THE RECENT fish death in the Las Piñas-Parañaque Wetland Park was due to low concentrations of dissolved oxygen in the water, which may have been caused by heavy rains, the Department of Environment and Natural Resources (DENR) said. On Oct. 11, more than 5,000 kilos of dead fish were gathered in the area. In a statement, DENR Secretary Roy A. Cimatu said laboratory results from tests undertaken by the Environmental Management Bureau (EMB) show three of the four stations in the area did not conform to the water quality guideline (WQG) set for commercial fish propagation. Recent heavy rains may have led to low levels of dissolved oxygen “that caused the flushing of decomposed organic matter from the surface run-offs and inland water tributaries eventually polluting the open seas,” EMB National Capital Region Director Domingo M. Clemente said. The four stations also exceeded the WQG for fecal coliform, while traces of cyanide were also found in the stations. In a follow-up test on Oct. 14, water pollution measures showed improvements. — Vincent Mariel P. Galang