Fate of Pentabrominated Diphenyl Ethers in Soil:  Abiotic Sorption, Plant Uptake, and the Impact of Interspecific Plant Interactions

Abstract

Polybrominated diphenyl ethers (PBDEs) are potentially harmful and persistent environmental pollutants. Despite evidence that soils are a major sink for PBDEs, little is known regarding their behavior in this medium. An environmentally relevant level of a commercial penta-BDE mixture (75 μg kg -1 ) was added to topsoil and the extractability of three congeners (BDE 47, 99, and 100) was monitored over 10 weeks in planted and unplanted treatments. The extractability of each congener decreased rapidly in the experimental soil due largely to abiotic sorption to soil particles, which was demonstrated by low PBDE recovery from sterilized and dry soils. Monoculture plantings of zucchini and radish did not affect the recovery of PBDEs from soil. However, PBDE recovery from mixed species plantings was nearly 8 times higher than that of unplanted and monoculture treatments, indicating that interspecific plant interactions may enhance PBDE bioavailablity in soil. Evidence for competitive interactions between the two species was revealed by reduced shoot biomass of zucchini plants in mixed treatments relative to pots containing only zucchini. Both plant species accumulated PBDEs in root and shoot tissue (< 5 μg kg -1 plant tissue). PBDE uptake was higher in zucchini and translocation of PBDEs to zucchini shoots was congener-specific. Our results suggest that although abiotic sorption may limit the potential for human exposure to PBDEs in soil, plants may increase the exposure risk by taking up and translocating PBDEs into aboveground tissues and by enhancing bioavailability in soil.

In vitro biotransformation of PBDEs by root crude enzyme extracts: Potential role of nitrate reductase (NaR) and glutathione S-transferase (GST) in their debromination

“…Previous studies have indicated that PBDEs in soils can be taken up by plants (Mueller et al, 2006;Huang et al, 2010;Wang et al, 2011a). Metabolites of lower debrominated PBDEs and OH-PBDEs were also detected in plant tissues (Wang et al, 2011b), which demonstrates that plants are able to transform PBDEs from higherto lower-brominated congeners as well as to OH-PBDE congeners.…”

The influence of land use on the concentration and vertical distribution of PBDEs in soils of an e-waste recycling region of South China

“…The sorption and desorption that occurs between PBDEs and organic matter are key processes that influence the mobilization and migration of PBDEs in soil (Hassanin et al, 2004;Mueller et al, 2006). PBDEs can adsorb to the surface of mineral particles or colloids in soil, particularly clay minerals (Weber et al, 1999;Harner and Shoeib, 2002).…”

Bioaccumulation of polybrominated diphenyl ethers and several alternative halogenated flame retardants in a small herbivorous food chain

“…Plant constitutes a significant fraction of the total biomass in the environment, and is known to bioaccumulate HFRs such as PBDEs (Mueller et al, 2006;Vrkoslavová et al, 2010;Huang et al, 2010Huang et al, , 2011. Therefore, they may play an important role in the transfer of these chemicals into the food chain.…”