Toxic metal ions in water and their prevalence in Uttarakhand, India Vinod Kumar Gupta, Rajendra Dobhal, Arunima Nayak, Shilpi Agarwal, Devi Prasad Uniyal, Prashant Singh, Bhavtosh Sharma, Shweta Tyagi and Rakesh Singh ABSTRACT Developmental activities, geological reasons and mixing of industrial wastes are responsible for the deteriorating quality of surface and ground water in the Himalayan state of Uttarakhand. The drinking water sources of 13 districts of Uttarakhand have been assessed for the presence of four toxic metal ions (arsenic, cadmium, chromium and lead). The health aspects of the four metal ions have also been reviewed according to the prescribed limits set up by the Bureau of Indian Standards (BIS) and World Health Organization (WHO). The present study reveals the absence of arsenic at almost all stations. Cadmium has been found only at Rudrapur, whereas chromium is found to be present in more than prescribed limits, in Kolti, Mussoorie and Dehradun. Signicant presence of lead in the six districts of the state is indicative of the fact that proper management strategy of toxic metal ion remediation is required. Chromium and lead have exceeded the prescribed limit in 1.3 and 4.5% samples, respectively. However, as per BIS standard, cadmium is higher than the prescribed limit in 0.6% samples but according to the WHO standard, cadmium has exceeded in about 26% samples. Out of the total 156 samples analyzed, 6.4 and 33.3% samples have been found to possess the toxic metal ions in more than the prescribed limits as per BIS and WHO guidelines, respectively. Vinod Kumar Gupta (corresponding author) Arunima Nayak Shilpi Agarwal Department of Chemistry, Indian Institute of Technology Roorkee, Roorkee 247 667, India E-mail: vinodfcy@gmail.com Rajendra Dobhal Devi Prasad Uniyal Uttarakhand State Council for Science and Technology, Dehradun 248 001(UK), India Prashant Singh Bhavtosh Sharma Shweta Tyagi Department of Chemistry, DAV (PG) College, Dehradun 248 001(UK), India Rakesh Singh Department of Chemistry, DBS (PG) College, Dehradun 248 001(UK), India Vinod Kumar Gupta Chemistry Department, King Fahd University of Petroleum & Minerals, Dhahran 31261, Saudi Arabia Key words | health, India, metal ions, Uttarakhand, water quality INTRODUCTION Uttarakhand is a relatively new Himalayan state of India, which has many natural water resources in the form of gla- ciers and rivers. But the surface, subsurface and ground waters are being continuously contaminated in the hilly areas due to the dissolution of the metal ions, mixing of rocks and leaching (Mittal et al. ; Jain et al. ; Kar ). Several reports have highlighted that some pharma- ceutical and metal processing industries are discharging their toxic efuents without prior treatment into the aqueous bodies (Kumar et al. ). The quality of ground and surface water is declining as a consequence of undesirable and higher concentration of certain toxic metal ions like arsenic, lead, cadmium and chromium (Goyer et al. ; Kar et al. ; Sood et al. ). These toxic metal ions are relatively difcult to detect in water because of their very low concentrations. Detection is further complicated by the fact that symptoms in people may not appear up to 515 years of drinking of con- taminated water. Monitoring of water quality is necessary to know the extent of metal ion pollution and source of metal pollutants. Some advanced techniques, like multivariate stat- istical technique and geostatistical mapping, have been used successfully and reported for water quality analysis ( Jain et al. , ; Gupta & Kumar ; Gupta et al. , a, b, , , a, b; Gupta & Agarwal ; Chehata et al. ; Gupta & Ali ; Liu et al. ; Shyu et al. ). 773 © IWA Publishing 2012 Water Science & Technology: Water Supply | 12.6 | 2012 doi: 10.2166/ws.2012.052