Drinking water quality in Rohri City, Sindh, Pakistan

Groundwater and surface water samples from Rohri city were analyzed for the presence of total coliform (TC), E. coli (Ec) and heterotrophic plate count (HPC). The samples were collected before and after storage. The bacteriological analysis was carried out by membrane filtration and spread plate count (SPC) technique. The pre-storage ground water samples were found to be contaminated with TC (25%), Ec (12.5%) and HPC (45%). All post-storage groundwater samples were found to be contaminated with TC (100%), Ec (41.6%) and with HPC (100%); the number of TC, Ec and HPC in post-storage groundwater samples was very high. The difference in number of colony forming units (cfu/100ml) between pre and post-storage groundwater samples was significant (p= 0.0001). The pre-storage surface water samples from main storage reservoirs and post-storage surface water samples from households were also found to be contaminated with TC (100%), Ec (100%) and HPC (100%). A significant (p= 0.002) difference in the number of cfu/ 100ml of ground water and in surface water samples was recorded. The quality of surface water was very poor as compared to groundwater in terms of microbial content and further declined after storage indicating lack of hygiene in the study population.