Tolerance capacity of macrobenthos to pH and ammonium in treated Phu Bai Industrial Park wastewater

Abstract

Our study, which focused on the effects of pH and ammonium concentration in the treated wastewater of the wastewater treatment plant of Phu Bai Industrial Park, has unveiled some concerning findings. The lethal time 100 - the time required to kill 100 % macrobenthos (LT100) of the tested macrobenthos, ranging from 6 to 18h, indicates a significant sensitivity of different macrobenthos species to pH and ammonium levels. The shrimp Palaemon mani and crab Siamthelphusa beauvoisi, in particular, were found to be more sensitive to pH and ammonium than mussels Elliptio dilatata, Corbicula lamarckiana, Corbicula luteola, Corbicula sandai. The snail Pila conica, however, exhibited the least susceptibility among the tested macrobenthos. Alarmingly, at values of pH (3 - 5) and ammonium (10 - 14 mg/L) exceeding the standards allowed by QCVN 40:2011/BTNMT, the LT100 values of the tested macrobenthos decreased significantly (6 - 14h), indicating a surge in environmental toxicity. Our study also revealed that the tested macrobenthos were more sensitive to ammonium than to pH, highlighting the urgent need for action to address these issues.