News Update on Heavy Metals in Soil Research: Dec – 2019

Effects of heavy metals in soil on microbial processes and populations (a review)

The effects of Cd, Cu, Zn, and Pb on soil microorganisms and microbially mediated soil processes are reviewed. the stress is placed on temperate forest soils. The sensitivity of various measurements is discussed, and data compiled to match relative toxicity of various metals. On the entire the relative toxicity of the metals (on a μg g−1 soil basis) decreased within the order Cd > Cu > Zn > Pb, but differences between different investigations were found. The influence of abiotic factors on metal toxicity is briefly discussed and particularly examplified by different soil organic matter content. Evidence of tolerance and adaptation within the soil environment and therefore the duration involved within the evolution of a metal-tolerant microbial community after metal exposure also are considered. [1]

Heavy metals in soil, vegetables and fruits in the endemic upper gastrointestinal cancer region of Turkey

The environmental exposure to heavy metals may be a well-known risk factor for cancer. We investigated levels of seven different heavy metals, (Co, Cd, Pb, Zn, Mn, Ni and Cu) in soil, fruit and vegetable samples of Van region in Eastern Turkey where upper gastrointestinal (GI) cancers are endemic. Heavy metal contents of the samples were determined by flame atomic absorption spectrometer. Four heavy metals (Cd, Pb, Cu and Co) were present in 2- to 50-fold higher concentrations whereas zinc levels were present in 40-fold lower concentrations in soil. The fruit and vegetable samples were found to contain 3.5- to 340-fold higher amounts of the six heavy metals (Co, Cd, Pb, Mn, Ni and Cu) tested. The volcanic soil, fruit and vegetable samples contain potentially carcinogenic heavy metals in such a high levels that these elements might be associated with the high prevalence of upper GI cancer rates in Van region. [2]

Determination of heavy metals in soil, mushroom and plant samples by atomic absorption spectrometry

The concentrations of heavy metals within the soil, mushroom and plant samples collected from Tokat, Turkey are determined by flame and graphite furnace atomic absorption spectrometry after dry ashing, wet ashing and microwave digestion. The study of sample preparation procedures showed that the microwave digestion method was the simplest. Good accuracy was assured by the analysis of ordinary reference materials. The relative standard deviations for all measured metal concentrations were less than 10%. altogether cases, quantitative analytical recoveries starting from 95 to 103% were obtained. Metal accumulation factors were calculated for mushroom and plant samples. High ratio of plants to soil cadmium, zinc and copper concentrations indicate that these elements are accumulated by mushrooms. Results obtained are in agreement with data reported within the literature. [3]

Ecological risk assessment on heavy metals in soils: Use of soil diffuse reflectance mid-infrared Fourier-transform spectroscopy

The bioavailability of heavy metals in soil is controlled by their concentrations and soil properties. Diffuse reflectance mid-infrared Fourier-transform spectroscopy (DRIFTS) is capable of detecting specific organic and inorganic bonds in metal complexes and minerals and thus, has been employed to predict soil composition and heavy metal contents. this study explored the potential of DRIFTS for estimating soil heavy metal bioavailability. Soil and corresponding wheat grain samples from the Chang Jiang Delta region were analyzed by DRIFTS and chemical methods. regression analyses were conducted to correlate the soil spectral information to the concentrations of Cd, Cr, Cu, Zn, Pb, Ni, Hg and Fe in wheat grains. [4]

Concentration of Heavy Metals in Soils at the Municipal Dumpsite in Calabar Metropolis

This research was administered to research the amount of heavy metals in soils at the municipal dumpsite in Calabar, Cross River State, Nigeria. Composite soil samples were collected from five different landscape positions along a toposequence (crest, upper slope, middle slope, lower slope and valley/swamp) at the dumpsite in Calabar. The control sample was taken from an adjacent plot. The control soil was slightly acidic (5.6) while soils from the dumpsite were slightly acidic (6.7 -7.4) to slightly alkaline in reaction. altogether the dumpsite locations the amount of Mercury (0.4-1.0 mg/kg), Chromium (0.66 – 200 mg/kg), Nickel (26 – 748.6 mg/kg), Lead (118 – 4548 mg/kg), and Zinc (1248 -2864 mg/kg) were above the permissible limits in soil whereas iron and copper concentrations were within soil limits. [5]

Reference

[1] Bååth, E., 1989. Effects of heavy metals in soil on microbial processes and populations (a review). Water, Air, and Soil Pollution, 47(3-4), (Web Link)

[2] Türkdoğan, M.K., Kilicel, F., Kara, K., Tuncer, I. and Uygan, I., 2003. Heavy metals in soil, vegetables and fruits in the endemic upper gastrointestinal cancer region of Turkey. Environmental toxicology and pharmacology, 13(3), (Web Link)

[3] Tüzen, M., 2003. Determination of heavy metals in soil, mushroom and plant samples by atomic absorption spectrometry. Microchemical Journal, 74(3), (Web Link)

[4] Ecological risk assessment on heavy metals in soils: Use of soil diffuse reflectance mid-infrared Fourier-transform spectroscopy
Cheng Wang, Wei Li, Mingxing Guo & Junfeng Ji
Scientific Reports volume 7, (Web Link)

[5] F. Ediene, V. and B. A. Umoetok, S. (2017) “Concentration of Heavy Metals in Soils at the Municipal Dumpsite in Calabar Metropolis”, Asian Journal of Environment & Ecology, 3(2), (Web Link)