Mercury in the terrestrial environment: a review

Abstract

Environmental contamination by mercury is and will continue to be a serious risk for human health. Pollution of the terrestrial environment is particularly important as it is a place of human life and food production. Publication presents a review of the literature on issues related to Hg pollution of the terrestrial environment: soil and plants and their transformations. Different forms of atmospheric Hg may be deposited on surfaces by way of wet and dry processes. These forms may be sequestered within terrestrial compartments or emitted back into the atmosphere, and the relative importance of these processes is dependent on the form of Hg, the surface chemistry, and the environmental conditions. On the land surface, Hg deposition mainly occurs in the oxidized form (Hg 2+ ), and its transformations are associated primarily with the oxidation-reduction potential of the environment and the biological and chemical processes of methylation. The deposition of Hg on ground with low vegetation as 3–5 times lower than that in forests. The estimation of Hg emissions from soil and plants, which occur mainly in the Hg 0 form, is very difficult. Generally, the largest amounts of Hg are emitted from tropical regions, and the lowest levels are from the polar regions.

Mercury in European topsoils: Anthropogenic sources, stocks and fluxes

“…Those are some additional sources of anthropogenic Hg contamination, which can be added to the past mining and coal combustion activities explaining the Hg outliers in Europe (Supplementary Material S4). Thus, we mapped the main 74 chlor-alkali plants using the recent literature reviews on the topic ( Brinkmann et al, 2014 ; Gworek et al, 2020 ).…”

“…The main sources of Hg anthropogenic emission are combustion (fossil fuels, municipal and medical waste, sewage sludge, crematories), high-temperature processes (smelting, cement and lime production), manufacturing/commercial, gold extraction, fluorescent lamps and mine spoils ( Huse et al, 1999 ; Mukherjee et al, 2004 ). A recent review has also addressed the Hg emissions close to mining activities and chrol-industries ( Gworek et al, 2020 ). The annual global anthropogenic Hg emissions amount to ~2000–2500 tonnes ( Zhang et al, 2016 ) and outweigh natural emissions (~500 tonnes yr −1 , mainly from rock weathering and volcanic eruptions) ( Amos et al, 2015 ; Bagnato et al, 2015 ) by an order of magnitude ( Futsaeter and Wilson, 2013 ).…”

Biomonitoring of Mercury Contamination in Poland Based on Its Concentration in Scots Pine (Pinus sylvestris L.) Foliage

“…The Żelazny Most flotation waste landfill is the largest of its kind in Europe, and has a negative impact on adjacent ecosystems through wind erosion and transport of pollutants—including trace elements—to both ground and surface waters [ 41 ]. In the case of the Legnica–Głogów Copper Mine District, it has already been reported by Barej et al [ 42 ] that the Hg content in plant material (e.g., grasses and wheat cereals) exceeds those in unpolluted areas (0.1 mg kg −1 according to Gworek et al [ 33 ]); however, the Hg concentrations found did not exceed the levels considered toxic, and the degree of contamination of plant material decreased over the 2002–2017 period [ 42 , 43 ]. The Hg concentrations in pine foliage in the vicinity of the flotation waste landfill in our study, although higher than those reported for the rest of Poland, also do not pose a threat to the environment.…”

“…Although Hg content in Scots pine foliage in Poland did not exceed the values found in ecosystems outside industrial emission areas, this study examined the spatial variation in mercury content across the country. According to Gworek et al [ 33 ], plants growing beyond the influence of high Hg emissions had less than 0.1 mg kg −1 Hg. Higher Hg concentrations in pine foliage were found in areas affected by industrial pollution, including in the catchment area ~20 km from a lignite power plant in Spain (average 0.060 mg kg −1 ) [ 34 ], and the area around a chloralkali plant in the Czech Republic (from 0.0202 mg kg −1 in the plant’s low-impact zone, up to 0.0615 mg kg −1 in the high-impact zone) [ 35 ].…”

Soil Contamination and Bioaccumulation of Heavy Metals by a Tropical Earthworm Species (Alma nilotica) at Informal E‐Waste Recycling Sites in Douala, Cameroon

“…The only other metal with a BAF above one was Co indicating a higher mobility rate of these two metals according to Aladesanmi et al (2019). Hg is a known toxic, persistent and mobile contaminant that has been listed as one of the 10 leading chemicals of concern (Gworek et al, 2020) and as one of the three most toxic elements on the planet (Rice et al, 2014). Given that Hg has the potential to biomagnify up trophic levels (Seco et al, 2021) the presence of Hg in the e‐waste soils, even at low concentrations observed in this study, is a cause for concern.…”