Trophic magnification of legacy persistent organic pollutants in an urban terrestrial food web

Biomagnification of persistent organic pollutants (POPs) in detritivorous, phytophagous, and predatory invertebrates: How POPs enter terrestrial food web?

Invertebrates are primary contributors to fluxes of nutrients, energy, and contaminants in terrestrial food webs, but the trophodynamic of contaminants in invertebrate food chains is not fully understood. In this study, occurrence and biomagnification of persistent organic pollutants (POPs) were assessed in detritivorous, phytophagous, and predatory invertebrate food chains. Detritivorous species (earthworm and dung beetle) have higher concentrations of POPs than other species. Different composition patterns and biomagnification factors (BMFs) of POPs were observed for invertebrate species. Negative correlations were found between BMFs and log KOW of POPs for detritivorous and most phytophagous species. In contrast, parabolic relationships between BMFs and log KOW were observed in snails and predatory species, possibly attributed to the efficient digestion and absorption of diet and POPs for them. Bioenergetic characteristics are indicative of the biomagnification potential of POPs in terrestrial wildlife, as suggested by the significant and positive correlation between basal metabolic rates (BMRs) and BMFs of BDE 153 for invertebrates, amphibians, reptiles, birds, and mammals. The estimations of dietary exposure suggest that the terrestrial predators, especially feeding on the underground invertebrates, could be exposed to high level POPs from invertebrates.

Advancing exposure assessment approaches to improve wildlife risk assessment

The exposure assessment component of a Wildlife Ecological Risk Assessment aims to estimate the magnitude, frequency, and duration of exposure to a chemical or environmental contaminant, along with characteristics of the exposed population. This can be challenging in wildlife as there is often high uncertainty and error caused by broad-based, interspecific extrapolation and assumptions often because of a lack of data. Both the US Environmental Protection Agency (USEPA) and European Food Safety Authority (EFSA) have broadly directed exposure assessments to include estimates of the quantity (dose or concentration), frequency, and duration of exposure to a contaminant of interest while considering "all relevant factors." This ambiguity in the inclusion or exclusion of specific factors (e.g., individual and species-specific biology, diet, or proportion time in treated or contaminated area) can significantly influence the overall risk characterization. In this review, we identify four discrete categories of complexity that should be considered in an exposure assessment-chemical, environmental, organismal, and ecological. These may require more data, but a degree of inclusion at all stages of the risk assessment is critical to moving beyond screening-level methods that have a high degree of uncertainty and suffer from conservatism and a lack of realism. We demonstrate that there are many existing and emerging scientific tools and cross-cutting solutions for tackling exposure complexity. To foster greater application of these methods in wildlife exposure assessments, we present a new framework for risk assessors to construct an "exposure matrix." Using three case studies, we illustrate how the matrix can better inform, integrate, and more transparently communicate the important elements of complexity and realism in exposure assessments for wildlife. Modernizing wildlife exposure assessments is long overdue and will require improved collaboration, data sharing, application of standardized exposure scenarios, better communication of assumptions and uncertainty, and postregulatory tracking. Integr Environ Assess Manag 2024;20:674-698. © 2023 SETAC.

New insights from an eight-year study on per- and polyfluoroalkyl substances in an urban terrestrial ecosystem

Per- and polyfluoroalkyl substances (PFAS) were analysed in a high number of terrestrial samples of soil, earthworm, bird eggs and liver from red fox and brown rat in an urban area in Norway from 2013 to 2020. PFOS and the long chain PFCAs were the most dominating compounds in all samples, proving their ubiquitous distribution. Other less studied compounds such as 6:2 FTS were first and foremost detected in earthworm. 8:2 FTS was found in many samples of fieldfare egg, sparrowhawk egg and earthworm, where the eggs had highest concentrations. Highest concentrations for both 6:2 FTS and 8:2 FTS were detected at present and former industry areas. FOSA was detected in many samples of the species with highest concentrations in red fox liver and brown rat liver of 3.3 and 5.5 ng/g ww. PFAS concentrations from the urban area were significantly higher than from background areas indicating that some of the species can be suitable as markers for PFAS emissions in an urban environment. Fieldfare eggs had surprisingly high concentrations of PFOS and PFCA concentrations from areas known to be or have been influenced by industry. Biota-soil-accumulation factor and magnification calculations indicate accumulation and magnification potential for several PFAS. Earthworm and fieldfare egg had average concentrations above the Canadian and European thresholds in diet for avian wildlife and predators. For earthworms, 18 % of the samples exceeded the European threshold (33 ng/g ww) of PFOS in prey for predators, and for fieldfare eggs, 35 % of the samples were above the same threshold. None of the soil samples exceeded a proposed PNEC of PFOS for soil living organisms of 373 ng/g dw.

Methods for assessing the bioaccumulation of hydrocarbons and related substances in terrestrial organisms: A critical review

This study investigates and reviews methods for the assessment of the terrestrial bioaccumulation potential of hydrocarbons and related organic substances. The study concludes that the unitless biomagnification factor (BMF) and/or the trophic magnification factor (TMF) are appropriate, practical, and thermodynamically meaningful metrics for identifying bioaccumulative substances in terrestrial food chains. The study shows that various methods, including physical-chemical properties like the KOA and KOW , in vitro biotransformation assays, quantitative structure-activity relationships, in vivo pharmacokinetic and dietary bioaccumulation tests, and field-based trophic magnification studies, can inform on whether a substance has the potential to biomagnify in a terrestrial food chain as defined by a unitless BMF exceeding 1. The study further illustrates how these methods can be arranged in a four-tier evaluation scheme for the purpose of screening assessments that aim to minimize effort and costs and expediate bioaccumulation assessment of the vast numbers of organic substances in commerce, identifies knowledge gaps, and provides recommendations for further research to improve bioaccumulation assessment. Integr Environ Assess Manag 2023;19:1433-1456. © 2023 The Authors. Integrated Environmental Assessment and Management published by Wiley Periodicals LLC on behalf of Society of Environmental Toxicology & Chemistry (SETAC).

Trophic Transfer of Halogenated Organic Pollutants in a Wetland Food Web: Insights from Compound-Specific Nitrogen Isotope of Amino Acids and Food Source Analysis

A trophic position (TP) model (TPmix model) that simultaneously considered trophic discrimination factor and βGlu/Phe variations was developed in this study and was first applied to investigate the trophic transfer of halogenated organic pollutants (HOPs) in wetland food webs. The TPmix model characterized the structure of the wetland food web more accurately and significantly improved the reliability of TMF compared to the TPbulk, TPAAs, and TPsimmr models, which were calculated based on the methods of stable nitrogen isotope analysis of bulk, traditional AAs-N-CSIA, and weighted βGlu/Phe, respectively. Food source analysis revealed three interlocking food webs (kingfisher, crab, and frogs) in this wetland. The highest HOP biomagnification capacities (TMFmix) were found in the kingfisher food web (0.24-82.0), followed by the frog (0.08-34.0) and crab (0.56-11.7) food webs. The parabolic trends of TMFmix across combinations of log KOW in the frog food web were distinct from those of aquatic food webs (kingfisher and crab), which may be related to differences in food web composition and HOP bioaccumulation behaviors between aquatic and terrestrial organisms. This study provides a new tool to accurately study the trophic transfer of contaminants in wetlands and terrestrial food webs with diverse species and complex feeding relationships.

Developing Methods for Assessing Trophic Magnification of Perfluoroalkyl Substances within an Urban Terrestrial Avian Food Web

We investigated the trophic magnification potential of perfluoroalkyl substances (PFAS) in a terrestrial food web by using a chemical activity-based approach, which involved normalizing concentrations of PFAS in biota to their relative biochemical composition in order to provide a thermodynamically accurate basis for comparing concentrations of PFAS in biota. Samples of hawk eggs, songbird tissues, and invertebrates were collected and analyzed for concentrations of 18 perfluoroalkyl acids (PFAAs) and for polar lipid, neutral lipid, total protein, albumin, and water content. Estimated mass fractions of PFCA C8-C11 and PFSA C4-C8 predominantly occurred in albumin within biota samples from the food web with smaller estimated fractions in polar lipids > structural proteins > neutral lipids and insignificant amounts in water. Estimated mass fractions of longer-chained PFAS (i.e., C12-C16) mainly occurred in polar lipids with smaller estimated fractions in albumin > structural proteins > neutral lipids > and water. Chemical activity-based TMFs indicated that PFNA, PFDA, PFUdA, PFDoA, PFTrDA, PFTeDA, PFOS, and PFDS biomagnified in the food web; PFOA, PFHxDA, and PFHxS did not appear to biomagnify; and PFBS biodiluted. Chemical activity-based TMFs for PFCA C8-C11 and PFSA C4-C8 were in good agreement with corresponding TMFs derived with concentrations normalized to only total protein in biota, suggesting that concentrations normalized to total protein may be appropriate proxies of chemical activity-based TMFs for PFAS, which predominantly partition to albumin. Similarly, TMFs derived with concentrations normalized to albumin may be suitable proxies of chemical activity-based TMFs for longer-chained PFAS, which predominantly partition to polar lipids.

Distinct biomagnification of chlorinated persistent organic pollutants in adjacent aquatic and terrestrial food webs

Biomagnification of persistent organic pollutants (POPs) in food webs has been studied for many years. However, the different processes and influencing factors in biomagnification of POPs in aquatic and terrestrial food webs still need clarification. Polychlorinated biphenyls (PCBs) and short-chain chlorinated paraffins (SCCPs) were measured in organisms from adjacent terrestrial and aquatic environment in this study. The median levels of PCBs in terrestrial and aquatic organisms were 21.7-138 ng/g lw and 37.1-149 ng/g lw, respectively. SCCP concentrations were 18.6-87.3 μg/g lw and 21.4-93.9 μg/g lw in terrestrial and aquatic organisms, respectively. Biomagnification factors (BMFs) of PCBs increased with higher log K_OW in all food chains. BMFs of SCCPs were negatively correlated with log K_OW in aquatic food chains, but positively correlated with log K_OW in terrestrial food chains. The terrestrial food web had similar trophic magnification factors (TMFs) of PCBs, and higher TMFs of SCCPs than the aquatic food web. Biomagnification of PCBs was consistent in aquatic and terrestrial food webs, while SCCPs had higher biomagnification potential in terrestrial than aquatic organisms. The distinct biomagnification of SCCPs was affected by the respiratory elimination for terrestrial organisms, the different metabolism rates in various species, and more homotherms in terrestrial food webs. Fugacity model can well predict levels of less hydrophobic chemicals, and warrants more precise toxicokinetic data of SCCPs.

Chemicals/materials of emerging concern in farmlands: sources, crop uptake and potential human health risks

Certain chemicals/materials that are contaminants of emerging concern (CECs) have been widely detected in water bodies and terrestrial systems worldwide while other CECs occur at undetectable concentrations. The primary sources of CECs in farmlands are agricultural inputs, such as wastewater, biosolids, sewage sludge, and agricultural mulching films. The percent increase in cropland area during 1950-2016 was 30 and the rise in land use for food crops during 1960-2018 was 100-500%, implying that there could be a significant CEC burden in farmlands in the future. In fact, the alarming concentrations (μg kg^-1) of certain CECs such as PBDEs, PAEs, and PFOS that occur in farmlands are 383, 35 400 and 483, respectively. Also, metal nanoparticles are reported even at the mg kg^-1 level. Chronic root accumulation followed by translocation of CECs into plants results in their detectable concentrations in the final plant produce. Thus, there is a continuous flow of CECs from farmlands to agricultural produce, causing a serious threat to the terrestrial food chain. Consequently, CECs find their way to the human body directly through CEC-laden plant produce or indirectly via the meat of grazing animals. Thus, human health could be at the most critical risk since several CECs have been shown to cause cancers, disruption of endocrine and cognitive systems, maternal-foetal transfer, neurotoxicity, and genotoxicity. Overall, this comprehensive review provides updated information on contamination of chemicals/materials of concern in farmlands globally, sources for their entry, uptake by crop plants, and their likely impact on the terrestrial food chain and human health.

Toxicological effects, environmental behaviors and remediation technologies of herbicide atrazine in soil and sediment: A comprehensive review

Atrazine has become one of the most popular applied triazine herbicides in the world due to its high herbicidal efficiency and low price. With its large-dosage and long-term use on a global scale, atrazine can cause widespread and persistent contamination of soil and sediment. This review systematically evaluates the toxicological effects, environmental risks, environmental behaviors (adsorption, transport and transformation, and bioaccumulation) of atrazine, and the remediation technologies of atrazine-contaminated soil and sediment. For the adsorption behavior of atrazine on soil and sediment, the organic matter content plays an extremely important role in the adsorption process. Various models and equations such as the multi-media fugacity model and solute transport model are used to analyze the migration and transformation process of atrazine in soil and sediment. It is worth noting that certain transformation products of atrazine in the environment even have stronger toxicity and mobility than its parent. Among various remediation technologies, the combination of microbial remediation and phytoremediation for atrazine-contaminated soil and sediment has wide application prospects. Although other remediation technologies such as advanced oxidation processes (AOPs) can also efficiently remove atrazine from soil, some potential problems still need to be further clarified. Finally, some related challenges and prospects are proposed.

Highly contaminated river otters (Lontra canadensis) are effective biomonitors of environmental pollutant exposure

River otters (Lontra canadensis) are apex predators that bioaccumulate contaminants via their diet, potentially serving as biomonitors of watershed health. They reside throughout the Green-Duwamish River, WA (USA), a watershed encompassing an extreme urbanization gradient, including a US Superfund site slated for a 17-year remediation. The objectives of this study were to document baseline contaminant levels in river otters, assess otters' utility as top trophic-level biomonitors of contaminant exposure, and evaluate the potential for health impacts on this species. We measured a suite of contaminants of concern, lipid content, nitrogen stable isotopes (δ¹⁵N), and microsatellite DNA markers in 69 otter scat samples collected from twelve sites. Landcover characteristics were used to group sampling sites into industrial (Superfund site), suburban, and rural development zones. Concentrations of polychlorinated biphenyls (PCBs), polybrominated diphenyl ether flame-retardants (PBDEs), dichlorodiphenyl-trichloroethane and its metabolites (DDTs), and polycyclic aromatic hydrocarbons (PAHs) increased significantly with increasing urbanization, and were best predicted by models that included development zone, suggesting that river otters are effective biomonitors, as defined in this study. Diet also played an important role, with lipid content, δ¹⁵N or both included in all best models. We recommend river otter scat be included in evaluating restoration efforts in this Superfund site, and as a potentially useful monitoring tool wherever otters are found. We also report ΣPCB and ΣPAH exposures among the highest published for wild river otters, with almost 70% of samples in the Superfund site exceeding established levels of concern.

Glyphosate, AMPA and glufosinate in soils and earthworms in a French arable landscape

Although Glyphosate-based herbicides are often marketed as environmentally friendly and easily biodegradable, its bioavailability and risks to wildlife raise significant concerns. Among non-target organisms, earthworms which live in close contact with the soil can be directly exposed to pesticides and harmed. We investigated soil contamination and the exposure of earthworms to glyphosate, its metabolite AMPA, and glufosinate in an arable landscape in France, both in treated (i.e. temporary grasslands and cereal fields under conventional farming), and nontreated habitats (i.e. hedgerows, permanent grasslands and cereal fields under organic farming) (n = 120 sampling sites in total). Glyphosate, AMPA and glufosinate were detected in 88%, 58% and 35% of the soil samples, and in 74%, 38% and 12% of the earthworm samples, respectively. For both glyphosate and AMPA, concentrations in soils were at least 10 times lower than predicted environmental concentrations. However, the maximum glyphosate soil concentration measured (i.e., 0.598 mg kg-1) was only 2 to 3 times lower than the concentrations revealed to affect earthworms (survival and avoidance) in the literature. These compounds were found both in conventional and organic farming fields, thus supporting a recent study, and for the first time they were detected in hedgerows and grasslands. However, glyphosate and AMPA were more frequently detected in soils from cereal fields and hedgerows than in grasslands, and median concentrations measured in soils from cereal fields were significantly higher than in the two other habitats. Bioaccumulation of glyphosate and AMPA in earthworms was higher than expected according to the properties of the molecules. Our findings raised issues about the high occurrence of glyphosate and AMPA in soils from cropped and more natural areas in arable landscapes. They also highlight the potential for transfer of these molecules in terrestrial food webs as earthworms are prey for numerous animals.

Specific-accumulation and trophic transfer of UV filters and stabilizers in marine food web

The occurrence and distribution of benzotriazole UV stabilizers (BUVs) and UV filters in marine environments (sediment and seawater) and 20 biota species in the South Korea were investigated to assess their transfer through the marine food web. The total concentrations in the seawater samples were 4.73-8.60 ng/L for BUVs and 1.20-4.88 ng/L for UV filters; while, the total concentrations in the sediment samples were 0.581-6.62 ng/g dw for BUVs and 1.05-6.79 ng/g dw for UV filters, respectively. The total concentrations of BUVs and UV filters were a little higher in benthic invertebrates (BUVs: 131 ng/g lipid weight [lw], UV filters: 41.7 ng/g lw) than fish (BUVs: 99.2 ng/g lw, UV filters: 28.0 ng/g lw) but there were no statistical differences (Mann-Whitney U test, p > 0.05). UV-326 was dominant (fish: 37.9%, benthic invertebrate: 48.7%) of the total BUVs. While, benzophenone-3 (fish: 34.1%, benthic invertebrate: 40.8%) and ethylhexyl methoxy cinnamate (fish: 41.0%, benthic invertebrate: 37.8%) were the dominant UV filters. The bioaccumulation factor and trophic magnification factor indicated that UV-326 can both bioaccumulate and biomagnify (bioaccumulation factor >5000 and biota-sediment accumulation and trophic magnification factors >1). Several other BUVs were found to be able to either bioaccumulate (UV-320, UV-P, UV-329, and UV-234) or biomagnify (UV-327 and UV-928). Most of the analyzed UV filters were found not to be likely to bioaccumulate.

Poisoned chalice: Use of transformed landscapes associated with increased persistent organic pollutant concentrations and potential immune effects for an adaptable carnivore

Wildlife around cities bioaccumulate multiple harmful environmental pollutants associated with human activities. Exposure severity can vary based on foraging behaviour and habitat use, which can be examined to elucidate exposure pathways. Carnivores can play vital roles in ecosystem stability but are particularly vulnerable to bioaccumulation of pollutants. Understanding the spatial and dietary predictors of these contaminants can inform pollutant control, and carnivores, at the top of food webs, can act as useful indicator species. We test for exposure to toxic organochlorines (OCs), including dichloro-diphenyl-trichloroethane (DDT) and polychlorinated biphenyls (PCBs), in a medium-sized felid, the caracal (Caracal caracal), across the peri-urban and agricultural landscapes of the city of Cape Town, South Africa. Concentrations in both blood (n = 69) and adipose tissue (n = 25) were analysed along with detailed spatial, dietary, demographic, and physiological data to assess OC sources and exposure risk. The analysis revealed widespread exposure of Cape Town's caracals to organochlorines: detection rate was 100% for PCBs and 83% for DDTs in blood, and 100% for both compounds in adipose. Caracals using human-transformed areas, such as vineyards and areas with higher human population and electrical transformer density, as well as wetland areas, had higher organochlorine burdens. These landscapes were also highly selected foraging areas, suggesting caracals are drawn into areas that co-incidentally increase their risk of exposure to these pollutants. Further, biomagnification potential was higher in individuals feeding on higher trophic level prey and on exotic prey. These findings point to bioaccumulation of OC toxicants and widespread exposure across local food webs. Additionally, we report possible physiological effects of exposure, including elevated white blood cell and platelet count, suggesting a degree of immunological response that may increase disease susceptibility. Cape Town's urban fringes likely represent a source of toxic chemicals for wildlife and require focused attention and action to ensure persistence of this adaptable mesocarnivore.

Environmental fate and trophic transfer of synthetic musk compounds and siloxanes in Geum River, Korea: Compound-specific nitrogen isotope analysis of amino acids for accurate trophic position estimation

Despite the extensive usage of synthetic musk compounds (SMCs) and siloxanes in various personal care products (PCPs), trophic magnification of such chemicals in aquatic environments remains unexplored. In June and September 2020, eleven SMCs and nineteen siloxanes were measured in water, sediments, and biota. Samples were collected from two sites where levels were expected to be influenced by the distance from the wastewater treatment plant (WWTP) in the Geum River, Republic of Korea, were expected. High concentrations of SMCs and siloxanes entered through WWTP were measured in water, sediment, and biota at the both sites and both seasons. The δ¹⁵N of amino acids provided a high-resolution food web and accurate trophic position (TP), which is an important factor for determining the trophic magnification factor (TMF). Among 24 TMFs, 19 of them were <1, ranging 0.7-0.8 for 1,3,4,6,7,8‑hexahydro‑4,6,6,7,8,8‑hexamethyl‑cyclopenta‑γ‑2‑benzopyran (HHCB), 0.6-0.8 for 6-Acetyl-1,1,2,4,4,7-hexamethyltetralin (AHTN), 0.7-0.8 for 4-tert-Butyl-3,5-dinitro-2,6-dimethylacetophenone (MK), 0.7-0.9 for octamethylcyclotetrasiloxane (D4), 0.1-0.4 for decamethylcyclopentasiloxane (D5), and 0.04-0.8 for dodecamethylcyclohexasiloxane (D6), and the remaining ones including HHCB, AHTN, MK, and D4 showed values close to 1 or slightly higher (TMF range: 1.0-2.3) indicating no or a little trophic magnification. The TMFs of these compounds were constant across sites and seasons. The TMF values of PCPs might be affected by species specificity and food web structure rather than by chemical properties such as log K_ow, which describes a wide range of TMF values in various environments. This study presents valuable implications for assessing risk and managing environmental fate and trophic transfer of SMCs and siloxanes in freshwater environments.

Effect of different doses of the catecholamine epinephrine on antioxidant responses of larvae of the flesh fly Sarcophaga dux

The production and use of pharmaceutical products have increased over the past decades, and several are considered potential or proved hazardous wastes. When contaminating the environment, they can severely impact biodiversity. The catecholamine epinephrine (adrenaline) is no exception. Epinephrine can be administered as growth promoter in cattle, and is used for anaphylaxis treatment in human. While a range of studies has examined the effects of this catecholamine on vertebrate tissues, and evidenced that it can disrupt the oxidative stress status, the effects epinephrine could have on insects have remained poorly considered. Here, we examined the physiological effects of different concentrations (0, 25, 50, and 100 μg/mL) of epinephrine on larvae of the flesh fly Sarcophaga dux. Following experimental treatments, levels of H₂O₂, GSH, CAT, GPx, and CEH were measured from the fat body, cuticle, gut, and hemolymph of 3rd instars. Significant differences are reported for these physiological endpoints among the considered body compartments, and epinephrine concentrations. Epinephrine treatments did not increase reactive oxygen species production (H₂O₂ amounts), except for gut tissues. Increased levels of GSH suggest that epinephrine may have enhanced glucose metabolism and flux towards the pentose phosphate pathway, while reducing glutamine oxidation. CAT activity was slightly increased when the concentration of epinephrine was higher. The decreased GPx activity in the fat body was consistent with GSH variations. In sum, the injection of epinephrine seemed to elicit the antioxidant response in S. dux larvae, in turn attenuating ROS production.

Continuing Persistence and Biomagnification of DDT and Metabolites in Northern Temperate Fruit Orchard Avian Food Chains

Dichlorodiphenyldichlorethane (1,1,1-trichloro-2,2-bis(p-chlorophenyl)ethane) (DDT) is an organochlorine insecticide that was widely used from the late 1940s to the 1970s in fruit orchards in the Okanagan valley, British Columbia, Canada, and in the process, contaminated American robin (Turdus migratorius) food chains with the parent compound and metabolite dichlorodiphenyldichloroethylene (1,1-dichloro-2,2-bis(4-chlorophenyl)ethylene) (p,p'-DDE). In the present study, we examined the biological fate of these DDT-related (DDT-r) compounds at the same sites/region 26 years after a previous study by: (1) collecting soil, earthworms, and American robin eggs from apple, cherry, and pear orchards; (2) characterizing the diet and trophic positions of our biota using stable isotope analyses of δ¹³ C and δ¹⁵ N; and (3) estimating fugacity, biota-soil-accumulation factors (BSAFs), and biomagnification factors (BMFs). Mean p,p'-DDE concentrations (soil: 16.1 µg/g organic carbon-lipid equivalent; earthworms: 96.5 µg/g lipid equivalent; eggs: 568 µg/g lipid equivalent) revealed that contamination is present at elevated levels similar to the 1990s and our average soil DDE:DDT ratio of 1.42 confirmed that DDT is slowly degrading. American robins appeared to feed at similar trophic levels, but on different earthworms as indicated by egg stable isotope values (mean δ¹⁵ N = 8.51‰ ± 0.25; δ¹³ C = -26.32‰ ± 0.12). Lumbricidae and Aporrectodea worms shared a roughly similar δ¹⁵ N value; however, Lumbricus terrestris showed a markedly enriched δ¹³ C isotope, suggesting differences in organic matter consumption and physiological bioavailability. Biota-soil-accumulation factors and BMFs ranged over several orders of magnitude and were generally >1 and our fugacity analyses suggested that p,p'-DDE is still thermodynamically biomagnifying in American robin food chains. Our results demonstrate that DDT-r in fruit orchards remains bioavailable to free-living terrestrial passerines and may pose a potential toxicological risk. Environ Toxicol Chem 2021;40:3379-3391. © 2021 Her Majesty the Queen in Right of Canada. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC. Reproduced with the permission of the Minister of Environment and Climate Change Canada.

Acute toxicity and metabolism of pesticides in birds

The median lethal dose of pesticide in acute oral toxicity, used as a conservative index in avian risk assessment, varies by the species with differences of less than one order of magnitude, depending on body size, feeding habit, and metabolic enzyme activity. The profiles of pesticide metabolism in birds with characteristic conjugations are basically common to those in mammals, but less information is available on their relevant enzymes. The higher toxicity of some pesticides in birds than in mammals is due to the lower activity of avian metabolic enzymes. The bioaccumulation in birds is limited for very hydrophobic pesticides resistant to metabolic degradation. Several in silico approaches using the descriptors of a pesticide molecule have recently been employed to estimate the profiles of acute oral toxicity and bioaccumulation.

Fugacity-Based Trophic Magnification Factors Characterize Bioaccumulation of Cyclic Methyl Siloxanes within an Urban Terrestrial Avian Food Web: Importance of Organism Body Temperature and Composition

Trophic magnification of cyclic volatile methyl siloxanes (cVMS) in a terrestrial food web was investigated by measuring concentrations of octamethylcyclotetrasiloxane (D4), decamethylcyclopentasiloxane (D5), and dodecamethylcyclohexasiloxane (D6) and two reference chemicals within air and biota samples from an avian food web located in a mixed urban-agricultural landscape. Terrestrial trophic magnification factors derived from lipid normalized concentrations (TMF_Ls) for D5 and D6 were 0.94 (0.17 SE) and 1.1 (0.23 SE) and not statistically different from 1 (p > 0.05); however, the TMF_L of D4 was 0.62 (0.11 SE) and statistically less than 1 (p < 0.001). TMF_Ls of PCB-153 and p,p'-DDE were 5.6 (2.2 SE) and 6.1 (2.8 SE) and statistically greater than 1 (p < 0.001). TMF_Ls of cVMS in this terrestrial system were similar to those reported in aquatic systems. However, trophic magnification factors derived on a fugacity basis (TMF_Fs), which recognize differences in body temperature and lipid composition between organisms, were greater than corresponding TMF_Ls primarily because a temperature-induced thermodynamic biomagnification of hydrophobic chemicals occurs when endothermic organisms consume poikilothermic organisms. Therefore, we recommend that biomagnification studies of food webs including endothermic and poikilothermic organisms incorporate differences in body temperature and tissue composition to accurately characterize the biomagnification potential of chemicals.

Ten Bird Species, Six Guilds, Three Habitats, and 59 Chlorinated and Brominated POPs: What do 64 Eggs from the Largest Economic Hub of Southern Africa tell us?

There is little information on how POPs in eggs of different terrestrial, wetland, and aquatic birds share a large urban and rural landscape relate. We collected and analysed 64 eggs belonging to ten species of six feeding guilds, and compared organic chlorinated pesticide (OCP), polychlorinated biphenyl (PCB), and brominated flame retardants (BFR) residue concentrations and compositions. The eggs were collected in the Gauteng and the northern part of the Free Sate provinces of South Africa, one of the largest economic hubs in Africa. White-breasted Cormorant and African Darter eggs (at the highest trophic level as large aquatic predators) had the highest ΣOCP and ΣPCB concentrations, and Cape Sparrow and Southern Masked Weaver (granivores) eggs had the lowest concentrations, corresponding to the lowest trophic level in our collection. The highest percentage p,p'-DDT were in eggs of the terrestrial insectivore Crowned Lapwing (24%) and the scavenging African Sacred Ibis (17%), and the lowest in African Darter (1.0%) and White-breasted Cormorant (0.9%) eggs, suggesting that recency of DDT releases in a region cannot be gauged by this metric. African Sacred Ibis and Southern Masked Weaver eggs had the highest ΣBFR concentrations, with Crowned Lapwing, Cattle Egret, and White-breasted Cormorant eggs the least. Based on feeding guilds, the mean ΣPOP concentrations increased from granivore, aquatic omnivore, scavenger, terrestrial insectivore, small aquatic predator, to large aquatic predator. Mean ΣPOP concentrations in eggs increased from terrestrial, to wetland, to aquatic habitat birds. Interesting patterns were observed with multivariate analyses. There were no significant regressions between egg size and any summed POP classes. ΣBFR concentrations were not correlated with ΣOCPs or ΣPCBs. Eggshell thinning of African Darter eggs was associated with p,p'-DDE and ΣPCB suggesting risk. Other metrics also suggest risk. Therefore, different species of terrestrial and aquatic birds from the same area acquire and deposit POPs in different proportions and quantities in their eggs. Trophic levels and habitat explain the overall patterns, but detailed differences were found, some of which we are unable to explain. Based on POPs residues in terrestrial, wetland, and aquatic bird eggs, different POPs classes behave differently in a shared large inland industrial area, complicating deductions about POPs and associated risks based on one or few species.

Determination of organic pollutants in meconium and its relationship with fetal growth. Case control study in Northwestern Spain

OBJECTIVES

Antenatal exposure to organic pollutants is a leading public health problem. Meconium is a unique matrix to perform prenatal studies because it enables us to retrospectively evaluate fetal exposure accumulated during the second and third trimester. The aim of the present study was to evaluate associations between organic pollutant levels in meconium and birth weight in NW Spain.

METHODS

In this study, we quantify the concentrations of 50 organic pollutants together with the total values of the most important chemical groups in meconium using gas chromatography coupled to tandem mass spectrometry.

RESULTS

Organochlorine pesticides, polychlorinated biphenyls and polybrominated diphenyl ethers were detected with the highest levels in meconium from small for gestational age newborns. It was estimated that several congeners were statistically significant (p<0.05). However, organophosphorus pesticides attained higher concentrations in newborns with an appropriate weight.

CONCLUSIONS

The occurrence of transplacental transfer can be confirmed. Prenatal exposure to organic pollutants was associated with a decrease in birth weight and, therefore, organic pollutants could have an impact on fetal growth. Nevertheless, these results need validation in larger sample sized studies.

Sublethal effects of DBE-DBCH diastereomers on physiology, behavior, and gene expression of Daphnia magna

1,2-dibromo-4-(1,2-dibromoethyl)-cyclohexane (DBE-DBCH) is a brominated flame retardant used in commercial and industrial applications. The use of DBE-DBCH containing products has resulted in an increased release into the environment. However, limited information is available on the long-term effects of DBE-DBCH and its effects in aquatic invertebrates. Thus, the present study was aimed at determining how DBE-DBCH diastereomers (αβ and γδ) affects aquatic invertebrates using Daphnia magna as a model organism. Survival, reproduction, feeding, swimming behavior and toxicogenomic responses to environmental relevant concentrations of DBE-DBCH were analyzed. Chronic exposure to DBE-DBCH resulted in decreased lifespan, and reduced fecundity. Expression of genes involved in reproductive processes, vtg1 and jhe, were also inhibited. DBE-DBCH also induced hypoxia by inhibiting the transcription of genes involved in heme biosynthesis and oxygen transport. Furthermore, DBE-DBCH also inhibited feeding resulting in emptiness of the alimentary canal. Increased expression of the stress response biomarkers was observed following DBE-DBCH exposure. In addition, DBE-DBCH diastereomers also altered the swimming behavior of Daphnia magna. The present study demonstrates that DBE-DBCH cause multiple deleterious effects on Daphnia magna, including effects on reproduction and hormonal systems. These endocrine disrupting effects are in agreement with effects observed on vertebrates. Furthermore, as is the case in vertebrates, DBE-DBCH γδ exerted stronger effects than DBE-DBCH αβ on Daphnia magna. This indicate that DBE-DBCH γδ has properties making it more toxic to all so far studied animals than DBE-DBCH αβ.

The transportation, transformation and (bio)accumulation of pharmaceuticals in the terrestrial ecosystem

Soil dwelling organisms, plants and many primary consumers in food webs face the challenge of exposure to contaminants of emerging concern (CECs) present in terrestrial systems, including thousands of substances derived from pharmaceutical and personal care products (PPCPs). The recent increase in the consumption of modern human or veterinary drugs has resulted in a surge of anthropogenic pharmaceuticals, frequently introduced into terrestrial environments via untreated/treated wastewater. Pharmaceuticals display diverse degradation and accumulation behaviours in receiving bodies, however their impact on soils has, at large, been overlooked. Details about adsorption, absorption, degradation and uptake behaviours, as well as the fate and actual environmental impact of pharmaceuticals are a prerequisite before the traditional transportation prediction models originally designed for the aquatic environment can be extrapolated to terrestrial systems. Without this knowledge, our ability for informed risk assessments and the resultant implementation of contamination management strategies of soils will remain limited. This review discusses the current knowledgebase pertaining the introduction of pharmaceuticals to soils via wastewater irrigation or the application of biosolids. The focus on the transportation, transformation and accumulation of pharmaceuticals through the food chain highlights the urgent need to strengthen our capabilities concerning their detection and characterization in the terrestrial ecosystem.

Exposure to persistent organic pollutants is linked to over-wintering latitude in a Pacific seabird, the rhinoceros auklet, Cerorhinca monocerata

Seabirds are wide-ranging organisms often used to track marine pollution, yet the effect of migration on exposure over the annual cycle is often unclear. We used solar geolocation loggers and stable isotope analysis to study the effects of post breeding dispersal and diet on persistent organic pollutant (POP) and mercury (Hg) burdens in rhinoceros auklets, Cerorhinca monocerata, breeding on islands along the Pacific Coast of Canada. Hg and four classes of POPs were measured in auklet eggs: organochlorine insecticides (OCs), polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs), and perfluoralkyl substances (PFASs). Stable isotope values of adult breast feathers grown during winter were used in conjunction with geolocation to elucidate adult wintering latitude. Wintering latitude was the most consistent and significant predictor of some POP and of Hg concentrations in eggs. The magnitude and pattern of exposure varied by contaminant, with ∑PCBs, ∑PBDEs and DDE decreasing with wintering latitude, and mirex, perfluoro-n-tridecanoic acid, and Hg increasing with latitude. We suggest that concentrations of these contaminants in rhinoceros auklet eggs are influenced by variation in uptake at adult wintering locations related to anthropogenic inputs and oceanic and atmospheric transport.

Organic farming: Does it contribute to contaminant-free produce and ensure food safety?

Organic farming for higher ecological and human health benefits has been adopted in about 186 countries, covering a total area of 71.5 Mha worldwide. Because of the associated practices, the flows of several environmental pollutants into the organic products threaten food safety and human health. The contaminants that occur at higher concentrations in organic produce include persistent organic pollutants (61.3-436.9 ng g^-1 lamb meat, and 0.28 pg g^-1-2.75 ng g^-1 bovine meat), heavy metals (0.5-33.0 mg kg^-1 lettuce), organochlorine pesticides (11-199 μg g^-1 carrots), cyclodienes, hexachlorocyclohexanes, hexabromocyclododecane (2-3 times higher than in conventionally produced porcine meat), hexachlorobenzene (1.38-14.49 ng g^-1 fat in milk), and non-brominated flame retardants (1.3-3.2 times higher than in conventional produce of greenhouse-grown tomato and cucumber). Moreover, some pollutants like per- and polyfluoroalkyl substances with a longer half-life (1.50-9.10 yrs) are reported to occur in several organic products. In fact, several legacy persistent organic pollutants are known for their significant trophic magnification in an urban terrestrial ecosystem. In addition, many plant functionalities are adversely affected in organic farming. Therefore, the long-term usage of organic products containing such pollutants poses a significant threat to human health. The major limitation in organic livestock production is the severe shortage of organic feed. Several variable standards and technical regulations set by the government and private agencies are the major obstacles in the global marketing of organic products. The present review critically addresses the impact of organic farming on hidden risks due to the use of composts as the amendment resources that enhance the phytoaccumulation and trophic transfer of pollutants, the functional diversity of the ecosystems, and poor harmonization among the policies and regulations in different countries for organic farming. The future directions of research have been suggested to mitigate unintended flows of pollutants into the organic products.

A small effect of conservation agriculture on soil biodiversity that differs between biological kingdoms and geographic locations

Larger easily visible animals and plants are negatively affected by agrochemicals used for intensive food production, but we do not understand the general spatial and temporal effects of agrochemicals on the multitudes of bacteria, fungi, and small invertebrate animals that underpin ecosystem productivity. We sequenced the 16S, ITS2, and COI DNA barcode regions from 648 New Zealand vineyard soil samples managed under either conventional or low-agrochemical-input conservation approaches across two regions and three seasons in 1 year and discovered at least 170,000 phylotypes (taxa) with >97% genetic identity. Management approach correlated with a significant 2%–10% difference in the abundances of phylotypes that differed over regions and seasons. Although the data show that agrochemicals do not have a large effect on soil biodiversity on average, the important finding is that the magnitude of impact differs between taxa types and locations, and some taxa most affected also influence the quality of agricultural produce.

•

Agrochemicals have a small effect on soil bacterial, fungal, and animal biodiversity

•

The effect differs in space (and less so time) and affects taxa abundances greatest

•

There is no effect of agrochemicals on taxa richness

•

The size of the effect differs between taxa but is greatest for eukaryotic taxa

Beyond bulk δ15N: Combining a suite of stable isotopic measures improves the resolution of the food webs mediating contaminant signals across space, time and communities

Top predators are used as indicators of contaminant trends across space and time. However, signals are integrated over complex food webs, and variation in diet may confound such signals. Trophic position, assessed by bulk δ¹⁵N, is widely used to infer the variation in diet relevant to contamination, yet a single variable cannot completely describe complex food webs. Thus, we examined relationships across three aquatic systems varying from a single species to a small food web using bulk values from four isotopes and 21 amino acid-specific values. Because variation in baseline ('source') δ¹⁵N can confound estimates of trophic position , we calculated trophic position from the difference between δ¹⁵N_trophic (δ¹⁵N for amino acids that change with trophic position) and δ¹⁵N_source (δ¹⁵N for amino acids that do not change with trophic position). Across all three systems, variation in δ¹⁵N_source explained over half of the variation in bulk δ¹⁵N, and stable isotope values that reflected the base of the food web (δ¹³C, δ¹⁸O, δ³⁴S) predicted contaminants as well or better than δ¹⁵N-which was supported by a meta-analysis of other studies. In ospreys feeding in lakes, variation in δ¹⁵N_source across space created a spurious relationship between ΣDDT and apparent trophic position, and masked a relationship between ΣPCB and trophic position. In a seabird guild, changes in diet over time obscured temporal variation in contaminants over five decades. In Arctic fish and invertebrates, more accurate trophic magnification factors were calculated using δ¹⁵N_{trophic-source}. Thus, (1) using δ¹⁵N_{trophic-source}, instead of bulk δ¹⁵N, avoided incorrect conclusions and improved accuracy of trophic magnification factors necessary to assess risk to top predators; and (2) diet assessed with multiple spatial isotopes, rather than δ¹⁵N alone, was essential to understand patterns in contaminants across space, time and biological communities. Trophic position was most important for lipophilic 'legacy' contaminants (ΣDDT, ΣPCB) and habitat was most important for other contaminants (ΣPBDE, ΣPFAS, mercury). We argue that the use of amino acid-specific analysis of δ¹⁵N alongside 'non-trophic' isotopes should be a core feature of any study that examines the influence of trophic position on chemical pollution, as required for a chemical to be added to international conventions such as the Stockholm Convention.

Linking landscape composition and biological factors with exposure levels of rodenticides and agrochemicals in avian apex predators from Germany

Intensification of agricultural practices has resulted in a substantial decline of Europe's farmland bird populations. Together with increasing urbanisation, chemical pollution arising from these land uses is a recognised threat to wildlife. Raptors are known to be particularly sensitive to pollutants that biomagnify and are thus frequently used sentinels for pollution in food webs. The current study focussed on anticoagulant rodenticides (ARs) but also considered selected medicinal products (MPs) and frequently used plant protection products (PPPs). We analysed livers of raptor species from agricultural and urban habitats in Germany, namely red kites (MIML; Milvus milvus), northern goshawks (ACGE; Accipiter gentilis) and Eurasian sparrowhawks (ACNI; Accipiter nisus) as well as white-tailed sea eagles (HAAL; Haliaeetus albicilla) and ospreys (PAHA; Pandion haliaetus) to account for potential aquatic exposures. Landscape composition was quantified using geographic information systems. The highest detection of ARs occurred in ACGE (81.3%; n = 48), closely followed by MIML (80.5%; n = 41), HAAL (38.3%; n = 60) and ACNI (13%; n = 23), whereas no ARs were found in PAHA (n = 13). Generalized linear models demonstrated (1) an increased probability for adults to be exposed to ARs with increasing urbanisation, and (2) that species-specific traits were responsible for the extent of exposure. For MPs, we found ibuprofen in 14.9% and fluoroquinolones in 2.3% in individuals that were found dead. Among 30 investigated PPPs, dimethoate (and its metabolite omethoate) and thiacloprid were detected in two MIML each. We assumed that the levels of dimethoate were a consequence of deliberate poisoning. AR and insecticide poisoning were considered to represent a threat to red kites and may ultimately contribute to reported decreased survival rates. Overall, our study suggests that urban raptors are at greatest risk for AR exposure and that exposures may not be limited to terrestrial food webs.

Spatiotemporal pattern models for bioaccumulation of pesticides in herbivores: An approximation theory for North American white-tailed deer

Dietary exposure is a major cause of pesticide bioaccumulation in herbivores. However, various types of natural conditions affect the structure of the complicated herbivores' diets, making it difficult to assess their exposure to pesticides. In this study, to evaluate the role of pesticides in the terrestrial food web, a dynamic hybrid dietary model was developed for North American white-tailed deer (or whitetails), which integrates different plant types and the digestibility of deer's foods. Moreover, an equivalent season approach was introduced to generalize the pesticide intake rate geographically. The results indicate that the soil-to-whitetail (meat) bioaccumulation factor (BAF) values in summer are significantly higher than those of other seasonal periods, owing to the high food availability and digestibility. Pesticides with low octanol/water partition coefficients have a high computed soil-to-plant BAF, but a low plant-to-whitetail (meat) BAF, because the transpiration process dominates the bioaccumulation process in plants. Lipid absorption plays a more important role in herbivores and lowers the biomagnification ratio (a smaller amount of pesticides flows to the next level of the food chain). According to the equivalent season approach, geographic locations with warmer climates facilitate pesticide bioaccumulation at a higher level of the terrestrial food web.