Soil heavy metal concentrations, microbial biomass and enzyme activities in a contaminated grassland ecosystem

Copper pollution decreases the resistance of soil microbial community to subsequent dry–rewetting disturbance

“…This result was in line with previous studies, that previously stressed soils were more affected by a subsequent disturbance than unstressed soils (Tobor-Kaplon et al, 2006). We speculated that organisms in the metal-contaminated soils might allocate more energy to detoxification and damage repair; therefore, it was harder for stressed soils to cope with additional disturbance (Kuperman and Carreiro, 1997). However, the resistance of SIR in the medium copper-stressed soils to DW disturbance was different in the two soils, which might be attributed to the extractable copper concentrations.…”

Chromium immobilization by extraradical mycelium of arbuscular mycorrhiza contributes to plant chromium tolerance

“…that soil phosphatases play an important role in P uptake by plants and mycorrhizal fungi, as these enzymes can mineralize organic P to inorganic P (Nannipieri et al, 2011), and therefore take an active part in P uptake by plants and mycorrhizal fungi. Cr contamination could possibly reduce soil phosphatase activities and thus decrease plant P uptake (Tyler, 1974;Kuperman and Carreiro, 1997). The decreased activities of soil phosphatases caused by Cr contamination probably could not be compensated by P application as previous study showed an inverse relation between P supply and acid phosphatase activity in soil (Spiers and McGill, 1979).…”

Lead Contamination and Microbial Lead Tolerance in Soils at Major Road Junctions in Benin City

“…This was not necessarily a direct effect of lead toxicity because the soils did not have plant communities; therefore, the lack of organic matter input could have reduced the microbial populations. Kuperman and Carreiro (1997) reported that soils contaminated with heavy metals had significantly less plant biomass and this affect the microbial population levels in the soils. The colony counts of the microorganisms on media containing different concentrations of lead showed that these microorganisms are capable of accumulating lead from dilute solutions of heavy metals (Norris and Kelly, 1979).…”

“…The distribution of lead as a toxic pollutant has been the subject of concern since the advent of the antiknock lead additives in gasoline (Kuperman andCarreiro 1997: Chow andEarl, 1970). There has been much discussion on the emission of lead from automobile exhaust and its possible harmful effects on microbial and human populations.…”