Environmental Exposure Distribution Research Articles

Exposure Assessment of Pesticides in Surface Waters of Ontario, Canada Reveals Low Probability of Exceeding Acute Regulatory Thresholds.

The objectives of this study were to: (1) characterize the exposure of aquatic ecosystems in Southern Ontario, Canada to pesticides between 2002 and 2016 by constructing environmental exposure distributions (EEDs), including censored data; and (2) predict the probability of exceeding acute regulatory guidelines. Surface water samples were collected over a 15-year period by Environment and Climate Change Canada. The dataset contained 167 compounds, sampled across 114 sites, with a total of 2,213 samples. There were 67,920 total observations of which 55,058 were non-detects (81%), and 12,862 detects (19%). The most commonly detected compound was atrazine, with a maximum concentration of 18,600 ngL- 1 and ~ 4% chance of exceeding an acute guideline (1,000 ngL- 1) in rivers and streams. Using Southern Ontario as a case study, this study provides insight into the risk that pesticides pose to aquatic ecosystems and the utility of EEDs that include censored data for the purpose of risk assessment.

Proteome changes in larval zebrafish (Danio rerio) and fathead minnow (Pimephales promelas) exposed to (±) anatoxin-a

Anatoxin-a and its analogues are potent neurotoxins produced by several genera of cyanobacteria. Due in part to its high toxicity and potential presence in drinking water, these toxins pose threats to public health, companion animals and the environment. It primarily exerts toxicity as a cholinergic agonist, with high affinity at neuromuscular junctions, but molecular mechanisms by which it elicits toxicological responses are not fully understood. To advance understanding of this cyanobacteria, proteomic characterization (DIA shotgun proteomics) of two common fish models (zebrafish and fathead minnow) was performed following (±) anatoxin-a exposure. Specifically, proteome changes were identified and quantified in larval fish exposed for 96 h (0.01–3 mg/L (±) anatoxin-a and caffeine (a methodological positive control) with environmentally relevant treatment levels examined based on environmental exposure distributions of surface water data. Proteomic concentration - response relationships revealed 48 and 29 proteins with concentration - response relationships curves for zebrafish and fathead minnow, respectively. In contrast, the highest number of differentially expressed proteins (DEPs) varied between zebrafish (n = 145) and fathead minnow (n = 300), with only fatheads displaying DEPs at all treatment levels. For both species, genes associated with reproduction were significantly downregulated, with pathways analysis that broadly clustered genes into groups associated with DNA repair mechanisms. Importantly, significant differences in proteome response between the species was also observed, consistent with prior observations of differences in response using both behavioral assays and gene expression, adding further support to model specific differences in organismal sensitivity and/or response. When DEPs were read across from humans to zebrafish, disease ontology enrichment identified diseases associated with cognition and muscle weakness consistent with the prior literature. Our observations highlight limited knowledge of how (±) anatoxin-a, a commonly used synthetic racemate surrogate, elicits responses at a molecular level and advances its toxicological understanding.

Social inequalities, green and blue spaces and mental health in 6-12 years old children participating in the INMA cohort.

Availability of green and blue spaces in the area of residence has been related to various health outcomes during childhood, including mental health. These environmental exposures are not evenly distributed among socioeconomic groups, which may increase social inequalities in mental health. The mechanisms through which natural environments may promote mental health are numerous and diverse. This study aimed to explore 1) the potential associations of socioeconomic variables (SES and maternal education attainment) with mental health scores and residential greenness, blueness and NO2 metrics, and, 2) the association between greenness and blueness metrics and mental health scores of children in the Spanish INfancia y Medio Ambiente (INMA) birth cohort at two different time points. The study samples were composed of 1738 six-to eight-year-olds (49% female) and 1449 ten-to twelve-year-olds (living in Asturias, Gipuzkoa, Sabadell and Valencia, Spain. Individual Normalized Difference Vegetation Index (NDVI) values in 100-, 300- and 500-m buffers and availability of green and blue spaces >5000m2 in 300-m buffers were calculated using Geographic Information Systems software. Residential NO2 values were estimated using land use regression models. Internalizing, externalizing and total problems scores were obtained with the Strengths and Difficulties Questionnaire (SDQ). Linear and logistic mixed-effects models revealed unequal distribution of environmental exposures by SES and maternal education but did not show statistically significant associations between greenness and blueness metrics and mental health indicators. The protective effect of green and blue spaces on children's mental health could not be confirmed in this study and therefore further research is required.

Effects of agricultural land types on microplastic abundance: A nationwide meta-analysis in China

Microplastics (MPs) accumulation in agricultural land that possibly poses threats to food security and human health has recently attracted increasing attention. Land use type probably is a key factor that drives the contamination level of soil MPs. Nevertheless, few studies have performed large-scale systematic analysis of the effects in different agricultural land soils on the MPs abundance. In this study, we constructed a national MPs dataset comprising 321 observations from 28 articles, summarised the current status of microplastic pollution in five agricultural land types in China through meta-analysis, and investigated the effects and key factors of agricultural land types on microplastic abundance. The results showed that among the existing soil microplastic research, vegetable soils maintained a higher environmental exposure distribution than other agricultural lands, and with the most common trend being vegetable land > orchard land > cropland > grassland. By combining agricultural practices, demographic economic factors and geographical factors, a potential impact identification method based on subgroup analysis was established. The findings demonstrated that agricultural film mulch significantly increased soil MPs abundance, especially in orchards. Increased population and economy (carbon emissions and PM2.5 concentrations) add MPs abundance in all kinds of agricultural lands. And the significant changes of effect sizes in high-latitude and mid-altitude areas suggested that geographical space differences exerted a certain degree of impact on the soil distribution of MPs. By the proposed method, different levels of MPs risk areas in agricultural soils can be more reasonably and effectively identified, which will provide type-specific policies technical and theoretical support for the precise management of MPs in agricultural land soils.

Policy relevant health related liveability indicator datasets for addresses in Australia’s 21 largest cities

Measuring and monitoring the spatial distribution of liveability is crucial to ensure that implemented urban and transport planning decisions support health and wellbeing. Spatial liveability indicators can be used to ensure these decisions are effective, equitable and tracked across time. The 2018 Australian National Liveability Study datasets comprise a suite of policy-relevant health-related spatial indicators of local neighbourhood liveability and amenity access estimated for residential address points and administrative areas across Australia’s 21 most populous cities. The indicators and measures encompass access to community and health services, social infrastructure, employment, food, housing, public open space, transportation, walkability and overall liveability. This national ’baseline’ liveability indicators dataset for residential address points and areas can be further linked with surveys containing geocoded participant locations, as well as Census data for areas from the Australian Statistical Geography Standard. The datasets will be of interest to planners, policy makers and researchers interested in modelling and mapping the spatial distribution of urban environmental exposures and their relationship with health and other outcomes.

A novel procedure for predicting chronic toxicities and ecological risks of perfluorinated compounds in aquatic environment

Perfluorinated compounds (PFCs) can pose adverse effect on aquatic species and community structure. However, little is known about how the characteristics of molecules of PFCs affect their chronic toxic potencies to aquatic species, and the species sensitivity distributions (SSDs) and ecological risk assessments of PFCs are hampered by limited available data of chronic toxicity. In the present study, a novel procedure is proposed to obtain the ecological risk of PFCs using existing exposure concentrations of PFCs and SSDs integrated with the chronic toxicity prediction through robust QSAR models. The results showed that the energy of the lowest unoccupied molecular orbital (ELUMO) exhibited the strongest correlation with the chronic toxicities of 15 PFCs (R2 > 0.844, F > 16.206, p < 0.05). SSDs of 15 PFCs on eight species were first constructed, and the SSD fitting parameters were significantly correlated with ELUMO (R2 > 0.610, F > 19.471, p < 0.05). The QSAR-SSDs support the evaluation of hazardous criteria of PFCs for which data are lacking. Given environmental exposure distributions (EEDs) of the national presence of PFCs in aquatic systems in China, the QSAR-SSDs models allow the development of the ecological risk assessment for PFCs. This way, it was concluded that negligible environmental risk (defined as 5% of the species being potentially exposed to concentrations able to cause effects in < 5% of the case) could be expected from exposure to PFCs in surface waters in China. This method may be helpful for providing an evidence-based approach to guide the risk management for PFCs in aquatic environment.

Adopting a "Compound" Exposome Approach in Environmental Aging Biomarker Research: A Call to Action for Advancing Racial Health Equity.

Background:In June 2020, the National Academies of Sciences, Engineering, and Medicine hosted a virtual workshop focused on integrating the science of aging and environmental health research. The concurrent COVID-19 pandemic and national attention on racism exposed shortcomings in the environmental research field’s conceptualization and methodological use of race, which have subsequently hindered the ability of research to address racial health disparities. By the workshop’s conclusion, the authors deduced that the utility of environmental aging biomarkers—aging biomarkers shown to be specifically influenced by environmental exposures—would be greatly diminished if these biomarkers are developed absent of considerations of broader societal factors—like structural racism—that impinge on racial health equity.Objectives:The authors reached a post-workshop consensus recommendation: To advance racial health equity, a “compound” exposome approach should be widely adopted in environmental aging biomarker research. We present this recommendation here.Discussion:The authors believe that without explicit considerations of racial health equity, people in most need of the benefits afforded by a better understanding of the relationships between exposures and aging will be the least likely to receive them because biomarkers may not encompass cumulative impacts from their unique social and environmental stressors. Employing an exposome approach that allows for more comprehensive exposure–disease pathway characterization across broad domains, including the social exposome and neighborhood factors, is the first step. Exposome-centered study designs must then be supported with efforts aimed at increasing the recruitment and retention of racially diverse study populations and researchers and further “compounded” with strategies directed at improving the use and interpretation of race throughout the publication and dissemination process. This compound exposome approach maximizes the ability of our science to identify environmental aging biomarkers that explicate racial disparities in health and best positions the environmental research community to contribute to the elimination of racial health disparities. https://doi.org/10.1289/EHP8392

A probabilistic risk assessment of microplastics in soil ecosystems

Plastics have a variety of applications due to their versatility, relative cost, and strength-to-weight ratio, and resistance to degradation. As a result, plastic waste can be found in all corners of the Earth. A class of plastic contaminants that have received increasing attention in terms of their potential impact on ecosystems is microplastics (≤5 mm). The greatest attention to date has been on their potential effect in marine ecosystems. However, a growing number of studies are examining their potential impact on soil ecosystems. The data reported in the literature on the environmentally-relevant concentrations of microplastics in soils and the concentration of microplastics that causes an adverse effect in soil biota were used to perform a probabilistic risk assessment of microplastics to soil biota. An environmental exposure distribution was constructed from the concentrations of microplastics reported in soil in the literature. Species sensitivity distributions were constructed using concentration of microplastics in soil that had no adverse effect on soil species (NOEC) or the lowest concentrations that had an adverse effect on soil species (LOEC) reported in the literature. The 95th centile of the environmental exposure distribution (8147 microplastic particles per gram of soil) was greater than 22 and 28% of the species sensitivity distribution constructed using NOECs and LOECs, respectively. The assessment concluded that environmentally relevant concentrations of microplastics reported in the literature could pose a considerable risk to soil biota. It is also important to note that due to the continued production of large quantities of plastic and the persistence of microplastics in the environment, environmentally-relevant concentrations of microplastics in soil are likely to only rise.

High-Frequency Sampling of Small Streams in the Agroecosystems of Southwestern Ontario, Canada, to Characterize Pesticide Exposure and Associated Risk to Aquatic Life.

The temporal dynamics of pesticide concentrations in streams remains poorly characterized in southwestern Ontario, a region of the province where land use is dominated by agriculture. Understanding the magnitude and duration of pulsed exposures to pesticides in these small streams is critical when estimating the risk of pesticides to these aquatic ecosystems. The present study investigated the application of a high-frequency water sampling approach paired with the collection of flow data to characterize the pulsed exposure of pesticides to small streams in southwestern Ontario. Six sites along 2 different streams with different magnitudes of agricultural land use in their upstream catchments were sampled using half-day composite samples from July to October 2018 and from May to September 2019. A total of 1043 samples were collected over the 2 yr, of which 210 were analyzed. Samples for analysis were chosen based on flow, water level, and precipitation data. Liquid and gas chromatography coupled with tandem mass spectrometry was used to measure >500 pesticides in each water sample. A total of 35 different compounds were detected over the 6 sampling sites. For pesticides that were detected in >10% of water samples above the method quantification limit, a deterministic risk assessment using water quality guidelines and a probabilistic risk assessment using species sensitivity distributions were performed. The calculated hazard quotients showed that 2,4-D, atrazine, metolachlor, and metribuzin exceeded a level of concern of 1 at the highest concentrations detected. In all cases, hazard concentrations that would be protective of 95% of species from the species sensitivity distributions were greater than the 95th centile of the environmental exposure distributions, meaning that the risk from the pesticides was low. Environ Toxicol Chem 2020;39:2570-2587. © 2020 SETAC.

Global scanning of cylindrospermopsin: Critical review and analysis of aquatic occurrence, bioaccumulation, toxicity and health hazards

Cylindrospermopsin (CYN), a cyanotoxin produced by harmful algal blooms, has been reported worldwide; however, there remains limited understanding of its potential risks to surface water quality. In the present study, we critically reviewed available literature regarding the global occurrence, bioaccumulation, and toxicity of CYN in aquatic systems with a particular focus on freshwater. We subsequently developed environmental exposure distributions (EEDs) for CYN in surface waters and performed probabilistic environmental hazard assessments (PEHAs) using guideline values (GVs). PEHAs were performed by geographic region, type of aquatic system, and matrix. CYN occurrence was prevalent in North America, Europe, and Asia/Pacific, with lakes being the most common system. Many global whole water EEDs exceeded guideline values (GV) previously developed for drinking water (e.g., 0.5 μg L−1) and recreational water (e.g., 1 μg L−1). GV exceedances were higher in the Asia/Pacific region, and in rivers and reservoirs. Rivers in the Asia/Pacific region exceeded the lowest drinking water GV 73.2% of the time. However, lack of standardized protocols used for analyses was alarming, which warrants improvement in future studies. In addition, bioaccumulation of CYN has been reported in mollusks, crustaceans, and fish, but such exposure information remains limited. Though several publications have reported aquatic toxicity of CYN, there is limited chronic aquatic toxicity data, especially for higher trophic level organisms. Most aquatic toxicity studies have not employed standardized experimental designs, failed to analytically verify treatment levels, and did not report purity of CYN used for experiments; therefore, existing data are insufficient to derive water quality guidelines. Considering such elevated exceedances of CYN in global surface waters and limited aquatic bioaccumulation and toxicity data, further aquatic monitoring, environmental fate and mechanistic toxicology studies are warranted to robustly assess and manage water quality risks to public health and the environment.

Distribution and ecological risk of neonicotinoid insecticides in sediment in South China: Impact of regional characteristics and chemical properties

Neonicotinoid insecticides have been frequently detected in surface water due to extensive use worldwide, however, little information is available for the regional characteristics and ecological risk of neonicotinoids in sediment. In the current study, six neonicotinoids were analyzed in 58 sediment samples from agricultural (vegetable and rice planting) and urban areas in South China. Neonicotinoids were ubiquitous in the sediments, with maximum, mean and median concentrations of 23.8, 4.21 and 2.73 ng·g−1 dry weight, respectively. Neonicotinoids were detected more often and at higher concentrations in vegetable planting and urban areas while clothianidin and imidacloprid dominated neonicotinoid composition in the rice-planting area. Multiple correspondence analysis showed the distribution of sediment-bound neonicotinoids were significantly affected by crop type, distance to the source, and physicochemical properties of neonicotinoids. While more hydrophilic neonicotinoids tended to migrate to the streams, those with log Kow > 0 are usually retained in the ditches near the treated fields. Neonicotinoids with shorter half-lives (acetamiprid and thiacloprid) were detected more frequently in vegetable planting areas, yet more persistent imidacloprid and clothianidin were more likely to be detected in rice planting areas. It was in accordance with application patterns of neonicotinoids in different crops. Environmental exposure distributions indicated that sediment-bound neonicotinoids, except for thiacloprid, posed considerable risk to aquatic invertebrates, which are important for ecological functioning of aquatic ecosystems, calling for better measures to control and manage of neonicotinoid risks.

Social inequalities in environmental noise exposure

Environmental noise is an important public health problem, being among the top environmental risks to health. The burden of noise exposure seems to be unequally distributed in societies. Up to now there is fragmentary evidence regarding which social groups are most affected. The aim of this review was to systematically assess published evidence on social inequalities in environmental noise exposure in the WHO European Region, taking different sociodemographic and socioeconomic dimensions as well as subjective and objective measures of environmental noise exposure into account. Articles published in English in a peer reviewed journal between 2010 and 2017 were included in the review. Eight studies were finally included in the review, four of them analysed aggregated data and four analysed individual data. Though results of social inequalities in noise exposures were mixed between and within studies, there was a trend that studies using indicators of material deprivation and deprivation indices showed higher environmental noise exposures in groups with lower socioeconomic position. More research on the social distribution of environmental noise exposure on a small spatial scale is needed, taking into account aspects of vulnerability and procedural justice.

Global scanning of anatoxins in aquatic systems: environment and health hazards, and research needs

Surface water contamination from the neurotoxic cyanotoxin anatoxin-a and its analogues present risks to global public health and the environment. Understanding aquatic hazards is critical for cyanobacterial blooms increasing in magnitude, frequency and duration. We examined published data to identify exceedances of guideline values (GVs) globally in various aquatic systems to understand hazards when exposure occurs. Environmental exposure distributions of surface water data (intra- and extracellular toxins) from recreational and potable source waters exceeded common GVs of 0.1, 1 and 300µgL–1 when blooms occur 79.62, 48.37 and 1.42% of the time respectively. In total, 66% of occurrences were from lacustrine ecosystems compared with reservoir, river, coastal and other systems, with almost all data from Asia–Pacific, Europe and North America, highlighting the need for more monitoring efforts in diverse systems and in developing regions. Reservoirs had greatest exceedances of the highest GV compared with other systems, especially in Europe, where an exceedance of 19.92% was observed. Aquatic toxicity and bioaccumulation data were examined and compared to these environmentally relevant concentrations, though a lack of high-quality data highlights major research needs. This study further identifies the utility of probabilistic cyanotoxins assessments to support identification of where environmental monitoring and research may be more effectively focused.

Assessment of risk to hoary squash bees (Peponapis pruinosa) and other ground-nesting bees from systemic insecticides in agricultural soil

Using the hoary squash bee (Peponapis pruinosa) as a model, we provide the first probabilistic risk assessment of exposure to systemic insecticides in soil for ground-nesting bees. To assess risk in acute and chronic exposure scenarios in Cucurbita and field crops, concentrations of clothianidin, thiamethoxam and imidacloprid (neonicotinoids) and chlorantraniliprole (anthranilic diamide) in cropped soil were plotted to produce an environmental exposure distribution for each insecticide. The probability of exceedance of several exposure endpoints (LC50s) was compared to an acceptable risk threshold (5%). In Cucurbita crops, under acute exposure, risk to hoary squash bees was below 5% for honey bee LC50s for all residues evaluated but exceeded 5% for clothianidin and imidacloprid using a solitary bee LC50. For Cucurbita crops in the chronic exposure scenario, exposure risks for clothianidin and imidacloprid exceeded 5% for all endpoints, and exposure risk for chlorantraniliprole was below 5% for all endpoints. In field crops, risk to ground-nesting bees was high from clothianidin in all exposure scenarios and high for thiamethoxam and imidacloprid under chronic exposure scenarios. Risk assessments for ground-nesting bees should include exposure impacts from pesticides in soil and could use the hoary squash bee as an ecotoxicology model.

Effect of Microcystis aeruginosa-Associated Microcystin-LR on the Survival of 2 Life Stages of Freshwater Mussel (Lampsilis siliquoidea).

Microcystin-LR is a toxin commonly produced by the cyanobacterium Microcystis aeruginosa. It is present in harmful algal blooms and is a concern for both human and environmental health in Canadian freshwater systems. Previous studies have investigated the toxicity of microcystin-LR to other organisms such as fish; however, it is important to assess its toxicity to native freshwater mussels (family Unionidae), which are considered imperiled. The present study examined the toxicity of microcystin-LR to fatmucket mussels (Lampsilis siliquoidea) at 2 different life stages. Juvenile mussels were exposed to microcystin-LR in a 28-d chronic test, and glochidia underwent a 72-h acute toxicity test. There was no significant relationship between glochidia viability and microcystin-LR concentration. The median lethal concentration (LC50) value for juvenile mussels after 28 d of exposure was 2.1 µg/L. To determine the environmental relevance of the observed toxicity, an environmental exposure distribution was created using Canadian and Canadian-US Great Lakes microcystin measurements. The 28-d LC50 value (2.1 µg/L) was greater than those values that occurred in the environment 95% of the time; however, the LC10 (0.45 µg/L) and LC25 (0.97 μg/L) values were not greater than the measured microcystin environmental values. This finding indicates that microcystins may exert toxic effects on juvenile mussels at environmentally relevant concentrations. Further investigation should be considered in terms of prolonged exposure to persistent microcystin-LR, and toxicity to sensitive species at different life stages. Environ Toxicol Chem 2019;38:2137-2144. © 2019 SETAC.

Social Inequalities in Environmental Noise Exposure: A Review of Evidence in the WHO European Region.

Environmental noise is an important public health problem, being among the top environmental risks to health. The burden of noise exposure seems to be unequally distributed in societies. Up to now there is fragmentary evidence regarding which social groups are most affected. The aim of this review was to systematically assess published evidence on social inequalities in environmental noise exposure in the WHO European Region, taking different sociodemographic and socioeconomic dimensions as well as subjective and objective measures of environmental noise exposure into account. Articles published in English in a peer reviewed journal between 2010 and 2017 were included in the review. Eight studies were finally included in the review, four of them analysed aggregated data and four analysed individual data. Though results of social inequalities in noise exposures were mixed between and within studies, there was a trend that studies using indicators of material deprivation and deprivation indices showed higher environmental noise exposures in groups with lower socioeconomic position. More research on the social distribution of environmental noise exposure on a small spatial scale is needed, taking into account aspects of vulnerability and procedural justice.

Occurrence and risk of neonicotinoid insecticides in surface water in a rapidly developing region: Application of polar organic chemical integrative samplers

Extensive use of neonicotinoid insecticides (NNIs) worldwide calls for further knowledge on their environmental occurrence and risk. The present study highlighted the need for more research on long-term exposure of NNIs in aquatic environment, which is important but remains elusive. Time weighted average concentrations of five commonly used NNIs in urban waterways of Guangzhou, China were measured using newly developed polar organic chemical integrative samplers (POCIS). Acetamiprid (from 18.8 ± 1.9 to 157 ± 31 ng/L; mean ± standard deviation), clothianidin (from 14.8 ± 3.7 to 47.6 ± 10.0 ng/L) and imidacloprid (from 32.9 ± 11.6 to 249 ± 19 ng/L) were detectable in all samples. Thiamethoxam was found at 71.4% of the 21 sampling sites (from not detected to 52.4 ± 9.4 ng/L), while thiacloprid was not detected at any site. Vegetable planting and sewage effluent were the main sources of NNIs in surface water in Guangzhou. Probabilistic environmental exposure distributions were subsequently constructed using the measured concentrations and the exceedances of predicted environmental concentrations of NNI to ecological thresholds were assessed. In Guangzhou, 63.5%, 16.2%, 87.8% and 17.2% of acetamiprid, clothianidin, imidacloprid and thiamethoxam, respectively, exceeded an interim chronic threshold of 35 ng/L for NNIs. Further risk assessment and control measures for the use of NNIs are advocated for protecting the integrity of aquatic ecosystems.

Does the presence of caffeine in the marine environment represent an environmental risk? A regional and global study

Caffeine is an emerging contaminant considered to be an indicator of human contamination that has been widely detected in various aquatic systems, especially in continental waters. Nevertheless, the extent of its possible environmental impact is yet to be determined. This study determined the presence of caffeine, and evaluated the environmental hazard posed by this substance, in the “Rías Gallegas”, a series of costal inlets in north-west Spain which are of great ecological value and in which fishing and bivalve farming, are a significant source of income. Caffeine was found to be present at concentrations higher than the limit of quantification (LOQ=3.07ngL−1) in 15 of the 23 samples analysed, with the highest seawater concentration being 857ngL−1 (the highest measured in seawater in Spain). Six out of 22 seawater samples resulted in a hazard quotient (HQ) from chronic exposure higher than 1 with the highest being 17.14, indicating a high probability of adverse effects in the aquatic environment. Environmental Exposure Distributions (EEDs) generated from a literature review of caffeine levels reported previously in four out of the five continents, showed that 28% of all seawater samples, and 69% of all estuary water samples where caffeine has ever been measured resulted in HQ>1 for chronic exposure. Further studies into the potential adverse effects that may arise from exposure to caffeine in aquatic systems are still required. Indeed, the need to gain a more in-depth understanding of the long-term ecotoxicological effects of caffeine is essential to ensure the quality of our health and environment.

Caffeine and paraxanthine in aquatic systems: Global exposure distributions and probabilistic risk assessment

This study presents one of the most complete applications of probabilistic methodologies to the risk assessment of emerging contaminants. Perhaps the most data-rich of these compounds, caffeine, as well as its main metabolite (paraxanthine), were selected for this study. Information for a total of 29,132 individual caffeine and 7442 paraxanthine samples was compiled, including samples where the compounds were not detected. The inclusion of non-detect samples (as censored data) in the estimation of environmental exposure distributions (EEDs) allowed for a realistic characterization of the global presence of these compounds in aquatic systems. EEDs were compared to species sensitivity distributions (SSDs), when possible, in order to calculate joint probability curves (JPCs) to describe the risk to aquatic organisms. This way, it was determined that unacceptable environmental risk (defined as 5% of the species being potentially exposed to concentrations able to cause effects in>5% of the cases) could be expected from chronic exposure to caffeine from effluent (28.4% of the cases), surface water (6.7% of the cases) and estuary water (5.4% of the cases). Probability of exceedance of acute predicted no-effect concentrations (PNECs) for paraxanthine were higher than 5% for all assessed matrices except for drinking water and ground water, however no experimental effects data was available for paraxanthine, resulting in a precautionary deterministic hazard assessment for this compound. Given the chemical similarities between both compounds, real effect thresholds, and thus risk, for paraxanthine, would be expected to be close to those observed for caffeine. Negligible Human health risk from exposure to caffeine via drinking or groundwater is expected from the compiled data.

Global scanning of antihistamines in the environment: Analysis of occurrence and hazards in aquatic systems

Concentration of the global population is increasingly occurring in megacities and other developing regions, where access to medicines is increasing more rapidly than waste management systems are implemented. Because freshwater and coastal systems are influenced by wastewater effluent discharges of differential quality, exposures in aquatic systems must be considered. Here, we performed a global scanning assessment of antihistamines (AHs), a common class of medicines, in surface waters and effluents. Antihistamines were identified, literature occurrence and ecotoxicology data on AHs collated, therapeutic hazard values (THVs) calculated, and environmental exposure distributions (EEDs) of AHs compared to ecotoxicity thresholds and drug specific THVs to estimate hazards in surface waters and effluents. Literature searches of 62 different AHs in environmental matrices identified 111 unique occurrence publications of 24 specific AHs, largely from Asia-Pacific, Europe, and North America. However, the majority of surface water (63%) and effluent (85%) observations were from Europe and North America, which highlights relatively limited information from many regions, including developing countries and rapidly urbanizing areas in Africa, Latin America and Asia. Less than 10% of all observations were for estuarine or marine systems, though the majority of human populations reside close to coastal habitats. EED 5th and 95th centiles for all AHs were 2 and 212ng/L in surface water, 5 and 1308ng/L in effluent and 6 and 4287ng/L in influent, respectively. Unfortunately, global hazards and risks of AHs to non-target species remain poorly understood. However, loratadine observations in surface waters exceeded a THV without an uncertainty factor 40% of the time, indicating future research is needed to understand aquatic toxicology, hazards and risks associated with this AH. This unique global scanning study further illustrates the utility of global assessments of pharmaceuticals and other contaminants to identify chemicals requiring toxicology study and regions where environmental monitoring, assessment and management efforts appear limited and necessary.