Heavy metals in soils of Mayabeque, Cuba: multifaceted and hardly discernable contributions from pedogenic and anthropogenic sources

Abstract

Cuba is a country with considerable potential for economic growth, and special efforts are made to increase the agricultural output. As food production depends on the quality of soils, heavy metal concentrations were measured in 39 soils in the province of Mayabeque, Cuba, and interpreted in light of anthropogenic activities and pedogenic conditions (soil type and properties). With median concentrations of 1.8 Cd, 60.3 Cr, 48.1 Cu, 36.2 Ni, 16.7 Pb, 55.0 Zn, and 0.1 mg/kg Hg, soils of Mayabeque were mostly below Cuban quality reference values (QRV) representing benchmarks of quality standards but no official threshold values. Only Cd concentrations were in many cases above the QRV of 0.6 mg/kg and some Cu concentrations above the one of 83 mg/kg. While Cd, Cr, and Ni concentrations were rather pedogenically driven, Cu, Pb, Zn, and Hg contents were rather anthropogenically influenced. When evaluated statistically, Cd and Cr showed most times a significant influence of both sources. In contrast, Ni and Zn could not be significantly related with the origins investigated in this study. Hence, the allocation of heavy metal concentrations to pedogenic or anthropogenic contamination or pollution sources is tentative and needs further investigations. Nevertheless, the present data adds information on soil heavy metal concentrations in the Caribbean region, serves as reference before further industrial development, and sets the ground for adaptation of the QRV for Cd and possibly future national environmental standards.

Heavy Metal Contamination in Soil: Implications for Crop Resilience and Abiotic Stress Management

“…Agricultural practices, especially fertilizers and pesticides, are another significant source of soil toxic metal/metalloid contamination. An investigation by Sosa et al [15] into the soil composition in Mayabeque, Cuba, revealed the presence of toxic metals/ metalloids such as Cu, Pb, Zn, and Hg, which are significantly influenced by agricultural activities. The study indicated that agricultural runoff, laden with these metals, considerably contributes to their accumulation in soil [15].…”