Evaluation on factors affecting bacteria growth in collected rainwater

Rainwater collected in rural areas may be contaminated and could affect health if consumed. Therefore, the rainwater quality is evaluated by identifying factors that affect the growth of bacteria and how they contribute to the growth. The factors are temperature, pH, oxygen and nutrient concentration which tested using thermometer, pH meter, DO meter and TOC Analyser. Bacteria densities were determined through MPN method using Colilert-18. Results showed Kuching samples have lower water temperature and TOC, less acidic but higher DO compared to Kota Samarahan samples. Evening samples showed lower water temperature and DO, but higher acidity and TOC compared to morning samples. Bacteria densities also showed decrease in readings and only Total Coliform are presence as rainwater collected in an open space. Samples temperature between 26°C and 28°C and pH readings between 5.59 and 6.05 shows that bacteria may adapt and exhibit growth but limited. DO and TOC also decreases between 0.33mg/L and 0.72mg/L and between 0.6340mg/L and 1.9338mg/L respectively. This indicates the uptake of oxygen and usage of organic carbon by the bacteria. These results correspond to the decreasing bacteria densities as due to limitation of oxygen and nutrients concentration and ideal range of temperature and pH for growth.