Siloxanes in freshwater food webs

Presence, sources and food web biomagnification of cyclic volatile methylsiloxanes (cVMS) was investigated in three Norwegian lakes (Mjøsa, Randsfjorden, Femunden). The high levels and food web biomagnification of the cVMS D5 in Mjøsa reported in 2010 was confirmed. The cVMS levels in lakes with discharge from waste water treatment plants were higher than in the reference lake with minor human impact (Femunden), suggesting that local sources are the major input of cVMS, rather than long range transport. The cVMS analysed for (D4, D5, D6) were found in effluent water from the investigated waste water treatment plants in Mjøsa and Randsfjorden. D5 and D6 biomagnified in the pelagic food web with trophic magnification factors above 1 in both Mjøsa and Randsfjorden. Results indicated that D4 is not subject to biomagnification, with decreasing concentrations with increasing trophic level.