Assessment of using bentonite, dolomite, natural zeolite and manure for the immobilization of heavy metals in a contaminated soil: The Copșa Mică case study (Romania)
The research paper investigates the effectiveness of various organic and inorganic amendments—specifically Na-bentonite, dolomite, natural zeolite, and manure—in immobilizing heavy metals (cadmium, lead, and zinc) in contaminated soils, focusing on the Copșa Mică area in Romania. The study is motivated by the increasing threat of heavy metal contamination to soil quality and human health, particularly in agricultural settings.
A field experiment was conducted over two years, where different amendments were applied to assess their impact on soil pH and metal availability. Results indicated that all treatments significantly increased soil pH, with dolomite and Na-bentonite showing the most substantial effects. The amendments reduced the availability of heavy metals compared to control plots, although the degree of reduction varied by metal and amendment type. Notably, dolomite and Na-bentonite effectively decreased lead and zinc concentrations in plants, but the levels remained insufficient for producing healthy food or fodder.
The study also highlighted that while manure increased biomass yield, its effect on metal extractability was moderate. The findings suggest that Na-bentonite and dolomite have high potential for reducing heavy metal toxicity in contaminated soils, but caution is advised regarding the temporary nature of liming effects and the potential for metal remobilization over time.
This research paper is significant in the field of environmental science and soil remediation, as it addresses the pressing issue of heavy metal contamination in agricultural soils, particularly in regions with historical industrial pollution. The research contributes to ongoing discussions about sustainable and cost-effective remediation strategies, emphasizing in-situ immobilization as a viable alternative to traditional, more expensive remediation methods. By providing empirical data on the effectiveness of various amendments, the study offers valuable insights for researchers, policymakers, and landowners seeking to mitigate the risks associated with contaminated soils. The findings underscore the importance of long-term monitoring and the need for periodic reapplication of amendments to ensure sustained effectiveness in reducing heavy metal availability.
