Communities Structure of Macrozoobenthos and Disability of Chironomid Larvae at Upstream of Cisadane River Bogor West Java.

Abstract

Anthropogenic activities on river ecosystems will cause river pollution. Pollution in the river resulted in a change of aquatic organisms communities. Biological indicators are used to support the physical and chemical indicators in evaluating the ecological status of waters. Macrozoobenthos is one of biological indicator that currently being developed. It because biological indicator has many advantages include widely distributed, sedentary life, long life cycle, the sampling method is easy and inexpensive, and identification keys are available. Chironomid larvae are macrozoobenthos groups that live in the sediment. Disability of Chironomid larvae is caused heavy metals contaminated, one of which Hg. Cisadane River has great benefits for the community in Bogor, Tangerang, and Jakarta area. The benefits are source of drinking water, fisheries, and sand mining. Human activities around the upstream of Cisadane River, such as household waste disposal, agriculture, animal husbandry, and Hg waste from traditional gold mining (gurandil) led to a decline in water quality. Research conducted by Sudarso (2009) between 2006-2008, upstream of Cisadane River showed that turbidity and conductivity increased from upstream to downstream (3,83 to 31,74 and 0,034 to 0,087μS/cm). Heavy metal (Hg) contamination was highest in Curug Bitung area. Hg in water is 6,89 μg/L and Hg sediment 16,62 μg/L. This study was aimed to: 1). Describe the status of waters based on the parameters of physics, chemistry, and biology; 2). Assessing the impact of changes in water quality (organic matter and Hg) on macrozoobenthos abundance in the upstream of Cisadane River and 3). Revealed Chironomid larvae disability found in the upstream of Cisadane River. The research was conducted in January-March 2012 at four locations in the upstream of Cisadane River, covering Cikuluwung (no anthropogenic activity), Cisarua (household waste disposal and mining of traditional gold), Curug Bitung (household waste disposal, agriculture, and mining of traditional gold), and Lukut (household waste disposal and mining of traditional gold). Water quality measurements include temperature, flow velocity, DO, TDS, conductivity, pH, TOM, organic sediment, and the amount of Hg in waters and sediments. Macrozoobenthos sampling system was implemented based on rapid assessment and a kick net was used to take macrozoobenthos. Data analysis of this study include Shannon Wiener Index, Evenness Index, Taxa Richness, Signal Index, EPT Index, one way ANOVA and Turkey test, Pollution Index, and Hg in Sediment Pollution Index. Status of waters in the upstream of Cisadane River based on Pollution Index and Heavy Metal Pollution Index (Hg) in sediments polluted relatively low, based on EPT Index is fair to moderate polluted, and Signal Index from low to moderate polluted. Water quality which affects the macrozoobenthos abundance using one way ANOVA analysis continued by Tukey's test were pH, temperature, TDS, and conductivity which covers an area Cikuluwung (ST 1) and Curug Bitung (ST 3) also ST 1 and Lukut (ST 4). Chironomid larvae were found in the upstream of Cisadane River which have disability at the mandible and mentum (Polypedilum and Orthocladinae subfamily) is caused by the presence of organic matter and Hg pollution.