Low Levels Of Pesticides Research Articles

Occurrence of aflatoxin M1in organic dairy products

Organic foods are perceived more nutritious, safer and healthier than conventional foods by consumers. Organic foods contain lower levels of pesticides and nitrates than conventional produce. However, studies on mycotoxin content of organic foods are limited. The aim of this study was to investigate aflatoxin M1 (AFM1) levels of organic milk and organic milk products produced in Turkey. In this study, 188 organic dairy products consisting of organic ultra-high temperature (UHT) milk (39 samples), organic yogurt (26 samples), organic cheese (91 samples) and organic butter (32 samples) were examined for AFM1. ELISA was used for analysis of the samples. Samples were collected from organic markets in Turkey. AFM1 was detected in 39 (100%) organic UHT milk samples (mean: 65 ng/kg; range: 57-78 ng/kg), 39 (43%) organic cheese samples (mean: 137 ng/kg; range: 9-487 ng/kg) and 26 (100%) organic yogurt samples (mean: 238; range: 125-269 ng/kg). AFM1 contamination was not detected in organic butter samples. AFM1 le...

Effects of agricultural pesticides on the health of Rana pipiens frogs sampled from the field

There is evidence that over the last 30 years, there have been mass declines in diverse geographic locations among amphibian populations due to disease outbreaks. Multiple causes have been suggested to explain this increase in disease incidence. Among these, climate changes, environmental pollution and reduced water quality are gaining attention. Indeed, some chemicals of environmental concerns are known to alter the immune system. It is possible that exposure to these pollutants could alter the immune system of anurans and render them more susceptible to different pathogens. In this study, we sampled Rana pipiens in five different sites near St. Lawrence River (Quebec, Canada) during the months of July and September in 2001. Two of these sites were protected areas, in which low levels of pesticides were detected, while the remaining three sites were located in areas with intensive corn and soybeans cultivations. Our results demonstrated that frogs living in agricultural regions are smaller in size and weight than frogs living in areas with lower levels of pesticides at both sampling times. Moreover, we have observed a significant decrease in the number of splenocytes (cellularity) and the phagocytic activity in frogs sampled in impacted sites. Taken together, these results suggest that frogs living in agricultural regions might be more vulnerable to infections and diseases through their smaller size and alteration of their immune system. Our results also contribute to the overall discussion on factors involved in amphibian declines.

Preformed Biomarkers Including Dialkylphosphates (DAPs) in Produce May Confound Biomonitoring in Pesticide Exposure and Risk Assessment

Low levels of pesticides and their metabolites/degradates occur in produce when pesticides are used in conventional or organic crop protection. Human dietary and nonoccupational urine biomonitoring studies may be confounded by preformed pesticide biomarkers in the diet. The extent of formation of putative urine biomarkers, including malathion specific (MMA, MDA; malathion mono- and diacids), organophosphorus generic (DMP, DMTP, DMDTP; dimethyl-, dimethylthio-, and dimethydithiophosphate), pyrethroid generic (3-PBA; 3-phenoxybenzoic acid), and captan-specific metabolites (THPI; tetrahydrophthalimide), was measured in produce samples containing the parent pesticide. Every produce sample of 19 types of fruits and vegetables contained biomarkers of potential human exposure. A total of 134 of 157 (85%) samples contained more molar equivalent biomarkers than parent pesticide. Malathion and fenpropathrin were sprayed (1 lb/A), and the time-dependent formation of pesticide biomarkers in strawberries was investigated under field conditions typical of commercial production in California. Malathion and fenpropathrin residues were always below established residue tolerances. Malathion, MMA, and MDA dissipated, while DMP, DMTP, and DMDTP increased, during a 20 day study period following the preharvest interval. The mole ratios of biomarkers/(malathion + malaoxon) were always greater than 1 and increased from day 4 to day 23 postapplication. Fenpropathrin and 3-PBA also dissipated in strawberries during each monitoring period. The mole ratios of 3-PBA/fenpropathrin were always less than 1 and decreased from day 4 to day 14. The absorption of pesticide biomarkers in produce and excretion in urine would falsely indicate consumer pesticide exposure if used to reconstruct dose for risk characterization.

Organochlorine Residues in Vegetables

Vegetables are important components of the human diet, and even low levels of pesticides in vegetables may have adverse effects for consumers. A study was carried out to assess residue levels of dichlorodiphenyltrichloroethane (DDT), hexachloro-cyclohexane (HCH), and endosulfan in vegetables. The total concentration of organochlorine pesticides (OCPs) ranged from 0.29 to 106.65 μg.kg−1 (wet weight). All vegetable samples had some levels of one or more organochlorine pesticide in them. Mean concentrations of ∑DDT, ∑HCH, and ∑endosulfan in vegetables were 4.20 ± 1.68, 3.12 ± 0.66, and 0.97 ± 0.21 μg.kg−1 (wet weight), respectively. The greatest OCP accumulation was in root vegetables, followed by fruit and flower and leaf vegetables. The ratio of α-HCH to γ-HCH isomers (α/γ HCH ratio) ranged from 0.03 to 3.77, which reflects the use of lindane as well as technical formulations of HCH. The ratio of (DDE + DDD)/∑DDT, and DDT/DDE were 0.55 and 1.30, respectively, indicating biotransformation and input of DDT to the environment. Vegetables had residue levels of OCPs much below recommended maximum residue limits set by the European Commission and Indian government, indicating minimal risk to the consumers.

Pesticide Concentrations in Vacuum Dust from Farm Homes: Variation between Planting and Nonplanting Seasons

The hazards of chronic low-level pesticide exposures inside homes have received little attention. Research to date does not provide answers regarding the long-term potential bioavailability of pesticides in homes and its risk factors. The purpose of this study was to investigate pesticide levels in Iowa homes during one year and assess the relationship between exposure levels and potential sources of pesticide contamination. The study involved sampling surveys of the target pesticide atrazine among 32 farm families in a three-county area of Iowa during the planting season (April–June) and nonplanting season (November-December). Dust samples were collected, and information gathered through questionnaires to evaluate pesticide migration inside homes. This study found that dust in every farm home surveyed was contaminated with atrazine during both seasons and these concentrations significantly decreased by the nonplanting season. Pesticide amounts, acreage, and spraying time determined the presence and persistence of this herbicide inside farm homes.

Sequential Remediation Processes for a Low Level Pesticide Wastewater

The aim of this study was to develop a remediation system for the treatment of a low-level pesticide wastewater that uses available onfarm organic matter as an absorption media, is capable of reducing the concentration of the pesticide to a safe level and is economically viable for implementation by farmers. The absorption capacity of chopped hay and soybean to the fungicide captan was evaluated under batch conditions and the effectiveness of the composting process in depredating captan in contaminated organic materials was evaluated. The results showed that both hay and soybean plant residues were very effective in absorbing 99.2% and 98.5% of captan form the wastewater after 4 hours, respectively. Because of its availability, hay can be used in an onfarm pesticide immobilization system that consists of shallow reinforced concrete pit (filled with hay) with steel bars across the top for machinery to roll onto and be washed. The wastewater can be retained for 24 hours which is a sufficient time for hay to absorb the captan. The contaminated hay can then be composted. The addition of used cooking oil raised the temperature of the composting mixture to 63?C. Small reductions in moisture content (from 60% to 58.9 %) and C:N ratio (from 30:1 to 28:1) were observed while reductions of 18.92%, 15.56% and 4.8% in the volatile solids, total carbon total Kjeldahl nitrogen were achieved after 10 d of composting, respectively. About 92.4% of the captan was degraded in the first 4 days of composting. Most of captan (92.4%) was degraded during the mesophilic stage (first 3 days). The degradation rate constant for the mesophilic stage (0.724 d-1) was 2.74 times the degradation rate constant for the thermophilic stage (0.264 d-1). An onfarm windrow composting process would be very effective in degrading captan contaminated hay. The captan contaminated hay could be mixed with equal amount poultry manure or dairy manure to provide the required bioavailable carbon and nutrients for the composting process. Some used cooking oil could also be added to maintain higher temperature within the compost matrix. The windrows should be mixed on a daily basis to provide sufficient oxygen for the composting microorganisms.

A SDME/GC–MS methodology for determination of organophosphate and pyrethroid pesticides in water

A rapid and simultaneous method for identification and quantification of pesticides residues in water samples have been developed and applied to the analysis of real samples. Tap and San Francisco River water samples were collected from Propria town and Aracaju city in the state of Sergipe, Brazil. A new single-drop microextraction (SDME) followed by gas chromatography–mass spectrometry techniques were used to determine the dimethoate, methyl parathion, ethion (organophosphates) and permethrin (pyrethroid) pesticides in water samples. The parameters linearity, linear range, precision, accuracy, sensitivity and robustness were studied for validation of the SDME/GC–MS method. An important point to this study is that plots of relative response and logarithmic concentrations were used to verify that the measurements were within the linear dynamic range of the method. In order to enhance high linearity of analytical curve, points that do not belong to 95 to 105% of linear range were excluded. Recovery tests of pesticides in different water samples (tap water and river water) were between 76.2 and 107% and this evaluation was used to demonstrate the reliability of the method. For all pesticides the method showed the limits of detection (LOD) in a range between 0.05 and 0.38μgL−1 and the limit of quantification (LOQ) between 0.15 and 1.1μgL−1. All these parameters demonstrate high sensitivity of the developed method and the capability for detecting and quantifying of low levels of pesticides in water samples.

Chronic toxicity of pesticides to the mRNA expression levels of metallothioneins and cytochrome P450 1A genes in rainbow trout

The hazardous effects of pesticides on various metabolic pathways are a great problem for environmental health and should be well determined. In the present study, the authors treated rainbow trout with 0.6 μg/L deltamethrin for 28 days and 1.6 mg/L 2,2-dichlorovinyl dimethyl phosphate for 21 days. After this time period, the authors observed alterations in mRNA expression levels of MT-A, MT-B and CYP-1A. Chronic exposure to low levels of pesticides may have a more significant effect on fish populations than acute poisoning. While both pesticides caused a significant increase on mRNA levels of MT-A and CYP-1A, MT-B mRNA levels were increased significantly only upon deltamethin administration. The significant increase in mRNA levels of the corresponding genes may be considered as a defence mechanism in addition to the antioxidants against oxidative stress, as well as a detoxification mechanism against adverse effects of pesticides.

Residue analysis of multi‐class pesticides in watermelon by LC‐MS/MS

As watermelon is farmed primarily by protected and successive cultivation techniques, a number of pesticides are required for the control of pests and diseases. To evaluate the harmful effects of pesticides in watermelon and to guarantee consumers' safety, a rapid screening process for pesticides is required. A LC-MS/MS method was applied for the direct quantitation of 44 pesticide residues in watermelon. A Zorbax XDB-C(18) column was selected for analysis, with a mobile phase consisting of a gradient system of water and 5 mM methanolic ammonium formate. MS/MS experiments were performed in ESI positive ion and multiple reaction monitoring modes. The LOQs were in the range of 1-26 microg/kg, thereby indicating good sensitivity. Most of the recoveries ranged between 70-131% with RSDs < or = 20%. We suggested that the amount of pesticide residues such as pyroquilon (pyn), boscalid (bd), and dimethomorph (di) in amides (AM) and cinosulfuron (ci) in ureas (UR) may have been overestimated for the pesticides owing to increased alpha-error risk, whereas the amounts of pesticide residues, such as imibenconazole (ie) in the triazoles (TR) and fenpyroximate (fee) in the imidazoles (IM), may have been underestimated as the result of increased beta-error risk. The current method allowed for the rapid quantitation and identification of low pesticide levels in the watermelon samples. No pesticide residues were detected in any of the surveyed watermelons obtained from eight local markets in the Republic of Korea. Statistical analysis of the recoveries classified the 44 pesticides into nine groups and three overall categories.

Bladder cancer incidence and mortality rates compared to ecologic factors among states in America

Smoking, inadequate vitamin D and pesticide exposure have been linked to bladder cancer (BCa) in past studies. The objective of this study is to explore associations between BCa rates and these risk factors. BCa incidence and mortality rates among states were compared to smoking; solar ultraviolet (UV) radiation levels and drinking water from a surface water supply (which has greater residual pesticide contamination than groundwater and both are used as sources for drinking water). Lack of health insurance, median family income and urbanization were included to adjust for access to health care and socioeconomic status. BCa incidence and mortality correlated directly with smoking and inversely with solar UV radiation for males and females. BCa mortality correlated directly with drinking surface water for both sexes. Lack of health insurance correlated inversely with BCa incidence for females and trended toward significance for males. Multivariable analyses identified solar UV radiation as the best predictor of BCa incidence in males and solar UV radiation and smoking in females. Solar UV radiation, smoking and drinking surface water were the best predictors of BCa mortality in males, while smoking and drinking surface water were the best predictors of mortality in females. BCa incidence and mortality for both sexes correlated directly with smoking and inversely with solar UV radiation levels. BCa mortality for both sexes correlated with drinking water from a surface water source. It is hypothesized that BCa mortality risks may increase from drinking water contaminated with low levels of pesticides.

Pesticides and Myocardial Infarction Incidence and Mortality Among Male Pesticide Applicators in the Agricultural Health Study

Acute organophosphate and carbamate pesticide poisonings result in adverse cardiac outcomes. The cardiac effects of chronic low-level pesticide exposure have not been studied. The authors analyzed self-reported lifetime use of pesticides reported at enrollment (1993-1997) and myocardial infarction mortality through 2006 and self-reported nonfatal myocardial infarction through 2003 among male pesticide applicators in the Agricultural Health Study. Using proportional hazard models, the authors estimated the association between lifetime use of 49 pesticides and fatal and nonfatal myocardial infarction. There were 476 deaths from myocardial infarction among 54,069 men enrolled in the study and 839 nonfatal myocardial infarctions among the 32,024 participants who completed the follow-up interview. Fatal and nonfatal myocardial infarctions were associated with commonly reported risk factors, including age and smoking. There was little evidence of an association between having used pesticides, individually or by class, and myocardial infarction mortality (e.g., insecticide hazard ratio (HR) = 0.91, 95% confidence interval (CI): 0.67, 1.24; herbicide HR = 0.74, 95% CI: 0.49, 1.10) or nonfatal myocardial infarction incidence (e.g., insecticide HR = 0.85, 95% CI: 0.66, 1.09; herbicide HR = 0.91, 95% CI: 0.61, 1.36). There was no evidence of a dose response with any pesticide measure. In a population with low risk for myocardial infarction, the authors observed little evidence of increased risk of myocardial infarction mortality or nonfatal myocardial infarction associated with the occupational use of pesticides.

Determination of Pesticide Residues in Honey Samples

Protocol for the determination of pesticides residues in honey samples have been standardized using a simple technique of liquid–liquid extraction. The method is sensitive to detect low levels of pesticides in honey. Honey sample was fortified with pesticides, namely, cypermethrin, fenvalerate, alphamethrin, lamba–cyhalothrin, endosulfan (α, β and sulfate) and chlorpyrifos. The method of extraction and clean up was optimized and validated in the laboratory. The method was applied to screen six samples of honey locally available for pesticides residues. Recoveries ranged from 60% to 90.6% with RSDs from 2% to 10%. Low recoveries were recorded for α and β -endosulfan in the range of 60%–71%. The LOQs, varied from 0.05 to 1.0 mg kg−1.

Short- and long-term exposure to low levels of pesticide and flavonoid mixtures modify endogenous antioxidants in tissues of rats

The objective of this study was to determine if interaction between phytochemical mixtures and low level exposure to pesticides would modify tissue endogenous antioxidants in rats. Two experiments were conducted using dietary flavonoid (F) and oral pesticide (P) mixtures (FM, PM) on changes in the activities of superoxide dismutase (SOD), glutathione peroxidase (GPX) and glutathione concentrations (GSH) in male Sprague Dawley rats (150–175 g) fed for 2 or 4 weeks the AIN 93M diet with or without equal amounts of quercetin, rutin, catechin (FM) at 1.0 mM or 5 mM/kg diet, and with/without PM fed orally at 0.1 mL/d/5d/wk (PM = chlorpyrifos, endosulfan, thiram at 25% LD50 in oil). Our data indicate that (compared to corresponding Control groups): (i) While, 2 weeks of feeding reduced liver and small intestinal mucosal (IM) SOD activity in the PFM1 (PM+FM1) group, 4 weeks of feeding increased only liver SOD activity in PM, FM1, FM5 and PFM1 and PFM5 groups; (ii) Liver and IM GSH levels increased in PFM groups after 2 or 4 weeks of exposure; plasma GSH increased in the groups fed FM5 with or without PM; (iii) Liver GPX activity declined in both 2 and 4 week experiments in the FM and PFM groups, respectively. These data suggests that metabolic interaction between FM and PM, and duration of exposure, can modify endogenous antioxidants. Data also underscore the prooxidant properties of flavonoids.

Multiresidue analysis of pesticides with hydrolyzable functionality in cooked vegetables by liquid chromatography tandem mass spectrometry

It would be preferable for pesticide residues substituted by hydrolyzable functionality to be analyzed after cooking because their structures are apt to degrade during boiling and/or heating. A liquid chromatography-tandem mass spectrometry (LC-MS/MS) method for the quantitative determination of 44 pesticide residues with hydrolyzable functional group in five typical vegetable widely consumed in Republic of Korea is described. The sample clean-up was carried out according to the method of Food Code No. 83 established by the Korea Food and Drug Administration (KFDA). Zorbox XDB-C(18) column was selected for the analysis because of the best peak separation. The LC mobile phase consisted of water and 5 mm methanolic ammonium formate, which resulted in a peak shape with good symmetry at each run. Tandem mass spectroscopic (MS/MS) experiments were performed in ESI positive mode and the multiple reaction monitoring modes. A conventional matrix effect was modified to more comprehensive form 100gamma(ij) (%). A high matrix effect (<-30%) was detected for the seven polar pesticides, namely thiamethoxam, clothianidin, acetamiprid, aldicarb, thiacloprid, pirimicarb and methabenzthiazuron. The limits of detection were in the range of 0.1-8.1 microg/kg, indicating a good sensitivity. Most of the recoveries ranged from 70 to 131% with RSDs <or= 20%. The current method allowed rapid quantitation and identification of low pesticide levels in the cooked vegetable samples. Of the screened pesticide residues, only fluquinconazole and dimethomorph below the maximum residue levels established by the KFDA were detected in onion and cucumber samples.

An investigation into advanced oxidation of three chlorophenoxy pesticides in surface water

The performance of Fenton's reagent in removing 2,4-D, MCPA and mecoprop from surface water has been evaluated here. Initial trials were undertaken at a pesticide concentration of 4.5 x 10(-5) mol l(-1) in deionised water at pH 3 and two different stoichiometric ratios of pesticide: Fe(II): H(2)O(2) (1:1:10, 1:10:10) were evaluated. At the 1:1:10 ratio, approximately 10 minutes were required to achieve a 50% removal of the pesticide. At the higher ratio the removal achieved after 1 minute, was >90%. Subsequent experiments studied the performance of Fenton (4.5 x 10(-4) mol l(-1) Fe(II): 4.5 x 10(-4) mol l(-1) H(2)O(2)) in surface water spiked with pesticides and the impact of pH on the rate and degree of pesticide degradation was investigated. The removal was significantly improved at pH 3 in comparison to pH 6.5. The effect of Fenton on DOC removal from surface water was followed. Experiments investigated the performance of Fenton at pesticide concentrations of 7.5 x 10(-9) mol l(-1) in surface water. Fenton was shown to be an effective treatment for removing low levels of pesticides from surface waters at pH 3 & 4.

Effect of Flavonoids and Low Level Pesticide Exposure on Copper and Zinc Homeostasis in Rats

The protective effect of flavonoids against disease is well‐documented, but little is known of their anti‐nutritional effects and potential interaction with pesticides. Two 30/d experiments (36 male SD rats each) were conducted to determine effect of administering flavonoid mixture (FM) with concomitant exposure to a pesticide mixture (PM) or FM at varied levels on changes in concentrations of zinc and copper in tissues. Experiment1: PM=chlorpyrifos, endosulfan and thiram at 25% LD50 was dissolved in SB oil and gavage‐fed 0.1mL 5days/wk; FM in SB oil was mixed in AIN‐93M diet at 1.0 and 5.0 mM/kg diet and fed at libitum. Groups = Control (CON), PM, FM1, FM5, PM+FM1 and PM+FM5. Experiment 2: FM in 1% polyethylene glycol was gavage‐fed (0.5mL/5 days/wk), at increasing levels(mg/kg bw): Groups = CON, FM5, FM25, FM50, FM100 and FM200. Experiment 1: PM plus FM increased tissue Cu as compared to the CON by: plasma16‐37%, liver (9‐20%), kidney (13‐41%), small intestinal mucosa (IM) 41% and small intestines (SI) 77%. Experiment 2: FM fed at higher levels decreased tissue Cu by: plasma 22‐36%, liver (23%), kidney (24‐44%), IM (17‐26%), SI (58 &amp; 77%) as compared to respective CON. Kidney zinc increased at higher concentrations of FM by 14‐34%. These results indicate that flavonoids can modify copper homeostasis depending on whether they are fed in the diet or by gavage. (USDA#KYX‐50‐03‐17H).

Biosafety of Flavonoids in Rats: Effects on Copper and Zinc Homeostasis and Interaction with Low-Level Pesticide Exposure

Two 30-day experiments (36 male Sprague-Dawley rats each) were conducted to determine effect of administering flavonoid mixture (FM) with concomitant exposure to a pesticide mixture (PM) or FM at varied levels on changes in concentrations of zinc and copper in tissues. In experiment 1, PM = chlorpyrifos, endosulfan, and thiram at 25% LD(50) was dissolved in soybean (SB) oil and gavage-fed 0.1 mL 5 days/week; FM in SB oil was mixed in AIN-93M diet at 1.0 and 5.0 mM/kg diet and fed ad libitum. The groups were Control (CON), PM, FM1, FM5, PM+FM1, and PM+FM5. In experiment 2, FM in 1% polyethylene glycol was gavage-fed (0.5 mL/5 days/week), at increasing levels(mg/kg body weight); the groups were CON, FM5, FM25, FM50, FM100, and FM200. In experiment 1, PM plus FM increased tissue Cu as compared to the CON by: plasma, 16-37%; liver, 9-20%; kidney, 13-41%; small intestinal mucosa (IM), 41%; and small intestines (SI), 77%. In experiment 2, FM fed at higher levels decreased tissue Cu by: plasma, 22-36%; liver, 23%; kidney, 24-44%; IM, 17-26%; and SI, 58% and 77%, as compared to respective CON. Kidney zinc increased at higher concentrations of FM by 14-34%. These results indicate that flavonoids can modify copper homeostasis depending on whether they are fed in the diet or by gavage.

Multiresidue analysis of 47 pesticides in cooked wheat flour and polished rice by liquid chromatography with tandem mass spectrometry

Liquid chromatography in conjunction with tandem mass spectrometry was used to directly quantify of 47 pesticide residues from cooked wheat flour and polished rice, which are the most widely consumed cereals in the Republic of Korea. The sample clean-up was carried out according to the method established by the Korea Food and Drug Administration. The mobile phase for liquid chromatography separation consisted of water and 5 mm methanolic ammonium formate. Tandem mass spectroscopy experiments were performed in electrospray ionization positive mode and the multiple reaction monitoring mode. The matrix effects estimated for the 47 pesticides had a mean value of 99% and ranged from 45 to 147%. High recoveries (70-140%) and relative standard deviations (< or = 20%) were achieved for most of the pesticides tested. The method used in this study allowed for rapid quantification and identification of low levels of pesticides in cooked wheat flour and polished rice samples. Of the screened pesticide residues, only tricyclazole and fenobucarb were found in polished rice samples. However, no samples contained residues above the MRL established by the Korea Food and Drug Administration.

Changes in Pest Infestation Levels, Self-Reported Pesticide Use, and Permethrin Exposure during Pregnancy after the 2000–2001 U.S. Environmental Protection Agency Restriction of Organophosphates

BackgroundWidespread residential pesticide use throughout the United States has resulted in ubiquitous, low-level pesticide exposure. The mix of active pesticide ingredients is changing in response to 2000–2001 regulations restricting use of the organophosphorus insecticides chlorpyrifos and diazinon.ObjectivesWe aimed to determine the impact of U.S. Environmental Protection Agency regulations on pest infestation levels, pesticide use, and pesticides measured in indoor air samples. METHODOLOGY: 511 pregnant women from innercity New York were enrolled between 2000 and 2006. Permethrin, a pyrethroid insecticide; piperonyl butoxide (PBO), a pyrethroid synergist; chlorpyrifos; and diazinon were measured in 48-hr prenatal personal air samples. Data on pest infestation and pesticide use were collected via questionnaire.ResultsEighty-eight percent of women reported using pesticides during pregnancy; 55% reported using higher-exposure pesticide applications (spray cans, pest bombs and/or professional pesticide applicators). Self-reported pest sightings and use of higher-exposure applications increased significantly after the regulations were implemented (p < 0.001). PBO, cis-, and trans-permethrin were detected in 75, 19, and 18% of personal air samples, respectively. Detection frequencies of PBO and cis- and trans-permethrin increased significantly over time (p < 0.05 controlling for potential confounders). Levels and/or detection frequencies of these compounds were significantly higher among mothers reporting use of high exposure pesticide applications (p ≤ 0.05). Chlorpyrifos and diazinon levels decreased significantly over time (p < 0.001).ConclusionIn this cohort, pest infestations, use of pesticides, and use of permethrin appear to increase after the residential restriction of organophosphorus insecticides. This is one of the first studies to document widespread residential exposure to PBO.

Risk of childhood cancers associated with residence in agriculturally intense areas in the United States.

BackgroundThe potential for widespread exposure to agricultural pesticides through drift during application raises concerns about possible health effects to exposed children living in areas of high agricultural activity.ObjectivesWe evaluated whether residence in a county with greater agricultural activity was associated with risk of developing cancer in children < 15 years of age.MethodsIncidence data for U.S. children 0–14 years of age diagnosed with cancer between 1995 and 2001 were provided by member registries of the North American Association of Central Cancer Registries. We determined percent cropland for each county using agricultural census data, and used the overall study distribution to classify agriculturally intense counties. We estimated odds ratios and 95% confidence intervals for all ages and 5-year age groups for total cancers and selected cancer sites using logistic regression.ResultsOur study results showed statistically significant increased risk estimates for many types of childhood cancers associated with residence at diagnosis in counties having a moderate to high level of agricultural activity, with a remarkably consistent dose–response effect seen for counties having ≥ 60% of the total county acreage devoted to farming. Risk for different cancers varied by type of crop.ConclusionsAlthough interpretation is limited by the ecologic design, in this study we were able to evaluate rarer childhood cancers across a diverse agricultural topography. The findings of this exploratory study support a continued interest in the possible impact of long-term, low-level pesticide exposure in communities located in agriculturally intense areas.