Aluminium leaching response to acid precipitation in a lime-affected soil

Abstract

Acid precipitation accelerates acidification process in the soil and facilitates nutrient leaching. The study aimed to explore the effects of long-term liming on aluminium (Al) leaching by comparing a limed soil with an unlimed soil at different acidity (pH) levels of simulated acid rain (SAR). The columns of unlimed and limed soil were watered with SAR at 5.4, 4.7 and 4.0 pH levels. Aluminium was extracted from the solid phase with the following solutions: ammonium oxalate (non-crystalline Al), sodium pyrophosphate (organically bound Al), copper chloride (organo-Al complexes of low and medium stability), lanthanum chloride (the most labile organo-Al complexes) and ammonium chloride (exchangeable Al). The total Al in the leachate was also determined. Long-term liming had a significant influence on the soil acidity and reduced all Al compounds in the in solid phase. The Al concentrations determined in the leachate of the limed soil were 0.12-0.92 mg L-1 and in that of the unlimed soil-1.63-2.62 mg L-1. Leaching losses of Al from limed and unlimed soil increased with decreasing acidity of the simulated acid rain. The losses were found to be high when the pH of SAR was 4.0. Al in the leachate was positively correlated with all Al fractions in a solid phase and showed this to be one of the reasons for increased Al leaching from acid soils. Al leaching from the soil depended not only on the pH of simulated acid rain, but also on the soil properties: acidity, Al saturation in the exchange sites (effective cations exchange capacity) and Al compounds in the solid phase of the soil. Limed soil, characterised by a higher buffer capacity (more Ca and Mg), is able to neutralize the effects of acid precipitation and reduce the solubility of Al-containing compounds.

Furoic Acid-Capped LaF3:Tb Nanoparticles for Al3+ Detection Based on Aggregation-Induced Luminescence Enhancement

“…The lifetime results are shown in Figure S8. The average lifetime of FA-LaF 3 :Tb 3+ NCs without an analyte is 5.07 ms. With the presence of Al 3+ ions in solution and with increasing concentrations, i.e., 5,10,20,50,100,200, and 400 μM, the lifetime of the Tb 3+ ion steadily decreases from 5.04, 4.99, 4.93, 4.87, 4.76, 4.78, and 4.92 ms, respectively. Changes in the luminescence lifetime correlate with changes in the absorption and emission properties and they are plausibly caused by modified interactions with solvent molecules and NCs through aggregation.…”

“…8,9 Due to acid rains, aluminum leaches out as Al 3+ into the soil, groundwater, and surface water. 10 Excessive use of aluminum-based food additives, aluminum cooking utensils, and aluminum foil for food packaging increases the daily intake of Al 3+ ions consumed with food. 11−13 The aluminum ions interact with the phosphate ions from fertilizers present in the soil and form AlPO 4 , making PO 4 3− ions unavailable for plants.…”

“…Aluminum has unique physical and chemical properties that are widely used in various applications such as electricity transportation, automobiles, space, aeronautics, construction, cooking utensils, food packaging, water treatment plants, food additives, medical devices, pharmaceuticals ( e.g. , antacids ), deodorants, antiprecipitants, paper industry, and textile industry. − The content of free aluminum in the environment and water reservoirs naturally increases as a result of the natural process of weathering and volcanic ejection. , Due to acid rains, aluminum leaches out as Al 3+ into the soil, groundwater, and surface water . Excessive use of aluminum-based food additives, aluminum cooking utensils, and aluminum foil for food packaging increases the daily intake of Al 3+ ions consumed with food. − The aluminum ions interact with the phosphate ions from fertilizers present in the soil and form AlPO 4 , making PO 4 3– ions unavailable for plants .…”