Assessment of Physicochemical Properties and Comparative Pollution Status of the Dhaleshwari River in Bangladesh

Abstract

The Dhaleshwari river which flows near Dhaka, the capital of Bangladesh, is currently under threat due to the recent relocation of the Hazaribagh tannery to the Savar area. This study investigated the physicochemical parameters of water quality along with the heavy metal levels in the Dhaleshwari river and performed a comparative analysis among the peripheral rivers around Dhaka City. Surface water quality parameters such as total dissolved solids (TDS), biochemical oxygen demand (BOD5), and chemical oxygen demand (COD) obtained for the Dhaleshwari river deviated by as much as 90% from World Health Organization (WHO) standards in certain instances due to direct discharge from untreated point sources. Concentrations of toxic metals such as chromium (Cr), cadmium (Cd), and nickel (Ni) were above the Food and Agriculture Organization (FAO) standards for heavy metals in surface waters. Strong correlations among the heavy metals indicated significant linear dependences. Based on the physicochemical and toxicity-based characterization, the river system in Dhaka city can be termed as severely polluted with respect to organic and solids discharge, while ecological risk indices (ERI) indicated disastrously high risk in the Dhaleshwari and Buriganga rivers. The study outcomes emphasize the necessity of frequent investigation while controlling the point and nonpoint urban pollution sources discharging into the peripheral rivers of Dhaka city.

Contaminant Discharge From Outfalls and Subsequent Aquatic Ecological Risks in the River Systems in Dhaka City: Extent of Waste Load Contribution in Pollution

“…Because of the propensity for significant ecological and human health problems, such contaminated river water is unsuitable for human consumption, fishing, and agriculture ( 9 ). As per the findings, the physicochemical characteristics of water and relative environmental damage level in Dhaka's surrounding rivers have significantly deteriorated in terms of water quality indicators ( 10 ). Multiple industrial facilities, particularly Garment industries, have been developed in the current decades in Dhaka district's Savar Upazila, primarily along the Dhaleshwari river's bank.…”

“…To the west of Dhaka, the Dhaleswari-Kaliganga River and Bangsi- Shitalakshya-Turag-Buriganga River systems are located, while the Balu-Lakhya River system is located to the east. The Dhaleshwari River begins in the Jamuna River at the Tangail district's northwestern border and finally flows into the Shitalakshya River around the Narayanganj district ( 10 ). The Dhaleshwari River is one of the main tributaries of the Jamuna River in Dhaka, central Bangladesh, which is 160 km long and has an overall depth of 37 m ( 10 ).…”

“…The Dhaleshwari River begins in the Jamuna River at the Tangail district's northwestern border and finally flows into the Shitalakshya River around the Narayanganj district ( 10 ). The Dhaleshwari River is one of the main tributaries of the Jamuna River in Dhaka, central Bangladesh, which is 160 km long and has an overall depth of 37 m ( 10 ). The Buriganga River system is situated in Bangladesh's North Central Zone's southeastern region, near the Padma (Ganges) and Upper Meghna rivers.…”

“…Water samples collected from all the rivers were analyzed in the Environmental Engineering Laboratory, Department of Civil Engineering, University of Asia Pacific for water quality characteristics. Total dissolved solids (TDS) concentrations were determined using DO700 EXTECH (Łódz, Poland) standard equipment ( 10 ). Electrical conductivity (EC), and total suspended solids (TSS) were measured with an EZDO (Taipei City, Taiwan) model “CTS-406” meter.…”

“…Electrical conductivity (EC), and total suspended solids (TSS) were measured with an EZDO (Taipei City, Taiwan) model “CTS-406” meter. A Twin (Santee, USA) model “B-221 pH” pH meter and a model “YK-22DO” dissolved oxygen meter were used to measure pH and dissolved oxygen (DO) (EZDO, Taipei City, Taiwan) ( 10 ) respectively. The 5-day biochemical oxygen demand (BOD 5 ) was measured using the BODTRAK technique with a BOD Trak II (Model: Hach) and a BOD incubator (Model: Hach FOC120E) with potassium hydroxide and BOD nutrient buffer pillow reagents ( 31 ).…”