Effects of heavy metal Cd pollution on microbial activities in soil

Abstract

Weilin Shi, Xiying Ma. Effects of heavy metal Cd pollution on microbial activities in soil. Ann Agric Environ Med. 2017; 24(4): 722-725. doi: 10.26444/aaem/80920 AbstractHeavy metal contamination of soil occurs when heavy metals are introduced to soil through human activities, leading to the gradual deterioration of the ecology and environment. Microorganism activity reflects the intensity of various biochemical reactions in soil, and changes in it reflect the level of heavy metal pollution affecting the soil. The effects were studied of heavy metal Cd on the microbial activity of soil at different concentrations by investigating the respiratory intensity, urease activity, and catalase activity in forest soil and garden soil. The results showed that the respiratory intensity, urease and catalase activities in the garden soil were all higher than in the forest soil. Cd has obvious inhibitory effects on microbial activities. The three parameters exhibited a downward trend with increasing concentrations of Cd. Catalase activity increased when the mass concentration of Cd reached 1.0 mg/kg, indicating that low concentrations of Cd can promote the activity of some microorganisms. Respiratory intensity and urease activity also increased when the concentration reached 10.0 mg/ kg, showing that respiratory intensity and urease activity have strong response mechanisms to adverse conditions. The effective state of Cd in soil, as well as inhibition of microbial activity, decreased with incubation time.

Assessment of Electrolytes and Metals Profile of the Faro Lake (Capo Peloro Lagoon, Sicily, Italy) and Its Impact on Mytilus galloprovincialis

“…Heavy metals are released into the environment from both anthropogenic and natural sources; these elements are highly reactive elements and often at low concentrations are toxic. These can enter the soil and groundwater, bioaccumulate in food webs and adversely affect the biota . At the same time metals play a vital role in various physiological processes and are linked to biomolecules in organisms homeostasis .…”

Neighbor Presence of Plant Growth-promoting Rhizobacteria (PGPR) and Arbuscular Mycorrhizal Fungi (AMF) Can Increase Sorghum Phytoremediation Efficiency in a Soil Treated with Pb Polluted Cow Manure

“…In a similar study, Shi et al (2017) assessed the effects of Cd pollution on soil microbial activities, reporting that heavy metals adversely affected soil microbial respiration. Although the mentioned study indicated that soil heavy metals variably affected soil microbial activity, the obtained results indicated that at lower Cd concentrations, soil microbes became resistant to heavy metals [38]; this is in line with our findings. According to the results of the present study, although increased soil contamination with Pb reduced microbial population, soil microbial respiration remained higher compared to the control soil samples.…”

The Influence of Potentially Toxic Elements on Soil Biological and Chemical Properties

“…A number of workers [30][31][32][33] have reported that potentially toxic elements particularly cadmium, copper, and zinc can disrupt the microbiological equilibrium of soil. Disturbances of the biological balance of soil caused by the excess of potentially toxic elements might be attributed to the disruption of physiological functions, denaturation of proteins and destruction of cellular membranes of soil microorganisms [34][35][36].…”

“…Potentially toxic elements immobilize soil bacteria, while microbial metabolites enhanced the mobility of potentially toxic elements [37][38][39]. Potentially toxic elements in different quantities and forms in soils cause changes in the counts of microorganisms, microbial biomass and microbial activity [33,[40][41][42][43] via inhibiting microbial community diversity, particularly that of fungal groups i.e., Ascomycota and Chytridiomycota) in the large-size fractions, which mainly depends on heterogeneous SOC availability across the PSFs. Potentially toxic elements create abiotic stresses [37,38] by inducing disorders in the metabolism of the microorganism.…”