Abstract |
Streams in the 'New Lead Belt' of SE Missouri were analyzed for copper, lead and zinc. This area, is rapidly developing into the largest lead-zinc mining district of the United States. The data of the study were compared to the results of a pre-mining investigation to determine if the mining activity contributed to the pollution of the streams by heavy metals. Data from an individual mine indicate that the milling waste waters can increase the heavy metal content of the receiving stream up to seven times. However, the heavy metal content of the stream decreases to background concentrations within a distance of three miles. The summarized data of the total area do not indicate a noticeable increase of the heavy metal content in the streams. The average concentrations in the streams at the time of the present investigation were 5.3 ppb for copper, 8.9 ppb for lead and 9.5 ppb for zinc. The calcium content is in the range of 2.45 ppm. The magnesium content in the range of l-30 ppm. The pH of the streams ranges from 7.0-8.8. It is concluded, that the mining activity presently does not significantly pollute the streams with heavy metals. (Author) |