Bacteriological and physicochemical studies of ground-water in Beith Lahia-Gaza strip-Palestine

ABSTRACT

Twenty wells of groundwater located in the vicinity of wastewater ponds were investigated to indicate the levels of water pollution during the four seasons of year [2000-2001]. Water samples were tested for the indicators of faecal pollution, heterotrophic plate count [HPC] at 25 and 37C, total coliform, faecal coliform, faecal streptococci, Clostridium perfringens, Pseudomonas aeruginosa, Campylobacter and Salmonella. Bacteriological analysis revealed that HPC at 25C exceeds that was counted at 37C in the examined water samples. A marked seasonal variation on the bacterial counts was observed where the high counts of most organisms were obtained in winter months. It recorded 130, 120 CFU/ml for TC and FC, respectively in the most contaminant well number [13], corresponding to 110, 90 CFU/ml in autumn season. Also, the secondary indicator microorganisms appeared relatively low counts while Salmonella sp. was not detected. High significant differences were observed between the tested bacterial counts, wells depth, distance from the wastewater ponds. Physicochemical analysis of water samples showed that some parameters such as turbidity, NH3+, NO2-, NO3-, K+, BOD5, COD and hardness exceeded the permissible level in many of tested wells. A relationship between the bacterial counts and physicochemical parameters was observed. Prepared questionnaire indicate that most the participants used to wells water without treatments suffering from various illnesses such as diarrhea, vomiting and other gastrointestinal problems specially in winter season