Amendments affect lead mobility and modulated chemo-speciation under different moisture regimes in normal and salt-affected lead-contaminated soils

详细信息    查看全文

• 作者：M. M. Iqbal ; G. Murtaza ; T. Naz ; J. Akhtar…
• 关键词：Inorganic amendments ; Lead immobilization ; Chemical speciation ; Visual MINTEQ ; Flooding regime ; Field capacity ; Incubation time
• 刊名：International Journal of Environmental Science and Technology
• 出版年：2017
• 出版时间：January 2017
• 年：2017
• 卷：14
• 期：1
• 页码：113-122
• 全文大小：
• 刊物主题：Environment, general; Environmental Science and Engineering; Environmental Chemistry; Waste Water Technology / Water Pollution Control / Water Management / Aquatic Pollution; Soil Science & Conservati
• 出版者：Springer Berlin Heidelberg
• ISSN：1735-2630
• 卷排序：14

文摘

The total lead content in the soil itself is insufficient as a measure to indicate the actual environmental risks related to the presence of lead in the soil. Understanding the mobility of lead and its chemical speciation in soil solution is of great importance for accurately assessing environmental risks posed by lead. Therefore, a laboratory study was carried out to evaluate the effect of inorganic amendments (gypsum, rock phosphate and di-ammonium phosphate) on lead mobility and chemical speciation under different moisture regimes (flooding regime and 75 % field capacity) in normal and salt-affected lead-contaminated soils. After 2, 7, 15, 30, 100 and 110 days of incubation, pore water samples were collected by using Rhizon soil moisture samplers. In order to estimate the chemical speciation of lead in pore water, Visual MINTEQ 3.0 modeling approach was used. The results showed that presence of free Pb2+, PbCl+, Pb(SO₄)₂2−, and PbH₂PO₄+ was significantly (P ≤ 0.05) affected by the soil moisture regime, incubation time and applied amendments in lead-contaminated soils. The Visual MINTEQ 3.0 predicted free Pb2+ species concentration was found higher in lead-contaminated soils, while PbCl+ was more pronounced in salt-affected soils. Gypsum increased the occurrence of Pb(SO₄)₂2−, while di-ammonium phosphate and rock phosphate enhanced the PbH₂PO₄+ species formation and decreased free Pb2+ species in pore water. Thus, gypsum is the most effective in reducing lead and free Pb2+ species concentrations in the pore water under different soil moisture regimes and incubation times in normal and salt-affected lead-contaminated soils.