Predictors of pesticide levels in carpet dust collected from child care centers in Northern California, USA

BACKGROUND

Young children may be exposed to pesticides in child care centers, but little is known about determinants of pesticide contamination in these environments.

OBJECTIVE

Characterize pesticide contamination in early care and education (ECE) centers and identify predictors of pesticide concentrations and loading in dust collected from classroom carpets.

METHODS

Carpet dust samples were collected from 51 licensed child care centers in Northern California and analyzed for 14 structural and agricultural pesticides. Program characteristics were collected through administration of director interviews and observational surveys, including an integrated pest management (IPM) inspection. Pesticide use information for the prior year was obtained from the California Department of Pesticide Regulation to characterize structural applications and nearby agricultural pesticide use.

RESULTS

The most frequently detected pesticides were cis-permethrin (98%), trans-permethrin (98%), bifenthrin (94%), fipronil (94%), and chlorpyrifos (88%). Higher bifenthrin levels were correlated with agricultural applications within 3 kilometers, and higher fipronil levels were correlated with professional pesticide applications in the prior year. In multivariable models, higher IPM Checklist scores were associated with lower loading of chlorpyrifos and permethrin. Placement of the sampled area carpet was also a predictor of chlorpyrifos loading. The strongest predictor of higher pesticide loading for the most frequently detected pesticides was location in California's San Joaquin Valley.

SIGNIFICANCE

Our findings contribute to the growing understanding that pesticides are ubiquitous in children's environments. Pesticide levels in carpet dust were associated with some factors that ECE directors may have control over, such as IPM practices, and others that are beyond their control, such as geographic location. IPM is an important tool that has the potential to reduce pesticide exposures in ECE environments, even for pesticides no longer in use.

IMPACT

One million children in California under six years old attend child care programs where they may spend up to 40 h per week. Children are uniquely vulnerable to environmental contaminants; however early care settings are under researched in environmental health studies. Little is known about predictors of pesticide levels found in environmental samples from child care facilities. This study aims to identify behavioral and environmental determinants of pesticide contamination in California child care centers. Findings can empower child care providers and consumers and inform decision makers to reduce children's exposures to pesticides and promote lifelong health.

The association of prenatal phthalates, organophosphorous pesticides, and organophosphate esters with early child language ability in Norway

BACKGROUND

Prenatal exposure to phthalates, organophosphate esters, and organophosphorous pesticides have been associated with neurodevelopmental deficits including language ability, however, few studies consider the effect of exposure mixtures and the potential longitudinal detriments over time.

OBJECTIVE

This study examines the influence of prenatal exposure to phthalates, organophosphate esters, and organophosphorous pesticides, on children's language ability from toddlerhood to the preschool period.

METHODS

This study includes 299 mother-child dyads from Norway in the Norwegian Mother, Father and Child Cohort Study (MoBa). Prenatal exposure to chemicals were assessed at 17 weeks' gestation, and child language skills were assessed at 18 months using the Ages and Stages Questionnaire communication subscale and at preschool age using the Child Development Inventory. We ran two structural equation models to examine the simultaneous influences of chemical exposures on parent-reported and teacher-reported child language ability.

RESULTS

Prenatal organophosphorous pesticides were negatively associated with preschool language ability through language ability at 18 months. Additionally, there was a negative association between low molecular weight phthalates and teacher-reported preschool language ability. There was no effect of prenatal organophosphate esters on child language ability at either 18 months or preschool age.

CONCLUSIONS

This study adds to the literature on prenatal exposure to chemicals and neurodevelopment and highlights the importance of developmental pathways in early childhood.

Personal air pollutant exposure monitoring in South African children in the VHEMBE birth cohort

The burden of disease associated with environmental exposures disproportionately impacts residents of low- and middle-income countries. Children living in rural regions of these countries may experience higher exposure to insecticides from indoor residual spraying used for malaria control and household air pollution. This study evaluated environmental exposures of children living in a rural region of South Africa. Quantifying exposure levels and identifying characteristics that are associated with exposure in this geographic region has been challenging due to limitations with available monitoring techniques. Wearable passive samplers have recently been shown to be a convenient and reliable tool for assessing personal exposures. In this study, a passive sampler wristband, known as Fresh Air wristband, was worn by 49 children (five-years of age) residing in the Limpopo province of South Africa. The study leveraged ongoing research within the Venda Health Examination of Mothers, Babies, and their Environment (VHEMBE) birth cohort. A wide range of chemicals (35 in total) were detected using the wristbands, including polycyclic aromatic hydrocarbons (PAHs), organochlorine pesticides, phthalates, and organophosphate esters (OPEs) flame retardants. Higher concentrations of PAHs were observed among children from households that fell below the food poverty threshold, did not have access to electric cookstoves/burners, or reported longer times of cooking or burning materials during the sampling period. Concentrations of p,p'-DDD and p,p'-DDT were also found to be elevated for children from households falling below the food poverty threshold as well as for children whose households were sprayed for malaria control within the previous 1.5 years. This study demonstrates the feasibility of using passive sampler wristbands as a non-invasive method for personal exposure assessment of children in rural regions of South Africa to complex mixtures environmental contaminants derived from a combination of sources. Future studies are needed to further identify and understand the effects of airborne environmental contaminants on childhood development and strategies to mitigate exposures.

Urinary pyrethroid metabolite and hearing threshold shifts of adults in the United States: A cross-sectional study

Hearing loss (HL) is a global health problem with a high prevalence and profound socioeconomic impact. Pyrethroids are one of the most commonly used insecticides. Although previous studies have reported the relationship between pyrethroids and neurotoxicity, little is known about the effect of pyrethroid exposure on the auditory system among the general population. This study is aimed to investigate the association of pyrethroid exposure with hearing threshold shifts of adults in the United States. A total of 726 adults, aged from 20 to 69 years from the 2011-2012 National Health and Nutrition Examination Survey (NHANES) data were included in the study. Urinary 3-phenoxybenzoic acid (3-PBA), a general pyrethroid metabolite, was used as a biomarker for pyrethroid exposure. HL was defined as a pure-tone average (PTA) at 0.5, 1, 2, 4 kHz ≥ 20 dB in the better ear. Analyses by using multivariate linear regressions were conducted to explore the associations of urinary 3-PBA with PTA hearing threshold shifts. There were no statistically significant correlations between Ln-transformed 3-PBA and either low-frequency or high-frequency hearing thresholds after adjusting for age, gender, race/ethnicity, education level, firearm noise exposure, occupational noise exposure, recreational noise exposure, serum cotinine, BMI, hypertension, and diabetes. However, associations of 3-PBA with both low-frequency and high-frequency hearing thresholds depended on age (P interaction < 0.0396 and 0.0017, respectively). Positive associations between Ln-transformed 3-PBA and both low-frequency and high-frequency hearing thresholds were observed in participants aged 20-39 years after adjusting confounders (β = 1.53, 95% CI: 0.04-3.01, and β = 3.14, 95% CI: 0.99-5.29, respectively) with the highest tertile (≥ 0.884 μg/g creatinine) of 3-PBA compared with the lowest tertile (< 0.407 μg/g creatinine). The possibility of interaction between 3-PBA and age on the hearing threshold shifts indicated that pyrethroid insecticides were prone to be more toxic to auditory system in younger adults than in older ones. Further studies will be required to confirm these findings.

Perspective: Young Workers at Higher Risk for Carcinogen Exposures

Young workers, those under the age of 25, are considered a vulnerable working population, primarily due to their increased risk of injury. In this study we investigate if young workers may also be at an increased risk for occupational exposure to carcinogens. Using the 2006 and 2016 Canadian Census of Population and previously obtained CAREX Canada data, this study aimed to identify sectors and occupations that have high proportions of young workers and where potential exists for exposure to known and suspected carcinogens. Key groups where young workers are likely at a higher risk for occupational exposure to carcinogens were identified. Our work shows that young workers in construction, outdoor occupations, and farming are key groups that warrant further investigation. These specific groups are highlighted because of the large number of young workers employed in these sectors/situations, the high number of possible carcinogen exposures, and the potential for higher risk behavior patterns that typically occur in these types of jobs. While there is no data available to develop carcinogen exposure estimates specific to young workers, it is our perspective that young workers are likely at a higher risk for occupational exposure to carcinogens. Our findings identify opportunities to improve the occupational health and safety for this vulnerable population, particularly for young construction workers, farm workers, and outdoor workers.

Association between increasing agricultural use of 2,4-D and population biomarkers of exposure: findings from the National Health and Nutrition Examination Survey, 2001-2014

BACKGROUND

2,4-Dichlorophenoxyacetic acid (2,4-D) is one of the most extensively used herbicides in the United States. In 2012, 2,4-D was the most widely used herbicide in non-agricultural settings and the fifth most heavily applied pesticide in the US agricultural sector. The objective of this study was to examine trends in 2,4-D urinary biomarker concentrations to determine whether increases in 2,4-D application in agriculture are associated with increases in biomonitoring levels of urine 2,4-D.

METHODS

Data from the National Health and Nutrition Examination Survey (NHANES) with available urine 2,4-D biomarker measurements from survey cycles between 2001 and 2014 were utilized. Urine 2,4-D values were dichotomized using the highest limit of detection (LOD) across all cycles (0.40 μg/L or 0.4 ppb). Agricultural use of 2,4-D was estimated by compiling publicly available federal and private pesticide application data. Logistic regression models adjusted for confounders were fitted to evaluate the association between agricultural use of 2,4-D and urine 2,4-D level above the dichotomization threshold.

RESULTS

Of the 14,395 participants included in the study, 4681 (32.5%) had urine 2,4-D levels above the dichotomization threshold. The frequency of participants with high 2,4-D levels increased significantly (p < .0001), from a low of 17.1% in 2001-2002 to a high of 39.6% in 2011-2012. The adjusted odds of high urinary 2,4-D concentrations associated with 2,4-D agricultural use (per ten million pounds applied) was 2.268 (95% CI: 1.709, 3.009). Children ages 6-11 years (n = 2288) had 2.1 times higher odds of having high 2,4-D urinary concentrations compared to participants aged 20-59 years. Women of childbearing age (age 20-44 years) (n = 2172) had 1.85 times higher odds than men of the same age.

CONCLUSIONS

Agricultural use of 2,4-D has increased substantially from a low point in 2002 and it is predicted to increase further in the coming decade. Because increasing use is likely to increase population level exposures, the associations seen here between 2,4-D crop application and biomonitoring levels require focused biomonitoring and epidemiological evaluation to determine the extent to which rising use and exposures cause adverse health outcomes among vulnerable populations (particularly children and women of childbearing age) and highly exposed individuals (farmers, other herbicide applicators, and their families).

Maternal pesticide exposure and child neuro-development among smallholder tomato farmers in the southern corridor of Tanzania

BACKGROUND

Exposure to pesticides with its associated effects prenatally and in early childhood has not received much attention. There is little scientific data on this aspect in Tanzania therefore this study was meant to contribute to the deficit in the subject.

METHOD

A cross-sectional study was conducted to a sample of 286 participants of mother to child pair, whereby 172 and 114 were exposed and non-exposed respectively. Mothers who had been working in tomato sprayed farms were exposed and mothers who had not been working in the tomato sprayed farms were un-exposed. Child aged 0-6 years was chosen from each mother sampled but only one child found to be the youngest with the classified age was enrolled. Malawi child development Tool (M-DAT) was employed to assess the child level of development, height, and weight of the children were collected and analyzed by the WHO anthropometric calculator. A checklist and questionnaire were used to observe and assess maternal exposure. Bivariate and Multivariate analysis were conducted to assess the relationship between various factors of exposure.

RESULTS

Overall 15% of the children examined were not well developed and the most used pesticides were those posing neuro-development effects. On the bivariate analysis model, mothers who worked while pregnant were more likely to have a child with neuro-developmental effect OR=5.8(1.29-26.3). On multivariate analyses adjusted for age of the mother, variables which remain in the model were a distance from home [AOR=9.4(4.2-20.5)], and working while pregnancy [AOR=5.8(1.29-26.3)] other were removed due to collinearity effect. None of confounders had a potential significant effect but only nutrition seems to be the effect modifier [AOR=7.8(1.29-36.3)] when analyzed with working while pregnancy.

CONCLUSIONS

The findings from this study have indicated that maternal pesticide exposure among farmworker residents in the SAGCOT area has a potential association with child developmental effect.

An educational intervention on the risk perception of pesticides exposure and organophosphate metabolites urinary concentrations in rural school children in Maule Region, Chile

BACKGROUND

Organophosphate (OP) pesticides can be hazardous to human health if not applied with appropriate precautions. There is evidence in the Maule region of Chile that rural schoolchildren are exposed to OP pesticides.

OBJECTIVE

To evaluate the effectiveness of an educational intervention on OP exposure and understanding of pesticides and their hazards (risk perception) in two school communities in the Maule Region of Chile during 2016.

METHOD

We conducted a quasi-experimental study about the effects on OP pesticide exposure of a community outreach and education program (COEP) administered in four 2-h sessions that's included hands-on activities among 48 schoolchildren from two rural schools. The intervention was directed to groups of parents and school-children separately, and aimed to educate them about the risks of exposure to pesticides and their effects on health. We measured 3,5,6-trichloro-2-pyridinol (TCPy), 2-isopropyl-4-methyl-6-hydroxypyrimidine (IMPY), malathion dicarboxylic acid (MDA), p-nitrophenol (PNP), specific urinary metabolites of the OP pesticides chlorpyrifos, diazinon, malathion and parathion, respectively, as well as the non-specific diethylakylphosphates (DEAPs) and dimethylalkylphosphates (DMAPs) in 192 urine samples of schoolchildren collected before and after the intervention. The risk perception of school children and their parents was also assessed through a questionnaire before and after the intervention. Generalized Estimated Equations were used to account for each child's repeated measures during four sessions, two in September 2016 (pre-intervention) and two in November 2016 (post-intervention).

RESULTS

The intervention level had significant effect on the risk perception of adults and children, which increased after the intervention. However, the intervention was not associated with reduced of urinary metabolites levels, with no significant differences between the pre and post measures. The detection frequencies were 1.1% (MDA), 71.4% (TCPy), 43.3% (IMPY), 98.96% (PNP), and 100% (DEAPs and DMAPs). Higher DEAPs urine concentrations were associated with eating more fruit at school (p = 0.03), a younger age (p = 0.03), and being male (p = 0.01). DMAPs showed no associations with potential predictor variables (e.g. OPs applied at home, fruit consumption at school, among others). Higher TCPy was associated with attending a school closer to farms (p = 0.04) and living in a home closer to farm fields (p = 0.01); higher PNP was marginally associated with children younger age (p = 0.035).

CONCLUSION

Environmental exposure to OP pesticides was unchanged even after behavior changes. It is possible that a longer time period is needed to observe changes in both behavior and urinary metabolites. The levels of DEP and DMP metabolites found here are above the reference population of the US, and our findings indicate exposure to a wide variety of OP pesticides. Given that individual-level interventions were not associated with lower exposures, efforts to reduce exposure must occur upstream and require stricter regulation and control of pesticide use by government agencies.

Levels of persistent organic pollutants in breast milk of Maya women in Yucatan, Mexico

In this study, 24 breast milk samples, obtained from rural Maya women, from municipalities of Yucatan, Mexico, were analyzed for organochlorine pesticide (OCP) residues by gas chromatography. Recent studies have shown that Maya communities have a poor perception about the proper usage and handling of OCP. The karstic soil in this area has a high vulnerability to groundwater pollution by the use of OCP in agriculture and livestock activities. The impact of the ecosystem on human health is much more critical due to the prevailing poverty and a very low educational level of these communities. About 30% of the Maya population consumes water directly from contaminated wells and sinkholes, resulting in a chronic exposure to OCP. The samples served to identify and quantify high levels of OCP residues (18.43 mg/kg of heptachlor epoxide and 1.92 mg/kg of endrin in the metropolitan zone; 2.10 mg/kg of dieldrin, 0.117 mg/kg of endosulfan II, 0.103 mg/kg of heptachlor, 0.178 mg/kg of endrin, and 0.127 mg/kg of endrin aldehyde in the main agricultural zone and on the west coast). The detected levels of OCP residues are a major concern and represent a potential risk to women and children in the region. This could be associated with the high rates of cervical uterine and breast cancer mortality in Yucatan. Thus, regulations on the usage of OCP and their enforcement are necessary, and it is important to establish a yearly monitoring program for OCP residues in breast milk and groundwater, as well as to implement health promotion programs for women in particular and the general population in general.