Levels and trends of toxaphene and chlordane-related pesticides in peregrine falcon eggs from South Greenland

An insights of organochlorine pesticides categories, properties, eco-toxicity and new developments in bioremediation process

Organochlorine pesticides (OCPs) have been used in agriculture, increasing crop yields and representing a serious and persistent global contaminant that is harmful to the environment and human health. OCPs are typically bioaccumulative and persistent chemicals that can spread over long distances. The challenge is to reduce the impacts caused by OCPs, which can be achieved by treating OCPs in an appropriate soil and water environment. Therefore, this report summarizes the process of bioremediation with commercially available OCPs, considering their types, impacts, and characteristics in soil and water sources. The methods explained in this report were considered to be an effective and environmentally friendly technique because they result in the complete transformation of OCPs into a non-toxic end product. This report suggests that the bioremediation process can overcome the challenges and limitations of physical and chemical treatment for OCP removal. Advanced methods such as biosurfactants and genetically modified strains can be used to promote bioremediation of OCPs.

Metabolomic profiling to assess the effects of chlordanes and its bioaccumulation characteristics in chicken embryo

Although chlordane-related compounds (CHLs) have been regulated, a variety of CHLs are still identified and detected in wild birds and eggs. Embryo is one of fragile periods and is very susceptible to toxic effects of pollutants. In this study, the fate of CHLs during embryo development and degradation of CHLs in neonatal chick were investigated. During embryo development, CHLs were mainly distributed to the liver and muscle, in which trans-nonachlor and an octachlorochlordane (MC5) were hardly metabolized and showed the high persistence, implying a greater risk to birds' offspring. CHLs with the lower K_ow were found to be higher uptake efficiency in embryo, implying contaminants with the lower lipophilicity may contribute to their transport to embryo. Furthermore, the effects of CHLs on the metabolome of neonatal chicks was evaluated. The ether lipid metabolism and glycerophospholipid metabolism were found to be significantly affected, which may disturb the angiogenesis and endothelial cell migration in embryogenesis. Taken together, the lipophilicity of contaminants might be a main factor influencing their transport to embryo, and metabolomics results improve understanding of the effects of CHLs on embryo.

Pesticide impacts on avian species with special reference to farmland birds: a review

For decades, we have observed a major biodiversity crisis impacting all taxa. Avian species have been particularly well monitored over the long term, documenting their declines. In particular, farmland birds are decreasing worldwide, but the contribution of pesticides to their decline remains controversial. Most studies addressing the effects of agrochemicals are limited to their assessment under controlled laboratory conditions, the determination of lethal dose 50 (LD₅₀) values and testing in a few species, most belonging to Galliformes. They often ignore the high interspecies variability in sensitivity, delayed sublethal effects on the physiology, behaviour and life-history traits of individuals and their consequences at the population and community levels. Most importantly, they have entirely neglected to test for the multiple exposure pathways to which individuals are subjected in the field (cocktail effects). The present review aims to provide a comprehensive overview for ecologists, evolutionary ecologists and conservationists. We aimed to compile the literature on the effects of pesticides on bird physiology, behaviour and life-history traits, collecting evidence from model and wild species and from field and lab experiments to highlight the gaps that remain to be filled. We show how subtle nonlethal exposure might be pernicious, with major consequences for bird populations and communities. We finally propose several prospective guidelines for future studies that may be considered to meet urgent needs.

Enantioselective characteristics, bioaccumulation and toxicological effects of chlordane-related compounds in laying hens

Chlordane-related compounds are ubiquitously detected in the environment and can transfer and accumulate to animals through food chain to cause adverse effects. In this study, the dynamic distribution and the enantiomeric profile of chlordane-related compounds in laying hens over time were investigated. The effect of these compounds on immune-associated cells in the intestinal tract and histopathology in some tissues were also evaluated after long-term exposure. The chlordane-related compounds preferentially accumulated in fat, followed by the intestines, ovum, and egg yolk during long-term exposure. The metabolites heptachlor epoxide and oxychlordane were mainly formed in the liver of hens by epoxidation or hydroxylation. The high accumulation ratios of trans-nonachlor and MC5 were found in ovum and egg yolk after long-term exposure, implying a greater risk to the hens' offspring. Chlordane-related compounds may cause abnormal lipometabolism and glycometabolism in liver of hens. Additionally, (-)-Cis-chlordane was dominant in all tissues of laying hens and its dominance increased over time. Conversely, (+)-isomer of metabolite oxychlordane was overwhelmingly dominant during the experiment. These findings about enantioselectivity, metabolic processes and toxicological effects are crucial in understanding the exposure risk of chlordane-related compounds.

Perfluoroalkyl substances (PFASs) and polychlorinated naphthalenes (PCNs) add to the chemical cocktail in peregrine falcon eggs

A suite of perfluoroalkyl substances (PFASs) and polychlorinated naphthalenes (PCNs) were determined in 41 peregrine falcon eggs collected in South Greenland between 1986 and 2014. Median concentrations of perfluorinated sulfonic acids (ΣPFSA) and perfluorinated carboxylic acids (ΣPFCA) were 303 ng/g dry weight (dw) (58 ng/g wet weight, ww) and 100 ng/g dw (19 ng/g ww), respectively, which was comparable to other studies. Perfluorooctane sulfonate (PFOS) accounted for 94% on average of all PFSAs, but did not show a significant time trend. Perfluorohexane sulfonate (PFHxS), perfluoroheptane sulfonate (PFHpS) and perfluorodecane sulfonate (PFDS) showed non-linear decreases over the study period, while some long-chain PFCAs increased significantly. The PCN profile was dominated by the penta-, hexa- and tetrachlorinated congeners CN-52/60, CN-66/67 and CN-42. CN-54, an indicator of combustion, accounted for 2.4% of ΣPCN on average. All PCN congeners showed a decreasing tendency, which was significant for lipid-normalized concentrations of CN-53, CN-54 and CN-63. The ΣPCN median concentration was 21 ng/g lipid weight, which is in the high end of concentrations reported for bird eggs. The PCN and PFAS concentrations add to an already high contaminant burden and a complex chemical cocktail in the peregrine falcon population in Greenland, mainly reflecting contaminant exposure during migration and winter stays in Central and South America.

Twenty years of monitoring of persistent organic pollutants in Greenland biota. A review

The Arctic Monitoring and Assessment Programme (AMAP) is a working group under the Arctic Council with the aim to monitor and assess temporal trends of contaminants in Arctic ecosystems. The Greenland AMAP Core programme was established to contribute to this effort. The Core programme includes three main components; routine monitoring, retrospective studies and new POP screening studies. The programme is based on an adaptive approach, which has led to changes throughout the years. An overview of the temporal trends during the last two to three decades is presently given together with selected examples of different characteristic trends of POPs. The results show how tissue banked samples and retrospective studies has helped in establishing time-series of compounds of emerging concern. Lastly, the statistical power of the Greenlandic time-series is discussed. The lesson learned is that trend monitoring improves with samples over time, and only pays off after decades of data are generated.

Dioxins, PCBs, chlorinated pesticides and brominated flame retardants in free-range chicken eggs from peri-urban areas in Arusha, Tanzania: Levels and implications for human health

The environment in the northern part of Tanzania is influenced by rapid population growth, and increased urbanization. Urban agriculture is common and of economic value for low income families. In Arusha, many households sell eggs from free-ranging backyard chicken. In 2011, 159 eggs from different households in five different locations in Arusha were collected, homogenized, pooled into 28 composite samples and analyzed for a wide selection of POPs. Levels of POPs varied widely within and between the locations. The levels of dieldrin and ΣDDT ranged between 2 and 98,791 and 2 and 324ng/g lipid weight (lw), respectively. EU MRLs of 0.02mg/kg dieldrin for eggs were exceeded in 4/28 samples. PCBs, HCHs, chlordanes, toxaphenes and endosulfanes were found at lower frequency and levels. Brominated flame retardants (BFRs), e.g polybrominated diphenylethers (PBDEs), hexabromocyclododecane (HBCD) and 1,2-bis(2,4,6-tribromphenoxy)ethane (BTBPE) were present in 100%, 60% and 46% of the composite samples, respectively. Octa-and deca-BDEs were the dominating PBDEs and BDE 209 levels ranged between <LOQ (limit of quantification) - 312ng/g lw. Dioxins were measured using the DR-LUC bio-assay and found in levels of <LOQ - 20pg bio-TEQs/g lw. Four samples (13%) exceeded the maximum level of 5pg/g total WHO-TEQs for hen eggs set by the Commission Regulation (EU) No 1259/2011. The daily/weekly intake was calculated and risk was characterized for all compounds comparing with available toxicity reference values (TRVs) such as the provisional tolerable intake (PTDI) or Reference Doses (RfDs). In one sample dieldrin exceeded the PTDI (100ng/kgbw/day). Correlation was found between bio-TEQs and lipid adjusted levels of ΣPBDEs, suggesting similar sources. Open fires in backyards may be one of the sources for contamination of eggs with BFRs and dioxins.

Toxaphene in the aquatic environment of Greenland

The octa- and nonachlorinated bornanes (toxaphene) CHBs 26, 40, 41, 44, 50 and 62 were analysed in Arctic char (Salvelinus alpinus), shorthorn sculpin (Myoxocephalus scorpius), ringed seal (Pusa hispida) and black guillemot eggs (Cepphus grylle) from Greenland. Despite their high trophic level, ringed seals had the lowest concentrations of these species, with a Σ6Toxaphene median concentration of 13-20 ng/g lipid weight (lw), suggesting metabolisation. The congener composition also suggests transformation of nona- to octachlorinated congeners. Black guillemot eggs had the highest concentrations (Σ6Toxaphene median concentration of 971 ng/g lw). Although concentrations were higher in East than in West Greenland differences were smaller than for other persistent organic pollutants. In a circumpolar context, toxaphene had the highest concentrations in the Canadian Arctic. Time trend analyses showed significant decreases for black guillemot eggs and juvenile ringed seals, with annual rates of -5 to -7% for Σ6Toxaphene. The decreases were generally steepest for CHBs 40, 41 and 44.