Retting of jute grown in arsenic contaminated area and consequent arsenic pollution in surface water bodies

Arsenic (As) toxicity of ground water in Bengal delta is a major environmental catastrophe. Cultivation of jute, a non edible crop after summer rice usually reduces arsenic load of the soil. However, during retting of jute As is present in the crop and thus increase its amount in surface water bodies. To test this hypothesis, a study was carried out in ten farmers' field located in As affected areas of West Bengal, India. As content of soil and variou the jute plant were recorded on 35 and 70 days after sowing (DAS) as well as on harvest date (110 DAS). During the study period, due to the influence of rainfall, As content of surface (0–150 mm) soil fluctuates in a narrow range. As content of jute root was in the range of 1.13 to 9.36 mg kg− 1. As content of both root and leaf attained highest concentration on 35 DAS and continuously decreased with the increase in crop age. However, in case of shoot, the As content initially decreased by 16 to 50% during 35 to 70 DAS and on 110 DAS the value slightly increased over 70 DAS. Retting of jute in pond water increased the water As content by 0.2 to 2.0 mg L− 1. The increment was 1.1 to 4 times higher over the WHO safe limit (0.05 mg L− 1) for India and Bangladesh. Microbiological assessment in this study reveals the total bacterial population of pre and post retting pond water. Bacterial strains capable in transforming more toxic As-III to less toxic AS-V were screened and six of them were selected based on their As tolerance capacity. Importantly, identified bacterial strain Bacterium C-TJ19 (HQ834294) has As transforming ability as well as pectinolytic activity, which improves fibre quality of jute.

► Arsenic content in jute crop attained the highest value at early growth stage, declined till harvest.
► Fibre of jute contained 2 to 3 fold higher arsenic than that of in stick.
► Retting of jute increased pond water arsenic content by 0.2 to 2.0 mg L− 1 water over the pre-retting state.
► The increment was 4 to 40 times higher than safe limit (0.05 mg L− 1 water) as recommended by the World Health Organisation.