Neutralization of Industrial Alkali-Contaminated Soil by Different Agents: Effects and Environmental Impact

Abstract

Industrial soil is susceptible to acid or alkali pollution, but studies focused on the remediation of such soil are still limited. This manuscript investigated the neutralization effect of five agents (hydrochloric acid, citric acid, ferrous sulfate, calcium superphosphate and raw gypsum) to alkali polluted soil. The results showed that regarding the initial pH after the neutralizing agent addition, it was better to set it lower than the target, as the pH would rebound. None of the five agents caused an obvious increase in the heavy metal contents of the leachates, but they all caused an increase in electrical conductivity, which indicated an increase in soil salinity. The leachates showed a luminous gain to Vibrio fischeri. However, remediation with hydrochloric acid would cause significant inhibition of germination and root elongation of pakchoi. In addition, the addition of neutralizing agents reshaped the soil microbial community structure in different patterns. Soils treated with hydrochloric acid and ferrous sulfate seemed to improve the microbial richness. The neutralization might be favorable for the biodegradation of polycyclic aromatic hydrocarbons (PAHs), which usually coexist in industrial contaminated soil. In general, the neutralization of alkaline industrial soils using ferrous sulfate, superphosphate and gypsum brought minimal environmental risk, among which ferrous sulfate was the first recommendation in industrial soil after a comprehensive comparison.

Solidification and Stabilization of Fluorine and Phosphorus in Phosphate Mine Tailings and the Mechanism of F and P Fixation During Soilization

“…Compared to CK, there was a large increase in IM conductivity from 952 μS/cm to 2251 μS/cm, which was attributed to the promotion of the release of solidified anions and cations from the phosphate mine tailings and the increase in the total value of Fe 2 + , Fe 3 + , Al 3 + , AlO 2 2À , and SO 4 2À under the treatment of ferrous sulphate and polymerised aluminium sulphate (Figure 4a). [30] Compared to CK, IM treatment caused a decrease in the leaching toxicity of fluorine (by 2 mg/L), which stabilized with time and formed AlF 3 (Figure 4b). In Figure 4c, the pH of IM was lower than that of CK.…”

Institutionalization of integrated pest management in the food estate development area, Sungai Mandau Subdistrict, Siak Regency, Riau

“…The use of dolomite at 2 tons/ha can increase soil pH by one point (10). In practice, farmers in this region generally apply dolomite before planting, with a minimum application of 100 kg/ha and a maximum of 700 kg/ha, so the application of dolomite is considered to be very insufficient to neutralize the acidity of the soil (11). The impact of this oxidation also results in the canal water as an irrigation channel having a low pH and potentially harming plant growth.…”