Spatiotemporal variation analysis of Tigris River water quality in Mosul, Iraq during 2020–2023 based on environmetric techniques

This study focuses on the temporal and spatial variations in water quality of Tigris River in Mosul, Iraq, from 2020 to 2023. It involved monthly monitoring of 17 water quality parameters at 10 different sampling stations along the river. The data were analyzed using different statistical methods, including one-way ANOVA, cluster analysis, and principal component analysis/factor analysis, to check the variation and identify potential pollution sources. The one-way ANOVA showed significant spatial and temporal differences for most of the water quality parameters, while BOD₅ and COD were relatively less variable. Cluster analysis classified the sampling sites into two distinct clusters, which were the upstream and downstream sites, indicating that urbanization significantly affects the water quality. PCA and FA revealed five key components that together comprised 87.9% of the overall variance in water quality. These components were associated with mineral content and salinity (30.5%), alkalinity and hardness (22.6%), oxygenation and organic matter (12.8%), nutrients (11.7%), and chemical oxygen demand (10.3%). The results indicate that the deterioration of water quality is mainly due to geological factors, urban runoff, agricultural activities, and domestic sewage discharge. This research provides the necessary knowledge regarding the processes that determine water quality in the Tigris River and gives a scientific basis for developing effective water resource management and pollution abatement strategies for the region.