Soils in lakes: the impact of inundation and storage on surface water quality

Abstract

The large-scale storage and inundation of contaminated soils and sediments in deep waterlogged former sand pits or in lakes have become a fairly common practice in recent years. Decreasing water depth potentially promotes aquatic biodiversity, but it also poses a risk to water quality as was shown in a previous study on the impact on groundwater. To provide in the urgent need for practical and robust risk indicators for the storage of terrestrial soils in surface waters, the redistribution of metals and nutrients was studied in long-term mesocosm experiments. For a range of surface water turbidity (suspended matter concentrations ranging from 0 to 3000 mg/L), both chemical partitioning and toxicity of pollutants were tested for five distinctly different soils. Increasing turbidity in surface water showed only marginal response on concentrations of heavy metals, phosphorus (P) and nitrogen (N). Toxicity testing with bioluminescent bacteria, and biotic ligand modelling (BLM), indicated no or only minor risk of metals in the aerobic surface water during aerobic mixing under turbid conditions. Subsequent sedimentation of the suspended matter revealed the chemical speciation and transport of heavy metals and nutrients over the aerobic and anaerobic interface. Although negative fluxes occur for Cd and Cu, most soils show release of pollutants from sediment to surface waters. Large differences in fluxes occur for PO 4 , SO 4 , B, Cr, Fe, Li, Mn and Mo between soils. For an indicator of aerobic chemical availability, dilute nitric acid extraction (0.43 M HNO 3 ; Aqua nitrosa) performed better than the conventional Aqua regia destruction. Both the equilibrium concentrations in surface waters, and fluxes from sediment, were adequately (r 2 = 0.81) estimated by a 1 mM CaCl 2 soil extraction procedure. This study has shown that the combination of 0.43 M HNO 3 and 1 mM CaCl 2 extraction procedures can be used to adequately estimate emissions from sediment to surface waters, and assess potential water quality changes, when former sand pits are being filled with soil materials.

Effect of Land use Change on Total Phosphorus and Its Fractions in North-Western Himalayas

“…Phosphorus in soil is dispersed among numerous geochemical phases, including soil solution and exchangeable phase, OM phase, Ca-bound phase, and Fe and Al-bound phases. The degree of P association with distinct geochemical forms greatly depends on soil physico-chemical characteristics owing to soil type, climate, and management approaches [7]. Under certain situations, these P fractions can be altered due to their different mobility, bioavailability, and chemical behaviors in soil.…”

“…It was reported that both inorganic P and Po concentrations reduced significantly. However, much remains unknown about cropping, along with how land management techniques affect P loss and how soil aggregates sustain and cycle P pools, particularly Po [7,11]. Only few studies have examined its effects on P forms.…”

Quantifying Turbidity Variation for Lakes in Daqing of Northeast China Using Landsat Images From 1984 to 2018

“…Traditionally, turbidity information has been collected primarily through field measurement and experimental analysis [20], [21]. However, using traditional methods to estimate turbidity requires a great deal of materials, time, and human resources; and it is difficult to obtain spatiotemporal patterns [18].…”