Urban Lakes, South Tangerang City Based on Water Quality Index and Phytoplankton Composition as Bioindicator

Abstract

An assessment of water quality in 8 urban lakes in South Tangerang City was conducted, as their condition was a concern. This research aims to assess water quality based on the condition of chemical-physical variables and phytoplankton composition. This research was conducted from late May to early October 2021 (the dry season until the inter-seasonal period). The Water Quality Index (WQI) ranged from 61.18-79.53 (medium-good). Phytoplankton composition consisted of 65 genera from 11 classes and 6 divisions. Oscillatoria, Euglena and Pediastrum were the dominant genera, meanwhile, Cyanophyceae and Chlorophyceae were the dominant class. Phytoplankton communities in all lakes were stable except RL and based on Jaccard index the value of inter-lakes show no identical similarities (≠ 1). In (Nygaard) values ranged from 2.50-undefined (slight-high eutrophication), and X (Saprobic indices) values ranged from 0.33-1.80 (very slight pollution-moderate pollution). The best correlations (both values were r = 0.53) in water quality between the variables were DO (ppm) and BOD (ppm) Urban lakes require further improvement in their lake management to be used as sources of drinking water.

Keywords

• water quality variables
• phytoplankton
• urban lakes