Gold concentrations in abiotic materials, plants, and animals: A synoptic review

Gold (Au) is ubiquitous in the environment and mined commercially at numerous locations worldwide. It is also an allergen that induces dermatitis in sensitive individuals. Gold concentrations were comparatively elevated in samples collected near gold mining and processing facilities, although no data were found for birds and non-human mammals. Maximum gold concentrations reported in abiotic materials were 0.001 μg L^-1 in rainwater; 0.0015 μgL^-1 in seawater near hydrothermal vents vs. <0.00004–0.0007 μg L^-1 elsewhere; 5.0 μg kg^-1 dry weight (DW) in the Earth's crust; 19.0 μg L^-1 in a freshwater stream near a gold mining site; 440 μg kg^-1  DW in atmospheric dust near a high traffic road; 843 μg kg^-1 DW in alluvial soil near a Nevada gold mine vs. <29 μg kg^-1 DW premining; 2.53 mg kg^-1 DW in snow near a Russian smelter vs. <0.35 mg kg^-1 DW at a reference site; 4.5 mg kg^-1 DW in sewage sludge; 28.7 mg kg^-1 DW in polymetallic sulfides from the ocean floor; and 256.0 mg kg^-1 DW in freshwater sediments near a gold mine tailings pile vs. <5 μg kg^-1 DW prior to mining. In plants, elevated concentrations of 19 μg Au kg^-1 DW were reported in terrestrial vegetation near gold mining operations vs. <4 μg kg^-1 DW at a reference site; 37 μg kg^-1 DW in aquatic bryophytes downstream from a gold mine; 150 μg Au kg^-1 DW in leaves of beans grown in soil containing 170 μg kg^-1 DW; up to 1.06 mg kg^-1 DW in algal mats of rivers receiving gold mine wastes; and 0.1–100 mg kg^-1 DW in selected gold accumulator plants. Fish and aquatic invertebrates contained 0.1–38.0 μg Au kg^-1 DW. In humans, gold concentrations up to 1.1 μg L^-1 were documented in urine of dental technicians vs. 0.002–0.85 μg L^-1 in reference populations; 2.1 μg L^-1 in breast milk, attributed to gold dental fillings and jewelry of mothers; 1.4 mg kg^-1 DW in hair of goldsmiths vs. a normal range of 6–880 μg kg^-1 DW; 2.39 mg L^-1 in whole blood of rheumatoid arthritis patients receiving gold thiol drugs to reduce inflammation (chrysotherapy) vs. a normal range of 0.2–2.0 μg L^-1; and 60.0 to 233.0 mg kg^-1 fresh weight (FW) in kidneys of rheumatoid arthritis patients undergoing active chrysotherapy vs. <42.0 mg kg^-1 FW kidney 140 months posttreatment.