Spatial and seasonal variability of water quality in the Mopanshan Reservoir (Harbin, Northern China) Available to Purchase

The purpose of this work is to evaluate the spatial and seasonal variability of water quality from the Mopanshan Reservoir, which is a typical reservoir in the northern cold regions of China. The results indicate that preventive or remediation actions are necessary to improve its water quality. Water samples were collected between 2012 and 2013 at five sampling stations at the Mopanshan Reservoir, and analyzed for COD_Mn and total nitrogen (TN). SPSS software was used to carry out analysis of variance and correlation analysis. Spatially, COD_Mn and TN exhibited a rather small distinction in the horizontal direction, but there was a significant difference regarding TN in the vertical orientation. The concentration of TN also increased with the increase in sampling depth. Seasonally, the concentration of COD_Mn and TN showed a pronounced seasonal pattern and was divided into four periods. COD_Mn reached a maximum in September and was at a minimum in June. And TN reached a maximum in June and was at a minimum in November or December. The use of correlation analysis shows that the regular variations of TN were primarily affected by temperature. The main form of nitrogen in the Mopanshan Reservoir is NO₃-N, and the change of TN is consistent with that of NO₃-N. By Pearson correlation coefficient, the seasonal variability of COD_Mn correlated to changes in the reservoir's water level. The results showed that the concentration of TN exceeded the guideline values in most months and COD_Mn was slightly over the standard limit. Thus, it is urgent that preventive actions and remediation processes are developed to improve the water quality in this reservoir.