AVALIAÇÃO DA MATÉRIA ORGÂNICA EM CORPOS HIDRICOS URBANOS: ESTUDO DE CASO NO MUNICÍPIO DE RIO VERDE,GOIÁS

Abstract

Urban water quality is strongly influenced by anthropogenic pressures such as domestic sewage discharges, diffuse pollution, and land use changes. Biochemical Oxygen Demand (BOD) and Chemical Oxygen Demand (COD), as well as the BOD/COD ratio, are widely used to assess organic load and biodegradability. This study evaluated water quality at two sites of an urban stream in Rio Verde, Goiás, Brazil, with distinct land use characteristics. Point 1, located under a bridge with partial riparian vegetation, showed waste accumulation, whereas Point 2, near a rural area with denser riparian cover, had lower human influence. Samples were collected from April to June 2025 and analyzed according to Standard Methods 5210 B and 5220 B/D. BOD ranged from 2.434 to 6.928 mg/L at Point 1 (mean 4.9 mg/L) and 1.816 to 6.408 mg/L at Point 2 (mean 3.8 mg/L), while COD varied from 4.33 to 114.33 mg/L. The BOD/COD ratio (0.04–0.11) indicated low biodegradability and diffuse urban pollution, associated with the first flush effect. Results suggest both sites are vulnerable to organic inputs, emphasizing the need for integrated sanitation strategies, stormwater management, and riparian vegetation preservation.