. Mainly four types of immunosensors are reported viz piezoelectric, optical, electrochemical or thermomet-ric.
Piezoelectric immunosensors: are more common due to label free detection of atrazine, parathion etc . A piezoelectric crystal can be coated with an Ag or Ab and the change in the mass by the binding of the analyte can be correlated to the concentration of the analyte . Optical immunosensors: Main optical immunosensros. In another type of optical immunosensor, the Ab is coated on the metal sheet causes a minute change in the refractive index when bound with the analyte and this change can be detected by the SPR device.
Another optical immunosensor is based on total internal reflection fluorescence TIRF. These biosensors are used to detect terbutryn, atrazine, parathion, polychlorophenol etc . These biosensors utilize the oxidation property of the nucleic acid base guanine . They are based on interaction of DNA molecules with pesticides. Such reactions can be detected by monitoring the change in redox potential. For this purpose electrochemical sensors like voltametry and potentiometry are used here DNA is immobilized on the electrodes.
Sometimes the change in electroactive analytes that are intercalated on DNA layer is also monitored. Nucleic acid biosensors have been extensively reviewed in a review published by Fang et al. Recent developments in enzyme based biosensors include use of gold nano particles to increase accuracy. Moreover these sensors have multiplexing facility which allows detection of trace amounts of pesticides. Because pesticides are present in trace amounts pre concentration and extraction steps are essential prior to detection.
Developments in nano materials particularly applications of carbon nano tubes as sorbant in solid phase micro extraction techniques has been elaborately discussed by Pyrzy-nska . These particles increase the adsorption and stability of ACE on planar gold electrode surface . Nanoparticle layer also improves the sensitivity and detection limit of the device. Slight change in the environment can disturb the charge based distribution of such sensors affecting the detection of pesticides. However, new studies and developments in surface chemistry and material physics along with proteomics can overcome this hurdle.
It delivers fine and accurate measurement of any environmental pollutant. Alvarez et al. In this method cantilevers are coated with DDT5 hapten molecules over a self assembled monolayer of alkanethiol with gold nano-partilce. Assay is performed by mixing the samples containing a fixed concentration of DDT monoclonal antibody with DDT solutions at different concentrations. After the incubation only the free antibody couples with the bioreceptor on the cantilever. The difference in the. It can be detected by a laser beam sensitive photodetector.
Gan et al. Organophosphates are detected by the inhibition of the acetyl cholinesterase catalyzed hydrolysis of ace-tylthiocholine. The biosensor could detect dimethoate from Chinese cabbage with comparable accuracy. Moreover, according to Palchetti et al. There advantages are possibility to operate in turbid media, comparable instrumental sensitivity, and possibility of miniaturization.
Other pesticides like monocrotophos, methyl parathion and carbamyl could be detected using a sol-gel-derived silicate network containing nanoparticles. This arrangement created a biocompatible microenvironment around the enzyme molecule which aided not only in stabilizing its biological activity but also preventing its runoff from the system . For detection of malathion, planar gold electrode coated with chitosan hydrogel containg gold nano particles was formulated. Here thiocholine was used as an indicator and the system was based on che-misortion and desorption of the indicator with LOD of 0.
Though use of nanoparticles is a promising option in pesticide detection techniques more studies are essential to ensure proper standardization and increase in sensitivity.
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Flow injection analysis is very sensitive, rapid and efficient tool used to detect presence of pesticides in different environmental samples. Other advantages of the technique are 1 low cost of instrumentation, 2 less labor cost and smaller sample size, 3 continuous sample injection, 4 better reproducibility and 5 high sampling rate with precision. This technique involves 3 steps viz 1 sample injection, 2 sample processing and 3 detection. The sample processing can be done by dilution, solvent extraction, medium exchange, enzymatic reactions, im-munoassays etc.
The detection and estimation of sample makes use of mass spectrometry, spectrophotometery and measurement of fluorescence or change in pH, use of. Biosensors combined with FIA are reported for detection of carbamate insecticides in water samples  and for carbofuran in food samples . In the latter method, ACE is incorporated in lipid films supported on a me-thylacrylate polymer. Similar enzyme system was used in the year for detection of organophosphorous pesticides. Here ACE is immobilized by adsorption on lead oxide which acts as an electrode.
It catalyzes the oxidative degradation of thiocholine in the reactor. Change in the electrochemical gradient due to oxidation of choline corresponds to the amount of pesticide present in the sample . Combination of biosensors with FIA overcomes limitations of biosensors. It also offers better option for standardization and optimization. The detection limits were found to be 0. The property of photolytic degradation of organophosphorous pesticides in presence of light has been utilized for screening the food samples for presence of or-ganophosphorous pesticides .
Photolysis can be due to absorption of UV or due to oxygen and hydrogen radicals. In this method FIA is used in combination with thermal lens spectrometry . Similar technique has also been employed for detection of dithiocarbamate fungicides  in water samples. FIA in combination with amperometry can also be used for detection of or-ganophosphates . FIA combined with immunochemilunisence assay to detect presence of atrazine in minute quantities 0. The immuno-reactor consists of antibody anti-antrazine immobilized on protein-A sepharose matrix packed in a glass capillary column.
This is then treated with atrazine and atrazine-horseradish peroxidase conjugate which facilitates competitive binding. For generation of photons the reactants are treated with hydrogen peroxide and lu-minal. The amount of pesticide present is inversely proportional to the number of photons generated [,]. Photo induced fluorosence PIF has been used with FIA for determination of a-cypermethrin pesticide residues in natural water samples .
In nature this pesticide has low fluorescence. It can be enhanced by treatment with UV radiation and cyclodextrins. FIA combined with chemiluminescence has been used for carbofuran atrazine and similar triazines detection . The method makes use of the property of the pesticides to get converted into methylamine upon exposure to UV. The methylamine generated is made to react with tris ruthenium. The light emitted in this reaction is proportional to the amount of pesticide present . Similar method has been employed for detection of the herbicide simetryn by Waseem et al.
The technique is based on the oxidation of luminol by the photoproducts of the simetryn in alkaline medium . Rapid quantitative analysis of pesticide residues in food and water samples is reported using FIA-MS . Bioassay technique provides a rapid and sensitive assay for screening water samples for presence of herbicides. The method makes use of the property of herbicides to inhibit functioning of photo system II in Chlamydomonas reinhardtii.
Briefly, C. The presence of herbicides is confirmed by observing the zone of inhibition around the disks. The advantage of the bioassay is that it can detect a wide range of herbicides including acifluorfen, chlorpropham, diclofopme-thyl DFM , glyphosate, isoxaben, pinnacle, trifluralin dichlorobenzonitrile DCB , 2,4-dichlorophenoxy-acteic acid 2,4-D , metobromuron, 2-ethylchlorophenoxya-cetic acid MCPA , metribuzin, atrazine, hexazinone, norflurazon and terbacil .
Similar method has been described by Amutha et al. Capillary electrophoresis can be employed for detection of certain pesticides . The technique is useful for detection of chiral pesticides like propiconazole. This technique is a useful analytical tool for measuring the kinetics of biotransformation of stereoisomers of chiral pesticides and other pollutants from soil sediment.
However the sensitivity of the method is comparatively low. Hence more studies are essential before using this method in routine practice. MS coupled with CE has high separation efficiency, low analysis time high resolution power, low consumption of samples and reagents . However the method has broad specificity and hence can be used only for screening of organo-phosphates from water samples . The persistence of pesticides in environmental samples is a global issue. With rules and regulations of organizations like EPA, innumerable methods have been developed to detect them.
Modifications in the traditional methods help in detection of specific pesticides in trace quantities. Newer methods like biosensors and nano particles, have overcome the limitations of classical methods. Use of cell based biosensors, has opened a new avenue with possibility of exploiting different microorganisms for detection purposes. Another important development is use of ELISA and monoclonal Abs for detection purpose with remarkable specificity and sensitivity.
Taking this into account the authors are of the opinion that there should be 1 uniformity in permitted use of specific pesticides all over the world, 2 consensus among various organizations on MRL of these pesticides, 3 mandatory rules and regulations to abide by the established norms and most importantly 4 uniformity in the protocols for measurement of MRL in environmental samples, particularly edible products. In fact, biopesticides are the best alternative to chemical pesticides.
However, government support, technology innovations, increase in social awareness and enhancement in the existing research and development are necessary to promote their use. All this will help in lowering the threats posed by the uncontrolled use of pesticides. The authors are indebted to Dr. Harley, K. Huen, R. Schall, N. Holland, A. Bradman, D. Barr and B. Azman and W. Abdullah, "General Classification Pesticides: Rodenticides," V-Manzanares, M.
Mathew, A. Pillai and V. Navaratne and N. Stoytcheva Ed. Gallova, "Conductometry," Kounaves, "Voltammetric Techniques," Bard and L. Wilson and J. Kanatiwela and N. Butz and H. Lautie, V. Stankovic and G. Niessen, P. Manini and R. TSeng, Y. Lin, H. Lee, S. Su, S. Chou and D. Podhorniak, J. Negron and F. Griffith Jr. Johnson, N. Saikia and A. Du, H. Liu, et al.