Pyrethroids in house dust from the homes of farm worker families in the MICASA study

Quantitative proteomic analysis reveals the mechanism and key esterase of β-cypermethrin degradation in a bacterial strain from fermented food

Beta-cypermethrin (β-CY) residues in food are an important threat to human health. Microorganisms can degrade β-CY residues during fermentation of fruits and vegetables, while the mechanism is not clear. In this study, a comprehensively investigate of the degradation mechanism of β-CY in a food microorganism was conducted based on proteomics analysis. The β-CY degradation bacteria Gordonia alkanivorans GH-1 was derived from fermented Pixian Doubanjiang. Its crude enzyme extract could degrade 77.11% of β-CY at a concentration of 45 mg/L within 24 h. Proteomics analysis revealed that the ester bond of β-CY is broken under the action of esterase to produce 3-phenoxy benzoic acid, which was further degraded by oxidoreductase and aromatic degrading enzyme. The up-regulation expression of oxidoreductase and esterase was confirmed by transcriptome and quantitative reverse transcription PCR. Meanwhile, the expression of esterase Est280 in Escherichia coli BL21 (DE3) resulted in a 48.43% enhancement in the degradation efficiency of β-CY, which confirmed that this enzyme was the key enzyme in the process of β-CY degradation. This study reveals the degradation mechanism of β-CY by microorganisms during food fermentation, providing a theoretical basis for the application of food microorganisms in β-CY residues.

Occurrence of pesticide residues in indoor dust of farmworker households across Europe and Argentina

Pesticides are widely used as plant protection products (PPPs) in farming systems to preserve crops against pests, weeds, and fungal diseases. Indoor dust can act as a chemical repository revealing occurrence of pesticides in the indoor environment at the time of sampling and the (recent) past. This in turn provides information on the exposure of humans to pesticides in their homes. In the present study, part of the Horizon 2020 funded SPRINT project, the presence of 198 pesticide residues was assessed in 128 indoor dust samples from both conventional and organic farmworker households across Europe, and in Argentina. Mixtures of pesticide residues were found in all dust samples (25-121, min-max; 75, median). Concentrations varied in a wide range (<0.01 ng/g-206 μg/g), with glyphosate and its degradation product AMPA, permethrin, cypermethrin and piperonyl butoxide found in highest levels. Regarding the type of pesticides, insecticides showed significantly higher levels than herbicides and fungicides. Indoor dust samples related to organic farms showed a significantly lower number of residues, total and individual concentrations than those related to conventional farms. Some pesticides found in indoor dust were no longer approved ones (29 %), with acute/chronic hazards to human health (32 %) and with environmental toxicity (21 %).

Assessment of Dermal and Inhalation Exposure to Permethrin During Field Treatment of Military Uniforms

INTRODUCTION

Permethrin is a common pesticide spray-applied to civilian clothing and military uniforms for protection against biting arthropods in an effort to reduce risks to arthropod-borne diseases. During mass clothing spray events, exposure is possible through the dermal, inhalation, and ingestion routes. The potentially exposed population during a spray event includes the pesticide applicator(s) and working party (personnel who handle clothing/uniforms by positioning on the ground, flipping, and removing after spraying is complete). Previous investigation is limited regarding permethrin exposure via multiple routes of entry. Additionally, most exposure assessments are limited to pesticide applicators rather than working party that support applicator personnel. The purpose of this investigation was to conduct a multi-route exposure assessment for all personnel normally participating in mass permethrin military uniform treatments.

MATERIALS AND METHODS

The protocol and Informed Consent Document were approved by the Uniformed Services University of the Health Sciences (USUHS) Institutional Review Board (IRB) before fieldwork initiation (IRB number: USUHS.2019-032). Sampling occurred during routine spray events performed by 14 U.S. Navy personnel (3 applicators and 11 working party) over 2 days. Personal exposures were measured with dermal sampling, and airborne concentrations were measured with area air sampling. Permethrin area air sampling and analysis were conducted using OSHA Versatile Sampler-2 sampling media (n = 36). Dermal exposure was measured using dosimeter gloves (n = 26) and a dermal patch (n = 26) worn by study participants.

RESULTS

All air samples were reported below the 0.4 µg limit of quantification. Glove sample results ranged from 45 to 120,000 µg and patch results ranged from 0.57 to 45 µg. A repeated-measures ANOVA showed non-statistically significant differences in dermal concentrations (P-value = .8340) between the applicators and working party in patches and gloves.

CONCLUSIONS

Results suggest dermal contact is the primary route of exposure compared to inhalation when mass spraying clothing with permethrin. Similar dermal exposures between these two occupations may necessitate reconsidering risk assessment procedures, training and personal protective equipment (PPE) requirements for mass spray uniform treatments. Specifically, while PPE requirements for applicators are highly regulated by the Armed Forces Pest Management Board and include items such as Tyvek suits, chemical protective gloves, and air-purifying respirators, PPE was not regulated for working party personnel before this investigation.

Human Exposure to Pesticides in Dust from Two Agricultural Sites in South Africa

Over the last decades, concern has arisen worldwide about the negative impacts of pesticides on the environment and human health. Exposure via dust ingestion is important for many chemicals but poorly characterized for pesticides, particularly in Africa. We investigated the spatial and temporal variations of 30 pesticides in dust and estimated the human exposure via dust ingestion, which was compared to inhalation and soil ingestion. Indoor dust samples were collected from thirty-eight households and two schools located in two agricultural regions in South Africa and were analyzed using high-performance liquid chromatography coupled to tandem mass spectrometry. We found 10 pesticides in dust, with chlorpyrifos, terbuthylazine, carbaryl, diazinon, carbendazim, and tebuconazole quantified in >50% of the samples. Over seven days, no significant temporal variations in the dust levels of individual pesticides were found. Significant spatial variations were observed for some pesticides, highlighting the importance of proximity to agricultural fields or of indoor pesticide use. For five out of the nineteen pesticides quantified in dust, air, or soil (i.e., carbendazim, chlorpyrifos, diazinon, diuron and propiconazole), human intake via dust ingestion was important (>10%) compared to inhalation or soil ingestion. Dust ingestion should therefore be considered in future human exposure assessment to pesticides.

Pesticide screening and health risk assessment of residential dust in a rural region of the North China Plain

Pesticides that have accumulated in arable soil could be easily transported by wind erosion, thereby potentially threating air quality and human health in surrounding areas. The risks this poses to farmers exposed to pesticide-associated dust is still unknown, especially in rural areas of China. In this study, we screened pesticide residues in dust (indoor and outdoor) collected from the homes and yards of pesticide sprayers (21 participants) and farm workers (14 participants) living in Quzhou County located in the North China Plain to assess health risks by exposed to pesticide-contaminated dust. The results showed that multiple pesticide residues were detected in the dust samples and more than 90% of the samples contained over 10 pesticide residues. The maximum detected number of residues was 23, out of the 25 pesticides currently used in the farming area. There was a wide range of pesticide concentrations with the geometric mean values measuring between 0.03 and 0.86 mg kg^-1. More residues and higher concentrations of pesticides were detected in indoor dust compared to outdoor dust. Over the monitoring period, the pesticide application has not caused significant pesticide accumulation in dust. The measured concentrations of carbendazim, dimethomorph, dimethomorph and pendimethalin paired indoor-outdoor dust samples were significantly correlated (p < 0.05). The health risks were assessed using the hazard index (HI) and highest HI was found for children under indoor exposure (HI = 0.82). In addition, based on the survey and statistics, pesticide preparation in the home was significantly correlated with the pesticide indoor exposure level. Therefore, farmers should take measures, such as preparing pesticides outside of the house or in the open fields with protection, in order to avoid the exposure risk of pesticides associated with dust.

Occurrence, exposure and risk assessment of semi-volatile organic compounds in Chinese homes

Indoor semi-volatile organic compounds (SVOCs) can have a significant impact on human health. Previous studies involved the detection of limited classes of indoor SVOCs in different regions of China. However, overall indoor pollution profiles and the associated health risks via multiple exposure pathways remain unclear. High-throughput screening of SVOCs would help clarify the overall indoor pollution status and identify high-risk pollutants. We collected indoor air and dust samples from 35 Chinese homes and investigated the occurrence of a wide range of SVOCs. Ninety-seven SVOCs including phthalate esters (PAEs), polycyclic aromatic hydrocarbons (PAHs), organophosphate esters, alcohols, fatty acids, phenols, etc., were detected in the air (total concentrations: 0.13-48 μg/m³; median: 3.4 μg/m³) and dust (total concentrations: 120-1500 μg/g; median: 490 μg/g) samples. PAEs were the most abundant, accounting for 55.3 ± 28.6% and 43.4 ± 16.9% of the total SVOC concentrations in the air and dust samples respectively. Human exposure and health risks of 34 SVOCs with detection frequencies >10% were assessed based on inhalation, ingestion and dermal absorption of SVOCs from air and dust by infants and adults. In the case of indoor SVOCs with log K_oa < 9, inhalation and dermal contact with air was >90% for adults and >69% for infants. The following five SVOCs in air samples posed significant non-carcinogenic risks and are listed based on their decreasing risk level: dibutyl phthalate > phenanthrene > stearic acid > methyl palmitate > lauryl alcohol. Four PAHs with 2-4 rings posed potential carcinogenic risks, with phenanthrene exceeding the acceptable risk level of 10^-4. The high risks posed by SVOCs were due to inhalation exposure. Therefore, keeping the air concentrations of SVOCs, especially that of PAEs and PAHs under check would greatly benefit human health in indoor environments.

Preschool-Age Children's Pesticide Exposures in Child Care Centers and at Home in Northern California

INTRODUCTION

Young children may be exposed to pesticides used in child care centers and their family homes. We examined pesticide use and environmental and behavioral factors potentially associated with child exposures in these settings.

METHOD

Preschool-age children (n = 125) wore silicone wristbands to assess pesticide exposures in their child care centers and home environments. Information about environmental and behavioral exposure determinants was collected using parent surveys, child care director interviews, and observations.

RESULTS

Commonly detected pesticides were bifenthrin, chlorpyrifos, cypermethrin, fipronil, and cis- and trans-permethrin. Pesticide chemical storage onsite, cracks in the walls, using doormats, observed pests, or evidence of pests were associated with child exposures. Exposures were higher in counties with higher agricultural or commercial pesticide use or when children lived in homes near agricultural fields.

DISCUSSION

Young children are being exposed to harmful pesticides, and interventions are needed to lower their risk of health problems later in life.

Cumulative Pesticides Exposure of Children and Their Parents Living near Vineyards by Hair Analysis

The aim of the present work was the application of hair biomonitoring to investigate exposure to pesticides in children and their parents residing in a vineyard area. Thirty-three children and 16 parents were involved in the study. Hair samples were self-collected before and after the application season (PRE- and POST-EXP samples). Information on study subjects and the use of pesticides in the area were obtained. Thirty-nine pesticides were analyzed by liquid chromatography tandem mass spectrometry, and thirty-one pesticides were quantifiable in at least one hair sample. Most frequently detected pesticides were chlorpyrifos, cycloxidim, dimethomorph, metalaxyl, spiroxamine, and tetraconazole. From PRE-EXP to POST-EXP the percentage of quantification and/or the concentration of pesticides increased; the concentration was typically in the low pg/mg hair range with comparable levels in children and parents. An inverse correlation was found between the total exposure to pesticides in POST-EXP hair samples and the distance between home and the treated fields (Spearman ρ = -0.380, p = 0.01). The results of this study show that the majority of the study pesticides were measured in the hair of subjects living in the close proximity of treated vineyards, supporting the determination of pesticides in hair for the purpose of biomonitoring cumulative exposure in the general population.

Contamination of pyrethroids in agricultural soils from the Yangtze River Delta, China

This study focused on contamination levels and spatial distributions of four common pyrethroids found in agricultural soils of the Yangtze River Delta (YRD), China. Pyrethroids were detected in 241 soil samples (88.8% detection rate) with total concentrations ranging from <LOD to 53.5 ng/g dry weight. Mean concentrations of the four pyrethroids were measured in descending order as follows: fenpropathrin (4.92 ng/g) > cypermethrin (1.10 ng/g) > deltamethrin (0.89 ng/g) > cyhalothrin (0.20 ng/g). The highest concentration of fenpropathrin was recorded as 37.6 ng/g. The highest detection rate of 63.9% was found for cyhalothrin. A distinct pattern of spatial distribution was observed where high concentrations of pyrethroids were detected in sites around Taihu Lake. Potential sources of pyrethroids in agricultural soils from the YRD region include pyrethroids used for pest control and wastewater irrigation in the region. Redundancy and correlation analyses show that the soil TOC values have played a significant role in the behavior of pyrethroids in agricultural soils of the YRD region. Potential ecological risks of pyrethroids in agricultural soils of the YRD region are low. Cypermethrin and cyhalothrin showed potential toxic effects on the ecological conditions of agricultural soils in 4.6% and 2.9% of the sampling sites, respectively. Further studies should pay more attention to the potential human health risks posed by pyrethroids in agricultural soils for the protection of soil quality and food safety.

Contamination of pyrethroids and atrazine in greenhouse and open-field agricultural soils in China

A national-scale survey was conducted to assess the levels and distribution of two extensively used pesticides (pyrethroids and atrazine) in greenhouse and open-field soils in 20 provinces across China. Concentrations between 1.30 and 113 ng/g and 0.51-85.4 ng/g for the total pyrethroids (PYs) and of LOD-137 ng/g and LOD-134 ng/g for atrazine were found in greenhouse and open-field soils, respectively. Higher contaminations were found in the greenhouse than in the open fields. The levels of total pyrethroids in 80% of the greenhouses and of atrazine in 60% of the greenhouses were significantly higher than those in the nearby open-field soils (p < 0.05), respectively. The contamination of PYs and atrazine was generally more serious in the northern provinces of China, such as Heilongjiang, Jilin, Liaoning, Beijing, and Hebei. Pearson correlation analysis revealed that the contamination of PYs was significantly correlated with the soil total organic carbon (TOC) value in both greenhouse and open-field soils. Canonical correspondence analysis (CCA) showed that PYs might have an impact on the microbial alpha diversity, while cyhalothrin and cypermethrin may be the key factors affecting the microbial community in the greenhouse and open-field soils. The soil samples containing pesticide residues showed distinct taxonomic and functional communities, where an increased diversity and abundance of microorganisms able to degrade pesticides was observed with high-level PYs contamination. These findings provide useful information for evaluating PYs and atrazine pollution and for contamination management in greenhouse agriculture.

Systematic Literature Review of the Take-Home Route of Pesticide Exposure via Biomonitoring and Environmental Monitoring

BACKGROUND

Exposure to pesticides via take-home can be an important pathway for farmworkers' families.

OBJECTIVE

The aim of this review was to summarize and analyze the literature published during the last decade of exposure to pesticides via take-home pathway in farmworkers' families.

METHODS

We conducted a systematic review to identify peer-reviewed articles of interest; only articles related to take-home pathway that included some sort of pesticide monitoring were considered for inclusion. Systematic reviews, literature reviews, and meta-analyses were excluded, resulting in a total of 39 articles elected for analysis. The articles were summarized based on the location of the study, population (sample size), pesticide analyzed, and type of sample.

RESULTS

The majority of the reviewed studies were conducted in the U.S., but there seems to be an increase in literature on pesticide take-home pathway in developing countries. Most of the articles provided evidence that farmworkers' families are exposed to pesticides at higher levels than non-farmworkers' families. The levels may depend on several factors such as seasonality, parental occupation, cohabitation with a farmworker, behavior at work/home, age, and gender. Community-based interventions disrupting the take-home pathway seem to be effective at reducing pesticide exposure.

DISCUSSION/CONCLUSION

The take-home pathway is an important contributor to overall residential exposures, but other pathways such as pesticide drift, indoor-residential applications, and dietary intake need to be considered. A more comprehensive exposure assessment approach is necessary to better understand exposures to pesticides.

An algorithm for quantitatively estimating non-occupational pesticide exposure intensity for spouses in the Agricultural Health Study

Residents of agricultural areas experience pesticide exposures from sources other than direct agricultural work. We developed a quantitative, active ingredient-specific algorithm for cumulative (adult, married lifetime) non-occupational pesticide exposure intensity for spouses of farmers who applied pesticides in the Agricultural Health Study (AHS). The algorithm addressed three exposure pathways: take-home, agricultural drift, and residential pesticide use. Pathway-specific equations combined (i) weights derived from previous meta-analyses of published pesticide exposure data and (ii) information from the questionnaire on frequency and duration of pesticide use by applicators, home proximity to treated fields, residential pesticide usage (e.g., termite treatments), and spouse's off-farm employment (proxy for time at home). The residential use equation also incorporated a published probability matrix that documented the likelihood active ingredients were used in home pest treatment products. We illustrate use of these equations by calculating exposure intensities for the insecticide chlorpyrifos and herbicide atrazine for 19,959 spouses. Non-zero estimates for ≥1 pathway were found for 78% and 77% of spouses for chlorpyrifos and atrazine, respectively. Variability in exposed spouses' intensity estimates was observed for both pesticides, with 75th to 25th percentile ratios ranging from 7.1 to 7.3 for take-home, 6.5 to 8.5 for drift, 2.4 to 2.8 for residential use, and 3.8 to 7.0 for the summed pathways. Take-home and drift estimates were highly correlated (≥0.98), but were not correlated with residential use (0.01‒0.02). This algorithm represents an important advancement in quantifying non-occupational pesticide relative exposure differences and will facilitate improved etiologic analyses in the AHS spouses. The algorithm could be adapted to studies with similar information.

Determinants of Exposure to Pyrethroid Insecticides in the VHEMBE Cohort, South Africa

Exposure to pyrethroid insecticides has been linked to adverse health effects, and can originate from several sources, including indoor residual spraying (IRS) for malaria control, home pest control, food contamination, and occupational exposure. We aimed to explore the determinants of urinary pyrethroid metabolite concentrations in a rural population with high pesticide use. The Venda Health Examination of Mothers, Babies and their Environment (VHEMBE) is a birth cohort of 752 mother-child pairs in Limpopo, South Africa. We measured pyrethroid metabolites in maternal urine and collected information on several factors possibly related to pesticide exposure, including IRS, home pesticide use, and maternal factors (e.g., dietary habits and body composition). We performed statistical analysis using both conventional bivariate regressions and Bayesian variable selection methods. Urinary pyrethroid metabolites are consistently associated with pesticide factors around homes, including pesticide application in yards and food stocks, and IRS in the home during pregnancy, while more distant factors such as village spraying are not. High fat intake is associated with higher metabolite concentrations, and women from homes drawing water from wells or springs had marginally higher levels. Home pesticide use is the most consistent correlate of pyrethroid metabolite concentrations, but IRS, dietary habits, and household water source may also be important exposure determinants.

Pesticides and Child's Health in France

PURPOSE OF REVIEW

The use of pesticides is predominant in agriculture, inducing environmental contamination, and has been extended to the domestic sphere. In France, > 500 pesticides were authorized for use in 2009; given their various toxicological properties, there are legitimate concerns about the possible consequences for child health. This review summarizes the recent French studies of good quality dealing with pesticides and child health.

RECENT FINDINGS

Three cohorts (mother-child, retrospective) and two case-control studies have been conducted in the last decade. Using various instruments for exposure assessment including biomarkers, they have suggested alterations of subclinical health parameters at birth, increased risk of otitis at age 2, and increased risk of several types of childhood cancer. However, there were no adverse neurodevelopmental outcomes at 6 years of age following prenatal exposure to pesticides. Both agricultural and domestic pesticides might be involved in such adverse health outcomes. Similar studies are lacking in Europe. Studies on fungicides and child health are scarce.

Pesticides in indoor and outdoor residential dust: a pilot study in a rural county of Taiwan

We conducted a pilot study to examine pesticides in dust of homes in a rural county of Taiwan. A total of 56 homes of pregnant women were included in the study. Indoor and outdoor dust was collected by a vacuum sampler and a dustpan/brush set, respectively. Nine pesticides were selected for analysis on gas chromatography-mass spectrometry with the detection limits being 0.088 ng/g or lower. The most detected pesticides were cypermethrin and chlorpyrifos, which appeared in 82.7 and 78.8% of indoor samples and 48.2 and 39.3% of outdoor samples, respectively. The detection of pesticides from indoor and outdoor dust, however, was not consistent, indicating different sources of pesticides. In addition to those two most detected, permethrin, prallethrin, and tetramethrin, which were common ingredients of insecticide products for indoor use, were also frequently found in indoor dust, suggesting that indoor use of such pesticide products may have been a major source. Fewer pesticides were found in outdoor dust, but the outdoor detection of chlorpyrifos was significantly associated with farms present inside the circles with radii of 50 and 100 m surrounding the homes (P = 0.021, 0.016). It is suggested that pesticide drift from agricultural areas to residential environments may have occurred. No seasonal effect on distribution of pesticides in dust was found, indicating that pesticides could be routinely used in Taiwan regardless of season. Compared with other international studies, this study shows relatively high levels of chlorpyrifos but low levels of pyrethroids (i.e., cypermethrin), reflecting a different pattern of pesticide use in Taiwan. Further studies need to be warranted for a better understanding of exposure to pesticides and the associated health effects.

Prenatal Exposure to Ambient Pesticides and Preterm Birth and Term Low Birthweight in Agricultural Regions of California

Findings from studies of prenatal exposure to pesticides and adverse birth outcomes have been equivocal so far. We examined prenatal exposure to agricultural pesticides in relation to preterm birth and term low birthweight, respectively, in children born between 1998 and 2010, randomly selected from California birth records. We estimated residential exposure to agriculturally applied pesticides within 2 km of residential addresses at birth by pregnancy trimester for 17 individual pesticides and three chemical classes (organophosphates, pyrethroids, and carbamates). Among maternal addresses located within 2 km of any agricultural pesticide application, we identified 24,693 preterm and 220,297 term births, and 4412 term low birthweight and 194,732 term normal birthweight infants. First or second trimester exposure to individual pesticides (e.g., glyphosates, paraquat, imidacloprid) or exposure to 2 or more pesticides in the three chemical classes were associated with a small increase (3⁻7%) in risk for preterm birth; associations were stronger for female offspring. We did not find associations between term low birthweight and exposure to pesticides other than myclobutanil (OR: 1.11; 95% CI: 1.04⁻1.20) and possibly the pyrethroids class. Our improved exposure assessment revealed that first and second trimester exposure to pesticides is associated with preterm delivery but is rarely linked with term low birthweight.

A review of semi-volatile organic compounds (SVOCs) in the indoor environment: occurrence in consumer products, indoor air and dust

As many people spend a large part of their life indoors, the quality of the indoor environment is important. Data on contaminants such as flame retardants, pesticides and plasticizers are available for indoor air and dust but are scarce for consumer products such as computers, televisions, furniture, carpets, etc. This review presents information on semi-volatile organic compounds (SVOCs) in consumer products in an attempt to link the information available for chemicals in indoor air and dust with their indoor sources. A number of 256 papers were selected and divided among SVOCs found in consumer products (n = 57), indoor dust (n = 104) and air (n = 95). Concentrations of SVOCs in consumer products, indoor dust and air are reported (e.g. PFASs max: 13.9 μg/g in textiles, 5.8 μg/kg in building materials, 121 ng/g in house dust and 6.4 ng/m³ in indoor air). Most of the studies show common aims, such as human exposure and risk assessment. The main micro-environments investigated (houses, offices and schools) reflect the relevance of indoor air quality. Most of the studies show a lack of data on concentrations of chemicals in consumer goods and often only the presence of chemicals is reported. At the moment this is the largest obstacle linking chemicals in products to chemicals detected in indoor air and dust.

Pesticides contaminated dust exposure, risk diagnosis and exposure markers in occupational and residential settings of Lahore, Pakistan

There are few studies documenting the dust loaded with pesticides as a potential non-dietary exposure source for occupational worker and populations living near agricultural farms and pesticides formulation plants. In present study we have evaluated the pesticide concentration in dust from potential sites and relevant health risk from dust ingestion. Furthermore, the effect of currently used pesticides was investigated on blood and urine parameters of subjects: farmer, factory worker, urban resident and rural resident and controlled subjects with presumably different levels of exposure. The urinary metabolites (TCPY and IMPY) were quantified as biomarkers of exposure to chlorpyrifos and diazinon in relation with biomarkers of effect including BuChE, LH, FSH, testosterone and oxidative stress. Results showed that chlorpyrifos and diazinon were present in higher concentration in dust and posed a high health risk to exposed subjects. The mean SOD value was high among the farmer (3048U/g Hb) followed by factory worker (1677.6U/g Hb). The urinary biomarkers - TCPY and IMPY- were found higher in exposed subjects as compared to control. Furthermore, testosterone was found in higher concentration in factory worker than control (12.63ng/ml vs 4.61ng/ml respectively). A decreased BuChE activity was noticed in occupational group and significant differences were observed in control verses exposed subjects. The PCA analysis evidenced the impact of pesticides on exposure biomarkers and male reproductive hormones. The study suggests that dust contaminated with pesticides engenders significant health risk particularly related to the nervous and endocrine system, not only for occupational workers exposed to direct ingestion but also for nearby residential community. Succinctly putting: Pesticides loaded dust in the city of Lahore, being a high priority concern for the government of Pakistan, demands to be addressed.

Use of Monte Carlo analysis in a risk-based prioritization of toxic constituents in house dust

Many chemicals have been detected in house dust with exposures to the general public and particularly young children of potential health concern. House dust is also an indicator of chemicals present in consumer products and the built environment that may constitute a health risk. The current analysis compiles a database of recent house dust concentrations from the United States and Canada, focusing upon semi-volatile constituents. Seven constituents from the phthalate and flame retardant categories were selected for risk-based screening and prioritization: diethylhexyl phthalate (DEHP), butyl benzyl phthalate (BBzP), diisononyl phthalate (DINP), a pentabrominated diphenyl ether congener (BDE-99), hexabromocyclododecane (HBCDD), tris(1,3-dichloro-2-propyl) phosphate (TDCIPP) and tris(2-chloroethyl) phosphate (TCEP). Monte Carlo analysis was used to represent the variability in house dust concentration as well as the uncertainty in the toxicology database in the estimation of children's exposure and risk. Constituents were prioritized based upon the percentage of the distribution of risk results for cancer and non-cancer endpoints that exceeded a hazard quotient (HQ) of 1. The greatest percent HQ exceedances were for DEHP (cancer and non-cancer), BDE-99 (non-cancer) and TDCIPP (cancer). Current uses and the potential for reducing levels of these constituents in house dust are discussed. Exposure and risk for other phthalates and flame retardants in house dust may increase if they are used to substitute for these prioritized constituents. Therefore, alternative assessment and green chemistry solutions are important elements in decreasing children's exposure to chemicals of concern in the indoor environment.

Occurrence of imidacloprid, carbendazim, and other biocides in Italian house dust: Potential relevance for intakes in children and pets

The occurrence of pesticides intended for non-agricultural use was investigated in 206 dust samples drawn from vacuum-cleaner bags from residential flats in Italy. The multi-residue analysis targeted on 95 different active principles was performed with UPLC-MS/MS, with a Limit of Quantification (LOQ) of 0.008 μg/g dry weight. The results indicated the presence of imidacloprid (IMI) and carbendazim (CARB) in 30% and 26% of the samples, with a mean and P95 concentration between 1.6 and 39 and between 0.08 and 4.9 μg/g, respectively. Combined presence of two biocides was noted in 19.4% samples, of three biocides in 9.2% samples, of four biocides in 3.4% samples, and of five and six biocides in 0.5% and 1% samples, respectively. According to the estimated dust intake in infants/toddlers aged 6-24 months (16-100 mg d^-1) and cats (200 mg d^-1), it was possible to obtain risk characterization with respect to the Acceptable Daily Intake (ADI) for IMI of 0.060 mg/kg body weight (bw) proposed by the European Food Safety Authority (EFSA) and the chronic Population Adjusted Dose (cPAD) of 0.019 mg/kg bw d^-1 by US-EPA. Under the worst-case scenario, the presence of IMI in dust indicates potential exceedance of the cPAD in kittens, to be considered as sentinel also accounting for combined exposure. This study highlights the relevance of consumer empowerment about the responsible use of pesticides as biocidal products in indoor environment.

Review of take-home pesticide exposure pathway in children living in agricultural areas

BACKGROUND

Children of farmworkers may be chronically exposed to pesticides via the take-home exposure pathway.

OBJECTIVE

The goal of this review was to analyze scientific literature evaluating the role of the take-home pesticide exposure pathway in children of agricultural workers.

METHODS

A systematic review was undertaken and inclusion criteria were applied to identify original articles of interest. Of the 30 articles included in this review, some belonged to the same studies, resulting in a total of 23 studies. Eight studies assessed environmental samples, nine collected biological samples, and the remaining six analyzed both. Eleven studies compared pesticide levels between farm and non-farm families.

RESULTS

There is convincing evidence that children of farmworkers are exposed to pesticides at higher levels than "non-agricultural" children, even when residing in the same agricultural communities. These levels were shown to depend on the season, occupation, number of farmworkers per home, and type of crops. Other factors such as age, gender and, sex seem to also influence this pathway. Some studies have shown that pesticides used solely in agriculture are found only in households of farmworkers spraying these pesticides. Moreover, intervention studies have shown that behaviors among farmworkers can significantly lower exposure of people living in the same households as farmworkers.

DISCUSSION AND CONCLUSION

The evidence presented here raises concerns regarding health effects associated with exposure to pesticides in children living in agricultural communities, and indicates that strategies should be developed to reduce exposures in these populations.

Determinants of children's exposure to pyrethroid insecticides in western France

Pyrethroids are insecticides frequently used in agriculture and in the home; exposure occurs through dietary and non-dietary pathways, including indoor and outdoor environmental contamination. Our objective was to study the potential determinants of pyrethroid metabolite concentrations measured in children's urine samples and in the dust of their homes. Specifically, we measured urinary metabolites from morning spot samples of 245 six-year-old children living in Brittany (France) in 2009-2012 and from dust vacuumed from the floor of their homes. Mothers reported home insecticide use, dietary habits, sociodemographic data; residential and school proximity to agricultural crops was assessed with spatialized data. The metabolites cis-DBCA, trans-DCCA, cis-DCCA, 3-PBA, and F-PBA were detected in 84, 95, 64, 63, and 16% of the urine samples, respectively. Permethrin, cypermethrin, cyfluthrin, deltamethrin, and tetramethrin pyrethroids were detected in 100, 56, 9, 15, and 26% of the dust samples, respectively. Multiple regression analysis suggested diet plays a role in children's exposure, in particular, the food groups "pasta, rice or semolina" (for cis-DCCA and F-PBA), fruit (3-PBA), "breakfast cereals and whole grain bread" (cis-DBCA), and the global proportion of organic food in diet (for cis-DBCA, trans-DCCA). Children with a parent occupationally exposed to pesticides were about 3-times more likely to have higher urinary concentrations of 3-PBA (OR=2.8, 95% CI [1.2; 6.5]). Dust content was correlated mainly with household insecticide use: higher mean concentrations of permethrin (β=0.8 [0.3; 1.3], in μg/g) and an increased risk of a detectable level of cyfluthrin (OR=4.7 [1.7; 12.9]) were observed in home dust, for indoor use of at least twice a year. Outdoor insecticide use at least once a year was associated with detection in dust of cypermethrin (OR=3.0 [1.3; 6.7]) and tetramethrin (OR=3.7 [1.6; 8.3]). Three positive and one negative correlations (out of 11) between urinary metabolite concentrations and home dust contents of their possible corresponding parent compounds were observed. The strength of this study lies in its concurrent use of biomarkers, environmental measurements, and potential sources of exposure. Its limitations include the use of a single urine sample and imprecise data about pyrethroid use in local agriculture.

An ethnographic study of salt use and humoral concepts in a Latino farm worker community in California's Central Valley

BACKGROUND

This article reports on the use of domestic or table salt for its perceived health effects and healing properties in a Latino farmworker community. It explores how contemporary salt usage beliefs can be seen to have roots in long-standing humoral theories of medicine and health.

METHODS

This qualitative investigation comprised 30 in-depth individual interviews and five focus groups conducted in Spanish with Mexican and Central American immigrants in one small city in California's Central Valley (N = 61 total participants). Interviews and focus groups were audiotaped, translated into English and transcribed. Several researchers independently and iteratively read transcripts, developed and applied codes, and engaged in thematic analysis.

RESULTS

Strongly emergent themes identified the importance of balance in health, and beliefs about the effects on salt on health. Valued for its culinary role, for bringing out the flavors in food, and used by people of all ages, salt use is part of a robust set of cultural practices. Salt was regularly mixed with foods in different combinations and ingested to restore balance, prevent disequilibrium or reduce vulnerability to diverse illnesses, promote rehydration, and address symptoms of exposure to extremes of temperature or physical or emotional stress. Statements made and practices engaged in by participants were highly suggestive of health and healing beliefs common to humoral belief systems based primarily on a hot-cold dichotomy in classifications of foods and healing behaviors. We evaluate these statements and practices in the context of the existing literature on historical and contemporary humoral beliefs in Latin American communities, in Mexico and Central America, and in the United States.

CONCLUSION

Humoral theory is a useful framework for understanding contemporary rural Latino migrant farmworkers' perceptions of the importance of salt for their health.

Measuring biomarkers in wastewater as a new source of epidemiological information: Current state and future perspectives

The information obtained from the chemical analysis of specific human excretion products (biomarkers) in urban wastewater can be used to estimate the exposure or consumption of the population under investigation to a defined substance. A proper biomarker can provide relevant information about lifestyle habits, health and wellbeing, but its selection is not an easy task as it should fulfil several specific requirements in order to be successfully employed. This paper aims to summarize the current knowledge related to the most relevant biomarkers used so far. In addition, some potential wastewater biomarkers that could be used for future applications were evaluated. For this purpose, representative chemical classes have been chosen and grouped in four main categories: (i) those that provide estimates of lifestyle factors and substance use, (ii) those used to estimate the exposure to toxicants present in the environment and food, (iii) those that have the potential to provide information about public health and illness and (iv) those used to estimate the population size. To facilitate the evaluation of the eligibility of a compound as a biomarker, information, when available, on stability in urine and wastewater and pharmacokinetic data (i.e. metabolism and urinary excretion profile) has been reviewed. Finally, several needs and recommendations for future research are proposed.

The use of the lymphocyte cytokinesis-block micronucleus assay for monitoring pesticide-exposed populations

Pesticides are widely used around the world, and hundreds of millions of people are exposed annually in occupational and environmental settings. Numerous studies have demonstrated relationships between pesticide exposure and increased risk of cancers, neurodegenerative and neurodevelopmental disorders, respiratory diseases and diabetes. Assessment of genotoxicity of pesticides and biomonitoring their effect in exposed populations is critical for a better regulation and protection, but it can be complicated because pesticides are often used as complex mixtures. The cytokinesis-block micronucleus assay in human lymphocytes (L-CBMN) is a validated method of assessment of DNA damage induced by clastogenic and aneuploidogenic mechanisms. The goal of this review is to provide an updated summary of publications on biomonitoring studies using this assay in people exposed to pesticides in different settings, and to identify gaps in knowledge, and future directions. A literature search was conducted through MedLine/PubMed and TOXLINE electronic databases up to December 2015. A total of 55 full-text articles, related to 49 studies, excluding reviews, were selected for in depth analysis, divided by the settings where exposures occurred, such as chemical plant workers, pesticide sprayers, floriculturists, agricultural workers and non-occupationally exposed groups. Majority of studies (36 out of 49) reported positive findings with L-CBMN assay. However, most of the studies of professional applicators that used single pesticide or few compounds in the framework of specific programs did not show significant increases in MN frequency. A decreased level of pesticide-induced genotoxicity was associated with the proper use of personal protection. In contrast, subjects working in greenhouses or during intensive spraying season and having acute exposure, showed consistent increases in MN frequency. Overall, this analysis confirmed that L-CBMN is an excellent tool for pesticide biomonitoring, and can validate the effects of educational and intervention programs on reducing exposure and genetic damage.

Urinary 3-phenoxybenzoic acid (3-PBA) levels among pregnant women in Mexico City: Distribution and relationships with child neurodevelopment

BACKGROUND

In recent years, pyrethroid pesticide use has increased in Mexico, the United States, and elsewhere, resulting in extensive human exposure. There is growing concern that pregnant women may be a particularly vulnerable population, as in utero fetal exposure during critical periods of development could adversely affect long-term neurobehavioral function.

METHODS

We measured maternal urinary 3-phenoxybenzoic acid (3-PBA) concentrations during the third trimester of pregnancy as a measure of in utero pyrethroid exposure to the fetus among participants in an established Mexico City birth cohort (n=187). In a subset of mothers, we measured 3-PBA during the first, second, and third trimester (n=21) to assess variability across pregnancy. We examined associations between third trimester 3-PBA concentrations and children's scores on the Mental Development Index (MDI) and Psychomotor Development Index (PDI) from the Bayley Scales for Infant Development (BSID-IIS) at 24 and 36 months of age.

RESULTS

3-PBA was detected in 46% of all urine samples, with similar detection rates and geometric mean concentrations across pregnancy among the 21 participants who provided repeat samples. Participants in the medium and high 3-PBA categories (≥LOD) had lower MDI scores at 24 months compared to those in the low 3-PBA category (<LOD) after adjustment for covariates (ptrend=0.07), with slightly stronger associations among female children. The 3-level categorical variable for third trimester in utero 3-PBA was not associated with MDI scores at 36 months, or with PDI scores at either time point.

CONCLUSION

Considering the widespread agricultural and residential use of pyrethroids worldwide and the implications of cognitive and behavioral deficits, our findings indicate that additional study of in utero pyrethroid exposure and neurodevelopment in a larger study population is needed.

Plant Growth Regulating Activity of Some N-Substituted Chloroacetylanilines

PURPOSE

The synthesis and physico-chemical characterization of six N-substituted chloroacetylanilines and testing their plant growth regulating activity.

MATERIAL/METHODS

The synthesis of the six N-substituted chloroacetylanilines was accomplished by condensation of N-substituted anilines, in an acidic medium, with chloroacetylchloride. Purified compounds obtained were physico-chemical characterized by elemental analysis and spectral analysis. Five different concentrations (0.1%, 0.5%, 0.75%, 1% and 5%) of the compounds solubilized in chloroform were used to analzyed their effects on the germination and mainly on the radicular elongation of wheat caryopses, Triticum aestivum subsp. aestivum (Poaceae), Dropia variety.

RESULTS

The N-substituted chloroacetylanilines were solid, differently colored, with high melting temperatures and high yields. Their structure was confirmed both by elemental analysis and by the spectral methods (UV-Vis, FTIR, 1H-NMR, 13C-NMR, GC-MS).

CONCLUSIONS

For the six analyzed compounds, at five different concentrations (0.1%, 0.5%, 0.75%, 1% and 5%), the experimental data obtained by the method of linear measurement, in the Triticum assay, showed the inhibition of mean radicular elongation compared with the reference.

Collecting Comparative Data on Farmworker Housing and Health: Recommendations for Collecting Housing and Health Data Across Places and Time

The substandard nature of the housing in which most farmworkers live has detrimental effects on their health, as well as on their children's health and development. However, little research has directly documented associations between farmworker housing and health; existing research is not always comparable due to differences in design and measurement. Comparative data can help determine actual causal links between housing characteristics and farmworker health and help to evaluate the efficacy of current housing policy. The goal of this paper is to provide guidelines promoting comparable research on farmworker housing and the association of this housing with health. This paper reviews general concepts relevant to measuring farmworker housing and health, issues that should be considered in designing farmworker housing and health research, data collection methods, and measures. It concludes with recommendations for a research agenda on farmworker housing and health.

Occurrence of biomarkers of pesticide exposure in non-invasive human specimens

Biomonitoring has been used in many types of investigations, including national programmes and epidemiological studies, to explore the occurrence of biomarkers of pesticide exposure in the general population or relevant groups. This review discusses recent studies that measure levels of biomarkers of pesticide exposure in non-invasive human specimens such as urine, breast milk, meconium and hair. Specific and non-specific metabolites of organophosphate and pyrethroid insecticides have been widely investigated in urine, where some of the suitable biomarkers present rates of detection higher than 80%, which stand for an ongoing chronic exposure to traces of these chemicals. Hair is a promising emerging matrix, but some issues on its suitability and the biological relevance needs further research. Breast milk was used in research investigations focused mainly on legacy pesticides, which provide useful information about time trends.

Hidden Farmworker Labor Camps in North Carolina: An Indicator of Structural Vulnerability

OBJECTIVES

We used geographic information systems (GIS) to delineate whether farmworker labor camps were hidden and to determine whether hidden camps differed from visible camps in terms of physical and resident characteristics.

METHODS

We collected data using observation, interview, and public domain GIS data for 180 farmworker labor camps in east central North Carolina. A hidden camp was defined as one that was at least 0.15 miles from an all-weather road or located behind natural or manufactured objects. Hidden camps were compared with visible camps in terms of physical and resident characteristics.

RESULTS

More than one third (37.8%) of the farmworker labor camps were hidden. Hidden camps were significantly larger (42.7% vs 17.0% with 21 or more residents; P ≤ .001; and 29.4% vs 13.5% with 3 or more dwellings; P = .002) and were more likely to include barracks (50% vs 19.6%; P ≤ .001) than were visible camps.

CONCLUSIONS

Poor housing conditions in farmworker labor camps often go unnoticed because they are hidden in the rural landscape, increasing farmworker vulnerability. Policies that promote greater community engagement with farmworker labor camp residents to reduce structural vulnerability should be considered.

Housing and Neighborhood Characteristics and Latino Farmworker Family Well-Being

Housing quality and neighborhood characteristics affect individual health and family well-being. This analysis describes characteristics of farmworker housing and neighborhoods and delineates the associations of housing and local neighborhood with indicators of family well-being. Mothers in North Carolina farmworker families (n = 248) completed interviews in 2011-2012. Family well-being measures included stress, family conflict, and outward orientation. Housing measures included ownership and facilities, and neighborhood measures included heavy traffic and driving time to grocery stores. Families experienced elevated stress and conflict, and limited outward orientation. Few owned their homes, which were generally crowded. Few had enclosed play spaces for their children. For many, traffic made it difficult to walk on the street. Housing and neighborhood characteristics were related to increased stress and limited outward orientation. Housing and neighborhood characteristics are important for research on the health of families in vulnerable populations, such as farmworker families.

Farmworker Housing in the United States and Its Impact on 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.

Associations between self-reported pest treatments and pesticide concentrations in carpet dust

BACKGROUND

Recent meta-analyses demonstrate an association between self-reported residential pesticide use and childhood leukemia risk. Self-reports may suffer from recall bias and provide information only on broad pesticide categories. We compared parental self-reported home and garden pest treatments to pesticides measured in carpet dust.

METHODS

Parents of 277 children with leukemia and 306 controls in Northern and Central California (2001-2007) were asked about insect and weed treatments during the previous year. Carpet dust samples were analyzed for 47 pesticides. We present results for the 7 insecticides (carbaryl, propoxur, chlorpyrifos, diazinon, cyfluthrin, cypermethrin, permethrin), 5 herbicides (2,4-dichlorophenoxyacetic acid [2,4-D], chlorthal, dicamba, mecoprop, simazine), and 1 synergist (piperonyl butoxide) that were present in home and garden products during the study period and were detected in ≥25% of carpet dust samples. We constructed linear regression models for the relative change in pesticide concentrations associated with self-reported treatment of pest types in cases and controls separately and combined, adjusting for demographics, housing characteristics, and nearby agricultural pesticide applications.

RESULTS

Several self-reported treatments were associated with pesticide concentrations in dust. For example, households with flea/tick treatments had 2.3 (95% Confidence Interval [CI]: 1.4, 3.7) times higher permethrin concentrations than households not reporting this treatment. Households reporting treatment for ants/cockroaches had 2.5 (95% CI: 1.5, 4.2) times higher cypermethrin levels than households not reporting this treatment. Weed treatment by a household member was associated with 1.9 (1.4, 2.6), 2.2 (1.6, 3.1), and 2.8 (2.1, 3.7) times higher dust concentrations of dicamba, mecoprop, and 2,4-D, respectively. Weed treatments by professional applicators were null/inversely associated with herbicide concentrations in dust. Associations were generally similar between cases and controls and were consistent with pesticide active ingredients in these products during the study time period.

CONCLUSIONS

Consistency between self-reported pest treatments, concentrations in dust, and pesticides in products lends credibility to the exposure assessment methods and suggests that differential recall by case-control status is minimal.

Global trends of research on emerging contaminants in the environment and humans: a literature assimilation

Available literature data on five typical groups of emerging contaminants (EMCs), i.e., chlorinated paraffins (CPs), dechlorane plus and related compounds (DPs), hexabromocyclododecanes (HBCDs), phthalate esters, and pyrethroids, accumulated between 2003 and 2013 were assimilated. Research efforts were categorized by environmental compartments and countries, so that global trends of research on EMCs and data gaps can be identified. The number of articles on the target EMCs ranged from 126 to 1,379 between 2003 and 2013. The numbers of articles on CPs, DPs, HBCDs, and pyrethroids largely followed the sequence of biota > sediment ≥ air > water ≥ soil > human tissue, whereas the sequence for phthalate esters was water > sediment > soil > human tissue ≥ biota ≥ air. Comprehensive studies on the target EMCs in biological samples and human tissues have been conducted worldwide. However, investigations into the occurrence of the target EMCs in soil of background areas and water are still scarce. Finally, developed and moderately developed countries, such as the USA, China, Canada, Japan, and Germany, were the main contributors to the global research efforts on EMCs, suggesting that economic prosperity may be one of the main factors propelling scientific research on EMCs.

Assessing exposure of young children to common endocrine-disrupting chemicals in the home environment: a review and commentary of the questionnaire-based approach

BACKGROUND

Although infants and young children are particularly vulnerable to endocrine disrupting chemical (EDC) exposure, there is an absence of comprehensive exposure data for this age group. As young children spend the majority of their time indoors, improved methods of exposure assessment are needed to characterise the health risks from exposures in the home environment. Biologic assessment, which has been considered the gold standard for exposure assessment in recent years, is difficult to conduct in young children. Questionnaires are an alternative and indirect method of predicting exposure, which may overcome some of the limitations of direct exposure assessment.

RESEARCH PROBLEM

The feasibility of using a questionnaire-based approach to predict exposure of young children to EDCs in the home has yet to be comprehensively reviewed. Moreover, there is no one questionnaire that has been validated for predicting the exposure of infants to common EDCs in the home.

AIMS AND OBJECTIVES

The aim of this review is to discuss the use and validation of the questionnaire-based approach to predict exposure of children to chemicals from three common classes of EDCs in the home, namely, plasticisers, flame retardants, and insecticides. We discuss the strengths and weaknesses of the questionnaire-based approach as well as the important pathways of exposure in the home environment, by which to guide the design and validation of future exposure questionnaires.

RESULTS

The findings from our review indicate that the questionnaire-based approach is a valuable tool in the prediction of exposure to persistent organic pollutants, as well as to toxicants that have consistent patterns of exposure. With improvements to the design and validation process, the questionnaire-based approach may also prove to be a reliable instrument in predicting exposure to EDCs with short-half lives, including bisphenol A, phthalates, and pyrethroid and organophosphate insecticides.

In vitro metabolism of cis- and trans-permethrin by rat liver microsomes, and its effect on estrogenic and anti-androgenic activities

Permethrin is a widely applied broad-spectrum pyrethroid insecticide that consists of a mixture of cis- and trans-isomers. We examined the changes of estrogenic and anti-androgenic activities resulting from metabolism of the isomers. Both cis- and trans-permethrin were hydrolyzed to 3-phenoxybenzyl alcohol (PBAlc) by rat liver microsomes, but the extent of hydrolysis of trans-permethrin was much greater than that of the cis-isomer. In the presence of NADPH, PBAlc was further transformed to 4'-hydroxylated PBAlc (4'-OH PBAlc), 3-phenoxybenzaldehyde (PBAld) and 3-phenoxybenzoic acid (PBAcid). cis-Permethrin, but not trans-permethrin, also afforded its 4'-hydroxylated derivative (4'-OH cis-permethrin). trans-Permethrin was an anti-androgen, but also showed weak estrogenic activity, while cis-permethrin was a weak estrogen and a weak anti-androgen. After incubation with rat liver microsomes in the presence of NADPH, cis-permethrin but not trans-permethrin was metabolically activated for estrogenic activity. On the other hand, estrogenic activity of trans-permethrin was not changed, but its anti-androgenic activity was enhanced after incubation. 4'-OH PBAlc and PBAlc showed estrogenic activity, while PBAld and PBAlc showed anti-androgenic activity. PBAcid showed neither activity. 4'-OH cis-permethrin showed both estrogenic and anti-androgenic activities. Overall, our results indicate that permethrin is metabolically activated for estrogenic and anti-androgen activities, and the microsomal transformation of permethrin to 4'-OH cis-permethrin, 4'-OH PBAlc and PBAlc contributes to the both metabolic activations.

Trends in long term exposure to propoxur and pyrethroids in young children in the Philippines

BACKGROUND/AIM

Pesticides are neurotoxic and can adversely affect children's neurobehavioral outcome. 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.

PATIENTS AND METHODS

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 by gas chromatography/mass spectrometry at 2, 4 and 6 years of age.

RESULTS

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 12.4% to 24.1% (p<0.001) but dramatically decreased to 1.7% at 6 years (p<0.001). For bioallethrin, the prevalence of exposure steadily increased from 2 years (0.7%, p<0.001) to 4 years (12.4%, p<0.001) and to 6 years (18.4% p<0.001). Exposure to transfluthrin significantly increased from 4 years (1.0%) to 6 years (9.2%, p<0.001). There were also significantly higher median concentrations of bioallethrin at 2 compared to 4 years and for propoxur at 2 years compared 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.

CONCLUSION

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.

Urinary pyrethroid and chlorpyrifos metabolite concentrations in Northern California families and their relationship to indoor residential insecticide levels, part of the Study of Use of Products and Exposure Related Behavior (SUPERB)

Since the 2001 U.S. federally mandated phase-out of residential uses of organophosphates (OPs), use of and potential for human exposure to pyrethroids in the indoor residential environment has increased. We report concentrations of common pyrethroids, pyrethroid metabolites, and chlorpyrifos in floor wipes, and urinary concentrations of pyrethroid metabolites and 3,5,6-trichloro-2-pyridinol (TCPy) in samples collected in 2007-2009 from 90 northern California families as part of the Study of Use of Products and Exposure Related Behavior (SUPERB). Correlation and regression analyses examined associations between floor wipe and urine sample concentrations. The most frequently detected urinary metabolites were TCPy (64.7%, median concentration of 1.47 ng/mL) and 3-phenoxybenzoic acid (3PBA) (62.4%, 0.79 ng/mL). Compared to the National Health and Nutrition Examination Survey (NHANES) 2001-2002 general U.S. population, this population had substantially higher pyrethroid metabolite and lower TCPy urinary concentrations. This may be related to the increased residential use of pyrethroids after the phase-out of OPs. Chlorpyrifos (98.7%), cis- and trans-permethrin (97.5%), bifenthrin (59.3%), and 3PBA (98.7%) were frequently detected in the floor wipes. Floor wipe concentrations for pyrethroid insecticides were found to be significant predictors of child creatinine-adjusted urinary metabolite concentrations (log-log regression coefficients ranging from 0.26 to 0.29; p < 0.05) suggesting that indoor residential exposure to pyrethroid insecticides is an important exposure route for children.