Water quality of roof runoff in sub-urban Malaysia

The purpose of this study is to investigate the composition of roof runoff pollutants and to determine the relationships between pollutants and seasons (wet and dry) from two commonly used roof types in Jengka, Pahang. Rainwater was collected from galvanized and ceramic roof runoff. The sampling regime was done in two different seasons; between November 2014- February 2015 (wet) and March-May 2015 (dry). A total of 60 rainwater samples were analysed for temperature, pH, EC, DO and selected heavy metals (Fe and Zn). Zn and Fe are higher in galvanized roof (Zn: 0.05 ± 0.11 mg/L, Fe: 0.06 ± 0.13 mg/L) compare to those in ceramic roof (Zn: 0.001 ± 0.00 mg/L, Fe: 0.01 ± 0.02 mg/L). There were no significant differences of metal elements found between wet and dry seasons (p>0.05). The concentrations of metal elements in the harvested rainwater are lower than the permitted heavy metal concentration limitation if to be used as drinking water. All water quality parameters from galvanized and ceramic roofs runoff in this study matched the drinking water guidelines proposed by the Ministry of Health, Malaysia and safe to be used for the domestic purposes.