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Mercury fractionation, bioavailability, and ecotoxicity in highly contaminated soils from chlor‐alkali plants
Author(s) -
Zagury Gerald J.,
Neculita CarmenMihaela,
Bastien Christian,
Deschênes Louise
Publication year - 2006
Publication title -
environmental toxicology and chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.1
H-Index - 171
eISSN - 1552-8618
pISSN - 0730-7268
DOI - 10.1897/05-302r.1
Subject(s) - environmental chemistry , bioconcentration , chemistry , eisenia andrei , mercury (programming language) , ecotoxicity , soil water , bioavailability , fractionation , bioaccumulation , hordeum vulgare , earthworm , soil contamination , contamination , botany , agronomy , poaceae , toxicity , chromatography , biology , ecology , bioinformatics , organic chemistry , computer science , programming language
Mercury (Hg) fractionation, speciation, bioavailability, and ecotoxicity wereinvestigated in three highly contaminated soils from chlor‐alkali plants. Single extractions and a validated four‐step sequential extraction scheme were used. Total, volatile, and methyl‐Hg concentrations were determined. Mercury was then separated in fractions defined as water‐soluble ( F1 ), exchangeable ( F2 ), organic ( F3 ), and residual ( F4 ). Germination and growth inhibition of barley ( Hordeum vulgare ) and mortality of earthworms ( Eisenia andrei ) were assessed, and tissue‐Hg concentrations of exposed organisms were determined. Results revealed highly (295 ± 18–11,500 ± 500 μg Hg/g) contaminated soils, but extracted fractions indicated relatively low mobility of Hg. Nevertheless, the water‐soluble and the CaCl 2 ‐extractable fractions represented significant Hg concentrations (299 ±18 μg/g in soil 3, 67.4 ± 2.3 μg/g in soil 1, and 9.5 ± 0.3 μg/g in soil 2), and volatile Hg ranged between 14 and 98% of total Hg. Overall, Hg concentrations reached 6,560 ± 240 μg/g in roots, 4,200 ± 1,070 μg/g in aerial plants, and 1,410 ± 120 μg/g in E. andrei . Earthworm mortality was 100% after exposure to the soil with the highest concentration of mobile Hg. In the latter soil, earthworm fragmentation and chlorotic plants were observed. Bioconcentration factors (BCFs) were higher in barley compared to earthworms, but BCFs yielded misleading values after exposure to the extremely contaminated soil. This study shows that Hg accumulated primarily in the roots, but results also indicate uptake of gaseous Hg by the aerial plants of barley. Tissue‐Hg concentrations of both exposed organisms were correlated with water‐soluble and CaCl 2 ‐extractable Hg, and growth inhibition was in agreement with Hg fractionation.