Effects of heavy metals on growth of species of Micrococcus and Pseudomonas in a crude oil/mineral salts medium

摘要

Bioassays were conducted to observe the responses of species of Micrococcus ann Pseudomonas to the metals zinc, lean, copper and manganese, added singly or in combination to a crude oil/mineral salts medium. Bacterial density decreased with increasing metal ion concentration. A 50% reduction (LC50) in the bacterial density of Micrococcus sp. occurred on the addition of either 0.46 mu g zinc/ml, 1.41 mu g lead/ml, 11.25 mu g copper/ml or 28.2 mu g managanese/ml. For Pseudomonas sp., the corresponding values were 0.43 mu g zinc/ml, 2.80 mu g lead/ml, 6.30 mu g copper/ml or 317.0 mu g manganese/ml. Of the metals tested, only zinc was found in higher concentrations in the oil contaminated site than the LC50 value obtained. (C) 1998 Elsevier Science Ltd. All rights reserved. [References: 28]