Seasonal Elevated and Variable Groundwater Iron in Chandrapur District, Central India

Abstract

Groundwater iron concentrations were monitored from rural area of the Chandrapur district, Central India during winter, summer and post-monsoon at 36 sampling locations so as to map and quantify its levels. Grab sampling was carried out for groundwater sampling from dug wells (DW) (n=2, 5.55%) and hand pumps (HP) (n=34, 94.44%). Iron concentration was determined by acid digestion method and further analysis by using ICP-OES. Maximum iron concentration in winter was 47.100 mg/L (Ballarpur, HP), 3.825 mg/L (Ballarpur, HP) in summer and 3.714 mg/L (Visapur, HP) in post-monsoon. Average iron concentration in winter, summer, and post-monsoon was 3.522 mg/L, 0.730 mg/L and 0.582 mg/L respectively, which were above the acceptable limit of the Indian Standard (IS) and WHO aesthetic limit for iron (0.3 mg/L). Seasonal variation in groundwater iron concentration was observed in the order of winter>post-monsoon>summer. Distribution of iron with IS revealed a number of samples above the permissible limit and in the order of summer>winter>post-monsoon. In case of a distribution on WHO, JECFA and IOM recommendations, number of samples in high to very high category was in the order of winter>summer>post-monsoon. It can be concluded that seasonal elevated and variable groundwater iron concentration was observed from the study area. A number of samples had the concentration several times above the IS acceptable limit and WHO aesthetic cut-off. The plausible reasons for these observations can be assigned to geology, water source type (HP/DW), space and time, the proximity of water source to minerals and ores present in the earth crust, physicochemical characteristics of water and dissolution and leaching of metal in groundwater