Internal Dynamics and Metabolism of Mercury in Biota: A Review of Insights from Mercury Stable Isotopes

Abstract

Monitoring mercury (Hg) levels in biota is considered an important objective for the effectiveness evaluation of the Minamata Convention. While many studies have characterized Hg levels in organisms at multiple spatiotemporal scales, concentration analyses alone often cannot provide sufficient information on the Hg exposure sources and internal processes occurring within biota. Here, we review the decadal scientific progress of using Hg isotopes to understand internal processes that modify the speciation, transport, and fate of Hg within biota. Mercury stable isotopes have emerged as a powerful tool for assessing Hg sources and biogeochemical processes in natural environments. A better understanding of the tissue location and internal mechanisms leading to Hg isotope change is key to assessing its use for biomonitoring. We synthesize the current understanding and uncertainties of internal processes leading to Hg isotope fractionation in a variety of biota, in a sequence of better to less studied organisms (i.e., birds, marine mammals, humans, fish, plankton, and invertebrates). This review discusses the opportunities and challenges of using certain forms of biota for Hg source monitoring and the need to further elucidate the physiological mechanisms that control the accumulation, distribution, and toxicity of Hg in biota by coupling new techniques with Hg stable isotopes.

Stochastic Dynamic Mass Spectrometric Quantitative and Structural Analyses of Pharmaceutics and Biocides in Biota and Sewage Sludge

“…The determination of pharmaceutics and biocides in biota, including the analysis of invertebrates, plankton, fish, human tissues and fluids, birds, and marine mammals, is importance for assessing the risk for human health and environmental damage [ 38 , 39 ], as well as determining the potential ecological risk index [ 38 , 39 , 40 ]. The biomonitoring includes saltwater and freshwater mussels [ 1 , 41 , 42 , 43 ].…”

Mercury Isotopes in Deep-Sea Epibenthic Biota Suggest Limited Hg Transfer from Photosynthetic to Chemosynthetic Food Webs

“…Previous studies on coastal benthic invertebrates revealed similar Δ 199 Hg values (0.11 ± 0.06‰ for bivalve, 0.18 ± 0.11‰ for shrimp, 0.20 ± 0.14‰ for cephalopod, 0.21 ± 0.07‰ for gastropod, and 0.25 ± 0.07‰ for crab) but significantly lower δ 202 Hg values (−2.05 to −1.49‰, group-specific mean values) . Increases of both δ 202 Hg and Δ 199 Hg are seen from coastal/estuarine fishes , to open marine fishes − and then to mammals/birds. − As compared to their nearby sulfides, δ 202 Hg and Δ 199 Hg in our hydrothermal biota are slightly shifted by 0.19–0.51‰ (site-specific means: Longqi: 0.19 ± 0.42‰, P = 0.28; Duanqiao: 0.23 ± 0.62‰, P = 0.44; Kairei/Edmond: 0.51 ± 0.53‰, P = 0.08) and 0.04–0.14‰ (site-specific means: Longqi: 0.14 ± 0.17‰, P = 0.07; Duanqiao: 0.06 ± 0.11‰, P = 0.22; Kairei/Edmond: 0.04 ± 0.07‰, P = 0.43), respectively. These positive shifts of δ 202 Hg and Δ 199 Hg could be caused by bioaccumulation and trophic transfer of MMHg. − However, the lack of significant correlations of MMHg% with δ 202 Hg and Δ 199 Hg (Figure S3) excludes this possibility.…”

Can Preserved Museum Specimens Be Used to Reconstruct Fish Mercury Burden and Sources through Time?

“…We suspect that changes observed in our experiment are primarily due to inadvertent fatty acid extraction, which is supported by the positive association between the initial C:N ratio (a surrogate for lipid content) and the Hg gains made following preservation (Figures S3–S5). MeHg also preferentially binds to sulfur and selenium moieties in biological tissue, , which are uncommon in amino acids and fatty acids, further supporting this hypothesis.…”