Biological Accumulation Factor Research Articles

Metals in Northern Forest Ecosystems: Role of Vegetation in Sequestration and Cycling, and Implications for Ecological Risk Assessment

Mass estimates of phytoaccumulated trace metal contaminants and transfers to soils are necessary to properly evaluate the impact of historic and continued anthropogenic metal deposition to northern forest ecosystems. An investigation of Cu, Ni, Pb, and Zn mass balances in plant communities subject to metal contamination from smelter emissions in Canada, found that accumulation of metals differed significantly among plant vegetation compartments (foliage, fine roots, bark, trunk, and branches). Analysis of plant community biological accumulation factors (BAFs), calculated using total soil metal and free soil metal ion (Me2+) found that free soil metal BAFs were more similar among locations than total soil metal BAFs, but that disparity still existed. Fine roots were found to dominate annual vegetation transfer of Cu, Ni, and Pb to soils, relative to foliage; fine root mortality played a smaller role than foliage for Zn plant-soil transfer. Plant-associated metal inputs were found to rival or exceed current estimates of atmospheric metal deposition, suggesting that potential benefits of future reductions in emissions to forests need to be evaluated within the context of phytocycling of metals already present.

Immobilization of microalgae for biosorption and degradation of butyltin chlorides.

Since the discovery of their biocidal properties in the 1950s, organotin compounds have found a large spectrum of industrial applications such as wood and textile preservatives, fungicides and pesticides, and antifouling paint on ships and fishing equipment. The fate and environmental impact of butyltins have been the subjects of a large body of research in the last decades. Biosorption and degradation of butyltin compounds by immobilized microalgae chlorella were studied in this paper, aiming to find an alternative way to solve organotin pollution problem. Chlorella emersonii cells were entrapped in a calcium aginate matrix. The cell growth rates, respiratory rate and chlorophyll a content were studied and compared. Results showed that immobilized chlorella had increased respiratory and growth rates, and almost equal chlorophyll a content when compared with free cells. Cell leakage was slight during the 20-day experimental period Cell leakage from the matrix was unrelated to cell growth within the matrix. Immobilized chlorella was applied to deal with butytin contaminated aquatic solutions. Immobilized chlorella had increased degradation rates of tri-, di-, and mono-butyltin chlorides in aquatic solutions, and lower biological accumulation factors on cells, than free cells, which indicates a potential use for tackleing organotin polluted water body.

TCDD in bottom sediments and eel around a refuse dump near Amsterdam, Holland

A north of Amsterdam rangeland located refuse dump, heavily contaminated with organochlorine waste compounds originating from 2,4,5-T production exerts its pollution effects on the surrounding area through the main drainage canal. Compounds demonstrated to be present thus far are the chlorobenzenes, chlorophenols, hexachlorocyclohexanes and the chlorodioxins, mainly 2,3,7,8-TCDD. Analysis of bottom sediments in the drainage canal was positive for 2,3,7,8-TCDD. Concentrations varied between 50 and 5,000 ppt on a dry weight basis. Lowest concentrations occurred in a small pond at about 1 kilometer distance from the dump. Sediment samples were analyzed by two laboratories, totally independent of one another. Results showed a fairly good agreement. Eel caught from the same aquatic habitat had about 1 ppt of 2,3,7,8-TCDD in its tissue. This was lower than calculated levels, based on knowledge of water-sediment partition coefficient and biological accumulation factors.