Sphagnum Moss in the Athabasca Bituminous Sands Region Reveals No Significant Atmospheric Contamination by "Heavy Metals"

Sphagnum moss were collected from three sites at each of twenty-one ombrotrophic (rain-fed) peat bogs in the vicinity of and surrounding open pit mines and upgrading facilities of Athabasca Bituminous Sands in Alberta. Compared with contemporary Sphagnum moss from multiple sites at each of four bogs in rural locations of southern Germany, the AB mosses yielded lower concentrations of Ag, Cd, Ni, Pb, Sb and Tl, similar concentrations of Mo, but greater concentrations of Ba, Th and V. Compared to the “cleanest”, ancient peat samples ever tested from the northern hemisphere and dating from the mid-Holocene (ca. 6,000 to 9,000 years old), with the exception of V, the concentrations of each of these metals in the AB mosses are within a factor of three of “natural, background” values. The concentrations of “heavy metals” in the mosses are proportional to the concentration of Th (a conservative, lithogenic element) and therefore are contributed to the plants primarily in the form of mineral dust particles. Although it has been claimed that bitumen mining is a significant source of atmospheric Pb contamination, compared with the surface layer (1 cm slice) of peat cores collected in recent years from across Canada (13 cores in five Provinces from British Columbia to New Brunswick), the Pb concentrations in the mosses from AB are far lower. Vanadium, the single most abundant trace metal in bitumen, is the only exception: on average V in the AB mosses exceeds that of ancient peat by a factor of six; it is therefore enriched in the mosses, relative to Th, by a factor of two.

SHOTYK W.;  BELLAND Rene;  DUKE John;  KEMPTER Heike;  KRACHLER Michael;  NOERNBERG Tommy;  VILE Melanie;  WIEDER Kelman;  ZACCONE Claudio;  ZHANG Shuangquan; 

2015-02-06

Society of Environmental Toxicology and Chemistry (SETAC)

JRC92770

1087-8939,   

https://publications.jrc.ec.europa.eu/repository/handle/JRC92770,