Spatio-temporal factors influencing coliform and Escherichia colicontamination in gross pollutant trap and wetland inlet, Putrajaya, Malaysia

This study investigated the spatial and temporal pattern of total coliform (TC) and Escherichia coli(E. coli) with the associated influencing environmental factors at GPT and lake inlets. Understanding these patterns is necessary in order to support management action in controlling pollution from urban stormwater systems. Water quality parameters such as temperature, dissolved oxygen, pH and turbidity were measured in-situover a week at four gross pollutant traps (GPT) and four inlets in Upper Bisa Wetland, Putrajaya.Water samples were collected using a Van Dorn sampler and analysed for TC, E. coli, total phosphorus and chemical oxygen demand. The parameters were analysed against spatial and temporal factors. The abundance of TC and E. colivaried between sites and storm water systems with the mean highest values recorded of 162,2857.1 CFU mL−1and 64,364.3 CFU mL−1respectively—high density residential landuse. Temporal variations had an impact on the abundance of TC and E. coli; E. coliabundance varied daily.The abundance of E. coliwas higher during dry periods while the abundance of TC was higher during the wet periods. However, no clear variation of the selected faecal indicator bacteria between morning and evening. Total coliform and E. coliwere negatively correlated (p< 0.05) with temperature. The main predictor of E. colivariation was GPT-inlet, TC, chemical oxygen demand and day. The presence of E. coliindicated inputs of sewage pollution possibly from the surrounding catchment and urban runoff. Continuous monitoring and maintenance of the GPTs are necessary to control pollution.