Analysis of heavy metals in seawater near a coal-fired power plant in a barangay

The seawater in a barangay of a city in the Philippines close to a coal-fired power station is being used for recreational activities like swimming and source of seafood. This study was conducted to describe the physicochemical characteristics of the saltwater in April 2023, including its pH, temperature, and salinity. Additionally, the study detected and measured the levels of heavy metals in the collected saltwater, including cadmium, copper, iron, lead, and zinc. This study further interpreted the quantity of heavy metals present when compared to the allowable levels. Three (3) samples from two (2) points of the seawater of a barangay were collected during a normal tide with a depth of around two (2) meters. The sample sites were approximately ten (10) meters from the shore and thirty meters apart from each other. A Hanna Instrument pH meter, a mercuric-filled thermometer, and a refractometer were used to measure the physicochemical parameters such as pH, temperature, and salinity of the seawater respectively. Atomic Absorption Spectrophotometer (AAS) analysis was used to determine the heavy metals. The findings indicated that the seawater had a pH of 8.45+0.38, temperature of 30.00+1.10°C, and salinity of 30.55+0.27ppt. They were within the allowable level in April 2023. The quantities of copper (0.02+0.01 mg/L), iron (0.61+0.01 mg/L), and zinc (0.02+0.01 mg/L) were within allowable amounts. However, lead (1.44+0.19 mg/L) and cadmium (0.02+0.01 mg/L), were found beyond allowable of the permitted amounts. This study demonstrated the need for ongoing monitoring of the seawater around coal-fired power plants because of the beyond-allowable amounts of cadmium and lead.