Occurrence of organochlorine pesticides in the environmental matrices from King George Island, west Antarctica

Soil's Hidden Power: The Stable Soil Organic Carbon Pool Controls the Burden of Persistent Organic Pollutants in Background Soils

Persistent organic pollutants (POPs) tend to accumulate in cold regions by cold condensation and global distillation. Soil organic matter is the main storage compartment for POPs in terrestrial ecosystems due to deposition and repeated air-surface exchange processes. Here, physicochemical properties and environmental factors were investigated for their role in influencing POPs accumulation in soils of the Tibetan Plateau and Antarctic and Arctic regions. The results showed that the soil burden of most POPs was closely coupled to stable mineral-associated organic carbon (MAOC). Combining the proportion of MAOC and physicochemical properties can explain much of the soil distribution characteristics of the POPs. The background levels of POPs were estimated in conjunction with the global soil database. It led to the proposition that the stable soil carbon pools are key controlling factors affecting the ultimate global distribution of POPs, so that the dynamic cycling of soil carbon acts to counteract the cold-trapping effects. In the future, soil carbon pool composition should be fully considered in a multimedia environmental model of POPs, and the risk of secondary release of POPs in soils under conditions such as climate change can be further assessed with soil organic carbon models.

Role of Microbes in the degradation of organic semivolatile compounds in polar ecosystems: A review

The Arctic and the Antarctic Continent correspond to two eco-regions with extreme climatic conditions. These regions are exposed to the presence of contaminants resulting from human activity (local and global), which, in turn, represent a challenge for life forms in these environments. Anthropogenic pollution by semi-volatile organic compounds (SVOCs) in polar ecosystems has been documented since the 1960s. Currently, various studies have shown the presence of SVOCs and their bioaccumulation and biomagnification in the polar regions with negative effects on biodiversity and the ecosystem. Although the production and use of these compounds has been regulated, their persistence continues to threaten biodiversity and the ecosystem. Here, we summarize the current literature regarding microbes and SVOCs in polar regions and pose that bioremediation by native microorganisms is a feasible strategy to mitigate the presence of SVOCs. Our systematic review revealed that microbial communities in polar environments represent a wide reservoir of biodiversity adapted to extreme conditions, found both in terrestrial and aquatic environments, freely or in association with vegetation. Microorganisms adapted to these environments have the potential for biodegradation of SVOCs through a variety of genes encoding enzymes with the capacity to metabolize SVOCs. We suggest that a comprehensive approach at the molecular and ecological level is required to mitigate SVOCs presence in these regions. This is especially patent when considering that SVOCs degrade at slow rates and possess the ability to accumulate in polar ecosystems. The implications of SVOC degradation are relevant for the preservation of polar ecosystems with consequences at a global level.

Nationwide assessment of atmospheric organochlorine pesticides over a decade during 2008-2017 in South Korea

Long-term nationwide atmospheric monitoring of organochlorine pesticides (OCPs) was performed in South Korea during 2008-2017. Their occurrences, seasonal and temporal variability, sources, and effect of ambient temperature were investigated. The OCPs are pronounced with a mean concentration of total OCPs ranging from 5.2 to 256 pg/Sm³. However, a decrease of 54 % was observed in the mean concentration of total OCPs from 2008 to 2017 associated with regulatory actions. OCP concentrations did not show any variations between the different site types, and OCPs were ubiquitously present at all site types. The mean concentration of total OCPs in summer was two-fold higher than in winter. The concentrations of DRINs, DDTs, ENDOs, and HCHs were significantly higher in summer, but the concentrations of chlordane and heptachlor were higher in winter. The diagnostic ratios identified major sources as ongoing sources, past use, and atmospheric transport. Clausius Clapeyron plots strongly suggested the re-emission of α-endosulfan, β-endosulfan, α-HCH, and β-HCH, and ΔH_sa (enthalpy of surface air exchange) values suggested the influence of the transport and/or new sources on aldrin, dieldrin, and chlordane. The occurrence of OCPs due to re-emissions, ongoing sources, and long-range atmospheric transport could be a challenge towards the complete phase-out of OCPs in South Korea.

Dissolved legacy and emerging organochlorine pesticides in the Antarctic marginal seas: Occurrence, sources and transport

Polar regions are recognized as final sinks of the persistent contaminants, however, environmental investigations in the Antarctica are greatly limited by harsh field conditions. In this study, seawater samples were collected in the Antarctic marginal seas during the austral summer of 2021 to investigate the environmental behavior and fate of organochlorine pesticides (OCPs). The concentrations and source markers of representative legacy hexachlorocyclohexane (HCH), hexachlorobenzene (HCB) and dichlorodiphenyltrichloroethanes (DDTs) indicated the coexistent sources of historical residues and fresh inputs. While the emerging OCPs, including quintozene, pentachloroaniline and dichlobenil, showed relatively lower detection frequency. Due to the differences in temperature and sea ice coverage, dissolved OCPs generally displayed higher concentrations in the eastern Antarctic than those in the western Antarctic. The 'surface depleted and depth enrichment' vertical profile of representative OCPs in the continental shelf of Prydz Bay was jointly controlled by biological pump and water mass structure.

Persistent organic pollutants and mercury in a colony of Antarctic seabirds: higher concentrations in 1998, 2001, and 2003 compared to 2014 to 2016

Over decades, persistent organic pollutants (POPs) and trace metals like mercury (Hg) have reached the remotest areas of the world such as Antarctica by atmospheric transport. Once deposited in polar areas, low temperatures, and limited solar radiation lead to long environmental residence times, allowing the toxic substances to accumulate in biota. We investigated the load of polychlorinated biphenyls (PCBs) and dichlorodiphenyltrichloroethane (DDTs) and metabolites (DDEs, DDDs) in embryos from failed eggs of the smallest seabird breeding in Antarctica, the Wilson's storm-petrel (Oceanites oceanicus) at King George Island (Isla 25 de Mayo). We compared samples of different developmental stages collected in 2001, 2003, and 2014 to 2016 to investigate changes in pollutant concentrations over time. We detected eight PCBs including the dioxin-like (dl) congeners PCB 105 and 118 (ΣPCBs: 59-3403 ng g−1 ww) as well as 4,4’-DDE, and 4,4’-DDD (ΣDDX: 19-1035 ng g−1 ww) in the embryos. Samples from the years 2001 and 2003 showed higher concentrations of PCBs than those from 2014 to 2016. Concentrations of DDX was similar in both time intervals. Furthermore, we determined Hg concentrations in egg membranes from 1998 to 2003, and 2014 to 2016. Similar to PCBs, Hg in egg membranes were higher in 1998 than in 2003, and higher in 2003 than in the years 2014 to 2016, suggesting a slow recovery of the pelagic Antarctic environment from the detected legacy pollutants. Embryos showed an increase in pollutant concentrations within the last third of their development. This finding indicates that contaminant concentrations may differ among developmental stages, and it should be taken into account in analyses on toxic impact during embryogenesis.

Organochlorine pesticides and polychlorinated biphenyls in high mountain lakes, Mexico

Pollution levels of organochlorine pesticides (OCPs) and polychlorinated biphenyls (PCBs) were investigated in the El Sol and the La Luna alpine lakes. The lakes are located in central Mexico, in the crater of the Nevado de Toluca volcano. The El Sol and the La Luna lakes are extremely relevant in Mexico and in the world because they are recognized as pristine regions and environmental reservoirs. Samples of atmospheric aerosol, sediment, plankton, and Tubifex tubifex (sludge worm) were collected at three different sample locations for three years (2017, 2018, and 2019) at three different times of year, meaning that the weather conditions at the time of sampling were different. Pollutants were analysed by gas chromatography-mass spectrometry with negative chemical ionisation (GC-MS/NCI). Endosulfan was the most frequent and abundant pollutant, showing the highest peaks of all. Atmospheric aerosol revealed Σ₂ = 45 pg/m³, including α and β, while sediment lakes displayed α, β and endosulfan sulfate as Σ₃ = 1963 pg/g, whereas plankton and Tubifex tubifex showed Σ₂ = 576 pg/g and 540 pg/g for α and β respectively. Results of endosulfan ratios (α/β) and (α-β/endosulfan sulfate) suggest that both fresh and old discharges continue to arrive at the lakes. This study shows for the first time the pollution levels of OCP and PCB in high mountain lakes in Mexico. These results that must be considered by policy makers to mitigate their use in the various productive activities of the region.

Assessment of Pesticide, Dioxin-like Polychlorinated Biphenyl, and Polycyclic Aromatic Hydrocarbon Existence around Galindez Island, and Comparison with the Organic Pollution Bibliography of the Antarctic Peninsula

Sediment, notothenioid fish, and moss samples were collected from the vicinity of Galindez Island, Antarctic Peninsula during the austral autumn of 2016 and 2017. Pesticide, Polycyclic Aromatic Hydrocarbon (PAH), and dioxin-like Polychlorinated Biphenyl (dl-PCB) concentrations were measured using High-Resolution Gas and Liquid Chromatography. Pollutant concentrations were below detection limits in sediment and moss samples. However, pesticides, PAH, and dl-PCB congeners were detected in the muscle tissue of fishes. Pesticide concentrations varied between 0.46 and 12.2 ng/g-dw, and Mecarbam was the dominant compound. Kresoxim-methyl, Mecarbam, Procymidone, Pyridaben, and Quinoxyfen were reported in the muscle tissue of the fishes, for the first time from the Antarctic. PCB-118, PCB-105, and PCB-156 were dominant dl-PCBs. The ∑12-dl-PCB concentration was 160,929 pg/g-dw, and WHO-TEQ-total dl-PCB was 8.30 pg/g-dw in Trematomus bernachii, over the consumable limit in fishes according to the European Commission. The PCB-126 concentration was 36 pg/g-dw in the muscle tissue of fish, the first reported from the Antarctic. Phenanthrene was the dominant PAH congener. The ∑16-PAH concentration was 22.5 ng/g-dw. PAH sources were local and petrogenic in the fishes, likely after long-term bioaccumulation. The flow rate is rather low around Galindez Island; accordingly, contaminant removal takes time and may demonstrate long-lasting effects including bioaccumulation in the marine food web.

Distribution and flux of organochlorine pesticides in sediment from Prydz Bay, Antarctic: Implication of sources and trends

Surface sediments were collected from Prydz Bay, Antarctica to investigate the distribution patterns, origins, annual fluxes, and trends of organochlorine pesticides (OCPs) in the marginal sea of polar areas. The concentrations of OCPs ranged from 0.80 to 7.90 ng/g dry weight, with dichlorodiphenytrichloroethanes (DDTs) as the main components. Levels of hexachlorocyclohexanes (HCHs) and DDTs in sediment from Prydz Bay were comparable to the majority of marine sediment worldwide. The distributions of OCPs were characterized by a distinct "quasi-concentric circle" pattern, which has significantly positive relationship with total organic carbon (TOC) of sediment and controlled by the local hydrodynamic conditions and sources of organic matter. Source apportionment demonstrated that HCHs and chlordanes in Prydz Bay were mainly derived from the long range atmospheric transport (LRAT) of these compounds from off regions. However, current inputs of DDT-based compounds and lindane are suggested to exist either as a result of the LART from the neighbouring countries or re-emission from melting glacier. The annual sedimentary fluxes of OCPs were 0.007 to 7.12 pg/cm²/yr, about one to three orders of magnitude lower than some data from the Arctic areas. Based on a rough calculation of r-HCH, only 0.3-1.5% of the air-seawater net deposition would be buried in sediment, implying a long active lifetime of OCPs in Antarctica. We preliminarily indicate an increase of OCP contamination in Antarctic environment afterwards when considering the possible occurrence of "fresh" sources and low proportion of sedimentary sink.

Regional Development Quality of Yangtze River Delta: From the Perspective of Urban Population Agglomeration and Ecological Efficiency Coordination

With the deepening of the development process of regional integration in the Yangtze River Delta, integration and high quality have become the key paths of regional development. On the basis of the panel data of 26 cities in the Yangtze River Delta urban agglomeration, from 2008 to 2018, this paper uses a DEA model to calculate the ecological efficiency of each city. On the basis of the visual expression of the population agglomeration degree, with the help of ArcGIS platform, the coupling coordination between the population agglomeration and the ecological efficiency is calculated by using the coupling degree model. The results show the spatiotemporal pattern changes of the coupling coordination degrees of 26 cities in the Yangtze River Delta urban agglomeration between population agglomeration and ecological environment, modeling the impact of urban population growth on the ecological environment. The research provides a scientific basis for determining the goal of urban population development, for coordinating the relationship between populations and the environment in urban development, and for realizing regional sustainable and high-quality development.

Within and between breeding-season changes in contaminant occurrence and body condition in the Antarctic breeding south polar skua

The Antarctic ecosystem represents a remote region far from point sources of pollution. Still, Antarctic marine predators, such as seabirds, are exposed to organohalogen contaminants (OHCs) which may induce adverse health effects. With increasing restrictions and regulations on OHCs, the levels and exposure are expected to decrease over time. We studied south polar skua (Catharacta maccormiciki), a top predator seabird, to compare OHC concentrations measured in whole blood from 2001/2002 and 2013/2014 in Dronning Maud Land. As a previous study found increasing organochlorine concentrations with sampling day during the 2001/2002 breeding season, suggesting dietary changes, we investigated if this increase was repeated in the 2013/2014 breeding season. In addition to organochlorines, we analyzed hydroxy-metabolites, brominated contaminants and per- and polyfluoroalkyl substances (PFAS) in 2013/2014, as well as dietary descriptors of stable isotopes of carbon and nitrogen, to assess potential changes in diet during breeding. Lipid normalized concentrations of individual OHCs were 63%, 87% and 105% higher for hexachlorobenzene (HCB), 1,1-dichloro-2,2-bis (p-chlorophenyl)ethylene (p,p'-DDE), and ∑Polychlorinated biphenyls (PCBs), respectively, in 2013/2014 compared to 2001/2002. South polar skuas males in 2013/2014 were in poorer body condition than in 2001/2002, and with higher pollutant levels. Poorer body condition may cause the remobilization of contaminants from stored body reserves, and continued exposure to legacy contaminants at overwintering areas may explain the unexpected higher OHC concentrations in 2013/2014 than 2001/2002. Concentrations of protein-associated PFAS increased with sampling day during the 2013/2014 breeding season, whereas the lipid-soluble chlorinated pesticides, PCBs and polybrominated diphenyl ether (PBDEs) showed no change. OHC occurrence was not correlated with stable isotopes. The PFAS biomagnification through the local food web at the colony should be investigated further.

Simulation and Optimization of Urban–Rural Settlement Development from the Perspective of Production–Life–Ecology Space: A Case Study for Aksu City

To explore the future development state of urban and rural settlements, we combined random forest algorithm (RFA) and cellular automata (CA) to simulate high precision in urban and rural settlements in Aksu city. The settlement distribution was predicted for the next 10 years, and suggestions for urban and rural settlements were proposed based on a “production–life–ecology” space. The results show the following: Transportation factors and administrative location have an important influence on the development of settlements, and infrastructure has a greater impact on the development of settlements. The overall accuracy of the 2019 settlement distribution obtained through the RFA–CA model simulation is 93.8%, with a G-mean coefficient of 0.815. The simulation accuracy is better and more suitable for the simulation and prediction of settlement expansion than the logistic-CA model. The forecasted settlement expansion in 2029 for Aksu city is 58.36 km2 of settlement expansion compared to the 2019 settlement distribution, with an overall growth trend for sparse north-south and dense central areas. This study analyzed the causes of settlement expansion in 19 regions of Aksu city, explored the main function of “production–life–ecology” space in different areas, and proposed layout optimizations from the perspective of production, life, and ecology. The results of this study can provide a reference for the spatial planning and rural revitalization strategy of Aksu city.

Hexachlorocyclohexane toxicity in water bodies of Pakistan: challenges and possible reclamation technologies

Pakistan is an agro-economy country where hexachlorocyclohexane (HCH) pesticides are being used to improve crop productivity, as a result the risk of contamination of soil and sediment has been increased. HCH exhibits all the characteristics of persistent organic pollutants (POP), and was therefore added to the list of 'new POPs' in 2009. This review report revealed that the major rivers of Pakistan such as the Indus Basin, River Ravi, River Chenab and their tributaries all are contaminated with HCH and the highest residual concentration (4,090 ng/g) was detected in a pesticide burial ground in Hyderabad city. Major sources of HCH contamination were identified as agricultural runoff, discharge of untreated industrial effluents and surface runoff. In order to manage HCH pollution, various ex-situ and in-situ remediation techniques along with their merits and demerits are thoroughly reviewed. Among these, microbial bioremediation is a low cost, environment friendly, effective in-situ remediation technique for remediation of HCH. Overall, the information provided in this manuscript will provide a future reference to the scientific community and bridge the knowledge gap between HCH release in the environment and their mitigation through proper treatment methods.

Accumulation and influencing factors of novel brominated flame retardants in soil and vegetation from Fildes Peninsula, Antarctica

The concentrations and distributions of nine novel brominated flame retardants (NBFRs) were analyzed in soil, lichen (Usnea aurantiaco-atra), and moss (Sanionia uncinata) samples collected from the Chinese Antarctic Great Wall Station and surrounding Fildes Peninsula area in west Antarctica. Total NBFR concentrations ranged from 61.2-225 pg/g dry weight (dw) in soil, 283-1065 pg/g dw in moss, and 135-401 pg/g dw in lichen, respectively. Decabromodiphenyl ethane (DBDPE) was the dominant NBFR in all samples, accounting for 65.2%, 50.1%, and 72.4% of cumulative NBFR concentration in soil, moss, and lichen, respectively. The concentrations of NBFRs in plant samples were higher than those in soil, which may be related to plant bioaccumulation. Significant log/log-linear correlations (p < 0.05) were found between the concentrations of BEHTEBP and total organic carbon (TOC) in soil, and between DBDPE and lipid content in mosses, indicating that TOC and lipid content potentially affect certain NBFRs in Antarctic soil and moss. This study presents the first report on NBFR contamination in soil and various vegetation in Antarctica.

Preliminary Studies of Organochlorine Pesticides (OCPs) in Sediment, Water and Fish Samples from Ethiope River, Abraka Axis, Southern Nigeria

Selected persistent organochlorine pollutants, including DDT and its metabolites, hexachlorobenzene, dieldrin, Aldrin, heptachlor, HCH as well as some of their isomers were determined in water, sediment and fish samples from the Ethiope River in Southern Nigeria. Twenty organochlorine pesticides were detected in both seasons from October 2012 – September 2013. Results revealed ∑HCH to be 0.620µg/L (water), 33 ng/g (sediment) and 29.00 ng/g (fish) for the rainy season while concentrations of 0.170 µg/L (water), 14 ng/g (sediment) and 28.00 ng/g (fish) were obtained for the dry season. 0.05–0.15 ng/g for aldrin, 0.12–5.8 ng/g for dieldrin, 0.22–0.64 ng/g for endrin, 0.24–6.37 ng/g for endosulfan and 0.21–8.81 ng/g for ΣDDT (p, p` -DDD, p, p` -DDE, p, p` -DDT). Among the OCPs, ∑HCH, endosulfan and PDDT were the most dominant compounds in the river sediments. γ- HCH was the most frequent detected compound in all the samples from this river. Among the cyclodiene compounds, aldrin was in abundance in most of the sediments, water and fish samples. γ-HCH, γ-HCH and HCB contributed this highest value for the water, sediment and fish sample respectively in the rainy season while aldrin, endrin and HCB were the highest contributors to the ΣOCPs to the mean of water, sediment and fish respectively. Hazard quotient and bioaccumulation analysis carried out on the fish sample revealed that the fishes were heavily contaminated with values >1 for both seasons which possess a possibility for ecological concern.

Atmospheric organophosphate esters in the Western Antarctic Peninsula over 2014-2018: Occurrence, temporal trend and source implication

Organophosphate esters (OPEs) were comprehensively investigated in the air samples collected using high-volume samplers near the Chinese Great Wall Station in the Western Antarctic Peninsula over the period of 2014-2018. The concentrations of ∑₈OPEs (gaseous + particle phases) ranged from 33.9 to 404 pg/m³ with a geometric mean of 119 ± 12.0 pg/m³. Tris [(2R)-1-chloro-2-propyl] phosphate (TCIPP) and tris(2-chloroethyl) phosphate (TCEP) dominated in the gaseous phase, while tris-n-butyl phosphate (TnBP) was the most abundant OPEs in the particle phase, followed by TCIPP and TCEP. An apparently temporal trend was observed for atmospheric ∑₈OPEs over the five years, with a doubling time of about 3.8 years, which indicated continuous inputs of OPEs into the sampling area. The particle-bound ∑₈OPEs accounted for 45% of the total, generally lower than that reported in the Arctic. Gas-particle partitioning modeling suggested that the partitioning of OPEs with higher logK_OA values approached the steady state in the Antarctic air. The back-trajectory modeling showed that high levels of OPEs were usually associated with air inputs from the northwest of the peninsula. This suggested that long-range transport from South America, which was confirmed by the no temperature dependencies of OPEs concentrations (excluding TnBP). Nevertheless, a steady high level of particle-bound TnBP implied local sources in the Western Antarctic Peninsula, which required further investigation in future works.

Preliminary Studies of Organochlorine Pesticides (OCPs) in Sediment, Water and Fish Samples from Ethiope River, Abraka Axis, Southern Nigeria

Selected persistent organochlorine pollutants, including DDT and its metabolites, hexachlorobenzene, dieldrin, Aldrin, heptachlor, HCH as well as some of their isomers were determined in water, sediment and fish samples from the Ethiope River in Southern Nigeria. Twenty organochlorine pesticides were detected in both seasons from October 2012 – September 2013. Results revealed ∑HCH to be 0.620µg/L (water), 33 ng/g (sediment) and 29.00 ng/g (fish) for the rainy season while concentrations of 0.170 µg/L (water), 14 ng/g (sediment) and 28.00 ng/g (fish) were obtained for the dry season. 0.05–0.15 ng/g for aldrin, 0.12–5.8 ng/g for dieldrin, 0.22–0.64 ng/g for endrin, 0.24–6.37 ng/g for endosulfan and 0.21–8.81 ng/g for ΣDDT (p, p` -DDD, p, p` -DDE, p, p` -DDT). Among the OCPs, ∑HCH, endosulfan and PDDT were the most dominant compounds in the river sediments. γ- HCH was the most frequent detected compound in all the samples from this river. Among the cyclodiene compounds, aldrin was in abundance in most of the sediments, water and fish samples. γ-HCH, γ-HCH and HCB contributed this highest value for the water, sediment and fish sample respectively in the rainy season while aldrin, endrin and HCB were the highest contributors to the ΣOCPs to the mean of water, sediment and fish respectively. Hazard quotient and bioaccumulation analysis carried out on the fish sample revealed that the fishes were heavily contaminated with values >1 for both seasons which possess a possibility for ecological concern.

Bioaccumulation and Trophic Transfer of Polybrominated Diphenyl Ethers and Their Hydroxylated and Methoxylated Analogues in Polar Marine Food Webs

Arctic and Antarctic marine ecosystems, which are important components of global biodiversity, have been severely threatened by environmental pollutants in recent decades. In this study, polybrominated diphenyl ethers (PBDEs) and their hydroxylated and methoxylated analogues (OH-PBDEs and MeO-PBDEs) were analyzed in seawater, sediment, and marine organisms (algae, invertebrates, and fishes) collected surrounding the Arctic Yellow River Station (n = 83) and the Antarctic Great Wall Station (n = 72). PBDEs and the analogues were detectable in all polar marine matrices, except MeO-PBDEs in seawater. The concentrations of ∑PBDEs, ∑MeO-PBDEs, and ∑OH-PBDEs in the marine organisms were in the range of 0.33-16 ng/g lipid weight (lw), n.d.-2.6 ng/g lw, and 0.12-2.3 ng/g lw in the Arctic and 0.06-31 ng/g lw, n.d.-5.8 ng/g lw, and 0.17-35 ng/g lw in Antarctica, respectively. Biota-sediment bioaccumulation factor (BSAF, g TOC/g lipid) values of MeO-PBDEs (0.002-0.14) and OH-PBDEs (0.004-0.18) were lower than the BSAF values of PBDEs (0.85-12). Trophic magnification was found for ∑MeO-PBDEs, whereas trophic dilution was observed for ∑OH-PBDEs in both regions. This is one of very few investigations on trophic transfer of PBDE metabolites in the Antarctic and Arctic regions and will further strengthen concerns about the ecological risk of PBDE metabolites in remote areas.

Plastics everywhere: first evidence of polystyrene fragments inside the common Antarctic collembolan Cryptopygus antarcticus

There is evidence and serious concern that microplastics have reached the most remote regions of the planet, but how far have they travelled in terrestrial ecosystems? This study presents the first field-based evidence of plastic ingestion by a common and central component of Antarctic terrestrial food webs, the collembolan Cryptopygus antarcticus. A large piece of polystyrene (PS) foam (34 × 31 × 5 cm) covered by microalgae, moss, lichens and microfauna was found in a fellfield along the shores of the Fildes Peninsula (King George Island). The application of an improved enzymatic digestion coupled with Fourier transform infrared microscopy (µ-FTIR), unequivocally detected traces of PS (less than 100 µm) in the gut of the collembolans associated with the PS foam and documented their ability to ingest plastic. Plastics are thus entering the short Antarctic terrestrial food webs and represent a new potential stressor to polar ecosystems already facing climate change and increasing human activities. Future research should explore the effects of plastics on the composition, structure and functions of polar terrestrial biota.

Age dependence accumulation of organochlorine pesticides and PAHs in needles with different forest types, southeast Tibetan Plateau

In this study, organochlorine pesticides (OCPs) and polycyclic aromatic hydrocarbons (PAHs) in needle leaves with different ages were measured in three prevalent coniferous forests including spruce, fir and pinus in southeast Tibetan Plateau (TP) to investigate accumulation behavior of persistent organic pollutants (POPs) during entire growth cycle of needles. The accumulation concentration of POPs was higher in pinus and fir needles than in spruce needles. Concentrations for most of OCPs significantly increased with needle ages, especially dichlorodiphenyltrichloroethane (DDT) and its metabolites showed more remarkable increasing trend than hexachlorocyclohexane isomers (HCHs) and hexachlorobenzene (HCB) in the three tree species. However, age dependence accumulation of PAHs was not observed in most cases, possibly due to its easier degradation property and the influence by dramatic change of ambient atmospheric concentration of PAHs. The lipid normalized concentrations in needles exhibited similar accumulation pattern with that of dry weight basis. The controlling factors for concentration variation in needles were identified using multiple linear regression. The suitability of these needle species acting as potential passive sampler for atmospheric POPs was evaluated. The different-age needles could reflect atmospheric OCP concentrations in the past long-term trend. Findings of this study provide guidance in use of needle as passive samples for the background monitoring of the atmospheric contamination at remote and poorly accessible locations such as the TP.

Exposure to organochlorine pesticides and the risk of type 2 diabetes in the population of East China

Organochlorine pesticides (OCPs) have been reported to be associated with an elevated risk of type 2 diabetes, although no study has focused on such associations in Chinese populations. In this case-control study, we aimed to explore the associations between OCPs and type 2 diabetes and their potential mechanisms in a population from East China. Participants diagnosed with type 2 diabetes and nondiabetic participants from Shandong Province, East China, were enrolled in this case-control study. Six OCPs (β-HCH, trans-chlordane, trans-nonachlor, p,p'-DDE, p,p'-DDT and mirex/kepone) were detected in more than 75% of serum samples. Logistic regression analysis and multiple linear regression analysis were used to assess the associations between OCP exposure and the outcomes. After adjusting for potential confounding factors such as age, sex and body mass index, all six OCPs showed positive associations with type 2 diabetes in a linear dose-response manner. Serum concentrations of β-HCH and p,p'-DDE were associated with higher levels of fasting plasma glucose in participants without diabetes, although no OCPs showed significant associations with hemoglobin A1c. In addition, certain OCPs showed significantly positive associations with triglycerides, total cholesterol, and low-density lipoprotein cholesterol and negative relationships with high-density lipoprotein cholesterol in nondiabetics, indicating that OCP exposure may disrupt lipid metabolism. Findings in the current study indicated that OCPs may be a diabetogenic factor in the population of this study. To our knowledge, this is the first study to investigate the associations between OCP exposure and type 2 diabetes in a Chinese population.

Arctic cleansing diet: Sex-specific variation in the rapid elimination of contaminants by the world's champion migrant, the Arctic tern

Contamination of Arctic marine environments continues to be a concern for wildlife managers. Because the Arctic is a sink for the long-range transport of persistent organic pollutants (POPs), many studies have detected high concentrations of POPs in various Arctic birds. In this study from high Arctic Canada, we show that male Arctic terns (Sterna paradisaea), which migrate from the Antarctic to the Arctic annually to breed, decline in concentrations of many hepatic POPs through the breeding season. This suggests that local Arctic food webs are less contaminated than regions where terns fed during or migration, despite that the terns appear to feed at a higher trophic level near their colony.

Presence of organochlorine pollutants in fat and scats of pinnipeds from the Antarctic Peninsula and South Shetland Islands, and their relationship to trophic position

Antarctica is still considered one of the few pristine areas in the globe. Despite this, several studies have shown phased out organic pollutants are present in several environmental abiotic and biological compartments. This study, based on blubber and fecal samples collected from five species of Antarctic pinnipeds, assessed the relationship between organochlorine pesticide (OCs) levels and trophic characterization using stable isotope analysis (δ¹³C and δ¹⁵N). The prevailing pollutants found in blubber were hexachlorocyclohexane isomers (HCHs), hexachlorobenzene (HCB), Heptachlor and Aldrin (0.84-564.11 ng g^-1 l.w.). We also report a high presence of HCHs, Endrin, Dichlorodiphenyltrichloroethane (DDTs) and Methoxychlor (4.50-363.86 ng g^-1 d.w.) in feces suggesting a detoxification mechanism. All the species tend towards high trophic positions (3.4-4.9), but with considerable variation in trophic niche and organochlorine pesticide concentrations per sampling site. This finding suggests that differences in pesticide levels in individuals are associated to foraging ecology.

Associations between Exposure to Persistent Organic Pollutants and Thyroid Function in a Case-Control Study of East China

Animal studies have indicated that persistent organic pollutants (POPs) affect thyroid hormone homeostasis, while epidemiological studies involving human have not shown consistent results. In this study, we investigated the associations between POP exposure and thyroid function among adult population of East China. One hundred eighty-six participants diagnosed with thyroid disease and 186 participants without thyroid disease from Shandong, China were enrolled in the case-control study during 2016 to 2017. We found that POP exposure was significantly and positively associated with the risk of thyroid disease. The association of thyroid disease with a sum of 17 POPs followed a nonmonotonic dose response, with an adjusted odds ratio of 2.09 (95% confidence intervals: 1.13-3.87, p = 0.019) for the second quartile. Among 186 participants in the control group, concentrations of POPs showed negative associations with triiodothyronine (T3), free T3 (FT3), thyroxine (T4), and free T4 (FT4) in males and positive associations with T4 and FT4 in females. Taken together, these findings suggest that POP exposure can disrupt thyroid hormone homeostasis and increase the risk of thyroid disease.

Persistent organic pollutants in lakes of Broknes peninsula at Larsemann Hills area, East Antarctica

Anthropogenic activity in East Antarctica has increased since the last 2-3 decades because of various scientific expeditions. Additionally, global pollution due to various newly introduced pollutants like pesticides is on use since the past century and many factors contribute to contamination even in Antarctica. During thirty fourth Indian Scientific Expedition to Antarctica (ISEA) in austral summer of 2014-2015, fifteen lake water samples were collected from five different lakes at Broknes peninsula, Larsemann Hills, East Antarctica. Persistent Organic Pollutants (POPs) residue levels found in lake water samples varied from 10.33-70.00 pg/mL in five different lakes. Presence of p,p'-DDT was detected in all different lakes but high concentration found in P4 lake water. After study confirms that Broknes peninsula in the Larsemann Hills area, East Antarctica has a trace amount of POPs which is an alarming situation and needs to be investigated further to maintain the pristine environment in Antarctica. The presence of POPs may be attributed to orographic effects, migratory birds, biomagnification and anthropogenic sources. In the future, new emerging pollutants must be analyzed like microplastics, phthalate, Paraxanthene etc.

Air monitoring of polychlorinated biphenyls, polybrominated diphenyl ethers and organochlorine pesticides in West Antarctica during 2011-2017: Concentrations, temporal trends and potential sources

Annual air samples were collected at various sites in the Fildes Peninsula, West Antarctica from December 2010 to January 2018 using XAD-2 resin passive air samplers to investigate concentrations, temporal trends and potential sources of persistent organic pollutants (POPs) in Antarctic air. Relatively low concentrations of polychlorinated biphenyls (PCBs) (Σ₁₉PCBs: 1.5-29.7 pg/m³), polybrominated diphenyl ethers (PBDEs) (Σ₁₂PBDEs: 0.2-2.9 pg/m³) and organochlorine pesticides (OCPs) (Σ₁₃OCPs: 101-278 pg/m³) were found in the atmosphere of West Antarctica. PCB-11, BDE-47 and hexachlorobenzene (HCB) were the predominant compounds in the atmosphere. The concentrations of PCBs, HCHs, DDTs and endosulfans were found to show decreasing temporal trends, whereas uniform temporal trends were observed for HCB. The atmospheric half-life values for PCBs, HCHs, DDTs and endosulfans in Antarctic air were estimated for the first time, using regressions of the natural logarithm of the concentrations versus the number of years, obtaining the values of 2.0, 2.0, 2.4 and 1.2 year, respectively. An increasing ratio of α-HCH/γ-HCH indicated long residence time for α-HCH and possible transformation of γ-HCH to α-HCH in the atmosphere. The ratios of p,p'-DDT/p,p'-DDE were mostly lower than unity in this study, which could be attributed to aged sources. It was found that long-range atmospheric transport was still considered to be the main contributing factor to the atmospheric levels of the POPs in West Antarctica whereas the contribution of human activities at the Chinese Great Wall Station was minor. The results of this study give a view on the most recent temporal trends and provide new insights regarding the occurrence of various POPs in the Antarctic atmosphere.

Characterization of Tibetan Soil As a Source or Sink of Atmospheric Persistent Organic Pollutants: Seasonal Shift and Impact of Global Warming

Background soils are reservoirs of persistent organic pollutants (POPs). After decades of reduced primary emissions, it is now possible that the POPs contained in these reservoirs are being remobilized because of climate warming. However, a comprehensive investigation into the remobilization of POPs from background soil on the largest and highest plateau on Earth, the Tibetan Plateau (TP), is lacking. In this study, a sampling campaign was carried out on the TP at three background sites with different land cover types (forest, meadow and desert). Field measurements of the air-soil exchange of POPs showed that previous prediction using empirical models overestimated the values of the soil-air partitioning coefficient ( K_SA), especially for chemicals with K_OA > 9. The direction of exchange for γ-HCH, HCB, and PCB-28 overlapped with the air-soil equilibrium range, but with a tendency for volatilization. Their emission fluxes were 720, 2935, and 538 pg m^-2 day^-1, respectively, and were similar in extent to those observed for background Arctic soil in Norway. Nam Co and Ngari are also permafrost regions, and most chemicals at these two sites exhibited volatilization. This is the first result showing that permafrost can also emit POPs. Seasonally, we found that chemicals tended to be re-emitted from soils to the atmosphere in winter and deposited from the air to the soil in summer. This finding is opposite to most previous results, possibly because of the higher air-soil concentration gradient caused by the prevailing transport of POPs in summer. Climate warming exerts a strong influence on air-soil exchange, with an increase of 1 °C in ambient temperature likely leading to an increase of Tibetan atmospheric inventories of POPs by 60-400%.

Mercury and Organochlorines in the Terrestrial Environment of Schirmacher Hills, Antarctica

We report the levels of mercury (Hg) and nine organochlorine pesticides [OCPs: α-hexachlorocyclohexane (HCH), β-HCH, γ-HCH, δ-HCH, α-Endosulfan, β-Endosulfan, Endosulfan sulfate, p,p'-dichlorodiphenyldichloroethylene (DDE) and p,p'-dichlorodiphenyldichloroethane (DDD)] in the terrestrial environment (moss and soil) and water (OCPs only) of Schirmacher Hills, Antarctica. This area has never been studied for mercury and not for OCPs since 1988. Mercury levels in moss, 66 ± 37 ng/g dry weight (dw), are comparable to other Antarctic locations. Levels of α-HCH, below detection to 4.48 ng/g dw, and p,p'-DDE, below detection to 31 ng/g dw, in mosses are lower or marginally higher than other Antarctic locations. No other OCPs were detected in moss. None of the OCPs were detected in soil. This suggests that Schirmacher Hills may be considered as a background site with respect to mercury and analyzed OCPs, despite the operation of two old research stations (Maitri, est. 1989, and Novolazarevskaya, est. 1961) in the region.

Factors influencing the ecological and human health risks of DDTs in soils and air at the isomeric and enantiomeric levels

Even though the application of dichlorodiphenyltrichloroethanes (DDTs) has been restricted for over 30 years, their ubiquitous existence still poses profound adverse impacts on ecosystem and human health. In this study, simultaneous soil and air sampling campaigns at different functional areas were conducted in warm and cold seasons. Based on the residue levels and enantiomeric signatures of DDT and its metabolites in soils and air, the parameters influencing ecological and human health risks were explored. ΣDDT concentrations in soils correlated positively with organic matter (OM) and negatively with pH, whereas atmospheric DDT levels were primarily facilitated by increased temperature. High temperature and low soil pH were also favorable for the transformation of DDT into its metabolites. The inhabitants living in agricultural regions or in areas with higher soil OM or pH < 7 were exposed to higher existing and potential health risks of soil DDTs. In addition, at lower temperatures, the existing and potential carcinogenic risks of DDTs from soil exposure were higher, whereas risks from air inhalation were lower. Health risks would be increased when considering the enantioselective toxicity of o,p'-DDT and o,p'-DDD. The results from this study could provide baseline support for risk control and avoidance of DDTs.

Occurrence and partitioning behavior of organophosphate esters in surface water and sediment of a shallow Chinese freshwater lake (Taihu Lake): Implication for eco-toxicity risk

Organophosphate esters (OPEs) are ubiquitous in the aquatic environment, which have been considered or suspected as carcinogens and neurotoxicants. In this study, the occurrence, spatial distribution, potential sources, partitioning character and potential risks of OPEs in the surface water and sediment collected from Taihu Lake were investigated. The concentrations of ∑12 OPEs varied from 1.0 × 10² to 1.7 × 10³ ng/L for the surface water and from 8.1 to 4.2 × 10² ng/g dw for the sediment. Trimethyl phosphate (TEP) was the predominant congener in the surface water, while Tris(2-ethylhexyl) phosphate (TEHP) in the sediment. Positive correlations between OPEs indicated that they may have the same sources and/or similar environmental behavior. The pseudo-partitioning values of OPEs ranged from 0.59 to 6.5 × 10⁴ L/kg. TEHP has the highest pseudo-partitioning coefficient, which indicated that TEHP inclined to be enriched in the sediment in Taihu Lake. Risk assessment (RQ) showed that individual OPEs in the surface water and sediment posed no/low risk to aquatic organisms, except 2-Ethylhexyl diphenyl phosphate (EHDPP) (moderate risk) in water.

Spatiotemporal distribution and risk assessment of organophosphate esters in sediment from Taihu Lake, China

The occurrence and spatiotemporal distribution of 12 organophosphate esters (OPEs) were investigated in the sediments collected from Taihu Lake. Compared to the same lake in 2012 (3.4-14 ng/g dw), the concentrations of ∑12 OPEs in sediments ranged from 10.76 to 335.37 ng/g dw and from 8.06 to 425.39 ng/g dw in 2015 and in 2016, respectively, indicating that the OPEs levels in Taihu Lake have aggravated, recently. TEHP was the most abundant compound of the OPEs, which suggested that TEHP was the most widely used around Taihu Lake recently. The positive correlations between some of individual OPEs and the principal components analysis suggested the same potential sources for them. The strong positive correlation between ∑BPs and TOC content indicated that TOC content was one of the factors affected the distribution of ∑OPEs in the sediment. Risk quotient (RQ) for OPEs showed no high eco-toxicity risk in sediment for aquatic organisms.

Tissue distribution and maternal transfer of persistent organic pollutants in Kentish Plovers (Charadrius alexandrines) from Cangzhou Wetland, Bohai Bay, China

Several persistent organic pollutants, including polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs), polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs) and organochlorine pesticides (OCPs), were comprehensively investigated in the egg, muscle and liver samples of Kentish Plover (Charadrius alexandrines) collected from Cangzhou Wetland in western Bohai Bay, China. DDTs were the most abundant contaminants (35.4-9853ngg^-1 lipid weight, lw), followed by HCHs, PCBs, PBDEs and HCB. PCDD/Fs exhibited the lowest concentrations in all tissues (8.74-4763pgg^-1 lw). PCBs and PCDD/Fs were dominated by penta- and hexa-homologs, and PBDEs mostly consisted of the signature congeners of BDE formulations, such as BDE-209, -47, -153 and -99. Significant correlations were found between the lipid-normalized concentrations in muscle and liver (r: 0.37-0.90, p<0.05) and no significant differences (p<0.05), indicating the homogenous distribution of POPs in tissue lipids at steady state. The ratios of concentrations in muscle and liver (M/L) ranged from 0.20 to 1.51, and higher ratios of M/L were found for those compounds with log K_ow in the range of 6.5-7.0, suggesting the preferential accumulation of mid-halogenated compounds in muscle. Significant correlations were generally observed between the concentrations in egg and the maternal tissue (p<0.05). The concentration ratios of egg to liver (E/L) were in the range of 0.10-1.24 except for p,p'-DDT (12.7), and compounds with log K_ow of 6.5-7.0 exhibited higher E/L ratios, suggesting the selective maternal transfer of mid-halogenated compounds.

Spatial and seasonal variations in air-soil exchange, enantiomeric signatures and associated health risks of hexachlorocyclohexanes (HCHs) in a megacity Hangzhou in the Yangtze River Delta region, China

Large amounts of hexachlorocyclohexanes (HCHs) have been historically applied in the Yangtze River Delta (YRD) region, China. Estimating the air-soil exchange of HCHs after >30years of restricted use is important for understanding their cycling in the environment. In this study, air and soil samples were concurrently collected in two seasons at agricultural and industrial sites from a megacity in the YRD region. The concentrations of HCH isomers and the enantiomeric fractions of chiral α-HCH were determined. The mean concentrations of ∑HCHs in soils from an agricultural area (AA) and an eco-industrial park (EIP) were 1.74ng/g and 0.652ng/g, respectively, in winter, and 0.723ng/g and 0.350ng/g, respectively, in summer. The mean concentrations of ∑HCHs in the air from the AA and the EIP were 31.2pg/m³ and 47.7pg/m³, respectively, in winter, and 45.0pg/m³ and 50.0pg/m³, respectively, in summer. The variations in spatial and seasonal distributions might be related to diverse geographical factors, soil properties and meteorological conditions. Source identification demonstrated that HCHs in most samples were residues from past use, which was further evidenced by the enantiomeric signatures of chiral α-HCH. A preferential degradation of (-)-α-HCH was showed in soils and summer air, while a preferential depletion of (+)-α-HCH was displayed in winter air. The values of the fugacity fraction (ff) of HCHs suggest a net volatilization from soils to air, but long-range transport may also partly contribute to the atmospheric HCHs according to the results from enantiomeric analysis. The human health risk assessments indicated an absence of noncarcinogenic risks and very low carcinogenic risks for HCHs in both soils and air to human health. Results from this study provide valuable data for assessing the fate and health risks of HCHs in the YRD region.

Removal of a mixture of pesticides by a Streptomyces consortium: Influence of different soil systems

Although the use of organochlorine pesticides (OPs) is restricted or banned in most countries, they continue posing environmental and health concerns, so it is imperative to develop methods for removing them from the environment. This work is aimed to investigate the simultaneous removal of three OPs (lindane, chlordane and methoxychlor) from diverse types of systems by employing a native Streptomyces consortium. In liquid systems, a satisfactory microbial growth was observed accompanied by removal of lindane (40.4%), methoxychlor (99.5%) and chlordane (99.8%). In sterile soil microcosms, the consortium was able to grow without significant differences in the different textured soils (clay silty loam, sandy and loam), both contaminated or not contaminated with the OPs-mixture. The Streptomyces consortium was able to remove all the OPs in sterile soil microcosm (removal order: clay silty loam > loam > sandy). So, clay silty loam soil (CSLS) was selected for next assays. In non-sterile CSLS microcosms, chlordane removal was only about 5%, nonetheless, higher rates was observed for lindane (11%) and methoxychlor (20%). In CSLS slurries, the consortium exhibited similar growth levels, in the presence of or in the absence of the OPs-mixture. Not all pesticides were removed in the same way; the order of pesticide dissipation was: methoxychlor (26%)>lindane (12.5%)>chlordane (10%). The outlines of microbial growth and pesticides removal provide information about using actinobacteria consortium as strategies for bioremediation of OPs-mixture in diverse soil systems. Texture of soils and assay conditions (sterility, slurry formulation) were determining factors influencing the removal of each pesticide of the mixture.

Correlations in the elemental and metabolic profiles of the lichenDirinaria pictaafter road traffic exposure

Diverse metabolites were identified in lichens and their correlations with heavy metals revealed metabolic toxicity and the detoxification mechanism.

Occurrence, profile and spatial distribution of organochlorines pesticides in soil of Nepal: Implication for source apportionment and health risk assessment

Nepal is a landlocked country located between world's two most populous countries-India and China where high level of organochlorines pesticides has been reported from multi-environmental matrices. In this study, we investigated the occurrence, distributions and profile of selected OCP chemicals in surface soil samples (N=72) from four major cities of Nepal. Overall, the sum of total OCPs in soil ranged from 20 to 250ng/g with Biratnagar being the most polluted site in Nepal. DDTs and endosulfans were the most abundant OCP chemicals in soil samples. The concentration of DDTs ranged from 8 to 230ng/g, 8-56ng/g, 8-63ng/g, and 8-27ng/g in surface soil, while endosulfans were in the range of 2.9-3.3ng/g, 2.8-8.7ng/g, 2.8-3.4ng/g, 2.8-3.2ng/g in Biratnagar, Kathmandu, Pokhara and Birgunj, respectively. The isomeric ratio of DDT and their metabolites suggested the ongoing usages of technical DDT as well as dicofol in this region. Lower ratio of α/β-endosulfan indicated past application of endosulfans in Nepal. HCHs were less detected OCPs in soil sample accounting only 4-9% of ∑OCPs. The isomeric ratio of α-/γ-HCH indicated that the HCHs may be originated from mixed source of technical HCH as well as lindane use. Scattered plot of TOC and BC showed they were weakly and positively related with concentration of OCPs in soil. Health risk assessment modeling study of OCPs in soil suggested moderate cancer risk with ingestion being the most potential pathway of OCPs exposure.

A model assessment of the ability of lake water in Terra Nova Bay, Antarctica, to induce the photochemical degradation of emerging contaminants

The shallow lakes located in Terra Nova Bay, Antarctica, are free from ice for only up to a couple of months (mid December to early/mid February) during the austral summer. In the rest of the year, the ice cover shields the light and inhibits the photochemical processes in the water columns. Previous work has shown that chromophoric dissolved organic matter (CDOM) in these lakes is very reactive photochemically. A model assessment is here provided of lake-water photoreactivity in field conditions, based on experimental data of lake water absorption spectra, chemistry and photochemistry obtained previously, taking into account the water depth and the irradiation conditions of the Antarctic summer. The chosen sample contaminants were the solar filter benzophenone-3 and the antimicrobial agent triclosan, which have very well known photoreactivity and have been found in a variety of environmental matrices in the Antarctic continent. The two compounds would have a half-life time of just a few days or less in the lake water during the Antarctic summertime, largely due to reaction with CDOM triplet states ((3)CDOM*). In general, pollutants that occur in the ice and could be released to lake water upon ice melting (around or soon after the December solstice) would be quickly photodegraded if they undergo fast reaction with (3)CDOM*. With some compounds, the important (3)CDOM* reactions might favour the production of harmful secondary pollutants, such as 2,8-dichlorodibenzodioxin from the basic (anionic) form of triclosan.

Persistent organic pollutants and polycyclic aromatic hydrocarbons in penguins of the genus Pygoscelis in Admiralty Bay - An Antarctic specially managed area

Persistent organic pollutants were assessed in fat samples of the Gentoo (Pygoscelis papua), Chinstrap (Pygoscelis antarcticus) and Adélie (Pygoscelis adeliae) penguins collected during the austral summers of 2005/06 and 2006/07 in Admiralty Bay, King George Island, Antarctica. The predominant organic pollutants were PCB (114 to 1115), polycyclic aromatic hydrocarbons (PAHs) (60.1 to 238.7), HCB (<0.3 to 132.2) and BDE-47 (<1.0 to 10.7) in ng g(-1) wet weight. The mean concentrations of the majority of organic pollutants were similar among the three species of penguins. Chicks of all three species showed similar profiles of PCB congeners, with predominance of lower chlorinated compounds. The distribution of PAHs was similar in all birds, with a predominance of naphthalene and alkyl-naphthalene, which are the main constituents of arctic diesel fuel. These data contribute to the monitoring of the continued exposure to organic pollutants in the Antarctic biota.