Mercury in Marine and Oceanic Waters—a Review

Abstract

Mercury contamination in water has been an issue to the environment and human health. In this article, mercury in marine and oceanic waters has been reviewed. In the aquatic environment, mercury occurs in many forms, which depend on the oxidation-reduction conditions. These forms have been briefly described in this article. Mercury concentrations in marine waters in the different parts of the world have been presented. In the relevant literature, two models describing the fate and behavior of mercury in saltwater reservoirs have been presented, a conceptual model which treats all the oceans as one ocean and the “ocean margin” model, providing that the ocean margins manifested themselves as the convergence of continents and oceans, covering such geological features, such as estuaries, inland seas, and the continental shelf. These two conceptual models have been summarized in the text. The mercury content in benthic sediments usually reflects is level in the water reservoir, particularly in reservoirs situated in contaminated areas (mines, metallurgical plants, chemically protected crops). The concentrations of mercury and its compounds determined in the sediments in surface waters in the different parts of the world have been presented. Due to the fact that the pollution caused by mercury is a serious threat for the marine environment, the short paragraph about mercury bioaccumulation in aquatic organisms has been included. The cited data demonstrated a large scatter of mercury contents both between the fish species and the water areas. Mathematical models, valuable tools which provide information about the possible responses of ecosystems, developed to simulate mercury emissions, both at a small scale, for local water reservoirs, and at a global scale, as well as to model mercury bioaccumulation in the chain web of aquatic systems have been described.

Biotic formation of methylmercury: A bio–physico–chemical conundrum

“…In marine waters, Hg II forms compounds with chlorine (HgCl 3 − and HgCl 4 2− ) to a greater extent than oxides, that are in turn formed in freshwaters (Mason and Fitzgerald ). A lower Hg II methylating activity in marine and estuarine sediments than in freshwater sediments has been attributed to the formation of charged chloride but also sulfide complexes, that undergo a slower methylation processes than other Hg II forms (Gårdfeldt et al ; Jonsson et al ; Gworek et al ).…”

Past, Present, and Future of Mercury Pollution Issues

“…Artisanal and small-scale gold mining (727 t in 2010, 37% of total anthropogenic emissions) and coal burning (474 t, 24%) were the largest components of anthropogenic emissions in 2010, followed by cement production (173 t), large-scale gold production (97 t), and consumer product waste (96 t). Gworek et al (2016) also showed the similar levels of mercury emission (total emission = 5000-6600 t year −1 ; anthropogenic emission = ~2200 t year −1 ) by citing many papers. Asia contributes almost half of global anthropogenic emissions, accounting 40% of the total emission by East and Southeast Asia, in which China accounts three-quarters (UNEP 2013).…”

“…Such studies may provide a useful clue as to resolving low-dose mercury issues in the global mercury cycle. Gworek et al (2016) described that the average residence time of mercury in oceanic waters, 20-30 years, is much longer than that in the atmosphere (0.8-2 years), resulting in that the mercury discharged into the ocean is removed from there much more slowly than the mercury emitted into the atmosphere and that an increase in the mercury concentration level in oceanic waters will be very slow and may take hundreds of years. This fact means that the mercury concentration will continue to increase gradually, even if anthropogenic emissions of mercury to the atmosphere stop right now.…”

Mix‐&‐Read Determination of Mercury(II) at Trace Levels with Hybrid Mesoporous Silica Materials Incorporating Fluorescent Probes by a Simple Mix‐&‐Load Technique

“…Mercury is a bioaccumulating and highly toxic heavy metal that causes serious human health problems even at low concentrations, most of all through contamination of drinking water and other natural water resources . This dangerous metal is accumulated in living organisms mainly in its methylated form (CH 3 Hg + ), most prominently in fish tissue along the food chain .…”