Sources, indicators, and assessment of soil contamination by potentially toxic metals

Authors: SHENTU, J - Zhejian University; HE, Z - Indian River State College; XIN, X - Indian River State College; ZHANG, T - Agriculture And Agri-Food Canada; YANG, X - Zhejian University; Baligar, Virupax

Submitted to: Sustainability
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/28/2022
Publication Date: 11/29/2022
Citation: Shentu, J., He, Z., Xin, X., Zhang, T., Yang, X., Baligar, V.C. 2022. Sources, indicators, and assessment of soil contamination by potentially toxic metals. Sustainability. 14:15878. https://doi.org/10.3390/su142315878.
DOI: https://doi.org/10.3390/su142315878

Interpretive Summary: Cacao in South America invariably grown on infertile acidic soils and on such soils application of fertilizer is vital to achieve economically sustainable yields. Foliar analysis of micro-micronutrients is widely adapted to assess nutrient sufficiency and deficiency in cacao. However, use of these leaf analysis as guide for recommendation for fertilizer application to achieve reasonable cocoa beans yield is lacking. In this paper we report findings of foliar analysis from 48 cacao cropping systems showed that the Zn/Cu and Ca/Mg ratios influenced cacao productivity and further the ratios that lead Cu as a denominator Mn/Cu, Ca/Cu, Mg/Cu, P/Cu, N/Cu and K/Cu also showed a positive nutritional balance that directly influences cacao productivity. This information will be useful to cacao producer, extension workers and analytical lab operators to find suitable fertilizer recommendation based on foliar analysis to improve yield potentials of cacao grown in an infertile acidic soil.

Technical Abstract: Soil pollution related to heavy metals or metalloids has become a worldwide environmental issue. Sources of heavy metal pollution include geogenic processes and anthropogenic activities. Soils may inherit heavy metals from parent materials, however most of soil pollution results from anthropogenic activities. Contamination by heavy metals can be indicated by the changes in chemical, biochemical, and microbial properties of soils and plant responses. Total concentration of heavy metals in soil is still the most widely used indicator for risk assessment although extractable amounts have been reported to be more closely related to plant uptake. Several models have been proposed for assessing soil contamination by heavy metals, but none of them are commonly accepted for application to a wide range of soils. Further research is needed to improve soil contamination diagnosis, regulatory standards and assessment models.