KARACHI: The water pollution in the Indus River is on the rise due to flow of municipal, industrial and other waste material from the cities, towns and villages as the relevant authorities are not sincere to save the river from the pollution.
According to a report, the Indus River is the largest river of Pakistan. The 3,120 km long river emerges in Mount Kailash in Western Tibet, flows northwest through the disputed region of Kashmir, bends sharply to the left after the Nanga Parbat massif, and flows south-by-southwest through Pakistan, before emptying into the Arabian Sea near the port city of Karachi.
The concentrations of Ag, As, Cd, Cr, Cu, Fe, Mn, Ni, Pb, Zn and Hg, together with Na, K, Ca and Mg in 19 species of fish, captured from the Indus River in Pakistan are estimated by the atomic absorption method.
Corresponding data for sediment and water from 11 sites along the down-stream route of the river are also reported. Mercury and arsenic concentrations were high (3.920 and 3.072 µg/g, respectively) in the muscle of fish from Guddu barrage as compared with those from other sites. Hetroptirus fossilus showed maximum concentrations of Ag, Cu and Pb in its muscle as compared with other fish. Labeo calbasu from Guddu barrage showed highest As concentration at 3.072 µg/g. Mystus vitatus from Chashma barrage contained maximum cadmium concentration at 0.990 µg/g.
Several other fish exhibited elevated levels of metals along the downstream route of the river, a trend exhibited also by the elevated metal contents of sediment and water at Guddu and Lloyd barrages. The study indicated a gross pollution of the sediment and water at various locations of the river, e.g. As (7.452 µg/g) in sediment from Lloyd barrage, Hg (5.710 µg/g) in sediment from Jinnah barrage, Pb (2.709 µg/g) in sediment from Guddu barrage and Mn (0.038 µg/g) in water from Lloyd barrage. The macronutrients showed an inverse relationship with trace metals. Hetroptirus fossilus could be used as indicator species for Ag, Cu and Pb.
A World Bank Report says more than 90 percent of plastic waste from the sample sites in Upper Indus Basin ends up in the river, wreaking havoc on the aquatic life and surrounding communities. Low-density polyethylene (LDPE), sanitary products, and multi-layered packaging are the top three types of plastics, accounting for a staggering 75 percent of all plastics in the river. LDPE, the most common SUP which is used to make bottles, grocery bags, and disposable containers, constitutes 43 percent of all plastics found in the river. Only 6 percent of the detected plastic waste is polyethylene terephthalate (PET) and high-density polyethylene (HDPE), which incidentally has higher recycling cash value for local waste-pickers.
Moreover, accumulated plastic waste at the barrages redistributes further into adjoining canals. With continued exposure to sunlight and mechanical factors, macroplastics, degrade into tiny microplastics and nanoplastics, resulting in additives and toxins that harm the environment, natural habitats, and upset the food chain. Through leaching, these toxins can potentially contaminate other freshwater reservoirs and groundwater. The diminishing water quality in turn increases the treatment costs for drinking water.
Marine and aquatic life is also not spared. A large part of the plastic waste from the Indus travels downstream through the Kotri Barrage to the Arabian Sea. As a result, out of over 11,977 tonnes per annum of plastic reaching the mouth of the Indus, nearly 10,000 tonnes makes its way to harm coastal and marine life. Frequent dumping of municipal waste into adjacent water bodies (including Malir and Lyari rivers, small nullahs, gullies, and open drains) further exacerbates the situation converting the Arabian Sea into a hotbed for municipal debris.
The microplastics disposed of in water bodies can end up bioaccumulating (pollutants building up in a single organism’s body over time) in any particular species or can cause biomagnification (increase in the concentration of the toxins as they move up the food chain) as they become part of the food chain. Consequent to high levels of such pollutants, significant reductions in fish species’ diversity and abundance are putting stress on the critically endangered Indus River Dolphin, whereas mangroves have nearly vanished in some areas of the lower Indus River in the past.
Widespread occurrences of Arsenic are reported in groundwater through a number of subsequent studies in the provinces of Punjab and Sindh, the two most populated provinces in the Indus River basin of Pakistan and thereby emerged as an issue of public health concern.
These studies have revealed that concentrations of As are elevated by a factor of 10–250 as compared to the WHO drinking water guideline. Both natural and anthropogenic processes have been primarily indicated as cause for elevated As concentration in groundwater. An increasing number of studies also show evidence that irrigation with As contaminated groundwater is associated with elevated As concentrations in agricultural products. The future research should therefore focus on the detailed understanding of the complexities of the geological and hydrogeological setting of Pakistan and to outline the sources of As and the mechanisms of transport to the Indus basin aquifers.
Water pollution in the Indus comes from a number of sources, including return flow from agriculture, which adds sodium nitrates, phosphates, and pesticides to the river. Additionally, untreated or incompletely treated sewage from cities along the Indus is discharged into the river.
A large part of the plastic waste from the Indus travels downstream through the Kotri Barrage to the Arabian Sea. As a result, out of over 11,977 tonnes per annum of plastic reaching the mouth of the Indus, nearly 10,000 tonnes makes its way to harm coastal and marine life. An estimated 624,200 tonnes of plastic is being produced annually in Pakistan, home to some 6, 000 plastic products’ manufacturers. The Indus River contributes 164,332 tonnes of plastic waste (to the sea) annually. The River Indus delivers around 10,000 tonnes of macro-plastics to the Arabian Sea each year, according to a World Bank survey made available on Saturday.
There is a need to take urgent steps to save the mighty Indus River from pollution as the Indus River System is a major source of life in Pakistan. The Indus River contributes towards 25% of the country’s gross domestic product, providing water for almost 90% of the food production in Pakistan.