English

 

Name of the Student : Abdellatif Dawod
Name of the supervisor/s : Dr. Khaled Swaileh
Title of the thesis :

Health risks Associated with consumption of untreated of water from Household Roof Catchment Systems.

Abstract :  

In Palestine, rain harvesting is a common practice especially in regions suffering from drinking water shortage or lacking drinking water distribution systems. Rain harvesting systems constitute a source of free water in a country where water prices are considered high and water supply is insufficient especially during the summer period. Rainwater is mostly harvested through roof-catchment systems and stored in underground concrete or rocky wells. Harvested rainwater is usually consumed without any treatment, although it could constitute a health hazard. The present study aims at evaluating health risks associated with drinking untreated rainwater harvested through roof catchment systems from the West Bank, Palestine.

Therefore, water samples from 21 wells were obtained during summer and winter of the years 2006-2007. Microbial and chemical quality of the harvested rainwater was investigated to determine potential health risks. Chemical and physical tests that affect water quality included: turbidity, salinity, total dissolved solids (TDS), electrical conductivity (EC), pH, temperature, nitrate and heavy metals (copper and lead). Microbial quality tests included HPC, total and fecal coli forms. In addition, 5 opportunistic and 6 pathogenic bacteria were tested using PCR technology.

Physical and chemical rainwater parameters were mostly within the WHO guidelines set for drinking water. Generally, summer samples included higher levels of TDS, salinity and EC compared to winter samples.

Classical microbial tests (HPC, total and fecal coliforms) revealed heavy contamination of rainwater with microbes. This indicates poor microbial quality especially if water is to be used for drinking purposes.

PCR results showed that opportunistic pathogens are very common in rainwater samples but pathogenic species were very rare. Only one pathogenic microbe was detected in the 2 samples out of 42 samples collected and analyzed during this study.
Harvested rainwater tested from Qalqilia and Ramallah regions needs to be disinfected before being used for drinking purposes. However, its chemical and physical quality is acceptable for drinking purposes.