A multivariate approach for comparative study of water and sediment at Juhu Koliwada and Haji Ali

Abstract

The Juhu Koliwada and Haji Ali are coastal locations situated in the suburbs of Mumbai and South Mumbai, Maharashtra, respectively. They are among the attraction points for tourists and are known for their marine diversity. The present study aims to investigate the physicochemical parameters of water and sediment of the rocky intertidal zone during low tides. A monthly sampling was conducted from April 2023 to July 2023, encompassing two distinct seasonal periods: pre-monsoon (April–May) and monsoon (June–July). Seasonal variations in seawater temperature, pH, TDS, salinity, turbidity, COD, electrical conductivity, PO₄-P, and NO₃-N were prominent. High standard deviation from the mean in physicochemical data indicates the presence of temporal and spatial variations caused by polluting sources. Principal Component (PC) 1 shows 62.87 % variance, with strong positive loadings of electrical conductivity (0.994), COD (0.973), water temperature (0.983), TDS (0.968), specific gravity (0.887), salinity (0.888), PO₄-P (0.794), turbidity (0.792), and total alkalinity (0.788). In comparison, PC 2 explains 22.98 % of the total variance and indicates a strong positive loading for DO (0.997), pH (0.976), and a moderate positive loading for NO₃-N (0.541). On the other hand, PC 3 accounts for 14.15 % of the variance and shows a strong positive loading for BOD (0.977) in the water. The magnitude of effluent discharge, rainfall, and other anthropogenic activities throughout the season affects the levels of phosphate, nitrate, and organic carbon in the sediment. Urban runoff, household greywater discharge, the non-organised sector, and unregulated tourism are among the anthropogenic factors that require urgent consideration for the continuous assessment of the coastline of Mumbai. This study provides baseline data to identify the physicochemical variables and their driving factors. A comparative study of similar marine ecosystems is essential for long-term conservation planning, as it demands the making of pollution control strategies and policy decisions to implement and improve environmental conservation and management.