Energy-dispersive X-ray microanalysis of the calciferous glands of Lumbricus terrestris L. (Oligochaeta) contaminated with heavy metals
1992
Schrader, S.
Laboratory experiments were conducted with Lumbricus terrestris to test the influence of several heavy metals on its calciferous glands. The earthworms were exposed to a substrate composed of artificial soil treated with sewage sludge. The sewage sludge was contaminated with heavy metals of known concentrations. After 8 weeks in the contaminated soil the earthworms were removed and dissected to obtain their calciferous glands and their calciferous sacs. Tissue samples of these organs were investigated by EDX measurements. Accumulations of some of the identified elements were visualized by elementary distribution mapping. The tissue between the intestine and the calciferous glands and sacs possessed the highest heavy metal concentrations. In the organs themselves the heavy metal content in the glands was greater than in the sacs. All the investigated tissues showed a considerable affinity to copper. Zinc and nickel were concentrated to a lesser extent. In the calcite concretions no heavy metals were identified at all. The elementary distribution maps of the gland tissue also showed calcium not to appear together with the heavy metals. The results indicate that the elimination of excess heavy metals by these organs occurs only by concentration and deposition in the gland and sac tissue but not by excretion, along with the calcite concretions, into the intestine.
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