Method for screening water physicochemical parameters to calculate water quality index based on these parameters'...

Water quality index (WQI) plays a crucial role in guiding water resource management. However, WQI calculation methods are not uniform, especially the selection of water parameters and the weighting given to each water parameter (P_i). To optimize WQI calculation, 132 water samples from seven rivers and from Chaohu Lake (33 sampling sites in Chaohu Lake Basin) in four seasons were collected, and the water parameters and microbiota composition were analyzed using high-throughput sequencing of 16 S rDNA. The correlation coefficient R² between water parameters and microbiota composition using redundancy analysis with the Monte Carlo method were calculated, and the water parameters that significantly correlated with the microbiota composition were selected to calculate WQI_min. The results showed that TP, COD, DO, and Chl a correlated significantly with water microbiota composition. WQI_b calculated by substituting R² for P_i was more consistent with the similarity between the microbiota compositions. WQI_minb calculated using TP, COD, and DO was consistent with WQI_b. The results of WQI_b and WQI_minb were more consistent than those of WQI and WQI_min. These results imply that using R² instead of P_i could help obtain a more stable WQI_b that could better reflect the biological characteristics of the Chaohu Lake Basin.