Impact of Pit Latrines on Groundwater Quality in Squatter Settlements in Zanzibar
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THE STATE UNIVERSITY OF ZANZIBAR
Groundwater is the major source of drinking water in Zanzibar. Most of the population in squatter settlement area in Zanzibar relies on shallow well due to insufficient tape water supply. The shallow wells are commonly drilled close to pit latrine without considering the safe distance. Pit latrines are characterized by pathogens and high levels of chemical nutrients that may change the groundwater quality. A study was therefore conducted to determine the impact of pit latrines on groundwater quality in selected squatter settlement in Zanzibar Municipality. Water samples were collected from 11 dug wells and 9 borehole-wells within the five selected areas: Mtopepo, Munduli, Mwera, Fuoni and Kinuni between February and March 2018. The collected samples were analyzed for faecal coliform (FC), total coliform, nitrates, chloride, electrical conductivity, turbidity, pH, dissolved oxygen, oxygen reduction potential, temperature and salinity. Results showed that, the physico-chemical parameters of the groundwater samples were within the World Health Organization (WHO) guidelines for drinking water quality except for turbidity, oxygen reduction potential, nitrate, total and faecal coliform which were not in compliance with WHO standards. Presence of total and faecal coliform bacteria was found in most of the water samples (50%). The presence of high nitrate concentrations along with microbiological indicators suggests that the water is potentially harmful to human health if it’s consumed without treatment. The study found that there is significant relationship between the level of contamination of chemical and microbiological contaminants with the distance from pit latrines and well water. Therefore, we recommend the construction of concrete and/ or lined pit latrine, septic tank systems and other low-cost technologies in order to reduce the potential risk of groundwater contamination.
Level of contamination of chemical and microbiological contaminants with the distance from pit latrines and well water.