Enzyme Activities in Reduction of Heavy Metal Pollution from Alice Landfill Site in Eastern Cape, South Africa

Abstract

Heavy metals are unbreakable, and most of them are poisonous to animals and people. Metals are particularly concerning among environmental contaminants since they are less apparent, have extensive effects on ecosystems, are poisonous, and bioaccumulate in ecosystems, biological tissues, and organs. Therefore, there is a need to use biological agents and phytoremediation processes such as enzymes because they have a high potential for effectively transforming and detoxifying polluting substances. They can convert pollutants at a detectable rate and are potentially suitable for restoring polluted environments. We investigated heavy metal concentrations in different soil samples collected in four sections in Alice and determined the enzyme activity levels present in the soil. The Pearson correlation analysis was conducted to check whether there was any relationship between heavy metal concentrations and enzyme activities in the soil. Samples were randomly collected in three weeks, and the microwave digestion method was used for sample treatment and preparation. Quantitation was achieved by inductively coupled plasma mass spectrometry (ICP-MS). The enzyme assay through incubation method was implemented for discovering the four selected enzymes (urease, invertase, catalase, and phosphatase), and their activity levels were examined colorimetrically by colorimetry spectrophotometer. The ICP-MS results revealed 16 predominating elements, namely: Al, Ba, Ca, Co, Cr, Cu, Fe, K, Mg, Mn, Na, Ni, Sr, and Zn, and the presence of a non-mental, which is phosphorus (P), and a metalloid in the form of silicon (Si) in all soil samples. Significant differences in metal concentrations were observed among the collection sites. The Al, Fe, K, Mg, and Ca concentrations were above WHO’s permissible limits. While Ba, Mn, Na, and P were in moderate concentration, Cu, Cr, Co, Zn, Sr, and Ni were in small amounts recorded mostly below the permissible values from WHO. Four soil enzyme activities were determined successfully (urease, invertase, phosphatase, and catalase). A negative non-significant correlation existed between urease, invertase, phosphatase enzyme activity, and the concentration levels of all selected metals (Al, Ba, Ca, Co, Cu, Fe, K, Mg, Mn, Na, Ni, Cr, Sr, and Zn. In contrast, the content of catalase activity was associated non-significantly but positively with the range of selected heavy metals. This study suggests proper monitoring of residences’ areas, which can provide detailed information on the impact of high heavy metal content on people’s health. They are easily dispersed and can accumulate in large quantities in the soil. The necessary implementation of waste management programs will help the municipality adopt a strategy that will promote recycling programs and protect the residence health from this threat.

Possible Molecular Mechanisms Underlying the Decrease in the Antibacterial Activity of Protamine-like Proteins after Exposure of Mytilus galloprovincialis to Chromium and Mercury

“…After all, it has been reported in the literature that some heavy metals can inhibit soil enzyme activity and can influence the spreading of AMPs in both negative and positive ways [28]. In fact, pollutant concentrations and soil enzyme activity have generally been shown to have a negative link [29]. The alterations in the properties of PLs that we detected after the exposure of mussels to certain heavy metals prompted us to investigate whether the antibacterial activity of these proteins could also be affected in some way after the exposure of mussels to those metals (chromium and mercury), which had produced greater changes in the other properties of these proteins.…”

“…The evaluation of the antimicrobial activity of M. galloprovincialis PLs was performed using the broth dilution method (MH broth), as previously described in Verrillo et al, 2021;2022;2023 [53,56,57], with a minor modification. The bacterial strains used in this study included Escherichia coli ATCC 35218, Pseudomonas aeruginosa ATCC 27355, Klebsiella pneumoniae ATCC 700503, Staphylococcus aureus ATCC 5538P, and Enterococcus faecalis ATCC 29212 (Table 5).…”

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

“…Toxic metals/metalloids can inhibit various plant enzymes, leading to various detrimental effects on plant physiology and soil health. Understanding these interactions is critical for managing toxic metal/metalloid contamination and protecting plant and soil health [80,[85][86][87][88].…”

“…For instance, Zn and Cu have been reported to inhibit dehydrogenase and urease activities in soil, which are essential for organic matter decomposition and nitrogen cycling [85]. This inhibition can lead to changes in soil properties, productivity limitations, and altered ecosystem function [87].…”