Are pulp and paper mills sources of toxaphene to Lake Superior and northern Lake Michigan?

Toxaphene was a broad-spectrum pesticide consisting of a mixture of highly chlorinated bornanes and bornenes. After its ban in 1982; toxaphene concentrations have shown a general decline in the environment as a whole and in most of the Great Lakes specifically. Recent work, however, shows that toxaphene concentrations are not decreasing in fishes from Lake Superior and northern Lake Michigan. Non-atmospheric, relatively localized sources are a possible explanation for these observations. For example, toxaphene could be inadvertently produced and released by pulp and paper mills, which could be synthesizing toxaphene-like compounds as a byproduct of bleached paper production. Reported here is a study of surficial river sediment collected upstream and downstream from seven pulp and paper mills, from five areas of previous toxaphene use, and from two presumed, pristine locations. Concentrations of toxaphene found downstream are similar to those found upstream from each of the pulp and paper mills. Concentrations in sediment from rivers near previous toxaphene use locations were higher than concentrations in the background samples. These data suggest that pulp and paper mills are not now sources of toxaphene but that toxaphene used as a pesticide in the Great Lakes basin (although these uses were very small compared to its use in the southern US,) could be a potential source.