Status Pencemaran Air Sungai Dengan Makrozoobentos sebagai Bioindikator di Sungai Batang Gadis Kecamatan Panyabungan Kabupaten Mandailing Natal Sumatera Utara

Abstract

Batang Gadis River is the longest and largest main river in Mandailing Natal. Activities carried out in the Batang Gadis River will affect water quality which results in pollution. Macrozoobenthos are organisms that are at the bottom of the substrate and are used as an indicator of the level of pollution in a waters because of their low mobility to avoid the effects of pollution. This study aims to determine the abundance and diversity of macrozoobenthos and the status of river pollution in the Batang Gadis River, Panyabungan District, Mandailing Natal Regency, North Sumatra Province based on the ABC Curve analysis. This research was conducted in September - November 2022 using a random purposive sampling method which was divided into 3 stations. The results showed that abundance values ranged from 523 ind/m2 – 1828 ind/m2, diversity index values (H') ranged from 0.67 to 1.08, uniformity index values (E) ranged from 0.78 to 0.97 and index values dominance ranged (C) ranged from 0.39 to 0.52. Based on the ABC (Abundance and Biomass Comparison) curve, it is stated that the pollution status of river water is declared polluted in the "moderate" category with overlapping macrozoobenthic biomass and density curves.