Mining activities can lead to the generation of large quantities of heavy metal laden wastes which are released in an uncontrolled manner, causing widespread contamination of the ecosystem Though some heavy metals classified as essential are important for normal life physiological processes, higher concentrations above stipulated levels have deleterious effects on human health and biota Bacteria able to withstand high concentrations of these heavy metals are found in the environment as a result of various inherent biochemical, physiological, and/or genetic mechanisms These mechanisms can serve as potential tools for bioremediation of heavy metal polluted sites This review focuses on the effects of heavy metal wastes generated from gold mining activities on the environment and the various mechanisms used by bacteria to counteract the effect of these heavy metals in their immediate environment

Heavy Metal Pollution from Gold Mines: Environmental Effects and Bacterial Strategies for Resistance.

Biological approaches to tackle heavy metal pollution: A survey of literature

Environmental problems have always received immense attention from scientists. Toxicants pollution is a critical environmental concern that has posed serious threats to human health and agricultural production. Heavy metals and pesticides are top of the list of environmental toxicants endangering nature. This review focuses on the toxic effect of heavy metals (cadmium (Cd), lead (Pb), copper (Cu), and zinc (Zn)) and pesticides (insecticides, herbicides, and fungicides) adversely influencing the agricultural ecosystem (plant and soil) and human health. Furthermore, heavy metals accumulation and pesticide residues in soils and plants have been discussed in detail. In addition, the characteristics of contaminated soil and plant physiological parameters have been reviewed. Moreover, human diseases caused by exposure to heavy metals and pesticides were also reported. The bioaccumulation, mechanism of action, and transmission pathways of both heavy metals and pesticides are emphasized. In addition, the bioavailability in soil and plant uptake of these contaminants has also been considered. Meanwhile, the synergistic and antagonistic interactions between heavy metals and pesticides and their combined toxic effects have been discussed. Previous relevant studies are included to cover all aspects of this review. The information in this review provides deep insights into the understanding of environmental toxicants and their hazardous effects.

Heavy Metals and Pesticides Toxicity in Agricultural Soil and Plants: Ecological Risks and Human Health Implications.

The most common laboratory procedure used for DHA determination is the method developed by Casida et al. (1964). According this method, specific dyes such as the triphenyltetrazolium chloride (TTC), that can specify the flow of electrons are useful indicators of electron transport system (ETS) activity. By the reduction of colorless, water soluble substrate (TTC) by dehydrogenases present in the soil environment, an insoluble product with red color (triphenylformazan-TPF) is formed. TPF can be easily quantified calorimetrically at the range of visible light (485 nm). This test however, reflected positive answer only at neutral range of pH and in presence of calcium carbonate for buffering soil system. Briefly, if the red colors of soil samples prepared for spectrophotometer analyses are more intensive, the measured level of DHA is higher. Consequently, soil samples without red colors or those with light red colors are characterized by lower DHA values.

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Dehydrogenase Activity in the Soil Environment

Trace Elements in Soils

Wpływ alkoholu izopentylowego i benzyloadeniny na plonowanie marchwi i aktywność drobnoustrojów glebowych

Aktywność dehydrogenaz w glebach zanieczyszczonych cynkiem, miedzią, niklem i kadmem

Mikrobiologiczne właściwości gleby zanieczyszczonej herbicydem Granstar 75 WG

Reakcje drobnoustrojów glebowych na zanieczyszczenie cynkiem

Soil contamination with cresol is a problem of the 21st century and poses a threat to soil microorganisms, humans, animals, and plants. The lack of precise data on the potential toxicity of o-cresol in soil microbiome and biochemical activity, as well as the search for effective remediation methods, inspired the aim of this study. Soil is subjected to four levels of contamination with o-cresol: 0, 0.1, 1, 10, and 50 mg o-cresol kg−1 dry matter (DM) of soil and the following are determined: the count of eight groups of microorganisms, colony development index (CD) and ecophysiological diversity index (EP) for organotrophic bacteria, actinobacteria and fungi, and the bacterial genetic diversity. Moreover, the responses of seven soil enzymes are investigated. Perna canaliculus is a recognized biosorbent of organic pollutants. Therefore, microbial biostimulation with Perna canaliculus shells is used to eliminate the negative effect of the phenolic compound on the soil microbiome. Fungi appears to be the microorganisms most sensitive to o-cresol, while Pseudomonas sp. is the least sensitive. In o-cresol-contaminated soils, the microbiome is represented mainly by the bacteria of the Proteobacteria and Firmicutes phyla. Acid phosphatase, alkaline phosphatase and urease can be regarded as sensitive indicators of soil disturbance. Perna canaliculus shells prove to be an effective biostimulator of soil under pressure with o-cresol.

Jan Kucharski

Papers

Wpływ alkoholu izopentylowego i benzyloadeniny na plonowanie marchwi i aktywność drobnoustrojów glebowych

Aktywność dehydrogenaz w glebach zanieczyszczonych cynkiem, miedzią, niklem i kadmem

Mikrobiologiczne właściwości gleby zanieczyszczonej herbicydem Granstar 75 WG

Reakcje drobnoustrojów glebowych na zanieczyszczenie cynkiem

Perna canaliculus as an Ecological Material in the Removal of o-Cresol Pollutants from Soil