Bacteria in lead contaminated soil.

Lead is a serious hazard to health, seeing as it is able to interfere with enzyme activity. Lead may accumulate in soil, posing as a hazard for children who come in contact. If a child is exposed to high, bioavailable levels, mental retardation can occur. Missouri has a problem with lead as a result of mining and smelting. The lead from these activities may be in several forms, some more toxic than the others. Land that is left untreated will continue to be hazardous for many years. Bacterial populations are also susceptible to lead. By looking at the populations of contaminated soil, we hope to see the effect of mining and smelting waste on living organisms. We looked at soil from near a lead mining activity. Lead contamination was 4,000 parts per million. We used several methods to assess the bacterial populations. After isolating single bacterial colonies on several kinds of compatible agar, we were able to gram stain all samples. Then we classified each bacterial sample under the microscope and found several different cocci, rods, and spirochetes. One bacterial strain we were able to decipher was Pseudomonas fluorescens. Although other bacteria were more difficult to identify, some other methods used to aid in classifying each bacterial sample were performed, including the oxidase test, catalase test, and stab cultures.

* Laflamme, C.L., L. Kulhanek, and T. Giblin. Department of Natural Sciences, Stephens College.