Fish vendors at a municipal market in Muang district of Prachin Buri are complaining that their daily sales have slumped as consumers worry that fish are being raised or caught in water contaminated with industrial waste.
Before the recent flooding in the province, vendors said they typically sold an average of 100kg of freshwater fish, including red tilapia, snakehead fish and catfish, per day. Sales have since plunged to just 20kg a day.
The vendors said they had switched to sourcing fish from farms in other provinces, but consumers remained reluctant to buy them for fear of industrial contamination.
Pornnarong Wongsunthorn, a fisherman who raises fish in cages in rivers in Ban Sang district, said he had suffered losses of about one million baht in the recent flooding. He said he was reluctant to stock the cages with fish fry until relevant agencies could assure him that the water in the Prachin Buri River was safe and contained sufficient dissolved oxygen (DO) for the fish to survive.
The Provincial Fisheries Office has tested nine fish species caught in five districts of the province. The tests found that mercury, cadmium and lead levels were within safety limits, but aluminium was not included in the analysis.
Meanwhile, the Pollution Control Department has analysed water quality in the Prachin Buri River, focusing particularly on ammonia and aluminium levels.
According to the National Environment Board, ammonia concentrations in natural waterways must not exceed 0.5mg/litre, while aluminium concentrations must remain below 0.75mg/litre to protect aquatic life.
The test results showed ammonia concentrations of 0.48mg/litre at some sampling points, while aluminium levels ranged from 0.559 to 3.547mg/litre.
Sonthi Kochawat, an environmental academic, said that if water from the Prachin Buri River were used to produce tap water, adding alum to help suspended particles settle would not resolve the problem. He said aluminium was difficult to remove from the water and could pose a health risk if it accumulated in the body over time.
