Physico-chemical Properties and Heavy Metal Contents of Ino-Capayang Mine-made Lake in Marinduque, Philippines

Abstract

Ino-Capayang mine-made lake is a monolith remains of mining in Marinduque, opened in 1968 and closed and abandoned in 1980. The lake is surrounded by barren lands and few vegetation scattered with metallic ores forming acid mine drainage continuously draining into the lake. To evaluate the water quality in the lake, water samples were collected from the lake and analyzed for physico-chemical parameters and heavy metal concentrations. Physico-chemical parameters were pH, temperature, electrical conductivity (EC), total dissolved solids (TDS) and oxidation-reduction potential (ORP) were measured on-site using digital measuring devices while heavy metal concentrations were analysed using flame atomic absorption spectrophotometer (FAAS). Results showed that the water in the lake measured with slightly alkaline pH (7.83) and mean temperature of 31.740C. Measured heavy metal concentrations of Cd (<0.006 mg/L), Cu (0.018 mg/L), Fe (0.151 mg/L), Pb (0.0089 mg/L), Mn (0.1404 mg/L) and Zn (0.1507 mg/L) were all within the regulated levels for the freshwater can be intended for propagation of fish and other aquatic resources as well as recreational activities such as boating, fishing, and for agriculture use. Other parameters, such as EC and TDS, were measured with lower levels compared to the characteristics of other mine-made lake in the country, while the measured ORP ORP indicates that the entire water in the lake has high oxidizing agent.