Bioaccumulation and Eco Toxic Potential

Mussels incubated in pulp mill recipient watercourses of the Kymijoki River Basin in 1986-1990 collected 8.5-34.8 ng g1 lw C5-PCBB congeners [43], and 20-89 ng g 1 lw chlororetenes (C4-PCPHs) [38]. In Kymijoki River recipient fish, an average C5-PCBBs content of 1.33 ng g 1 lw has been measured [38]. 

While very few fish and mussel data were available, estimation of bioaccumulation power of alkylaromatic chlorohydrocarbons was also made from accumulation from effluent to biosludge. The rank order of highest to lowest accumulation factor (AF, mean value) obtained was [38, 54] RPCN (4120) RPCPH (2680) RPCFL (2500) CYMS (1227) RPCBB (375) CYMD (158). 

While RPCNs, RPCPHs, RPCFLs, and RPCBBs are not readily biodegradable, they must be classified as persistent bio accumulative chemicals. Their (eco)to-xicity has not been tested. 

The non-chlorinated skeleton compound of C4-PCPHs, retene, occurs at high levels in pulp mill effluents and in recipient sediments up to 2 mg g 1 dw.Retene causes MFO induction in fish and is toxic to early life-stages of zebrafish at LOEL of 16 pg 1 h TEF of egg mortality related to 2,3,7,8-tetrachlorodibenzo-p-dioxin is on average about 0.007 [59]. Accordingly, chlorinated retenes are of concern as possible dioxin-type of persistent xenobiotics. 

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