Analysis of Water Quality Index of Hatirjheel Lake, Dhaka

Abstract

The study was conducted to know the status of water quality of Hatirjheel lake in Dhaka city. There are nine water samples from different locations of this lake has been analyzed for various physiochemical parameters including pH, TDS, TSS, EC, DO, Free CO2, Total Acidity, Total Alkalinity, Total Hardness, Ca2+ Hardness at dry season of 2021 (16th January 2021). The mean ± SD of pH 6.80 ± 0.18, TDS 488.89 ± 41.67ppm, TSS 0.02 ± 0.010ppm, EC 558.89 ± 30.19 μS/cm, DO 4.12 ± 0.95mg/L, Total Acidity 385.78 ± 75.79 mg/L, Total Alkalinity 248 ± 1256.68 mg/L, Total Hardness 392 ± 35.72 mg/L, Ca2+ Hardness 122.44 ± 25.59 mg/L and they are compared to Bangladesh Standard (ECR, 1997) and WHO standard (WHO, 2004, WHO, 2011). The study found that the lower concentration of DO is below 6 mg/L which exceeds the Bangladesh standard (ECR, 97) in all of the water samples around the lake that severely harmed the aquatic organism and degrade their habitat. On the other hand, the concentration of f, free CO2 is extremely high as the high concentration of CO2 decrease the pH level of the water and it affects shallowwater marine organisms. Parameters such as pH varied from 6.5-7.05, EC varied from 510-600 μS/cm, TDS varied from 450-590ppm, TSS varied from 0-0.034ppm, Total Acidity varied from 224-500 mg/L, Total Alkalinity varied from 80-392 mg/L, Total Hardness varies from 348-452 mg/L, Ca2+ Hardness varied form 74-162 mg/L, Free CO2 varied form 730.4-1170.4 mg/L and DO varied from 2.7-5.5 mg/L. There are four positively strong significant relation found between pH and EC (r = 0.802), pH and Acidity (r =0.893), pH and Total Hardness (r = 0.879), EC and TDS (r = 0.814). Also, there are two positively moderate significant relationship found between pH and TDS (r = 0.702), EC and Total Hardness (r = 0.774). Although Hatirjheel plays a significant role in the drainage system of the storm water, many drainage discharges form the industrial area affects the water quality. In this consequence proper monitoring of the water quality of those discharge point should be implemented in order to prevent lake contamination.