Metals on microorganisms

Strategies to Mitigate Deleterious Effects of Metals on Microorganisms. 420... 

STRATEGIES TO MITIGATE DELETERIOUS EFFECTS OF METALS ON MICROORGANISMS... 

In 1978, Jackson and Morgan [3] identified four difficulties that they considered were limiting our understanding of the effects of trace metals on microorganisms ... 

Electrolysis has the potential advantage that a metal can be recovered in its most valuable forms as metal film or powder and sold or recycled to the process. Cf. also Walsh, Ref. [133]. Heavy metals, such as copper from metal complex dyes, or from catalysts in industrial effluents, have become a problem in clarification plants because of their toxic effects on microorganisms. Their disposal through deposition after chemical or physical treatment is senseless,... 

Our laboratory first called attention to the bacterial effects of the simpler complexes in 1965. Over the next few years, in cooperative studies with microbiologists, a number of papers were published describing a multiplicity of effects on microorganisms caused by various complexes of platinum group metals platinum, palladium, ruthenium, rhodium, osmium, and iridium. 

Complexation of metals and trace anions (e.g., phosphate) by humic substances leads to a decrease of toxicity of certain metals toward microorganisms and increases the availability of some metals, but decreases phosphorus resources. At this time, the role of humic substances in reducing the toxicity of trace metals is more clearly understood than the other roles. Adsorption of micropollutants by aquatic humic substances may enhance their toxicity toward microorganisms in many cases. The specific modes of action, however, are mostly unknown. On the other hand, dissolved humic substances may assist in the degradation of organic pollutants. Under environmental conditions, the predominating process is not obvious. 

In this chapter, some aspects of the transformation and mobilization of metals by microorganisms in relation to the soil environment have been outlined. It seems evident that metal-microbe interactions are important in several soil contexts, not least in the biogeochemical cycling of metals, associated elements, and nutrients, and in plant productivity. The application and potential of many natural microbial and microbe-plant processes are also growing topics in the area of bioremediation. However, analysis and understanding of the effects of toxic metals on microbial communities is relatively limited despite extensive research, and many studies are site specific. Clearly, the complexity of interactions between metal species and soil components, as well as between metal... 

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