Scavenging Amphipods: Sentinels for Penetration of Mercury and Persistent Organic Chemicals into Food Webs of the Deep Arctic Ocean

摘要

Archived specimens of the scavenging amphipod Eurythenes gryllus, collected from 2075 to 4250 m below the surface on five expeditions to the western and central Arctic Ocean between 1983 and 1998, were analyzed for total mercury (ΣHg), methyl mercury (MeHg), polychlorinated biphenyls (PCBs) and other industrial or byproduct organochlorines (chlorobenzenes, pentachloroanisole, octachlorostyrene), organochlorine pesticides (OCPs), and polybrominated diphenyl ethers (PBDEs). Median ΣHg concentrations ranged from 70 to 366 ng g~(-1) wet weight (ww). MeHg concentrations (3.55 to 23.5 ng g~(-1) ww) accounted for 1.7 to 20.1% (median 3.7%) of ΣHg. ΣHg and MeHg were positively and significantly correlated with ww (ΣHg R~2 = 0.18, p = 0.0004, n = 63; MeHg r~2 = 0.42, p = 0.0004, n = 25), but not significantly with δ~(13)C nor δ~(15)N. Median concentrations of total persistent organic pollutants (POPs) ranged from 9750 to 156 000 ng g~(-1) lipid weight, with order of abundance: ΣTOX (chlorobornanes quantified as technical toxaphene) ＞ΣPCBs ＞ ΣDDTs ＞ Σchlordanes＞Σmirex compounds ＞ ΣBDEs ～ Σchlorobenzenes ～ octachlorostyrene ＞ α-hexachlorocydohexane ～ hexachlorobenzene ～ pentachloroanisole. Enantioselective accumulation was found for the chiral OCPs o,p'-DDT, cis- and trans-chlordane, nonachlor MC6 and oxychlordane. Lipid-normalized POPs concentrations were elevated in amphipods with lipid percentages ≤10%, suggesting that utilization of lipids resulted in concentration of POPs in the remaining lipid pool. Multidimensional Scaling (MDS) analysis using log-transformed physiological variables and lipid-normalized organochlorine concentrations distinguished amphipods from the central vs western arctic stations. This distinction was also seen for PCB homologues, whereas profiles of other compound classes were more related to specific stations rather than central-west differences.