Investigation of spatial and seasonal variation of water quality along the mid-Black Sea coast (from Sinop to Ordu) of Turkey, by multivariate statistical techniques

Abstract

The Black Sea is a closed basin surrounded by six countries and is the last spill point for the rivers from different watersheds. Due to these discharges from surrounding countries, the Black Sea is exposed to high and moderate pollution levels. Therefore, monitoring water quality changes in the mid-Black Sea coastal area is necessary to develop pollution control strategies. This study aims to examine the temporal and spatial changes of seawater quality along the mid-Black Sea coast of Samsun, Turkey. The samples were collected from 13 monitoring stations from the three distances in four seasons in 2013. The samples were analyzed for 22 parameters: nitrate-nitrogen (NO3-N), ammonium-nitrogen (NH4-N), phenol, methylene blue active substances (MBAS), total carbon (TC), total inorganic carbon (TIC), total organic carbon (TOC), iron (Fe), aluminum (Al), manganese (Mn), chromium (Cr), nickel (Ni), copper (Cu), zinc (Zn), cadmium (Cd), lead (Pb), pH, temperature (T), dissolved oxygen (DO), electrical conductivity (EC), total dissolved solids (TDS) and salinity. Multivariate statistical techniques (Principal component analysis (PCA), factor analysis (FA), and cluster analysis (CA)) were applied to analyze seawater quality variations. Factor analysis of seawater chemical variables was found to be eight factors in total. These eight factors account for 79.13%, 82.27%, 78.60%, and 78.69% of the total variances in winter, spring, summer, and fall, respectively. Cluster analysis classified the monitoring sites into two groups based on similarities of seawater characteristics.