Atmospheric deposition of current use pesticides in the Arctic: snow core records from the Devon Island Ice Cap, Nunavut, Canada

Distribution, sources, and eco-risk of Current-Use Pesticides (CUPs) in the coastal waters of the northern Shandong Peninsula, China

This study investigated the spatial distributions and seasonal variations of 19 CUPs in the coastal areas of the Shandong Peninsula and its surrounding rivers and assessed their ecological risk. In freshwater and seawater, insecticides (chlorpyrifos, methoxychlor, and pyridaben), as well as fungicides (fenarimol) and herbicides (dichlobenil) were the main pollutants (Detection Frequency: 100 %). Spatially, during winter, the regional pollution levels of Σ19CUPs in seawater showed a trend of Laizhou Bay (LZB, mean:4.13 ng L-1) > Yellow River Estuary (YRE, mean:2.57 ngL-1) > Bohai Bay (BHB, mean:2.21 ng L-1) > Yanwei Area (YWA, mean:1.94 ng L-1). The similarities of major substances between rivers and the marine environment suggest that river discharge is the main source of CUPs pollution in coastal areas. In summer, CUPs in rivers posed a high risk. In winter, the risk significantly decreased, indicating a moderate overall risk. Seawater exhibited a low risk in winter.

Occurrence, vertical distribution and transport of organic amine pesticides in the seawater from the East China Sea and the South China Sea

Organic amine pesticides (OAPs) are widely used as insecticides, fungicides and herbicides in agricultural production. China is a large agricultural country, and the sprayed pesticides may impact the fragile marine environment through surface runoff. This study revealed the pollution characteristics of thirty-three OAPs in the East China Sea (ECS) and the South China Sea (SCS) and investigated their vertical variations in water columns. The ∑OAPs ranged from below method detection limits to 3.4 ng/ L, with an average value of 0.93 ng/ L. Diphenylamine and beflubutamid were the two most abundant compounds, contributing 64 % and 14 % of the ∑OAPs, respectively. The ∑OAPs in the ECS were significantly (M-W U test, p < 0.01) higher than that in the SCS, and OAPs exhibited different composition profiles. Diphenylamine was the most abundant compound in the ECS, while beflubutamid was dominant in the SCS, which may be related to industrial production (such as rubber synthesis) and agricultural activities. In the water columns, OAPs concentrations were higher in deep layers compared to that in surface seawater, which may be due to weak light and low temperature reducing the degradation of pesticides, indicating the deep ocean is a sink for OAPs. Under the dilution of seawater, the concentrations of OAPs decreased from the Pearl River Estuary to the open sea, and the South China Sea Warm Current also caused the decrease of OAPs from south to north. A preliminary risk assessment indicated that OAPs in the water pose no significant risk to aquatic organisms.

Concerted Evaluation of Pesticides in Soils of Extensive Grassland Sites and Organic and Conventional Vegetable Fields Facilitates the Identification of Major Input Processes

The intensive use of pesticides and their subsequent distribution to the environment and non-target organisms is of increasing concern. So far, little is known about the occurrence of pesticides in soils of untreated areas─such as ecological refuges─as well as the processes contributing to this unwanted pesticide contamination. In this study, we analyzed the presence and abundance of 46 different pesticides in soils from extensively managed grassland sites, as well as organically and conventionally managed vegetable fields (60 fields in total). Pesticides were found in all soils, including the extensive grassland sites, demonstrating a widespread background contamination of soils with pesticides. The results suggest that after conversion from conventional to organic farming, the organic fields reach pesticide levels as low as those of grassland sites not until 20 years later. Furthermore, the different pesticide composition patterns in grassland sites and organically managed fields facilitated differentiation between long-term persistence of residues and diffuse contamination processes, that is, short-scale redistribution (spray drift) and long-scale dispersion (atmospheric deposition), to offsite contamination.

Current use pesticides in soil and air from two agricultural sites in South Africa: Implications for environmental fate and human exposure

Concerns about the possible negative impacts of current use pesticides (CUPs) for both the environment and human health have increased worldwide. However, the knowledge on the occurrence of CUPs in soil and air and the related human exposure in Africa is limited. This study investigated the presence of 30 CUPs in soil and air at two distinct agricultural sites in South Africa and estimated the human exposure and related risks to rural residents via soil ingestion and inhalation (using hazard quotients, hazard index and relative potency factors). We collected 12 soil and 14 air samples over seven days during the main pesticide application season in 2018. All samples were extracted, purified and analyzed by high-performance liquid chromatography coupled with tandem mass spectrometry. In soils, nine CUPs were found, with chlorpyrifos, carbaryl and tebuconazole having the highest concentrations (up to 63.6, 1.10 and 0.212 ng g^-1, respectively). In air, 16 CUPs were found, with carbaryl, tebuconazole and terbuthylazine having the highest levels (up to 25.0, 22.2 and 1.94 pg m^-3, respectively). Spatial differences were observed between the two sites for seven CUPs in air and two in soils. A large dominance towards the particulate phase was found for almost all CUPs, which could be related to mass transport kinetics limitations (non-equilibrium) following pesticide application. The estimated daily intake via soil ingestion and inhalation of individual pesticides ranged from 0.126 fg kg^-1 day^-1 (isoproturon) to 14.7 ng kg^-1 day^-1 (chlorpyrifos). Except for chlorpyrifos, soil ingestion generally represented a minor exposure pathway compared to inhalation (i.e. <5%). The pesticide environmental exposure largely differed between the residents of the two distinct agricultural sites in terms of levels and composition. The estimated human health risks due to soil ingestion and inhalation of pesticides were negligible although future studies should explore other relevant pathways.

Breeding seabirds as vectors of microplastics from sea to land: Evidence from colonies in Arctic Canada

The presence and persistence of microplastics in the environment is increasingly recognized, however, how they are distributed throughout environmental systems requires further understanding. Seabirds have been identified as vectors of chemical contaminants from marine to terrestrial environments, and studies have recently identified seabirds as possible vectors of plastic pollution in the marine environment. However, their role in the distribution of microplastic pollution in the Arctic has yet to be explored. We examined two species of seabirds known to ingest plastics: northern fulmars (Fulmarus glacialis; n = 27) and thick-billed murres (Uria lomvia; n = 30) as potential vectors for the transport of microplastics in and around breeding colonies. Our results indicated anthropogenic particles in the faecal precursors of both species. Twenty-four anthropogenic particles were found in the fulmar faecal precursor samples (M = 0.89, SD = 1.09; 23 fibres and one fragment), and 10 anthropogenic particles were found in the murre faecal precursor samples (M = 0.33, SD = 0.92; 5 fibres, 4 fragments, and one foam). Through the use of bird population surveys and the quantification of anthropogenic particles found in the faecal precursors of sampled seabirds from the same colony, we estimate that fulmars and murres may deposit between 3.3 (CI_boot 1.9 × 10⁶-4.9 × 10⁶) and 45.5 (CI_boot 9.1 × 10⁶-91.9 × 10⁶) million anthropogenic particles, respectively, per year into the environment during their breeding period at these colonies. These estimates indicate that migratory seabirds could be contributing to the distribution and local hotspots of microplastics in Arctic environments, however, they are still likely a relatively small source of plastic pollution in terms of mass in the environment and may not contribute as much as other reported sources such as atmospheric deposition in the Arctic.

Spatial and temporal distribution of Persistent Organic Pollutants and current use pesticides in the atmosphere of Argentinean Patagonia

XAD-based passive air samplers (PAS) were used to evaluate organochlorine pesticides (OCPs), polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs) and some current use pesticides (chlorotalonil, trifluralin and dichlofluanid) in the atmosphere of Argentinian Patagonia. The PAS were deployed for 12 months during three consecutive years along a longitudinal (Rio Negro watershed) and a latitudinal (Patagonian coast) transect. Endosulfan, trifluralin and DDT-related substances were the most prevalent pesticides in the Rio Negro watershed, an intensive agricultural basin, consistent with ongoing use of endosulfan at the time of sampling. Concentrations of industrial contaminants were low (mean 25 pg/m³ and 1.9 pg/m³ for Σ₃₈ PCBs, and Σ₅PBDEs, respectively) and similar among sites. However, along the Patagonian coast, air concentrations of total contaminants were highly variable (14-400 pg/m³) with highest values recorded at Bahia Blanca, an important industrial area that is also downwind of the most intensively agriculturally used area of Argentina. Contaminant levels decreased toward the south, with the exception of the southernmost sampling site (Rio Gallegos) where a slight increase of total pollutant levels was observed, mainly due to the lower chlorinated PCB congeners. Interannual variability was small, although the last year tended to have slightly higher levels for different contaminant groups at most sampling sites. This large-scale spatial atmospheric monitoring of POPs and some CUPs in the South of Argentina highlights the important and continuing role of rural and urban areas as emission sources of these chemicals.

Atmospheric Deposition of Organochlorine Pesticides and Industrial Compounds to Seasonal Surface Snow at Four Glacier Sites on Svalbard, 2013-2014

Winter snow from four glacial sites on Svalbard was analyzed for atmospheric deposition of 36 organochlorine pesticides (OCPs) and 7 industrial compounds (OCICs) by GC-high-resolution MS. Thirteen of the OCPs and all OCICs were detected at all sites. Sampling sites are 230 km apart from west to east, but are at varying elevations, ranging from 700 to 1202 m a.s.l. Total OCP flux was greater than total OCIC at all sites and was 5 times greater at Lomonosovfonna, and 3 times greater at Austfonna, the most easterly site. Chlorpyrifos dominated OCP flux at Lomonosovfonna (81.7 pg cm^-2 yr^-1) and Kongsvegen (60.6 pg cm^-2 yr^-1), and at Austfonna, but not at Holtedahlfonna where dieldrin dominated. trans-chlordane was a major contributor to OCPs. These three pesticides comprised at least 50% of total OCP at each site. OCIC flux was dominated by pentachloroanisole (PCA) at Lomonosovfonna (23.5 pg cm^-2 yr^-1) and Kongsvegen (14.1 pg cm^-2 yr^-1). PCA and hexachlorobenzene comprised at least 63% of all OCICs at each site. Air mass frequency from likely source areas showed that Austfonna had the most frequent long-distance air flow, but showed lower amounts of chlorpyrifos and PCA, suggesting local sources of these compounds to other sites.

Persistent organic pollutants in the polar regions and the Tibetan Plateau: A review of current knowledge and future prospects

Due to their low temperatures, the Arctic, Antarctic and Tibetan Plateau are known as the three polar regions of the Earth. As the most remote regions of the globe, the occurrence of persistent organic pollutants (POPs) in these polar regions arouses global concern. In this paper, we review the literatures on POPs involving these three polar regions. Overall, concentrations of POPs in the environment (air, water, soil and biota) have been extensively reported, with higher levels of dichlorodiphenyltrichloroethane (DDT) and hexachlorocyclohexane (HCH) detected on the Tibetan Plateau. The spatial distribution of POPs in air, water and soil in the three polar regions broadly reflects their distances away from source regions. Based on long-term data, decreasing trends have been observed for most "legacy POPs". Observations of transport processes of POPs among multiple media have also been carried out, including air-water gas exchange, air-soil gas exchange, emissions from melting glaciers, bioaccumulations along food chains, and exposure risks. The impact of climate change on these processes possibly enhances the re-emission processes of POPs out of water, soil and glaciers, and reduces the bioaccumulation of POPs in food chains. Global POPs transport model have shown the Arctic receives a relatively small fraction of POPs, but that climate change will likely increase the total mass of all compounds in this polar region. Considering the impact of climate change on POPs is still unclear, long-term monitoring data and global/regional models are required, especially in the Antarctic and on the Tibetan Plateau, and the fate of POPs in all three polar regions needs to be comprehensively studied and compared to yield a better understanding of the mechanisms involved in the global cycling of POPs.

Critical assessment of pendimethalin in terms of persistence, bioaccumulation, toxicity, and potential for long-range transport

Pendimethalin (PND, CAS registry number 40487-42-1) is a dinitroaniline herbicide that selectively controls broad-leaf and grassy weeds in a variety of crops and in noncrop areas. It has been on the market for about 30 yr and is currently under review for properties related to persistence (P), bioaccumulation (B), and toxicity (T) in the European Union (EU). A critical review of these properties as well as potential for long-range transport (LRT) was conducted. Pendimethalin has a geometric mean (GM) half-life of 76-98 d in agriculturally relevant soils under aerobic conditions in the lab. The anaerobic half-life was 12 d. The GM for field half-lives was 72 d. The GM half-life for sediment-water tests in the lab was 20 d and that in field aquatic cosms ranged from 45 to 90 d. From these data PND is not persistent as defined in the Annex II of EC regulation 1107/2009. The GM bioconcentration factor for PND was 1878, less than the criterion value. This was consistent with lack of biomagnification or accumulation in aquatic and terrestrial food chains. The GM no-observed-effect concentration (NOEC) value for fish was 43 µg/L, and 11 µg/L for algae. These do not trigger the criterion value for toxicity. In air, the DT50 of PND was estimated to be 0.35 d, which is well below the criterion of 2 d for LRT under the United Nations Economic Commission for Europe (UNECE) Aarhus protocol. Modeling confirmed lack of LRT. Because of its volatility, PND may be transported over short distances in air and was found in samples in local and semiremote regions; however, these concentrations are not of toxicological concern. Unlike other current-use pesticides, PND has not been found in samples from remote regions since 2000 and there is no apparent evidence that this herbicide accumulates in food chains in the Arctic.

Source attribution of poly- and perfluoroalkyl substances (PFASs) in surface waters from Rhode Island and the New York Metropolitan Area

Exposure to poly and perfluoroalkyl substances (PFASs) has been associated with adverse health effects in humans and wildlife. Understanding pollution sources is essential for environmental regulation but source attribution for PFASs has been confounded by limited information on industrial releases and rapid changes in chemical production. Here we use principal component analysis (PCA), hierarchical clustering, and geospatial analysis to understand source contributions to 14 PFASs measured across 37 sites in the Northeastern United States in 2014. PFASs are significantly elevated in urban areas compared to rural sites except for perfluorobutane sulfonate (PFBS), N-methyl perfluorooctanesulfonamidoacetic acid (N-MeFOSAA), perfluoroundecanate (PFUnDA) and perfluorododecanate (PFDoDA). The highest PFAS concentrations across sites were for perfluorooctanate (PFOA, 56 ng L^-1) and perfluorohexane sulfonate (PFOS, 43 ng L^-1) and PFOS levels are lower than earlier measurements of U.S. surface waters. PCA and cluster analysis indicates three main statistical groupings of PFASs. Geospatial analysis of watersheds reveals the first component/cluster originates from a mixture of contemporary point sources such as airports and textile mills. Atmospheric sources from the waste sector are consistent with the second component, and the metal smelting industry plausibly explains the third component. We find this source-attribution technique is effective for better understanding PFAS sources in urban areas.

Current-use pesticides in seawater and their bioaccumulation in polar bear-ringed seal food chains of the Canadian Arctic

The distribution of current-use pesticides (CUPs) in seawater and their trophodynamics were investigated in 3 Canadian Arctic marine food chains. The greatest ranges of dissolved-phase concentrations in seawater for each CUP were endosulfan sulfate (less than method detection limit (MDL) to 19 pg L(-1) ) > dacthal (0.76-15 pg L(-1) ) > chlorpyrifos (less than MDL to 8.1 pg L(-1) ) > pentachloronitrobenzene (less than MDL to 2.6 pg L(-1) ) > α-endosulfan (0.20-2.3 pg L(-1) ). Bioaccumulation factors (BAFs, water-respiring organisms) were greatest in plankton, including chlorothalonil (log BAF = 7.4 ± 7.1 L kg(-1) , mean ± standard error), chlorpyrifos (log BAF = 6.9 ± 6.7 L kg(-1) ), and α-endosulfan (log BAF = 6.5 ± 6.0 L kg(-1) ). The largest biomagnification factors (BMFs) were found for dacthal in the capelin:plankton trophic relationship (BMF = 13 ± 5.0) at Cumberland Sound (Nunvavut), and for β-endosulfan (BMF = 16 ± 4.9) and α-endosulfan (BMF = 9.3 ± 2.8) in the polar bear-ringed seal relationship at Barrow and Rae Strait (NU), respectively. Concentrations of endosulfan sulfate exhibited trophic magnification (increasing concentrations with increasing trophic level) in the poikilothermic portion of the food web (trophic magnification factor = 1.4), but all of the CUPs underwent trophic dilution in the marine mammal food web, despite some trophic level-specific biomagnification. Together, these observations are most likely indicative of metabolism of these CUPs in mammals. Environ Toxicol Chem 2016;35:1695-1707. © 2016 SETAC.

Atmospheric pathways of chlorinated pesticides and natural bromoanisoles in the northern Baltic Sea and its catchment

Long-range atmospheric transport is a major pathway for delivering persistent organic pollutants to the oceans. Atmospheric deposition and volatilization of chlorinated pesticides and algae-produced bromoanisoles (BAs) were estimated for Bothnian Bay, northern Baltic Sea, based on air and water concentrations measured in 2011-2012. Pesticide fluxes were estimated using monthly air and water temperatures and assuming 4 months ice cover when no exchange occurs. Fluxes were predicted to increase by about 50 % under a 2069-2099 prediction scenario of higher temperatures and no ice. Total atmospheric loadings to Bothnian Bay and its catchment were derived from air-sea gas exchange and "bulk" (precipitation + dry particle) deposition, resulting in net gains of 53 and 46 kg year(-1) for endosulfans and hexachlorocyclohexanes, respectively, and net loss of 10 kg year(-1) for chlordanes. Volatilization of BAs releases bromine to the atmosphere and may limit their residence time in Bothnian Bay. This initial study provides baseline information for future investigations of climate change on biogeochemical cycles in the northern Baltic Sea and its catchment.

The delivery of organic contaminants to the Arctic food web: why sea ice matters

For decades sea ice has been perceived as a physical barrier for the loading of contaminants to the Arctic Ocean. We show that sea ice, in fact, facilitates the delivery of organic contaminants to the Arctic marine food web through processes that: 1) are independent of contaminant physical-chemical properties (e.g. 2-3-fold increase in exposure to brine-associated biota), and 2) depend on physical-chemical properties and, therefore, differentiate between contaminants (e.g. atmospheric loading of contaminants to melt ponds over the summer, and their subsequent leakage to the ocean). We estimate the concentrations of legacy organochlorine pesticides (OCPs) and current-use pesticides (CUPs) in melt pond water in the Beaufort Sea, Canadian High Arctic, in 2008, at near-gas exchange equilibrium based on Henry's law constants (HLCs), air concentrations and exchange dynamics. CUPs currently present the highest risk of increased exposures through melt pond loading and drainage due to the high ratio of melt pond water to seawater concentration (Melt pond Enrichment Factor, MEF), which ranges from 2 for dacthal to 10 for endosulfan I. Melt pond contaminant enrichment can be perceived as a hypothetical 'pump' delivering contaminants from the atmosphere to the ocean under ice-covered conditions, with 2-10% of CUPs annually entering the Beaufort Sea via this input route compared to the standing stock in the Polar Mixed Layer of the ocean. The abovementioned processes are strongly favored in first-year ice compared to multi-year ice and, therefore, the dynamic balance between contaminant inventories and contaminant deposition to the surface ocean is being widely affected by the large-scale icescape transition taking place in the Arctic.