Risk and Water Quality Assessment over view of River Sitalakhya in Bangladesh

Mohammad Naushad Alam¹, Professor Dr. Fazle Elahi², Professor Dr. Md. Didar-Ul-Alam³

^1,2,3Department of Soil, Water and Environment

University of Dhaka, Bangladesh

Keywords: Industrial effluents, Agrochemicals, Risk and Quality Assessment

ABSTRACT

In terms of quality, the river water of the Sitalakhya is vulnerable to pollution from untreated industrial effluents and municipal wastewater, runoff from chemical fertilizers and pesticides, and oil and lube spillage in and around the operation of river ports. The present investigation (2001 - upwards) to previous works (1980 - 2000) on Sitalakhya River, the physicao – chemical variables, namely temperature, transparency, total dissolve solids, suspended solids, electrical conductivity, hardness, pH, dissolve oxygen, biochemical oxygen demand, chemical oxygen demand, nitrate, ammonium, phosphate were significantly differs (at <0.05 level by DMRT) in the spatial (pollution source) and temporal (seasonal) sources of variation affecting and consideration measures to be taken for the safe aquatic lives as well as human health.

INTRODUCTION

Water is the most vital element among the natural resources, and is crucial for the survival of all living organisms including human, food production, and economic development. Today, nearly 40 percent of the world’s food supply is grown under irrigation, and a wide variety of industrial processes depends on water (BCAS, 2000). Moreover, in Bangladesh, the environment, economic growth, and developments are all highly influenced by water - its regional and seasonal availability, and the quality of surface and groundwater. Spatial and seasonal availability of surface and groundwater is highly responsive to the monsoon climate and physiography of the country. In terms of quality, the surface water of the country is vulnerable to pollution from untreated industrial effluents and municipal wastewater, runoff from chemical fertilizers and pesticides, and oil and lube spillage in the coastal area from the operation of sea and river ports. Water quality also depends on effluent types and discharge quantity from different type of industries, types of agrochemicals used in agriculture, and seasonal water flow and dilution capability by the river system (DHV, 1998). In Narayanganj,

The industrial units such as chemicals, fertilizer, pesticides, textile, oil, PowerStation, ship repairing dock, cement and tannery (Table 1) are located in and around the Sitalakhya River (DoE, 1991).

The river Sitalakhya is one of the most prominent rivers in the flood plain region of Bangladesh. It is located in Narayanganj City, the second most vital industrial zone of the country. Various types of industrial units have been established on the bank of the Sitalakhya River; most of these industries directly or indirectly discharging a huge quantities of wastes and effluents into the river without any treatment and also municipal and domestic sewage sludge’s from Narayanganj urban area, find their way untreated into this river. Moreover, the river is the route of the communication with Chandpur, Chittagong as the port of cargo. Besides these, the people live on and around the Sitalakhya River utilizing its water for their household washing, bathing and other necessary daily works. Therefore, the risks of pollution impact are rising upwards sequentially (WARPO, 2000b).

Table 1 List of the polluting Industries situated on and around the Sitalakhya River (DoE, 1991)

Type of Industry	Number
1. Fertilizer Industry	2
2. Cement Industry	2
3. Oil Industry ()	4
4. Oil Industry ()	2
5. Dock yard	3
6. Jute Industry^*	12
7. Textile Industry	2
8. Tannery Industry¹	3
9. Iron Industry²	2
10. Power Station	2
11. Chemical Industry	1

^* Data from 1990; ^1,2 Non – point source

The concerns over water quality relate not just to the water itself, but also to the danger of diffusion of toxic substances into other ecosystems. The aquatic environment for living organisms can be affected and bioaccumulation of harmful substances in the water-dependent food chain can occur. A variation of inland surface water quality is noticed due to seasonal variation of river flow, operation of industrial units and use of agrochemicals. Overall, inland surface water quality in the monsoon season is within tolerable limit with respect to the standard set by the Department of Environment (DoE) given in table 2.

However, quality deteriorates in the dry season. The toxic intrusions in this region and pollution problems in industrial areas are significant. In particular, water quality around Dhaka and Narayanganj is so poor that water from the surrounding rivers can no longer be considered as a source of water supply for human consumption (DoE, 2001).

The wastes, effluents and agrochemicals contain heavy metals, toxic substances, germs and nitrogen containing toxic substances. They pollute the natural system of Sitalakhya River, which actually act as a sink. They thereby create serious environmental hazards, endanger human health and cause problems to aquatic lives. To add this, the slums in and around Narayanganj city make their toilets in the open air and lead to the microbiological pollution of river system, which is used by the surrounding people for drinking, bathing and cooking purposes (Ahmed and Reazuddin, 2000).

Table 2 Standards for drinking water (DoE, 1997)

Sl. No.	Parameter	Unit	Standards
1.	Aluminum	mg/l	0.2
2.	Ammonia (NH₃)	,,	0.5
3.	Arsenic	,,	0.05
6.	BOD520°C	,,	0.2
7.	Boron	,,	1.0
8.	Cadmium	,,	0.005
9.	Calcium	,,	75
10.	Chloride	,,	150 – 600
16.	Chromium (total)	,,	0.05
17.	COD	,,	4
20.	Color	Hazen	15
21.	Copper	mg/l	1
24.	DO	,,	6
26.	Hardness (as CaCO₃)	,,	200 – 500
27.	Iron	,,	0.3 – 1.0
28.	Kjeldhl Nitrogen (total)	,,	1
29.	Lead	,,	0.05
30.	Magnesium	,,	30 – 35
31.	Manganese	,,	0.1
34.	Nitrate	,,	10
36.	Odor	,,	Odorless
38.	pH	,,	6.5 – 8.5
40.	Phosphate	,,	6
41.	Phosphorus	,,	0
42.	Potassium	,,	12
47.	Sodium	,,	200
48.	Suspended particulate matters	,,	10
50.	Sulfate	,,	400
51.	Total dissolved solids	,,	1000
52.	Temperature	°C	20-30
55.	Zinc	mg/l	5

METHODOLOGY

An investigation was conducted with seasonal variation of water quality of Sitalakhya River, Narayanganj district during the year 1980 to upward due to Industrial discharges and agrochemicals came from point and non – point sources. The study area of Sitalakhya River is located between 23⁰ 36' 24'' N to 23⁰ 45' 15'' N latitudes and 90⁰ 30' 30'' E to 90⁰ 30' 50'' E longitudes. The study area is also interconnected with the river Brahmaputra, Lakhya, Balu, and Turag on the northeast.

The Sitalakhya River herself and other interlinked rivers were likely to be significant sites of chemical pollution. Based on this evaluation, the river system was divided into two zones based on geological and other factors: zone І, the upstream and zone ІІ, the reach downstream above the Meghna River.

Zone І and zone І І center on the Sitalakhya River and includes untreated sewage inputs from the town of Narayanganj Sadar and Bandar; waste water and air emissions from a large working smelter; and numerous other contaminant sources, such as small – manufacturing facilities (e.g., a tannery and battery factory) and significant non – point agricultural activities. Moreover, other important pollution sources such as industrial inputs from a paint factory, an electric power station, a building materials facility, and the solid waste. It also has multiple open sewage discharges from combined sewers that drain directly into the river, and receives sewage effluents from the sewer system of the town.

RESULT AND DISCUSSION

ASSESSMENT OVERVIEW OF SITALAKHYA RIVER

Industrial pollution is an area of growing environmental concern in Bangladesh. The country still has a relatively small industrial base contributing about 20% of GDP. The manufacturing sub-sector accounts for about half of this contribution and it grew at a rate of 5.04% between 1982 and 1992. The growth rates of some of the important sectors are shown in Figure 1(Bhattacharya et al., 1995). With the growth of the ready-made garments sector, the textile sector is also growing at a high rate in recent years.

Figure 1 Growth rates of important industrial sectors (Bhattacharya et al., 1995)

The major polluting industries such as tanneries, pulp and paper, sugar, fertilizer, pharmaceuticals, metal, and chemical industries are mostly located in and around the major cities in Bangladesh. Some of these are also located on the banks of major rivers and lakes (World Bank. 1997).

Among the polluted areas, the worst problems are in the second most polluted river is the Sitalakhya, flowing from the east of Dhaka. The major polluters of the river are Ghorashal Urea Fertilizer Factory and an oil terminal situated on the bank of the river. Industrial units at Narayanganj and Demra are also sources of the pollution. Monitoring data of the DoE demonstrated that the concentration of dissolved oxygen in the river Sitalakhya beside the fertilizer factory varies between 2.1 to 2.9 mg/l during low tide (Saad, 2000) and pH varies between 7.1 to 6.5 at 1981 to 1990 shown in figure 3 (BCAS, 2000). Monitoring data of the Surface Water Modeling Centre (SWMC) on the same river, showed a degrading trend for water quality in the dry season. The lowest level of DO was observed at the end of February 1998, when the concentration became less than one (Figure 2).

Figure 2 Concentration of Dissolve oxygen in various years

The overall surface water quality in the monsoon season is within tolerable limits, with a few exceptions, including the rivers Buriganga, Balu, Sitalakhya, Karnaphuli, and Rupsha. However, concerns over surface water quality are gradually emerging due to the dispersed locations of polluting industries, and the adverse effect on surrounding land and aquatic ecosystems, as well as subsequent impacts on the livelihood system of the local community. The extreme examples of this type of effect are near Dhaka at Konabari and Savar, where industrial effluents are discharged into nearby land and water bodies without any treatment.

Figure3 pH values in various years (BCAS, 2000)

The Bangladesh Center for Advanced Studies (BCAS), analyzed that EC of Sitalakhya River cross the limit and it was 110 mgL^- during 1980 but aggressive industrialization and improper agricultural activities, it is rise up to 1440 mgL^- during 1998 and TDS rises 216 to 446 mgL^- (figure 4 and figure 5). A number of textile and leather industries discharge their industrial effluents into a nearby small water body, the results showed that levels of COD, TSS and DO in the water exceeded standard limits. It also showed that the total chromium concentration in sediments and wastewaters near the discharge points of the local tannery and textile industries is very high. The concentrations of zinc, lead, and cadmium were also found to be higher than the national standards (BCAS, 2000).

Figure 4 Electrical Conductivity (µS) changing rate at different year (BCAS, 2000)

Figure 5 Total Dissolve Solids (mg/l) changing rate at different year (BCAS, 2000)

APPROACH TO EVALUATING WATER QUALITY

The prediction that a water quality-related problem will occur requires evaluation of the potential of the water to create soil conditions that may restrict its use or that may require the use of special management techniques to maintain acceptable yields. There are a number of procedures available for this evaluation but regardless of which one is used, emphasis should focus on relating the potential problem to the field situation since solutions to water quality problems usually must be implemented at the farm level rather than at the project level.

If problems do occur in combination, they are more easily understood and solved if each factor is considered individually. Therefore, the guidelines and discussion, which follow, treat each problem and its solution separately, so that a number of factors are evaluated for each of the problem areas, such as:

X the type and concentration of salts causing the problem;

X the soil-water-plant interactions that may cause the loss in crop yield;

X the expected severity of the problem following long-term use of the water;

X the management options that are available to prevent, correct, or delay the onset of the problem.

Some of the important physical and chemical properties of irrigation water are necessary to be known to assess its suitability for irrigation (Hassan et al., 1998).

CONCLUSION

This has been relevant estimated the total pollution loads to water by all the industrial sectors of Bangladesh using the Industrial Pollution Protocol System (IPPS) method developed by the World Bank. In terms of pollution, the most polluting sector is the food industry, where the sugar mills and oil/fat factories cause most of the pollution. Pulp and paper industry is the worst water polluter. Metal industries (ferrous and nonferrous) rank first in terms of toxic metals emission. The largest amounts of toxic chemicals are released by the tanneries and leather industries (raw and processed). In terms of the total emission to air, water, and land, the top three most polluting industries are pulp and paper, food industry and tanneries/leather. These industries are large in size or are located in large clusters (tanneries), thus can be identified and managed as point sources of pollution. The other significant polluters include the metal and textile industries. These are dispersed all over the country and will be more difficult to manage from pollution control point of view.

Due to lack of resources, modern technology, and awareness, not much is being done to trap the harmful pollutants and reuse/recycle these chemicals. Recycling is practiced only when it is part of the production process, and not as a part of pollution mitigation activity. If strict environmental monitoring is enforced as per the Environmental Conservation Rules of 1997 and other relevant environmental laws, many of the industries of Bangladesh will be found in violation of the emission limits.

REFERENCE

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Technical College - Bourgas,