Contributions and perspectives of Indigenous Peoples to the study of mercury in the Arctic

Arctic Indigenous Peoples are among the most exposed humans when it comes to foodborne mercury (Hg). In response, Hg monitoring and research have been on-going in the circumpolar Arctic since about 1991; this work has been mainly possible through the involvement of Arctic Indigenous Peoples. The present overview was initially conducted in the context of a broader assessment of Hg research organized by the Arctic Monitoring and Assessment Programme. This article provides examples of Indigenous Peoples' contributions to Hg monitoring and research in the Arctic, and discusses approaches that could be used, and improved upon, when carrying out future activities. Over 40 mercury projects conducted with/by Indigenous Peoples are identified for different circumpolar regions including the U.S., Canada, Greenland, Sweden, Finland, and Russia as well as instances where Indigenous Knowledge contributed to the understanding of Hg contamination in the Arctic. Perspectives and visions of future Hg research as well as recommendations are presented. The establishment of collaborative processes and partnership/co-production approaches with scientists and Indigenous Peoples, using good communication practices and transparency in research activities, are key to the success of research and monitoring activities in the Arctic. Sustainable funding for community-driven monitoring and research programs in Arctic countries would be beneficial and assist in developing more research/ monitoring capacity and would promote a more holistic approach to understanding Hg in the Arctic. These activities should be well connected to circumpolar/international initiatives to ensure broader availability of the information and uptake in policy development

Per- and Polyfluoroalkyl Substances (PFASs)

60 pages, 5 figures, 4 tablesPer- and polyfluoroalkyl substances (PFASs) are anthropogenic contaminants of emerging concern that are ubiquitous in the marine environment. This chapter provides recent insights into the main aspects of research on this class of compounds in the oceans. It describes their main uses and predominant sources in the marine environment and provides an update on the analytical procedures fit for marine matrices. Occurrence and processes affecting these compounds in abiotic compartments are addressed, followed by a focus on bioaccumulation and biomagnification in biota. The biological effects in marine organisms are then reviewed per taxa. In agreement with recent literature, recommendations for future research are proposed, which should guide future efforts toward the key environmental questions on PFASsPeer reviewe

Transcriptomic, cellular and life-history responses of <i>Daphnia magna</i> chronically exposed to benzotriazoles: Endocrine-disrupting potential and molting effects

<div><p>Benzotriazoles (BZTs) are ubiquitous aquatic contaminants used in a wide range of industrial and domestic applications from aircraft deicers to dishwasher tablets. Acute toxicity has been reported in aquatic organisms for some of the BZTs but their mode of action remains unknown. The objectives of this study were to evaluate the transcriptomic response of <i>D</i>. <i>magna</i> exposed to sublethal doses of 1H-benzotriazole (BTR), 5-methyl-1H-benzotriazole (5MeBTR) and 5-chloro-1H-benzotriazole (5ClBTR) using RNA-sequencing and quantitative real-time PCR. Cellular and life-history endpoints (survival, number of neonates, growth) were also investigated. Significant effects on the molting frequency were observed after 21-d exposure to 5MeBTR and 5ClBTR. No effects on molting frequency were observed for BTR but RNA-seq results indicated that this BZT induced the up-regulation of genes coding for cuticular proteins, which could have compensated the molting disruption. Molting in cladocerans is actively controlled by ecdysteroid hormones. Complementary short-term temporal analysis (4- and 8-d exposure) of the transcription of genes related to molting and hormone-mediated processes indicated that the three compounds had specific modes of action. BTR induced the transcription of genes involved in 20-hydroxyecdysone synthesis, which suggests pro-ecdysteroid properties. 5ClBTR exposure induced protein activity and transcriptional levels of chitinase enzymes, associated with an impact on ecdysteroid signaling pathways, which could explain the decrease in molt frequency. Finally, 5MeBTR seemed to increase molt frequency through epigenetic processes. Overall, results suggested that molting effects observed at the physiological level could be linked to endocrine regulation impacts of BZTs at the molecular level.</p></div

Effects of food-borne exposure of juvenile rainbow trout (Oncorhynchus mykiss) to emerging brominated flame retardants 1,2-bis(2,4,6-tribromophenoxy)ethane and 2-ethylhexyl-2,3,4,5-tetrabromobenzoate

Brominated flame retardants (BFRs) represent a large group of chemicals used in a variety of household and commercial products to prevent fire propagation. The environmental persistence and toxicity of some of the most widely used BFRs has resulted in a progressive ban worldwide and the development of novel BFRs for which the knowledge on environmental health impacts remains limited. The objectives of this study were to evaluate the effects of two emerging BFRs, 1,2-bis(2,4,6-tribromophenoxy)ethane (BTBPE) and 2-ethylhexyl-2,3,4,5-tetrabromobenzoate (EH-TBB), in diet exposed juvenile rainbow trout (Oncorhynchus mykiss). Both compounds were detected in fish carcasses at 76% and 2% of the daily dosage of BTBPE and EH-TBB, respectively, indicating accumulation of BTBPE and by contrast extensive depuration/metabolism of EH-TBB. Liver gene transcription analysis using RNA-sequencing indicated that the chronic 28-d dietary exposure of trout to EH-TBB down-regulated one single gene related to endocrine-mediated processes, whereas BTBPE impacted the transcription of 33 genes, including genes involved in the immune response, reproduction, and oxidative stress. Additional analysis using qRT-PCR after 48-h and 28-d of exposure confirmed the impact of BTBPE on immune related genes in the liver (apolipoprotein A-I, lysozyme) and the head-kidney (complement c3-4). However, the activity of lysozymes measured at the protein level did not reflect transcriptomi

Characteristics of the three benzotriazoles used in this study.

<p>Log <i>K</i>ow represent octonaol-water partition coefficients from Hart et al. [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0171763#pone.0171763.ref002" target="_blank">2</a>].</p

Chitinase activity measured in <i>D</i>. <i>magna</i> homogenates after 21-d of exposure to 2 and 2000 μg/L of (A) BTR, (B) 5MeBTR and (C) 5ClBTR.

<p>* indicates a significant difference from the control (<i>p</i><0.05).</p

Number of annotated up- and down-regulated genes measured by RNA-sequencing in response to 2 mg/L exposure to BTR, 5MeBTR and 5ClBTR.

<p>Number of annotated up- and down-regulated genes measured by RNA-sequencing in response to 2 mg/L exposure to BTR, 5MeBTR and 5ClBTR.</p

RNAseq data showing up- and down-regulated genes (x axis represents positive and negative fold changes, respectively) in <i>D</i>. <i>magna</i> exposed to 2 mg/L of (A) BTR, (B) 5MeBTR and (C) 5ClBTR.

<p>Genes highlighted in red are significantly differentially transcribed between exposed and control samples (log₂FC ± 2, <i>p</i><0.05). Annotated genes with a predicted function related to molting and 20HE-mediated processes are indicated. Acronym definition can be found in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0171763#pone.0171763.s008" target="_blank">S6 Table</a>.</p

Acute toxicity values for BTR, 5MeBTR and 5ClBTR in aquatic organisms.

<p>Acute toxicity values for BTR, 5MeBTR and 5ClBTR in aquatic organisms.</p