Pollution of the Cauvery River, India

Problems

• Problems Facing the Kaveri River

  The Cauvery River is one of the major rivers in South India, originating from Talakaveri in Karnataka and flowing through Tamil Nadu before joining the Bay of Bengal. The river is a source of water for irrigation, drinking, power generation, and tourism for millions of people. However, the river is also facing severe threats from various sources of pollution that affect its water quality and ecosystem.
  
  Causes of water pollution in the Cauvery River:
  • Sewage and Wastewater Pollution
  One of the most pressing issues facing the Kaveri River is the rampant sewage and wastewater pollution. With rapidly growing urban centers like Bangalore, a significant portion of untreated sewage flows into the river, exacerbating water quality issues. 
  
  According to recent reports, Bangalore alone generates around 1,800 million liters of sewage per day, but less than half of it is treated. The untreated wastewater contains harmful pathogens, heavy metals, and chemicals that reduce oxygen levels in the water, making it unfit for consumption. 
  
  The presence of high Biochemical Oxygen Demand (BOD) and Chemical Oxygen Demand (COD) values further indicates the severity of pollution. The Kaveri, which once provided freshwater for agriculture, is now struggling to support the same due to this pollution.
  
  • Solid Waste Dumping
  In addition to sewage, the Kaveri faces the dumping of solid waste. Plastic waste, construction debris, household garbage, and other non-biodegradable materials are regularly discarded into the river, especially in urban areas. 
  
  In cities like Mysore, the increase in population has resulted in an alarming amount of waste being dumped into the river. A recent survey found that approximately 50 tons of solid waste is dumped into the Kaveri River every day. 
  
  This waste not only contaminates the water but also obstructs the natural flow of the river, leading to stagnation and further degradation of the ecosystem.
  
  • Water Quality Degradation
  The degradation of water quality is one of the most visible impacts of pollution in the Kaveri. Dissolved Oxygen (DO) levels in the river have drastically dropped, which is detrimental to aquatic life. 
  
  In many places, heavy metals like lead, mercury, and cadmium are present in concentrations that exceed permissible limits, further harming the water’s integrity. 
  
  The river’s once clear waters are now murky, with signs of algal blooms and foul odors. This degraded water quality not only affects the biodiversity of the river but also poses significant health risks to the millions who depend on the Kaveri for drinking and irrigation.
  
  • Loss of Biodiversity
  The biodiversity of the Kaveri River has been severely impacted by pollution, over-exploitation, and habitat destruction. Historically, the river was home to a wide variety of aquatic species, including fish like the Indian major carps and the Mahseer. 
  
  However, due to pollution and the introduction of invasive species, the number of native species has drastically declined. According to a study by the Indian Council of Agricultural Research, the diversity of aquatic species in the Kaveri has reduced by over 40% in recent decades. 
  
  The loss of these species not only diminishes the ecological value of the river but also affects local communities that rely on fishing as a primary livelihood.
  
  • Riverbank Encroachment
  Urbanization along the Kaveri has led to significant riverbank encroachment. Slums, illegal constructions, and waste dumping sites have emerged along the riverbanks, contributing to both physical and environmental degradation. 
  
  • Groundwater Contamination
  The pollution in the Kaveri River also has indirect effects, such as groundwater contamination. The leaching of pollutants from the river into the surrounding groundwater aquifers has been a major concern. 
  
  According to the Central Ground Water Board (CGWB), regions along the Kaveri, particularly near Bangalore and Mysore, have reported elevated levels of nitrates and heavy metals in groundwater, which pose a significant risk to drinking water safety. 
  
  The contamination of groundwater sources further exacerbates the water crisis in these areas, making it more difficult for residents to access clean and safe water.

• Microplastic pollutants in the Cauvery River

  Microplastics, industrial and agricultural waste being dumped into the Cauvery are causing hypoxic conditions in the river’s waters, harming marine life.
  Microplastics are small pieces of plastic, less than 5 mm (0.2 inches) in length, that occur in the environment as a consequence of plastic pollution.
  
  Microplastics are present in a variety of products, from cosmetics to synthetic clothing to plastic bags and bottles. Many of these products readily enter the environment in waste.
  They can be classified into two categories based on their origin-
  Primary microplastics: include microbeads found in personal care products, plastic pellets (or nurdles) used in industrial manufacturing, and plastic fibers used in synthetic textiles (e.g., nylon).
  Secondary microplastics originate from the breakdown of larger plastics. Plastic bottles, bags, fishing nets, and food packaging are some examples of the larger pieces that break down into microplastics, eventually finding their way into the soil, water, and the air we breathe.
  
  Microplastics are found in several household and industrial products, and chemicals containing the cyclohexyl group, such as cyclohexyl isocyanate, are commonly used in agriculture and the pharmaceutical industry.
  
  Microplastics and other pollutants may be causing growth defects and skeletal deformities in fish inhabiting the Cauvery River, a study led by researchers from the Indian Institute of Science (IISc), Bengaluru, has found.
  
  The researchers analysed water samples from the river for levels of pollutants and studied their microplastic composition. They then studied embryos of zebrafish incubated in these samples in the lab and found them to have growth and skeletal deformities, reduced heart rate, reduced life span, and DNA damage.
  
  The damage was attributed to molecules called Reactive Oxygen Species (ROS), which are highly reactive chemicals derived from oxygen molecules, in the cells of the fish.
  In water, microplastics can enter fish and other organisms, and in turn, pass higher up the food chain, even ending up on human plates. In animals, they can cause a range of damage to cells and DNA, affecting ecosystems across the world.

• Impacts of microplastic pollution оn health

  Human exposure to microplastics is to come from airborne dust, drinking water (including treated tap water and bottled water)
  Microplastics can reach our stomach, where they can either be excreted, get entrapped in the stomach and intestinal lining, or move freely in body fluids such as blood, thereby reaching various organs and tissues of the body.
  Negatively affects the nervous system, hormones, immune system and has cancer-inducing properties.
  
  On marine organisms, when consumed, microplastics are stuck in their digestive tracts and also alter their feeding behavior.
  Accumulation of toxic plastics in the stomach leads to starvation and death, resulting in reduced growth and reproductive outputs.
  Magnify marine pollution: by acting as a binding and transporting agent for heavy metals and organic pollutants because of its water-repellent properties.

• Pollution of the Cauvery River with pharmaceutically active compounds

  According to a two-year study by the Indian Institute of Technology Madras (IIT-M), the Cauvery River water is polluted by a range of emerging contaminants, including pharmaceutically active compounds.
  These contaminants are discharged into the river from untreated or partially treated sewage.
  
  The study found that the levels of pharmaceutical contaminants in the river water were extraordinarily high, posing a medium to high risk to aquatic lifeforms.
  
  When released even in minuscule amounts into water bodies, these drug compounds can harm human beings and the ecosystem in the long run. The study also found significant contamination by metals such as arsenic, zinc, chromium, lead, and nickel, which can cause various health problems.
  
  Seasonal variations influenced the water quality and levels of contaminants in the Cauvery River. The post-monsoon period showed increased pollutants due to reduced riverine flow and continuous waste discharge from multiple sources. The study suggested a need to upgrade wastewater treatment systems and implement strict regulations to reduce the levels of contaminants in the river. Abnormal levels of sodium can lead to hypertension and reproductive toxicity in humans.

• Public Health Risks

  One of the most immediate and severe consequences of the neglect of the Kaveri River is the rise in public health risks. Contaminated water, coupled with untreated sewage and waste, leads to the proliferation of waterborne diseases such as cholera, dysentery, and typhoid. 
  
  According to the World Health Organization (WHO), unsafe water contributes to around 3.4 million deaths annually worldwide. In areas around the Kaveri River, particularly in urban centers like Bangalore and Mysore, the lack of proper water treatment and sanitation systems has significantly contributed to the spread of diseases. 
  
  A report by the Karnataka Health and Family Welfare Department found a steady increase in waterborne illnesses linked directly to the river’s contamination, highlighting the urgent need for intervention to protect public health.