Distribution of Arsenic Fraction in Soil Around Abandoned Mining Area and Uptake by Rice

Abstract

Arsenic (As) contamination of agricultural soils resulting from mining activity has caused major concern due to the potential health risk. Therefore the current study was carried out to investigate the relationship between fractionation of As in soil and rice uptake and to provide a basic information for adequate management of As contaminated agricultural soil. Twenty agricultural soils and rice affected by the abandoned mining sites were collected. Soil chemical properties and As concentrations (total and sequential extracted) in soils were determined and As concentrations in polished rice were analyzed. The average concentration of As in non-specifically adsorbed (F1), specifically adsorbed (F2), amorphous hydrous oxides of Fe and Al (F3), crystalline hydrous oxides of Fe and Al (F4) and residual phase (F5) were 0.08, 1.38, 10.34, 3.26 and 10.98 mg kg -1 , respectively. Both soil pH and available phosphorus were positively correlated with the concentrations of As in F1 and F2. These results indicate that increasing the soil pH and available phosphorus can significantly increase the easily mobile fractions of As (F1 and F2). The average concentration of As in polished rice was 0.09 mg kg -1. The concentrations of As in F1 and F2 showed a positive correlation with the concentrations of As in polished rice. Therefore soil pH and available phosphorus affect the distribution of As fractionation in soils and thus affect As bioavailability.Key words: Arsenic, pH, Phosphorus, Fractionation, Polished rice Distribution of As in sequentially extracted fractions of soils from the abandoned metal mine areas.

Identification of a Proper Phytoavailable Arsenic Extraction Method Associated with Arsenic Concentration in Edible Part of three Crops in Soils Near Abandoned Mining Areas

“…각 유효태 침출법으로 침출한 비소 함량의 평균치를 비교했을 때 침출법에 따라 차이가 있 었으며, 침출액의 비소 농도가 높은 침출법은 (NH 4 ) 2 H 2 PO 4 침출법이고, Mehlich 3, EDTA, NaHCO 3, Ca(NO 3 ) 2 침출 법 순으로 비소 농도가 낮아졌다. 침출법 중 (NH 4 ) 2 H 2 PO 4 을 이용한 침출법이 가장 높은 비소 농도를 보인 것은 인산 염 (phosphate)과 비산염 (arsenate)의 화학적 형태가 유사하고 토양 흡착에도 경쟁적이므로, 인산으로 인해 토양 중 비소 침출이 증가한 것으로 판단된다(Kim et al, 2015;Woolson et al, 1971). 비소농도가 가장 낮았던 Ca(NO 3 ) 2 침 출법에서는 고추, 벼, 콩을 재배한 총 180개 토양 중 42%에서 비소가 검출되지 않았다.…”