A 50-year retrospective of persistent organic pollutants in the fat and eggs of penguins of the Southern Ocean

New and legacy persistent organic pollutants (POPs) in breeding seabirds from the East Antarctic

Persistent organic pollutants (POPs) are pervasive and a significant threat to the environment worldwide. Yet, reports of POP levels in Antarctic seabirds based on blood are scarce, resulting in significant geographical gaps. Blood concentrations offer a snapshot of contamination within live populations, and have been used widely for Arctic and Northern Hemisphere seabird species but less so in Antarctica. This paper presents levels of legacy POPs (polychlorinated biphenyls (PCBs), organochlorine pesticides (OCPs) and polybrominated diphenyl ethers (PBDEs)) and novel brominated flame retardants (NBFRs) in the blood of five Antarctic seabird species breeding within Prydz Bay, East Antarctica. Legacy PCBs and OCPs were detected in all species sampled, with Adélie penguins showing comparatively high ∑PCB levels (61.1 ± 87.6 ng/g wet weight (ww)) compared to the four species of flying seabirds except the snow petrel (22.5 ± 15.5 ng/g ww), highlighting that legacy POPs are still present within Antarctic wildlife despite decades-long bans. Both PBDEs and NBFRs were detected in trace levels for all species and hexabromobenzene (HBB) was quantified in cape petrels (0.3 ± 0.2 ng/g ww) and snow petrels (0.2 ± 0.1 ng/g ww), comparable to concentrations found in Arctic seabirds. These results fill a significant data gap within the Antarctic region for POPs studies, representing a crucial step forward assessing the fate and impact of legacy POPs contamination in the Antarctic environment.

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.

Evaluation of PCDD/Fs, PCBs and PBDEs in two penguin species from Antarctica

Persistent Organic Pollutants (POPs) are a global threat, but impacts of these chemicals upon remote areas such as Antarctica remain unclear. Penguins can be useful species to assess the occurrence of POPs in Antarctic food webs. This work's aim was the evaluation of polychlorodibenzo-p-dioxins and furans (PCDD/Fs), polychlorinated biphenyls (PCBs) and polybrominated diphenyl ethers (PBDEs) in eggs of two penguin species, chinstrap (Pygoscelis antarticus) and gentoo penguins (Pygoscelis papua), breeding in the South Shetland Islands. Results showed a common pattern in POP levels regardless of the species, characterized by a major abundance of PCBs (98 %), followed by PBDEs (1-2%) and PCDD/Fs (<1 %). Concentrations of POPs in chinstrap and gentoo penguin eggs were 482 and 3250 pg/g l.w., respectively. PCBs, PBDEs and PCDD/Fs were found at higher concentrations in chinstrap penguin eggs, being these differences significant for PBDEs. Interspecies differences in POP levels agree well with potential trophic position differences among species due to changes in prey composition and foraging areas. POP profiles were dominated by congeners with a low degree of halogenation. Our results therefore suggest similar sources of POPs in the food webs exploited by both species and in both cases attributable to the long-range transportation rather than to the presence of local sources of POPs. TEQs were found between 1.38 and 7.33 pg/g l.w. and followed the pattern non-ortho dl-PCBs > PCDFs > PCDDs > mono-ortho dl-PCBs. TEQ values were lower than the threshold level for harmful effects in birds of 210 pg/g WHO-TEQ/g l.w.

A Pest or Otherwise? Encounter of Oryctes rhinoceros (Coleoptera: Scarabaeidae) with Persistent Organic Pollutants

Simple Summary

A native, widely spread beetle, Oryctes rhinoceros, in Southeast Asia may clean up some of the persistent organic pollutants (POPs) for us if guarded in a controlled manner. Some xenobiotics persisting in our environment may cause harmful effects to the living creatures within their food web via a so-called “bioaccumulation effect”. The encounter of wild creatures with the POPs appears inevitable. Luckily, this study revealed that the proper breeding of the commonly seen beetle could degrade more than 95% of some studied POPs simply by ingestion. The beetle larvae tolerated different POPs at various extents, yet through an acclimation operation, the beetle’s mortality rate could be greatly reduced. Even though O. rhinoceros is considered a pest for some valuable corps, its removal of POPs in a natural, efficient and passive (i.e., fewer energy inputs) manner makes this alternative promising and deserving of further explorations.

Abstract

The potential use of invertebrates as bioreactors to treat environmental pollutants is promising and of great interest. Three types of the persistent organic pollutants (POPs), namely pentachlorophenol (PCP), PAHs (naphthalene and phenanthrene) and dieldrin (DLN), were spiked in soil and treated by using Oryctes rhinoceros larvae, a known pest of coconut trees in southeast Asia, and also the indicators of POP toxicity and the fate and degradability of the ingested POPs were assessed. The larvae were tested at various levels of the POPs and went through an acclimation process. Without acclimation, the tolerance limits of the larvae toward PCP, PAHs and DLN were 200, 100 and 0.1 mg/kg-soil, respectively, yet with acclimation, the tolerance levels increased to 800, 400 and 0.5 mg/kg-soil, respectively. Biodegradation rates of all the tested POPs were >90% by week 2, with <5% and nearly 0% remaining in the feces and body of the larvae, respectively. The results suggest that the use of the beetle larvae in soil POP decontamination is doable.

Occurrence, distribution, and bioaccumulation of new and legacy persistent organic pollutants in an ecosystem on King George Island, maritime Antarctica

The occurrence and bioaccumulation of new and legacy persistent organic pollutants (POPs), organochlorine pesticides (OCPs), polychlorinated biphenyls (PCBs), polychlorinated naphthalenes (PCNs), hexabromocyclododecanes (HBCDs), and Dechlorane Plus (DPs) and their related compounds (Dechloranes) in an ecosystem on King George Island, Antarctica are investigated. The new and legacy POPs were widely detected in the animal samples collected from Antarctica, which included Limpet, Antarctic cod, Amphipods, Antarctic icefish, Gentoo and Chinstrap penguins, Kelp gull, and South polar skua. The trophic magnification factors indicated that the levels of PCNs and HBCDs, as well as the legacy POPs, were magnified through the food web, whereas DPs might be diluted through the trophic levels contradicting the classification of Dechloranes as POPs. This is one of the first extensive surveys on PCNs, HBCDs, and Dechloranes, which provides unique information on the distribution and trophic biomagnification potential of the new and legacy POPs in the Antarctic region.

Legacy and Emerging Persistent Organic Pollutants in Antarctic Benthic Invertebrates near Rothera Point, Western Antarctic Peninsula

Pollutant levels in polar regions are gaining progressively more attention from the scientific community. This is especially so for pollutants that persist in the environment and can reach polar latitudes via a wide range of routes, such as some persistent organic pollutants (POPs). In this study, samples of Antarctic marine benthic organisms were analyzed for legacy and emerging POPs (polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs), and organochlorine pesticides) to comprehensively assess their current POP concentrations and infer the potential sources of the pollutants. Specimens of five benthic invertebrate species were collected at two distinct locations near Rothera research station on the Antarctic Peninsula (67°35'8 ̋ S and 68°7'59 ̋ W). Any impact of the nearby Rothera station as a local source of pollution appeared to be negligible. The most abundant chemicals detected were hexachlorobenzene (HCB) and BDE-209. The highest concentrations detected were in limpets and sea urchins, followed by sea stars, ascidians, and sea cucumbers. The relative congener patterns of PCBs and PBDEs were similar in all of the species. Some chemicals (e.g., heptachlor, oxychlordane, and mirex) were detected in the Antarctic invertebrates for the first time. Statistical analyses revealed that the distribution of the POPs was not only driven by the feeding traits of the species but also by the physicochemical properties of the specific compounds.

Microplastics in gentoo penguins from the Antarctic region

There is growing evidence that microplastic pollution (<5 mm in size) is now present in virtually all marine ecosystems, even in remote areas, such as the Arctic and the Antarctic. Microplastics have been found in water and sediments of the Antarctic but little is known of their ingestion by higher predators and mechanisms of their entry into Antarctic marine food webs. The goal of this study was to assess the occurrence of microplastics in a top predator, the gentoo penguin Pygoscelis papua from the Antarctic region (Bird Island, South Georgia and Signy Island, South Orkney Islands) and hence assess the potential for microplastic transfer through Antarctic marine food webs. To achieve this, the presence of microplastics in scats (as a proof of ingestion) was investigated to assess the viability of a non-invasive approach for microplastic analyses in Antarctic penguins. A total of 80 penguin scats were collected and any microplastics they contained were extracted. A total of 20% of penguin scats from both islands contained microplastics, consisting mainly of fibers and fragments with different sizes and polymer composition (mean abundance of microplastics: 0.23 ± 0.53 items individual^-1 scat, comprising seven different polymers), which were lower values than those found for seabirds in other regions worldwide. No significant differences in microplastic numbers in penguin scats between the two regions were detected. These data highlight the need for further assessment of the levels of microplastics in this sensitive region of the planet, specifically studies on temporal trends and potential effects on penguins and other organisms in the Antarctic marine food web.

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.

Solar UV radiation in a changing world: roles of cryosphere-land-water-atmosphere interfaces in global biogeochemical cycles

Global change influences biogeochemical cycles within and between environmental compartments (i.e., the cryosphere, terrestrial and aquatic ecosystems, and the atmosphere). A major effect of global change on carbon cycling is altered exposure of natural organic matter (NOM) to solar radiation, particularly solar UV radiation. In terrestrial and aquatic ecosystems, NOM is degraded by UV and visible radiation, resulting in the emission of carbon dioxide (CO2) and carbon monoxide, as well as a range of products that can be more easily degraded by microbes (photofacilitation). On land, droughts and land-use change can reduce plant cover causing an increase in exposure of plant litter to solar radiation. The altered transport of soil organic matter from terrestrial to aquatic ecosystems also can enhance exposure of NOM to solar radiation. An increase in emission of CO2 from terrestrial and aquatic ecosystems due to the effects of global warming, such as droughts and thawing of permafrost soils, fuels a positive feedback on global warming. This is also the case for greenhouse gases other than CO2, including methane and nitrous oxide, that are emitted from terrestrial and aquatic ecosystems. These trace gases also have indirect or direct impacts on stratospheric ozone concentrations. The interactive effects of UV radiation and climate change greatly alter the fate of synthetic and biological contaminants. Contaminants are degraded or inactivated by direct and indirect photochemical reactions. The balance between direct and indirect photodegradation or photoinactivation of contaminants is likely to change with future changes in stratospheric ozone, and with changes in runoff of coloured dissolved organic matter due to climate and land-use changes.

Emerging contaminants and nutrients in a saline aquifer of a complex environment

The quality and availability of water has become a pressing issue worldwide, being particularly important in semi-arid regions, where climate change has aggravated the problem. The use of anthropogenic chemicals, classified as emerging pollutants, adds to the problem representing a treat, since they are not regulated and have a potential impact on human and environmental health. This pressing problem has not been studied widely in complex environments like the one we present here. Distribution and seasonal variability of fecal sterols, alkylphenols, pesticides (emerging pollutants) and nutrients were determined in 35 wells used for agriculture and human consumption in the Valley of Maneadero, located in the semi-arid region of Baja California, Mexico. The presence of the tested pollutants in the saline aquifer was heterogeneous, showing important differences in concentration and distribution. Wells destined for household use showed the highest variability. In these wells, anthropogenic fecal sterols were detected and, alkylphenols, such as octyphenol and nonylphenol had maximum concentrations (2.7 ng/mL). In agriculture and urban wells, we identified DDT and organochlorine pesticides, as well as myclobutanil, which is considered a modern pesticide. Nitrates were identified in concentrations above international standards, mainly during the dry season, in both the agricultural and urban areas. As emerging pollutants represent a negative effect on environmental and human health, this is the first paper showing the importance of measuring this type of pollutant in agricultural/semi-urban areas, especially in aquifers that have been overexploited and communities that have relied on the use of septic tanks for decades.