Physico-chemical analysis and assessment of river waters discharged by sugar milling companies in Negros Occidental

Abstract

This cross-sectional study was focused on the river waters discharged by six sugar milling companies in Negros Occidental. These companies utilize river water in order to operate and may alter the characteristics of the waters. This study aims to analyze and assess the physical characteristics, namely pH, oil and grease, temperature, salinity, turbidity, and color, and the chemical characteristics, namely biological oxygen demand (BOD), dissolved oxygen (DO), ammonia, phosphorus, and lead content, of these waters in order to identify the alterations upon its usage, detect abnormal characteristics, and eventually determine possible environmental and health hazards. Three samplings were done for each river’s downstream and upstream portions. The following tests and instruments were performed and were used on the samples: pH Meter for pH, DO Meter for DO, Wrinkler’s Test for BOD, PE Ascorbic Acid Test for phosphorus, Spectrophotometry for turbidity, Phenate Test for Ammonia, Hand Refractometer for salinity, Visual Comparison for color, Digital Thermometer for temperature, Flame Atomic Absorption Spectrophotometry for lead content, and Petroleum Ether Extraction Method for oil and grease. It was discovered most of the discharged river waters apparently had decreased pH and DO and increased BOD, temperature, salinity, ammonia, phosphorus, turbidity, and oil and grease content. Lead was detected on the all of the downstream portions. The pH and DO of most of the discharged river waters were ostensibly below the acceptable values while the oil and grease, ammonia, phosphorus, salinity, and lead content were above the acceptable ones. Temperature, color, and turbidity were the only parameters which fell within the acceptable values. Therefore, there can seemingly be environmental and health hazards posed on the residents living downstream since they are having direct or indirect contact with the contaminated or polluted water. It is recommended that laws should be made with regards to how the residents use the water and that the implementation of existing laws should be strengthened. Lastly, it is strongly advised that the DENR should increase the number of parameters analyzed during their regular monitoring, that the SMCs should improve the treatment of the waters, and that the effects of farmlands and communities on the river should be identified.