Characterization of organophosphate pesticides in urine and home environment dust in an agricultural community.

CONTEXT: Organophosphorus insecticides (OPs) have been used to control agricultural pests found in Washington state. Farmworkers (FW) have higher exposure to OP pesticides than non-farmworkers (NFW), and FW children may in turn have higher exposure than NFW children. OBJECTIVE: To examine the association between the concentration in house dust of five OPs used commonly in pome fruit orchards and the concentration in urine of dialkylphosphate metabolites (DAP), in a cohort of Hispanic FW and NFW and their children. METHODS: Parents and children participated in three data collection periods over the course of one year. Urine samples were evaluated for the DAPs characteristic of OP exposure, and dust from homes and vehicles was evaluated for intact OP residues. RESULTS: Geometric mean (GM) concentrations of OPs in house and vehicle dust were higher in FW households than NFW households in all agricultural seasons. GM concentration of urinary DAPs was higher for children in FW households than NFW households. DISCUSSION: Regression analysis found a positive association between OP residues in house dust and the children's urinary DAPs. CONCLUSIONS: To our knowledge, this study is the first to report an association between pesticides in house dust and their biological metabolites in urine.

Urinary microRNAs as potential biomarkers of pesticide exposure.

MicroRNAs (miRNAs) are post-transcriptional regulators that silence messenger RNAs. Because miRNAs are stable at room temperature and long-lived, they have been proposed as molecular biomarkers to monitor disease and exposure status. While urinary miRNAs have been used clinically as potential diagnostic markers for kidney and bladder cancers and other diseases, their utility in non-clinical settings has yet to be fully developed. Our goal was to investigate the potential for urinary miRNAs to act as biomarkers of pesticide exposure and early biological response by identifying the miRNAs present in urine from 27 parent/child, farmworker/non-farmworker pairs (16FW/11NFW) collected during two agricultural seasons (thinning and post-harvest) and characterizing the between- and within-individual variability of these miRNA epigenetic regulators. MiRNAs were isolated from archived urine samples and identified using PCR arrays. Comparisons were made between age, households, season, and occupation. Of 384 miRNAs investigated, 297 (77%) were detectable in at least one sample. Seven miRNAs were detected in at least 50% of the samples, and one miRNA was present in 96% of the samples. Principal components and hierarchical clustering analyses indicate significant differences in miRNA profiles between farmworker and non-farmworker adults as well as between seasons. Six miRNAs were observed to be positively associated with farmworkers status during the post-harvest season. Expression of five of these miRNA trended towards a positive dose response relationship with organophosphate pesticide metabolites in farmworkers. These results suggest that miRNAs may be novel biomarkers of pesticide exposure and early biological response.

Seasonal variation in cortisol biomarkers in Hispanic mothers living in an agricultural region.

CONTEXT: Characterization of stress exposure requires understanding seasonal variability in stress biomarkers. OBJECTIVE: To compare acute and chronic stress biomarkers between two seasons in a cohort of rural, Hispanic mothers. METHODS: Stress questionnaires and cortisol measurements (hair, blood and saliva) were collected in the summer and fall. RESULTS: Cortisol biomarkers were significantly different and stress questionnaires were significantly correlated between seasons. DISCUSSION: The variability in cortisol and relative stability of questionnaires between seasons may indicate that cortisol responds to subtle stressors not addressed in questionnaires. CONCLUSIONS: There are significant differences in stress biomarkers in our cohort between seasons.

A Hazard-Based Framework for Identifying Safer Alternatives to Classes of Chemicals: A Case Study on Phthalates in Consumer Products.

BACKGROUND: Humans are exposed to hazardous chemicals found in consumer products. In 2019, the Pollution Prevention for Healthy People and Puget Sound Act was passed in Washington State. This law is meant to reduce hazardous chemicals in consumer products and protect human health and the environment. The law directs the Washington State Department of Ecology to assess chemicals and chemical classes found in products, determine whether there are safer alternatives, and make regulatory determinations. OBJECTIVES: To implement the law, the Department of Ecology developed a hazard-based framework for identifying safer alternatives to classes of chemicals. METHODS: We developed a hazard-based framework, termed the "Criteria for Safer," to set a transparent bar for determining whether new chemical alternatives are safer than existing classes of chemicals. Our "Criteria for Safer" is a framework that builds on existing hazard assessment methodologies and published approaches for assessing chemicals and chemical classes. DISCUSSION: We describe implementation of our criteria using a case study on the phthalates chemical class in two categories of consumer products: vinyl flooring and fragrances used in personal care and beauty products. Additional context and considerations that guided our decision-making process are also discussed, as well as benefits and limitations of our approach. This paper gives insight into our development and implementation of a hazard-based framework to address classes of chemicals in consumer products and will aid others working to build and employ similar approaches. https://doi.org/10.1289/EHP13549.

Alteration of oral microbiome composition in children living with pesticide-exposed farm workers.

Our prior work shows that azinphos-methyl pesticide exposure is associated with altered oral microbiomes in exposed farmworkers. Here we extend this analysis to show the same association pattern is also evident in their children. Oral buccal swab samples were analyzed at two time points, the apple thinning season in spring-summer 2005 for 78 children and 101 adults and the non-spray season in winter 2006 for 62 children and 82 adults. The pesticide exposure for the children were defined by the farmworker occupation of the cohabitating household adult and the blood azinphos-methyl detection of the cohabitating adult. Oral buccal swab 16S rRNA sequencing determined taxonomic microbiota proportional composition from concurrent samples from both adults and children. Analysis of the identified bacteria showed significant proportional changes for 12 of 23 common oral microbiome genera in association with azinphos-methyl detection and farmworker occupation. The most common significantly altered genera had reductions in the abundance of Streptococcus, suggesting an anti-microbial effect of the pesticide. Principal component analysis of the microbiome identified two primary clusters, with association of principal component 1 to azinphos-methyl blood detection and farmworker occupational status of the household. The children's buccal microbiota composition clustered with their household adult in ∼95% of the households. Household adult farmworker occupation and household pesticide exposure is associated with significant alterations in their children's oral microbiome composition. This suggests that parental occupational exposure and pesticide take-home exposure pathways elicit alteration of their children's microbiomes.

Regulation of Persistent Chemicals in Hazardous Waste: A Case Study of Washington State, USA.

Despite ongoing controversy, several strategic frameworks for defining chemicals of concern (e.g., persistent, bioaccumulative, toxic [PBT]; persistent, mobile, toxic [PMT]; persistent organic pollutant [POP]) share persistence as a key criterion. Persistence should be considered over the entire chemical life cycle from production to disposal, including hazardous waste management. As a case study, we evaluate persistence criteria in hazardous waste regulations in Washington state, USA, illustrate impacts on reported waste, and propose refinements in these criteria. Although Washington state defines persistence based on half-life (>1 y) and specific chemical groups that exceed summed concentration thresholds in waste (i.e., >0.01% halogenated organic compounds [HOCs] and >1.0% polycyclic aromatic hydrocarbons [PAHs]), persistence is typically addressed with HOC and PAH evaluation but seldom with half-life estimation. Notably, persistence is considered (with no specific criteria) in corresponding federal regulations in the United States (Resource Conservation and Recovery Act). Consequently, businesses in Washington state report annual amounts of state hazardous waste (including persistent waste) separately from federal hazardous waste. Total state-only waste, and total state and federal waste combined, nearly doubled (by weight) from 2008 to 2018. For the period 2016 to 2018, persistence criteria captured 17% of state-only waste and 2% of total state and federal waste combined. Two recommendations are proposed to improve persistence criteria in hazardous waste regulations. First, Washington state should consider aligning its half-life criterion with federal and European Union PBT definitions (e.g., 60-120 d) for consistency and provide specific methods for half-life estimation. Second, the state should consider expanding its list of persistent chemical groups (e.g., siloxanes, organometallics) with protective concentration thresholds. Ultimately, to the extent possible, Washington state should strive toward harmonizing persistence in hazardous waste regulations with corresponding criteria in global PBT, PMT, and POP frameworks. Integr Environ Assess Manag 2021;17:455-464. © 2020 SETAC.

A Case study on the utility of predictive toxicology tools in alternatives assessments for hazardous chemicals in children's consumer products.

Children's consumer products represent an important exposure source for many toxicants. Chemicals of high concern, as designated by the Washington State Child Safe Product Act include phthalates, Bisphenol A (BPA) and parabens, among others. As regulation and reporting requirements increase, so has demand for safer alternatives. This project examines how predictive toxicology and exposure comparison tools can fill gaps in alternatives assessments for hazardous chemicals found in children's products. Phthalates, parabens, BPA and their alternatives were assessed for endocrine disruption and reproductive toxicity using authoritative lists and US Environmental Protection Agency's (EPA) predictive toxicology and exposure comparison tools. Resources included the European Chemical Agency's Endocrine Disruptor Substances of Concern database, Global Harmonization System and Classification of Labeling Chemicals, Quantitative Structural Activity Relationships from the Toxicity Estimation Software Tool, the Toxicological Prioritization Index (ToxPi) score calculated from the ToxCast Database, and No Observable Adverse Effects Levels (NOAELs)/Highest No Effects Levels (HNEL) from animal studies found in the CompTox Chemistry Dashboard. Exposure was assessed using ExpoCast predictions. Though alternatives were rarely included in authoritative lists, predictive toxicology tools suggested that BPA alternatives may not be safer but paraben and phthalate alternatives may be safer. All four paraben and no bisphenol or phthalate alternatives were listed on EPA's Safer Chemical Ingredients List. Overall, we found that predictive toxicology tools help fill gaps for alternatives assessments when existing classifications are incomplete.

Characterizing the Neurodevelopmental Pesticide Exposome in a Children's Agricultural Cohort.

The exposome provides a conceptual model for identifying and characterizing lifetime environmental exposures and resultant health effects. In this study, we applied key exposome concepts to look specifically at the neurodevelopmental pesticide exposome, which focuses on exposures to pesticides that have the potential to cause an adverse neurodevelopmental impact. Using household dust samples from a children's agricultural cohort located in the Yakima Valley of Washington state, we identified 87 individual pesticides using liquid chromatography-tandem mass spectrometry. A total of 47 of these have evidence of neurotoxicity included in the Environmental Protection Agency (EPA) (re)registration materials. We used a mixed effects model to model trends in pesticide exposure. Over the two study years (2005 and 2011), we demonstrate a significant decrease in the neurodevelopmental pesticide exposome across the cohort, but particularly among farmworker households. Additional analysis with a non-parametric binomial analysis that weighted the levels of potentially neurotoxic pesticides detected in household dust by their reference doses revealed that the decrease in potentially neurotoxic pesticides was largely a result of decreases in some of the most potent neurotoxicants. Overall, this study provides evidence that the neurodevelopmental pesticide exposome framework is a useful tool in assessing the effectiveness of specific interventions in reducing exposure as well as setting priorities for future targeted actions.

Application of improved approach to evaluate a community intervention to reduce exposure of young children living in farmworker households to organophosphate pesticides.

The take-home pathway is a significant source of organophosphate pesticide exposure for young children (3-5 years old) living with an adult farmworker. This avoidable exposure pathway is an important target for intervention. We selected 24 agricultural communities in the Yakima Valley of Washington State and randomly assigned them to receive an educational intervention (n = 12) to reduce children's pesticide exposure or usual care (n = 12). We assessed exposure to pesticides in nearly 200 adults and children during the pre and post-intervention periods by measuring metabolites in urine. We compared pre- and post-intervention exposures by expressing the child's pesticide metabolite concentration as a fraction of the adult's concentration living in the same household, because the amount of pesticides applied during the collection periods varied. Exposures in our community were consistently higher, sometimes above the 95th percentile of the exposures reported by the National Health and Nutrition Examination Survey (NHANES). While intervention and control communities demonstrated a reduction in the ratio of child to adult exposure, this reduction was more pronounced in intervention communities (2.7-fold, p < 0.001 compared to 1.7-fold, p = 0.052 for intervention and control, respectively). By examining the child/adult biomarker ratio, we demonstrated that our community-based intervention was effective in reducing pesticide exposure to children in agricultural communities.

Evaluation of the relationship between residential orchard density and dimethyl organophosphate pesticide residues in house dust.

Reducing residential pesticide exposure requires identification of exposure pathways. Compared to the agriculture worker 'take-home' and residential use pathways, evidence of the 'drift' pathway to pesticide exposure has been inconsistent. Questionnaire data from individuals (n = 99) and dust samples (n = 418) from households across three growing seasons in 2011 were from the For Healthy Kids! study. Summed dimethyl organophosphate pesticide (OP) (Azinphos-Methyl, Phosmet, and Malathion) concentrations were quantified from house dust samples. Spatially-weighted orchard densities surrounding households were calculated based on various distances from homes. Regression models tested associations between orchard density, residential pesticide use, agriculture worker residents, and summed dimethyl OP house dust concentrations. Estimated relationships between orchard density and dimethyl OP in house dust were mixed: a 5% increase in orchard density resulted in 0.3 and 0.5% decreases in dimethyl OP house dust concentrations when considering land-cover 750 m or 1250 m away from households, respectively, but null associations with land-cover 60 m or 200 m away. Dimethyl OP house dust concentrations were 400% higher within homes where at least two residents were agriculture workers. Despite inconclusive evidence for the drift pathway due to potential for bias, relationships between number of agriculture workers and dimethyl OP house dust concentration underscores the take-home pathway.

Longitudinal, Seasonal, and Occupational Trends of Multiple Pesticides in House Dust.

BACKGROUND: Children are especially vulnerable to pesticide exposure and can suffer lasting health effects. Because children of farmworkers are exposed to a variety of pesticides throughout development, it is important to explore temporal patterns of coexposures. OBJECTIVES: The objectives of this study were to characterize the pesticide co-exposures, determine how they change over time, and assess differences between farmworker and nonfarmworker households. METHODS: Dust collected from 40 farmworker and 35 nonfarmworker households in the Yakima Valley of the State of Washington in 2005 and then again in 2011 was analyzed for 99 pesticides. Eighty-seven pesticides representing over 28 classes were detected. Pesticides were grouped into classes using U.S. EPA pesticide chemical classifications, and trends in concentrations were analyzed at the class level. RESULTS: Levels of organophosphates, pyridazinones, and phenols significantly decreased between 2005 and 2011 in both farmworker and nonfarmworker households. Levels of anilides, 2,6-dinitroanilines, chlorophenols, triclosan, and guanidines significantly increased in both farmworker and nonfarmworker households in 2011 vs. 2005. Among farmworkers alone, there were significantly lower levels of N-methyl carbamates and neonicotinoids in 2011. CONCLUSIONS: We observed significant reductions in the concentrations of many pesticides over time in both farmworker and nonfarmworker households. Although nonfarmworker households generally had lower concentrations of pesticides, it is important to note that in comparison with NHANES participants, nonfarmworkers and their families still had significantly higher concentrations of urinary pesticide metabolites. This finding highlights the importance of detailed longitudinal exposure monitoring to capture changes in agricultural and residential pesticide use over time. This foundation provides an avenue to track longitudinal pesticide exposures in an intervention or regulatory context. https://doi.org/10.1289/EHP3644.

Variability in metagenomic samples from the Puget Sound: Relationship to temporal and anthropogenic impacts.

Whole-metagenome sequencing (WMS) has emerged as a powerful tool to assess potential public health risks in marine environments by measuring changes in microbial community structure and function in uncultured bacteria. In addition to monitoring public health risks such as antibiotic resistance determinants, it is essential to measure predictors of microbial variation in order to identify natural versus anthropogenic factors as well as to evaluate reproducibility of metagenomic measurements.This study expands our previous metagenomic characterization of Puget Sound by sampling new nearshore environments including the Duwamish River, an EPA superfund site, and the Hood Canal, an area characterized by highly variable oxygen levels. We also resampled a wastewater treatment plant, nearshore and open ocean sites introducing a longitudinal component measuring seasonal and locational variations and establishing metagenomics sampling reproducibility. Microbial composition from samples collected in the open sound were highly similar within the same season and location across different years, while nearshore samples revealed multi-fold seasonal variation in microbial composition and diversity. Comparisons with recently sequenced predominant marine bacterial genomes helped provide much greater species level taxonomic detail compared to our previous study. Antibiotic resistance determinants and pollution and detoxification indicators largely grouped by location showing minor seasonal differences. Metal resistance, oxidative stress and detoxification systems showed no increase in samples proximal to an EPA superfund site indicating a lack of ecosystem adaptation to anthropogenic impacts. Taxonomic analysis of common sewage influent families showed a surprising similarity between wastewater treatment plant and open sound samples suggesting a low-level but pervasive sewage influent signature in Puget Sound surface waters. Our study shows reproducibility of metagenomic data sampling in multiple Puget Sound locations while establishing baseline measurements of antibiotic resistance determinants, pollution and detoxification systems. Combining seasonal and longitudinal data across these locations provides a foundation for evaluating variation in future studies.

Developing the Regulatory Utility of the Exposome: Mapping Exposures for Risk Assessment through Lifestage Exposome Snapshots (LEnS).

BACKGROUND: Exposome-related efforts aim to document the totality of human exposures across the lifecourse. This field has advanced rapidly in recent years but lacks practical application to risk assessment, particularly for children's health. OBJECTIVES: Our objective was to apply the exposome to children's health risk assessment by introducing the concept of Lifestage Exposome Snapshots (LEnS). Case studies are presented to illustrate the value of the framework. DISCUSSION: The LEnS framework encourages organization of exposome studies based on windows of susceptibility for particular target organ systems. Such analyses will provide information regarding cumulative impacts during specific critical periods of the life course. A logical extension of this framework is that regulatory standards should analyze exposure information by target organ, rather than for a single chemical only or multiple chemicals grouped solely by mechanism of action. CONCLUSIONS: The LEnS concept is a practical refinement to the exposome that accounts for total exposures during particular windows of susceptibility in target organ systems. Application of the LEnS framework in risk assessment and regulation will improve protection of children's health by enhancing protection of sensitive developing organ systems that are critical for lifelong health and well-being. https://doi.org/10.1289/EHP1250.

FARME DB: a functional antibiotic resistance element database.

Antibiotic resistance (AR) is a major global public health threat but few resources exist that catalog AR genes outside of a clinical context. Current AR sequence databases are assembled almost exclusively from genomic sequences derived from clinical bacterial isolates and thus do not include many microbial sequences derived from environmental samples that confer resistance in functional metagenomic studies. These environmental metagenomic sequences often show little or no similarity to AR sequences from clinical isolates using standard classification criteria. In addition, existing AR databases provide no information about flanking sequences containing regulatory or mobile genetic elements. To help address this issue, we created an annotated database of DNA and protein sequences derived exclusively from environmental metagenomic sequences showing AR in laboratory experiments. Our Functional Antibiotic Resistant Metagenomic Element (FARME) database is a compilation of publically available DNA sequences and predicted protein sequences conferring AR as well as regulatory elements, mobile genetic elements and predicted proteins flanking antibiotic resistant genes. FARME is the first database to focus on functional metagenomic AR gene elements and provides a resource to better understand AR in the 99% of bacteria which cannot be cultured and the relationship between environmental AR sequences and antibiotic resistant genes derived from cultured isolates.Database URL: http://staff.washington.edu/jwallace/farme.

Seasonal and occupational trends of five organophosphate pesticides in house dust.

Since 1998, the University of Washington's Center for Child Environmental Health Risks Research has followed a community-based participatory research strategy in the Lower Yakima Valley of Washington State to assess pesticide exposure among families of Hispanic farmworkers. As a part of this longitudinal study, house dust samples were collected from both farmworker and non-farmworker households, across three agricultural seasons (thinning, harvest and non-spray). The household dust samples were analyzed for five organophosphate pesticides: azinphos-methyl, phosmet, malathion, diazinon, and chlorpyrifos. Organophosphate pesticide levels in house dust were generally reflective of annual use rates and varied by occupational status and agricultural season. Overall, organophosphate pesticide concentrations were higher in the thinning and harvest seasons than in the non-spray season. Azinphos-methyl was found in the highest concentrations across all seasons and occupations. Farmworker house dust had between 5- and 9-fold higher concentrations of azinphos-methyl than non-farmworker house dust. Phosmet was found in 5-7-fold higher concentrations in farmworker house dust relative to non-farmworker house dust. Malathion and chlorpyriphos concentrations in farmworker house dust ranged between 1.8- and 9.8-fold higher than non-farmworker house dust. Diazinon showed a defined seasonal pattern that peaked in the harvest season and did not significantly differ between farmworker and non-farmworker house dust. The observed occupational differences in four out of five of the pesticide residues measured provides evidence supporting an occupational take home pathway, in which workers may bring pesticides home on their skin or clothing. Further, these results demonstrate the ability of dust samples to inform the episodic nature of organophosphate pesticide exposures and the need to collect multiple samples for complete characterization of exposure potential.

A Toxicological Framework for the Prioritization of Children's Safe Product Act Data.

In response to concerns over hazardous chemicals in children's products, Washington State passed the Children's Safe Product Act (CSPA). CSPA requires manufacturers to report the concentration of 66 chemicals in children's products. We describe a framework for the toxicological prioritization of the ten chemical groups most frequently reported under CSPA. The framework scores lifestage, exposure duration, primary, secondary and tertiary exposure routes, toxicokinetics and chemical properties to calculate an exposure score. Four toxicological endpoints were assessed based on curated national and international databases: reproductive and developmental toxicity, endocrine disruption, neurotoxicity and carcinogenicity. A total priority index was calculated from the product of the toxicity and exposure scores. The three highest priority chemicals were formaldehyde, dibutyl phthalate and styrene. Elements of the framework were compared to existing prioritization tools, such as the United States Environmental Protection Agency's (EPA) ExpoCast and Toxicological Prioritization Index (ToxPi). The CSPA framework allowed us to examine toxicity and exposure pathways in a lifestage-specific manner, providing a relatively high throughput approach to prioritizing hazardous chemicals found in children's products.

Metagenomic frameworks for monitoring antibiotic resistance in aquatic environments.

BACKGROUND: High-throughput genomic technologies offer new approaches for environmental health monitoring, including metagenomic surveillance of antibiotic resistance determinants (ARDs). Although natural environments serve as reservoirs for antibiotic resistance genes that can be transferred to pathogenic and human commensal bacteria, monitoring of these determinants has been infrequent and incomplete. Furthermore, surveillance efforts have not been integrated into public health decision making. OBJECTIVES: We used a metagenomic epidemiology-based approach to develop an ARD index that quantifies antibiotic resistance potential, and we analyzed this index for common modal patterns across environmental samples. We also explored how metagenomic data such as this index could be conceptually framed within an early risk management context. METHODS: We analyzed 25 published data sets from shotgun pyrosequencing projects. The samples consisted of microbial community DNA collected from marine and freshwater environments across a gradient of human impact. We used principal component analysis to identify index patterns across samples. RESULTS: We observed significant differences in the overall index and index subcategory levels when comparing ecosystems more proximal versus distal to human impact. The selection of different sequence similarity thresholds strongly influenced the index measurements. Unique index subcategory modes distinguished the different metagenomes. CONCLUSIONS: Broad-scale screening of ARD potential using this index revealed utility for framing environmental health monitoring and surveillance. This approach holds promise as a screening tool for establishing baseline ARD levels that can be used to inform and prioritize decision making regarding management of ARD sources and human exposure routes. CITATION: Port JA, Cullen AC, Wallace JC, Smith MN, Faustman EM. 2014. Metagenomic frameworks for monitoring antibiotic resistance in aquatic environments. Environ Health Perspect 122:222­228; http://dx.doi.org/10.1289/ehp.1307009

Using a biokinetic model to quantify and optimize cortisol measurements for acute and chronic environmental stress exposure during pregnancy.

To fully understand the potentially harmful effects of prenatal stress exposure impacts, it is necessary to quantify long-term and episodic stress exposure during pregnancy. There is a strong body of research relating psychological stress to elevated cortisol levels in biomarkers. Recently, maternal hair has been used to measure cortisol levels, and provides the unique opportunity to assess stress exposure throughout gestation. Understanding how cortisol in the hair is related to more common biomarkers, such as, blood, saliva and urine is currently lacking. Therefore, we developed a biokinetic model to quantify the relationships between hair, blood, saliva and urine cortisol concentrations using published literature values. Hair concentrations were used to retrospectively predict peaks in blood and saliva concentrations over days and months. Simulations showed realistic values in all compartments when results were compared with published literature. We also showed that the significant variability of cortisol in blood leads to a weak relationship between long-term and episodic measurements of stress. To our knowledge, this is the first integrative biokinetic cortisol model for blood, urine, hair and saliva. As such, it makes an important contribution to our understanding of cortisol as a biomarker and will be useful for future epidemiological studies.