Toxic potency assessment of non- and mono-ortho PCBs, PCDDs, PCDFs, and PAHs in northwest Mediterranean sediments (Catalonia, Spain).

Forty-five marine sediments from the Catalonian coast were analyzed for non-ortho and mono-ortho chlorine substituted PCB congeners, PCDDs and PCDFs, and 16 PAHs. Concentrations of total PCBs ranged from 1.1 to 311 ng/g dry weight (d.w.), and the levels of the sum of the 16 PAHs analyzed ranged between 13.4 ng/g d.w. and 16.7 microg/g d.w. The PCB and PAH contamination was greater near the sites of urban and industrial impact. Total toxicity equivalent (TEQ) values were calculated using the toxicity equivalent factors (TEFs) proposed by WHO for dioxin-like PCBs, PCDDs, and PCDFs. These levels ranged between 0.03 and 24.8 pg WHO-TEQ/g d.w. for PCBs and from 0.4 to 39.2 pg WHO-TEQ/g d.w. for PCDDs/PCDFs. Therefore, the suggested sediment quality guideline was sometimes exceeded. Moreover, TEA values were calculated for PAH concentrations, applying different TEFs proposed by the literature. The results obtained were between 0.3 pg TEQ/g d.w. and 18.4 ng TEQ/g d.w. and showed that the TEQ(PCDD/F) and TEQ(PCB) values were several times lower than the TEQ(PAH) values in the marine sediment samples investigated.