Distribution characteristics and indicator significance of Dechloranes in multi-matrices at Ny-lesund in the Arctic

In recent years, Dechloranes have been widely detected in the environment around the world.However, understanding and knowledge of Dechloranes in remote regions, such as the Arctic,remain lacking. Therefore, the concentrations of 5 Dechloranes in surface seawater, sediment,soil, moss, and dung collected from Ny-lesund in the Arctic were measured with the concentrations 93 pg/L, 342, 325, 1.4, and 258 pg/g, respectively, which were much lower than those in Asian and European regions. The mean ratios of anti-Dechlorane Plus（DP） to total DP（fanti） in seawater, sediment, soil, moss, dung, and atmospheric samples were 0.36, 0.21, 0.18,0.27, 0.66, and 0.43, respectively. Results suggested that the main source of DP in seawater,sediment, soil, and moss was long-range atmospheric transport. However, the ratio identified in dung was different, for which the migration behavior of the organism is probably the main source of DP.

Bioavailability and tissue distribution of Dechloranes in wild frogs(Rana limnocharis) from an e-waste recycling area in Southeast China

Dechlorane Plus （DP）,a flame retardant used as an alternative to decabromodiphenylether, has been frequently detected in organisms, indicating its bioaccumulation and biomagnification potential in aquatic and terrestrial species. However, little data is available on the bioaccumulation of DP in amphibians. Dechlorane Plus and its analogs （DPs） were detected in the liver, muscle and brain tissues of wild frogs （Rana limnocharis）, which were collected from an e-waste recycling site, Southeast China. DP, Mirex, Dec 602 and a dechlorinated compound of DP （anti-Cll I-DP） varied in the range of 2.01-291, 0.650-179, 0.260-12.4, and not detected （nd）-8.67 ng/g lipid weight, respectively. No difference of tissue distribution was found for syn-DP, Mirex and Dec 602 between the liver and muscle tissue （liver/muscle concentration ratio close to 1, p 〉 0.05）. However, higher retention was observed for anti-DP and anti-Cll1-DP in the frog muscle relative to the liver tissue （liver/muscle concentration ratio 〈 1, p 〈 0.05）. Additionally, the blood-brain barrier was found to work efficiently to suppress these compounds entering brain tissues in this species （liver/brain concentration ratio 〉 l, p 〈 0.05）, and the molecular weight was a key factor impacting the extent of the blood-brain barrier. Compared to levels in the muscle and brain tissue, a preferential enrichment of syn-DP was observed in the liver tissue, suggesting the occurrence of stereo-selective bioaccumulation in the wild frog.

Dechloranes exhibit binding potency and activity to thyroid hormone receptors

Dechloranes are a group of halogenated flame retardants with a basic bicyclo[2.2.1]heptene,including Dechlorane Plus(DP),Dechlorane 602(Dec 602),Dechlorane 603(Dec 603)and Dechlorane 604(Dec 604).A few epidemiological investigations and animal experiments have shown that DP exhibited thyroid-interfering effects.In the present study,we investigated whether DP and three other dechloranes could interfere the thyroid function through thyroid hormone receptors(TRs,TRαand TRβ)signaling pathways.The binding affinities of the four dechloranes to the two TRs were determined by fluorescence competitive binding assay.It was found that all the four dechloranes could bind with the two TRs.The relative potency(RP)values ranged from nd(not detectable)to 0.0667.Between the two TRs,dechloranes were more inclined to bind with TRβ,which implies that the thyroid interference effect of dechloranes may have selectivity in different tissues and organs.TRs-mediated luciferase reporter gene assay and T-screen assay showed that all the four dechloranes exhibited antagonistic activity to TRs in the cells.Taken together,our results demonstrated that dechloranes might interfere with thyroid function by binding with TRs and acting as TR antagonists.The health risk of highly exposed human populations should be of serious concern because of the high hazard quotient calculated from our cell assay results.

Plastic ingestion and associated additives in Faroe Islands chicks of the Northern Fulmar Fulmarus glacialis

Northern Fulmars(Fulmarus glacialis)are a pelagic seabird species distributed at northern and polar latitudes.They are often used as an indicator of plastic pollution in the North Sea region,but data are lacking from higher latitudes,especially when it comes to chicks.Here,we investigated amounts of ingested plastic and their characteristics in fulmar chicks from the Faroe Islands.Plastic particles(≥1 mm)in chicks of two age classes were searched using a digestion method with KOH.In addition,to evaluate if additive tissue burden reflects plastic ingestion,we measured liver tissue concentrations of two pollutant classes associated with plastic materials:polybrominated diphenyl ethers(PBDEs)and several dechloranes,using gas chromatography with high-resolution mass spectrometry.The most common shape was hard fragment(81%)and the most common polymer was polyethylene(73%).Plastic contamination did not differ between either age class,and we found no correlation between neither the amount and mass of plastic particles and the concentration of additives.After comparison with previous studies on adult fulmars,we do not recommend using chicks for biomonitoring adults because chicks seem to ingest more plastics than adults.