Multivariate statistical technique in the assessment of coastal water quality of Oman

Coastal water plays a significant role in the growth and productivity of marine organisms; and is the source of many important economic activities including fishery, coastal recreation and socio-economic development. Coastal water quality is highly influenced by the physical, chemical and biological processes in the ocean. The present study assessed 17 physico-chemical water quality parameters along the Omani coastline of Capital Muscat at Mina Al Fahal, Al Ghubrah, Barka and Quriyat. The results showed that the level of dissolved oxygen (O₂) was lower than 5 mg/l at the Mina Al Fahal (2.24 mg/l) and Quriyat stations (3.68 mg/l), signifying a threat to coastal species. Relatively high total dissolved solids (>40 000 mg/l), total coliform (>500 most probable number (MPN)/100 ml) and Escherichia coli (>35 MPN/100 ml) at the Al Ghubrah and Barka stations indicated contamination from brine disposal, local run-offs, decomposition of organic waste and domestic effluent discharges. The higher phosphate–phosphorus level of 0.14 mg/l at Quriyat suggested pollution from local fish waste and sediment decomposition. The analysed parameters were further evaluated using multivariate statistical techniques such as cluster analysis (CA) and principal component analysis/factor analysis (PCA/FA). CA provided five clusters after grouping the parameters based on similarity. PCA/FA identified four main loading factors, with a total variance of 74.2%. The analysis showed contamination from desalination plants, domestic waste, local discharge and natural fish wastes and weathering of seabed rocks and sediments as the main contributors to the elevated concentrations affecting the water quality in the study locations.