The occurrence of PCBs in raw materials, processes, products and environmental samples were analysed with the aim of resolving the sources and pathways of PCBs in the processes and environment of paper mills producing recycled paper products. In the wastepaper grades examined, PCBs were observed only in archival paper (0.47-1.0 mg/kg). In the deinking process, PCBs were observed in deinking sludge, but it was not observed in pulper stock, recycled fibre pulp, tissue paper reject or process waters. In deinking sludge, PCBs were mainly observed in samples from a pulper that used wastepaper from offices as its raw material. Between 1993 and 2002 PCB concentrations in the latter decreased from 1.3 mg/kg to 0.14 mg/kg. PCBs were also observed in the wastewater treatment plant in sludge, but not in wastewater. Between 1993 and 2004 concentrations in biosludge decreased from 0.56 mg/kg to 0.13 mg/kg. The PCB fingerprint in raw material and process samples corresponded to the fingerprint from
Aroclor 1242. The greater proportion of recycled paper products did not contain PCBs. Low concentrations of PCB were however observed in hand towel sheet (0.02-0.07 mg/kg) and toilet tissue (0.02-0.14). The PCB fingerprint in the recycled paper products corresponded to the fingerprint from Aroclor 1242. The PCB concentrations in pike (Esox lucius) caught in Lake Melasjärvi, a small lake basin downstream from the Mänttä mill an<l from lakes from the region of Tampere and Nokia were low (0.02-0.07 mg/kg). The PCB concentrations in sediment from lakes upstream and downstream from the Mänttä mill were below 0.05-0.15 mg/kg, except in samples from Mäntänlahti (0.12-0.23 mg/kg) just below the paper mill. PCBs were also observed in soil and sediment at the former industrial site of Mänttä mill (0.05-0.08 mg/kg). In the case of the Mänttä mill it was notable that the fingerprint of PCB in fish, soil and sediment did not correspond to the fingerprint from Aroclor 1242, which was observed in the paper mill processes, but corresponded to the fingerprint from Aroclor 1260, which has been used, for example, as a dielectric fluid in transformers. For the purpose of comparison PCB concentrations in sediment were also determined in lake basins downstream from the Nokia and Kaipola mills. PCBs were observed (0.05 mg/kg) only in sediment downstream from the Kaipola mill. In the latter mill it was notable that the PCB fingerprint in sediment corresponded to the fingerprint from Aroclor 1242, which is typically observed in paper mills using wastepaper as a raw material. On the basis of these results it could be concluded that the production of recycled fibre pulps and recycled paper products were not the main source of increasing PCB concentrations in mussels incubated in the vicinity of Mänttä mill. The most probable source was Aroclor 1260, which was found in sediment just downstream from the Mänttä mill.
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