Analysis of water quality and primary productivity in Welang, Gembong, and Rejoso rivers, Pasuruan East Java, Indonesia

Welang, Gembong, and Rejoso are large rivers that flow in the Pasuruan area and empty into the Madura Strait. The high human activity in the area can cause both physical and chemical in the waters. The purpose of this study was to determine the condition of water quality and primary productivity in the Welang River, Gembong River, and Rejoso River, based on the abundance of periphyton. According to the results of this research, it can be concluded that the water quality in the Welang, Gembong, and Rejoso rivers has been moderate-to-severe pollution levels that exceeded the quality standards in the three rivers are: total suspended solids (TSS), alkalinity, and cadmium. Meanwhile, the primary productivity in these rivers is classified as oligotrophic.