Combined Multivariate Statistical Techniques and Water Quality Index (WQI) to Evaluate Spatial Variation in Water...

Area of Science:

• Environmental Science
• Water Quality Assessment
• Analytical Chemistry

Background:

• Rawal Lake is a critical drinking water source for Islamabad and Rawalpindi, Pakistan.
• Assessing its water quality is vital for public health.
• Understanding spatial variations in water quality is necessary.

Purpose of the Study:

• To assess the Water Quality Index (WQI) of Rawal Lake and its tributaries.
• To investigate spatial variations in 11 water quality parameters.
• To identify sources of contamination, particularly heavy metals.

Main Methods:

• Integrated approach using Water Quality Index (WQI) and Principal Component Analysis (PCA).
• Analysis of 11 water quality parameters across five major tributaries.
• Statistical analysis including Pearson correlation.

Main Results:

• Most parameters (temperature, TDS, pH, conductivity, chlorides, sulfates) were within WHO limits.
• Cadmium and lead levels exceeded WHO permissible limits in Bari Imam and Rumli tributaries.
• PCA identified three major factors accounting for 96.5% of variance, with pH, TDS, alkalinity, chlorides, sulfates, and zinc being significant.

Conclusions:

• Water from Bari Imam and Rumli tributaries is highly contaminated with heavy metals and unsuitable for drinking.
• Heavy metal contamination poses a significant risk to Rawal Lake's water quality.
• Future water quality management plans must integrate heavy metal monitoring and control.