Biomagnification of mercury through the benthic food webs of a temperate estuary: Masan Bay, Korea

Abstract

The authors examined food web magnification factors of total mercury (THg) and methylmercury (MeHg) for the benthic organisms in Masan Bay, a semiclosed, temperate estuary located on the southeastern coast of Korea. For benthic invertebrates, concentrations of THg and MeHg (%MeHg) ranged from 9.57 to 195 and 2.56 to 111 ng/g dry weight (12.2-85.6%), respectively. Benthic fish THg and MeHg (%MeHg) concentrations ranged widely from 10.8 to 618 and 2.90 to 529 ng/g dry weight (22.9-93.9%), respectively. The linear regression slopes of log [Hg] relative to δ(15)N (i.e., food web magnification factors) found for the Masan Bay benthic organisms were 0.119 for THg and 0.168 for MeHg. These values are similar to the food web magnification factors of benthic organisms and lower than those of pelagic organisms of various coastal marine environments. It suggests that pelagic organisms might be at greater risk of THg and MeHg accumulation than benthic biota.

Bioaccumulation of methylmercury within the marine food web of the outer Bay of Fundy, Gulf of Maine

“…These calculations assume that our 25–66μm size fraction is largely autotrophic and the processes of mercury species ad-, ab- and desorption are at equilibrium. These values fall within the range of oceanic BCF values derived from, albeit, a limited number of field studies that enable this calculation ( Table 4 ; [ 26 , 74 , 91 – 97 ]). Earlier experimental work showed that mercury could enter the marine food chain preferentially as MeHg through adsorption to phytoplankton surfaces and absorption into the cytoplasm [ 68 , 69 , 98 ].…”

“…The first attempt to describe mercury biomagnification in a reasonably complete marine food web was done in the arctic in the 1990s with the aid of stable isotopes for trophic interpretations [ 21 ]. There are now several relatively complete marine food-chain studies of mercury bioaccumulation in the arctic [ 21 – 23 ], but fewer in the subarctic [ 24 ], temperate [ 25 , 26 ], subtropical [ 27 ] and tropical latitudes [ 28 ]. The present study is a descriptive field study in which we cover the transition from phytoplankton to the second and third trophic levels in greater detail than previous studies with the hope of gaining more insight into the transition from predominantly sorption to trophic transfer of mercury.…”

Mercury bioaccumulation in cartilaginous fishes from Southern New England coastal waters: Contamination from a trophic ecology and human health perspective

“…This result suggests that benthic associations may increase biotic Hg concentrations via dietary intake or proximate contact with Hg-contaminated sediments, as reported elsewhere (Storelli et al, 1998; Hosseini et al, 2013). Other studies, however, indicate that pelagic-feeding organisms (depleted δ 13 C signatures) have increased Hg exposure (Chen et al, 2009; Kim et al, 2012). Ultimately, the fate of Hg through feeding pathways depends on the number of trophic steps and consumer's utilization of different prey assemblages (Kim et al, 2012), which likely vary across discrete aquatic ecosystems.…”

“…Other studies, however, indicate that pelagic-feeding organisms (depleted δ 13 C signatures) have increased Hg exposure (Chen et al, 2009; Kim et al, 2012). Ultimately, the fate of Hg through feeding pathways depends on the number of trophic steps and consumer's utilization of different prey assemblages (Kim et al, 2012), which likely vary across discrete aquatic ecosystems.…”

Mercury accumulation in hydrothermal vent mollusks from the southern Tonga Arc, southwestern Pacific Ocean

“…For the biota, approximately 0.2-0.5 g of freeze-dried tissues were digested in 20% KOH overnight in a methanol (w/v) solution at 50°C (Hintelmann and Nguyen, 2005;Kim et al, 2012). The aliquots of the DCM extracts and alkaline digestates were converted to volatile ethylmethyl Hg by reacting with a sodium tetraethylborate solution and were collected on Tenax Ò traps through purging with nitrogen gas.…”