The water quality, ecological and public health risk assessment of the wastewater collected at supper intensitive shrimp farming ponds in My Xuyen district, Soc Trang province

Abstract

Although shrimp farming industry brings high export value, it generates high amount of waste, including sludge and wastewater, due to periodic water exchanges, shrimp cultivation and shrimp pond preparation. In this study, we collected wastewater samples at three shrimp ponds in My Xuyen district, Soc Trang province to analyze and evaluate their water quality. Risk impact of chemical components in shrimp pond wastewater on the environment and public health was assessed through calculating the WQI index, using semi-quantitative risk assessment methods and risk matrix methods. The results show that the WQI values of the wastewater samples are in the range of 10 and 100. The wastewater samples meet class B water standards according to the QCVN 40:2011/BTNMT, and as well as meeting the National technical regulation on brackish water shrimp culture farm  according to the QCVN 02 - 19: 2014/BNNPTNT. The results showed that the water samples had a low WQI index for COD and BOD indicating that those ponds contain a lot of degradable organic matters. The existence of organic substances and harmful pathogens in shrimp pond wastewater is the cause of environmental and human health issues at moderate-to-high risk levels. There are three main factors that affected the wastewater quality, and they account for 58,6 %, 22,3 % và 9,7 %, respectively.