Mobilisation of arsenic in soils and in rice (Oryza sativa L.) plants affected by organic matter and zinc application in irrigation water contaminated with arsenic

Abstract

The experiments were conducted to study the effects of arsenic-contaminated irrigation water, zinc and organic matter on the mobilization of arsenic in an Aeric Endoaquept in relation to rice (cv. IET 4786). The results show that the amount of extractable arsenic increased with the progress of submergence decreased with zinc application. The magnitude of such decrease varied with the Zn amount, being greater (0.70 to 1.08 mg/kg) in the treatment where zinc was applied at the rate of 20 mg/kg. With regards to organic matter application, the arsenic content in soil markedly decreased, especially with farmyard manure application. The results of the greenhouse experiment with exposure of graded doses of arsenic to rice suggest that the upper toxic limit of arsenic in soil was 10 mg/kg for rice. The results of the field experiment show that the grain yield of continuous flooding (4.84 t/ha) and intermittent flooding up to 40 days after transplanting followed by continuous flooding (4.83 t/ha) with the application of ZnSO 4 at the rate of 25 kg/ha did not vary significantly. The lowest grain yield (3.65 t/ha) was recorded in the treatment where the intermittent flooding was maintained throughout the growth period without the application of zinc. The amount of arsenic was, however, much lower in the treatment where intermittent flooding was maintained throughout the growing period combined with zinc sulphate application.

Assessment of arsenic toxicity in rice plants in areas of West Bengal

“…The As accumulation by the plant parts generally followed the order: root>stem>leaf>economic produce (Table 2), in agreement with the findings of Das et al,(2008). The As accumulation by the plant parts was observed to increase with the increase of added As.…”

“…The As contaminated groundwater had been in use in these areas for drinking as well as irrigation purpose to crops which eventually finds its way to animal and human continuum. The use of As-contaminated irrigation water in West Bengal has been found to cause accumulation of As in rice plants (Das et al, 2008). Estimates showed that As in rice and other food sources could contribute to about 30% of the total As ingestion (Huq et al, 2007).…”

Possibilities of some methods for risk assessment of arsenic load in soils

“…The pentavalent form of As was found less toxic (Weis and Weis 1991). Although As human and zoo toxicity is usually reported, many authors deal with As influence on plant growth and plant physiology (Pavlíková et al 2007, Das et al 2008). …”

Combined Effect of Arsenic and Phosphorus on Mineral Element Concentrations of Sunflower

“…In contrast to this, As reduced K, Ca, Mg, Si, Fe, Zn, Cu, Rb, and Sr concentration of the sunflower plants. Interaction between As, Fe, and Zn was previously reported by Hartley and Lepp (2008) and Das, Sur, and Das (2008). They suggested that the As contamination in soils may be reduced by applying Fe oxides and Zn sulfates to the soil.…”