Assessment of the water quality using multivariate statistics and the water quality index: a case study of the Yaglidere Stream (Giresun) in the Eastern Black Sea region, Turkey.

In this study, the water quality of the Yaglidere Stream passing through Espiye (Giresun-NE Turkey) and Yaglidere districts, where old and new mining activities are present, was evaluated, and characterized by using the water quality index (WQI), multivariate statistical, and GIS techniques. The downstream aquifer of the Yaglidere Stream, which originates from Erimez Mountains and reaches the sea from the west of Espiye district, meets the domestic and drinking water needs of Yaglidere and Espiye districts. In addition, activities such as energy production and fish farming are carried out along the stream. Therefore, it is of great importance to investigate the water quality of the stream. In order to evaluate the water quality, 50 water samples were taken from 10 sampling points (5 periods) along the flow direction of the stream. Parameters other than T, DO, Mg, F, NH3, CN, and HS show significant spatial variations indicating the influence of geogenic and anthropogenic activities. Some of the investigated parameters (T, DO, Ca2+, Mg2+, SO42-, NH3, CN, Fe, Se) exhibit important seasonal variations due to high seasonality in water temperature and water flow. Principal component analysis/factor analysis reveals that the parameters responsible for water quality changes in the Yaglidere Stream are mainly related to the geogenic structure, mining wastes, agricultural activities, and domestic wastes. According to the WQI values, the water samples taken from the upstream and middle part of the stream are in the water quality between "Excellent" and "Good", on the other hand, in the downstream regions where anthropogenic and geogenic effects are dominant, the water samples are in the quality of "Poor water" and "Unsuitable for drinking". The most effective water quality parameters on WQI are Al, Fe, and Mn and the water quality in the basin is negatively affected by geogenic and anthropogenic effects.

Using Canadian Water Quality Index method to evaluate the spatio-variation of water quality and the impacts of quality parameters: a case study of Amasya's surface water (Northern Turkey).

In this study, the spatial variation of water quality in Yesilirmak River passing through Amasya was investigated using the Canadian Water Quality Index (CWQI). For this aim, the measured 15 parameters in 3-month periods between the years 2008 and 2015 were used at 11 sample points from the Yesilirmak River and its tributaries. The calculated CWQI scores using parameters of pH, Dissolved Oxygen (DO), Chemical Oxygen Demand (COD), ammonia, ammonium, nitrite, nitrate, phosphate, iron, copper, zinc, potassium, sulfate, sulfite and chlorine range from 33 to 64. These scores indicate that the surface waters in the studied area are poor to marginal in quality. The effect of each parameter on the CWQI scores by excluding each parameter, one by one, considering the water quality of the Yesilirmak River was investigated using the Hierarchical Cluster Analysis (HCA) method. It was determined that the presence and/or absence of the parameters, which caused an increase or decrease in CWQI scores, were ammonia, phosphate, COD, sulfide, iron, ammonium, nitrite, DO. On the other hand, the parameters having positive effects on CWQI are nitrate, chlorine and potassium. The HCA statistical analysis method is suitable for interpreting complex water quality datasets and understanding time/location dependent changes in water quality. HCA can be used effectively to group parameters in river water quality monitoring programs.