Interactive Effect of Radioactive and Heavy-Metal Contamination on Soil Enzyme Activity in a Former Uranium Mine

Abstract

Radioactivity and heavy metal toxicity of multi-metal deposits coexisting with the element uranium (U) could have long-term adverse impacts on soil biological processes and the health of soil ecosystems. Soil enzyme activities are considered bioindicators for assessing soil health. An experiment was designed to investigate invertase and ß-glucosidase activity in multi-metal deposits. Radioactivity and heavy metals were also investigated during this study. Our results showed that the invertase and ß-glucosidase activities were significantly lower in the core mining area than the control area (p<0.05). Activities of the two enzymes decreased with increasing metal concentrations and radioactivity. Cu and Zn showed significant negative effects on ß-glucosidase and invertase activities in a multi-metal deposit at the study site. A significant nonlinear relationship was recorded between soil enzyme activities, radiation dose (R 2 = 0.71, 0.63; p<0.05), Zn (R 2 = 0.34, 0.41; p<0.05) and Cu concentrations (R 2 = 0.46, 0.45; p<0.05). There were turning points at 1 µGy h-1 , 250 µg g-1 , and 30 µg g-1 for radiation dose, Zn and Cu contents, respectively. The findings could provide more information regarding the toxic effects of radiation and heavy metals on the soil health of multi-metal deposits, which can more precisely guide environmental protection.

Distribution of heavy metals, soil microbial enzymes and their relationship in Kano, Northwestern Nigeria

“…This result is contrary to the results of Gang et al (2017); Tang et al (2019) who revealed significant inhibition of soil enzymes by increases of heavy metals. Furthermore, high temperature and pH at contaminated locations encourage soil microbial activities and influence the solubility, availability, and toxicity of heavy metals to soil microbes respectively, thus, decrease the effect of heavy metals on the biochemical reaction in the soil.…”

Speciation Distribution of Heavy Metals in Uranium Mining Impacted Soils and Impact on Bacterial Community Revealed by High-Throughput Sequencing

“…It consists of mine deposits of different sizes. This mining was explored during 1970–1990s and has been abandoned from approximately 20 years (Yang et al, 2018). Soils of the region have been seriously polluted by numerous metals due to mining activities.…”

Heavy Metals/Metalloids in Soil of a Uranium Tailings Pond in Northwest China: Distribution and Relationship with Soil Physicochemical Properties and Radionuclides

“…As a rule, these waste materials still contain huge amounts of long-lived radionuclides, for example, uranium, thorium, radium and others, as well as associated typical heavy metals (for example, Cd, Pb, Cr, etc.) and metalloids (for example, As) [7,[9][10][11]15]. These radionuclides and heavy metals/metalloids may be influenced by natural or human factors and may migrate into environmental media, thus affecting the soil ecosystem, food chain, and human health around tailings ponds [9,10,15].…”

“…and metalloids (for example, As) [7,[9][10][11]15]. These radionuclides and heavy metals/metalloids may be influenced by natural or human factors and may migrate into environmental media, thus affecting the soil ecosystem, food chain, and human health around tailings ponds [9,10,15]. Researchers in Portugal, the UK, and China have carried out investigations on the distribution of radionuclides and heavy metals/metalloids in uranium mining areas.…”