Dr Prasath Annamalai

A study was undertaken to determine the effects of different concentrations of arsenic (As) in irrigation water on Boro (dry-season) rice (Oryza sativa) and their residual effects on the following Aman (wet-season) rice. There were six treatments, with 0, 0.1, 0.25, 0.5, 1, and 2 mg As L-1 applied as disodium hydrogen arsenate. All the growth and yield parameters of Boro rice responded positively at lower concentrations of up to 0.25 mg As L-1 in irrigation water but decreased sharply at concentrations more than 0.5 mg As L-1. Arsenic concentrations in grain and straw of Boro rice increased significantly with increasing concentration of As in irrigation water. The grain As concentration was in the range of 0.25 to 0.97 µg g-1 and its concentration in rice straw varied from 2.4 to 9.6 µg g-1 over the treatments. Residual As from previous Boro rice showed a very similar pattern in the following Aman rice, although As concentration in Aman rice grain and straw over the treatments was almost half of the As levels in Boro rice grain. Arsenic concentrations in both grain and straw of Boro and Aman rice were found to correlate with iron and be antagonistic with phosphorus. Copyright © Taylor & Francis Group, LLC.

Arsenic contamination of ground water is well understood while other environmental systems are rarely considered to be contaminated by arsenic. A vital issue is whether or not appreciable arsenic transmits through the food chain. Reportedly, ayurvedic herbal medicine products (AHMPs) manufactured in Asia were found to be contaminated by harmful level of Arsenic. This study was aimed to quantify the arsenic levels in water, herbal and soil samples collected from the same origin using highly accurate neutron activation analysis (NAA) technique. Harmful level of arsenic was detected in most of the water and soil samples. Moreover, a considerably harmful level of Arsenic was detected in herbal samples collected from the same origin. As a result, AHMPs manufactured in Asia might be contaminated by arsenic through arsenic contaminated herb plants. © 2007 Springer Science+Business Media, LLC.

This investigation reports the levels of arsenic (As) in irrigation waters, soils and Boro (dry season) rice grain from 100 shallow tube well (STW) areas over the sadar upazila of Chapai Nawabganj. The As concentrations for all samples (soil, water and rice grain) varied widely between locations. The shallow tube well (STW) water As concentration ranged from 0.015-0.352 µg/ml with a mean of 0.075 µg/ml, the concentration being lower in shallow well depth, reaching to a maximum about at 25 m depth and then decreased with increasing depths. The levels of total As in soils over the locations ranged from 5.8-17.7 µg/g with a mean of 11.2 µg/g. Total As content in soils was positively correlated with irrigation water-As indicating a possibility of As build up in soil with time. The rice grain-As concentration was in the range of 0.24-1.30 µ/g g having a mean of 0.76 µg/g. 22% of the grain samples had As level <0.5 µg/g, 39% in the range of 0.50-0.75 µg/g, 36% in the range of 0.75-1.0 µg/g and the rest 12% more than 1.0 µg/g. The grain-As was poorly correlated with soil-As as well as irrigation water-As. 94% of the rice grain grown in Chapai Nawabganj irrigated with As contaminated water may lead to an intake of more than 100% maximum tolerable daily intake (MTDI) for an adult of 60 kg body weight.