PBDEs in pasture

Polybrominated diphenyl ethers (PBDE) are used as flame-retardants and are widely distributed into the environment. In the first controlled study of PDBE concentrations looking at soil, grass and the milk of cows grazed on flood-prone land on industrial river catchments, it was found that even if the land itself becomes polluted these river sediments do not introduce an increased health risk in cow’s milk.¹

Soil and grass were collected from the same areas of fields from five flood-prone farms on the River Trent, UK, and five neighbouring flood-free farms along with milk produced on the ten farms. Samples were analysed by GC–MS, which targeted 16 PBDE congeners. Higher PBDE levels were detected in soil on flood-prone compared with control farms; median 770 vs 280 ng/kg dry weight. However these higher levels were not reflected in the grass samples, which the study suggests indicates that PBDE contamination on soils is not transferred efficiently to grass. According to the study, this observation, and the fact that cows on flood-prone farms spend time on non-flood-prone land and eat a lot of commercial food, could explain why no significant difference was seen in flood-prone and control milks.

1. I.R. Lake et al., Environ. Sci. Technol., 45(11), 5017–5024 (2011).

This story originally appeared in The Column. Click here to view that issue.