A Comparison of Mercury Biomagnification through Lacustrine Food Webs Supporting Brook Trout (Salvelinus fontinalis) and Other Salmonid Fishes

Abstract

Methylmercury (MeHg) bioaccumulation in lower-trophic-level organisms and its subsequent biomagnification through food webs differs in magnitude among lakes and results in intraspecific variability of MeHg in top predator fishes. Understanding these differences is critical given the reproductive and neurotoxic effects of MeHg on fishes and their predators, including humans. In this study we characterized the food webs of five lakes in New Brunswick, Canada, supporting Brook Trout (Salvelinus fontinalis) using measures of relative trophic position ( 15 δ N) and carbon sources ( 13 δ C), determined the concentrations of MeHg in invertebrates and total Hg (THg) in fishes, and quantified MeHg biomagnification from primary to tertiary consumers. Methyl Hg and THg concentrations were highest in biota from lakes with lower pH. The trophic magnification slopes (TMS; log Hg vs. 15 δ N) varied significantly among lakes (0.13-0.20; ANCOVA, p = 0.031). When combined with data from other salmonid lakes in temperate and Arctic Canada (n = 36), among-system variability in TMS was best, but weakly, positively predicted by aqueous total phosphorous (p = 0.028, 2 R = 0.109). These results suggest that lake productivity adj directly or indirectly influences the biomagnification of MeHg through diverse food webs supporting salmonids.

Mayflies (Ephemeroptera) and Their Contributions to Ecosystem Services

“…Mayflies fulfil the criteria for good indicators because they are: (i) abundant and sufficiently diverse in their habits and habitats, (ii) sensitive and predictable in their response to changes in environmental conditions, (iii) relatively easily sampled and identifiable to meaningful taxonomic resolutions, and (iv) bioaccumulate chemicals such that the pathways of toxins in the environment can be traced [123,124]. As biological indicators, their response to changing conditions is integrated over time and space, potentially lowering sampling effort and cost compared to the high intensity of sampling often required when relying on chemical variables to detect certain impacts [125].…”

Harvest and Mercury Levels of Striped Bass in Miramichi River, New Brunswick, Canada

“…The fish were immediately filleted, and the two fillets were placed in a plastic bag and weighed on a Brecknell Electrosamson hanging balance to the nearest g to provide a reference of fillet yield (Table 1). A 50-g sample of the dorsal muscle from all 34 Striped Bass was then retained from the fillets and stored in a labelled, plastic sample tube and frozen immediately for mercury analysis (Finley et al 2016).…”

Mercury Contamination in Fish and Its Effects on the Health of Pregnant Women and Their Fetuses, and Guidance for Fish Consumption—A Narrative Review

“…Hg is released from a variety of natural and anthropogenic sources into the three phases of natural water bodies, i.e., solid, aqueous and biological phases; it exists mainly in the forms of Hg 2+ , Hg(OH) 2 , CH 3 Hg + , CH 3 Hg(OH), CH 3 HgCl, and C 6 H 5 Hg + in the aqueous phase, in the forms of Hg + , Hg 0 , HgO, HgS, CH 3 Hg(SR), and (CH 3 Hg) 2 S in the solid phase, and in the forms of Hg 2+ , CH 3 Hg + , and CH 3 HgCH 3 in the biological phase. In natural water bodies, highly toxic methylmercury (MeHg) transformed through some hydrophytic microorganisms (i.e., bacteria) is a major source of Hg exposure to the general population of fish, and causes bio-magnification which disrupts the aquatic food web [ 28 ]. Moreover, it is presumed that MeHg is the predominant form of Hg transmission through food chains [ 29 , 30 , 31 ].…”