Toxicity analyses of ground water of some industrial areas of Bogra sadar upazila

An investigation was carried out to assess the extent of ionic toxicity of ground water samples for agricultural usage in in the AEZ-04 viz., Karatoya-Bangali Floodplain (2,577 sq. km). Thirty water samples were collected from five industrial areas of Bogra sadar upazila to assess the dissolved chemical constituents and also to classify them on the basis of their comparative stability for agricultural usage. Water samples were collected from ground water sources namely shallow tube wells at Bogra sadar upazila. The chemical analyses included pH, electrical conductivity (EC), total dissolved solids (TDS), Ca, Mg, K, Na, Zn, Cu, Fe, Mn, Cd, Pb, B, As, CO3, HCO3, PO4, SO4 and Cl. The pH indicated that ground water samples were acidic to alkaline in nature (pH = 6.5-8.8 and pH = 7.2-8.7). Among them only 2 ground water samples were found ‘unsuitable’ for irrigation. The electrical conductivity (EC) and sodium absorption ratio (SAR) revealed that all the ground water samples were categorized as ‘medium salinity’ (C2) and ‘low alkalinity’ (S1) hazards with ‘excellent’ and ‘good’ in quality combining expressed as C2S1. Considering total dissolved solids (TDS) all the ground waters were as ‘freshwater’. Soluble sodium percentage (SSP) indicated that all the ground water samples were ‘excellent’ and ‘good’ classes. Residual sodium carbonate (RSC) categorized the ground water samples as ‘suitable’ in quality for irrigation. All the ground waters were classified as ‘moderately hard’ and ‘hard’ classes. As the status of Ca, Mg, Na, K, Zn, Cu, As, B, Fe, CO3, SO4, PO4, and Cl were not hazards in the investigated area because these detected ions were far below the recommended limits for irrigation. In all ground water samples, HCO3 ion was considered as pollutant for irrigating crops, 15 samples for Cd, 11 samples for Pb and 3 samples for Mg and only 1 sample for PO4 were found unsuitable for irrigation. Rest ionic constituents were suitable for irrigation purposes. As, B, SO4, Cl and total dissolved solids (TDS) were not problematic for drinking, total dissolved solids (TDS), Cd, Cu and Zn were not hazardous for livestock usage and SO4 and hardness (HT) were not problematic for aquaculture. But rest ionic constituents for these respective usages were toxic