Assessment of Cd, Co, Cu and B in the shallow aquifers of Jia-Bharali river basin, North Brahmaputra plain, India

Unconfined, shallow alluvial aquifers of the lower Jia Bharali catchment and adjoining areas in central part of North Brahmaputra Plain (NBP), India, with a general southward flow are largely tapped for domestic use through numerous dug well attached with almost every household. This study has presents the first ever systematic database on trace elements viz., Cd, Co, Cu, and B from the shallow aquifers in north Brahmaputra plain based on water samples from 50 monitoring wells collected in both dry and wet seasons. The data was analysed with respect to WHO standards for drinking water and significantly, the aquifers of the basin have considerable presence of Cd, Co, Cu and B. 10% of the samples in the rainy season and 54% in the dry season show Cd content higher than the WHO desirable limit of 0.005 mg/L. Cobalt did not show any systematic presence (0.006 – 0.089 mg/L) in the area with respect to spatial distribution. Similarly, Cu (range 0.02 to 0.59 mg/L) contents are low and not significant. The nutrient boron has its presence in most of the aquifers at values less than the toxicity level.