Mitigating arsenic contamination in rice plants with an aquatic fern, Marsilea minuta.

Dangers of arsenic contamination are well known in human civilization. The threat increases when arsenic is accumulated in food and livestock through irrigated crops or animal food. Hence, it is important to mitigate the effects of arsenic as much as possible. This paper discusses a process for reducing the level of arsenic in different parts of rice plants with an aquatic fern, Marsilea minuta L. A pot experiment was done to study the possibility of using Marsilea minuta as a phytoremediator of arsenic. Rice and Marsilea minuta were allowed to grow together in soils. As a control, Marsilea minuta was also cultured alone in the presence and absence of arsenic (applied at 1 mg/L as irrigation water). We did not find any significant change in the growth of rice due to the association of Marsilea minuta, though it showed a reduction of approximately 58.64% arsenic accumulation in the roots of rice grown with the association of fern compared to that grown without fern. We measured a bioaccumulation factor (BF) of > 5.34, indicating that Marsilea minuta could be a good phytoremediator of arsenic in rice fields.

Assessment of concentration and toxicological (Cancer) risk of lead, cadmium and chromium in tobacco products commonly available in Bangladesh.

This study aimed to assess the concentrations of heavy metal ('lead (Pb)''cadmium (Cd)', and 'chromium (Cr)') in various brands of four types of tobacco products (zarda, gul, cigarettes, and bidi) as well as calculate toxicological risk as a lifetime cancer risk for Pb, Cd, and Cr. In smokeless tobacco products, the metal concentration ranged from 0.99 to 10.02 µg/g for Pb, 1.05-3.53 µg/g for Cd, and 1.23-7.29 µg/g for Cr, respectively. Metal concentrations in the smoke-based tobacco products ranged from 0.98 to 3.07 µg/g for Pb, 0.91-3.46 µg/g for Cd, 1.08-6.75 µg/g for Cr, respectively. When assuming a 100% transfer of these metals, the calculated lifetime cancer risk was found 'unacceptable' in 33 out of 35 tobacco samples which exceeded the U.S. Environmental Protection Agency (USEPA) benchmark of an 'acceptable' cancer risk range of 10E-4 to 10E-6. Our study demonstrated higher levels of Pb, Cd, and Cr in various tobacco products of Bangladesh compared to GOTHIATEK standard. This study shows the need for the development of industry standards and regulation for tobacco products to reduce the levels of heavy metals.