Background Fish is one of the main sources of food and income in Tanzania, with 25% of the population depending on fishing activities as a source of food, income, and employment. But fish consumers are vulnerable to exposure to toxic pollutants including PCBs due to the lipophilic nature of the pollutants which accumulate in fish. Results The estimated mean NDL PCBs concentration level was 0.84 ng/g w/w and the mean fish consumption rate among fishermen was 0.4 kg/day. Mean exposure of the fishermen and fish vendors to total PCBs ranged between 9.62 and 36.12 ng/kg bw/day depending on the estimation scenario (lower bound/upper bound) for both normal and higher fish consumers. The general population exposure to total PCBs was 0.4 and 0.8 ng/kg bw/day in lower‐bound and upper‐bound estimation scenarios respectively. The estimated lifetime carcinogenic and non‐carcinogenic hazard indices from intake of estimated total PCBs by fishermen and fish vendors exceeded the recommended tolerable daily intake, TDI, raising serious concerns for adverse health effects to fishermen and fish vendors. However, for the general population, there was no concern for any potential health effects as the estimated hazard indices were far below the recommended levels for intake of total PCBs. Conclusion The exposure levels of fishermen and fish vendors to PCBs via consumption of Rastrelliger kanagutra (Indian mackerel) in Dar es Salaam are high enough to course serious health concerns, especially for high fish consumers and efforts should be taken to encourage diversification of fish species intake.

The occurrence of polychlorinated biphenyls (PCBs) in marine fish and their potential health risks was assessed in Dar es Salaam region. Six indicator PCBs were assessed in selected marine fish species, Rastrelliger kanagutra and Siganus sutor collected from the Kivukoni-Feri, the major fish market and fishermen landing site in Dar es Salaam. Fish samples were extracted using the QuEChERS method and quantified by GC-MS/MS. The concentration of detected PCBs congeners in the analysed fish species was relatively low, ranging from <LOD to 3.71 ng/gw/w in R. kanagutra and from <LOD to 0.58 ng/g w/w in S. sutor species. However, the sum of mean PCBs concentration levels was below the maximum residue limit (MRL) of 75 ngg-1w/w set by the European Commission (EC) in the muscle of fish and fishery products. Estimated lifetime cancer risks were categorised as very low in both children and adults, with indices values ranging from 1.24E-08 to 6.14E-07 for children and 5.14E-09 to 2.55E-07 for adults, while non-carcinogenic risks were insignificant as the estimated hazard indices were less than 0.1 for both children and adults.