Only man can develop, and only man can destroy.
Analysis of the impairment humankind has caused to the river has been the hardest part to study in this mission. It wrenches us to see how an oppressive race vandalizes natural resources to an extent that their remediation seems impractical. Such is the harm caused to River Yamuna that even after an investment of more than 800 crores under Yamuna Action Plans I & II, the river brims with contaminants. A detailed investigation is therefore made in our project to understand the major hassle in the river’s hindered health.
Due to the deposition of immobile debris, choking plastic, clothes, etc., the river width has become narrowed. This scanty width has made banks of river Yamuna in the city the most flood-prone regions in its entire course. Multiple monsoon season statistics suggest the prevalence of flood like conditions despite little rainfall experienced in the entire course of the river.
Turbidity is seen to be increasing in the river as it proceeds into the city. With increase in the discharge of rotting pollutants from Wazirabad to Okhla barrages, the city observes an increase in the trajectory of biological demand of oxygen. As per the CPCB report in 2016 on Yamuna river, chemical oxygen demand (COD) increased from 36 ppm in Wazirabad to over 140 ppm in Okhla, suggesting a heavy increase in organic pollutants.
Massive ammoniacal froth deposits near Okhla and a severely foul smell confirms the presence of amino acids in the river. In spite of being harmful for the water body, these organic wastes are dumped by multiple sources like factories, households, religious offerings etc., and inhibit the levels of dissolved oxygen (DO) in the water. Reducing from 8.65 ppm near Palla to 0.85 ppm near Okhla, a massive decline is seen in the DO levels of the river.
Abnormally high water conductivity is noted in the river due to excessive contamination of heavy metals like Iron, Chromium, Nickel, Zinc and Lead, and ionic pollutants like sulphates, phosphates and chlorides. Increase of total dissolved solids (TDS) in water results in bioaccumulation in aquatic life which poses a major threat in their metabolic, larval growth and reproductive machinery. Passing these dangerous chemicals increases toxicity in next trophic levels of the food chain through biomagnification. It should be noted that these chemicals may be slow sedatives, carcinogenic or simply poisonous for organisms to consume. Biomagnification is observed as a serious threat in the food web of river Yamuna. Nickel, a carcinogenic metal, is accumulated in significant amounts near Okhla water. It has a high cancer causing tendency of 17.02X104, one of the highest in all metals. Studies by NCBI suggest that some fish like O. niloticus (common carp), an invasive fish in Yamuna, has shown accumulation of Nickel metal. This fish when consumed by some predatory birds like vultures, eagles and flamingos increases their chance of vulnerability.
Pharmaceutical industry outflow has increased the levels of drugs and hormones in the river. A NMCG NEERI report on Ganga basin suggested the increase of hormones like Diclofenac sodium salt, progesterone and testosterone. It further highlighted the increase in the level of drugs like paracetamol, antibiotics like chloramphenicol, tranquilizers and sedatives.
Increase in the nutrient richness has provided a medium for microbial breeding. There is a rapid increase in the levels of aerobic and anaerobic bacteria. The CPCB report 2016 mentions that the highest levels of total coliform population grew from 54 thousand MPN/L in Wazirabad to 160 million MPN/L in Okhla. The levels of faecal bacterias also experience an avalanche in the city water.
The worst hit by water quality degradation of river Yamuna are the organisms inhabited to it. Many phytoplanktons, plants, zooplanktons, fish, turtles and other organisms which are native to the river have seen a critical decline in population. The Gharial reptiles (Gavialis gangeticus) are one of the largest freshwater crocodiles in the world and River Yamuna is one of the few strongholds in the world. These reptiles are essential for the rich heritage in Yamuna. Due to the consumption of these contaminants, Gharials have endured a reduction in population. They are critically endangered species and if not taken care of, can become extinct as per the report of India environment portal. River Yamuna has been a habitat for the national aquatic animal Platanista gangetica (gangetic dolphin). As a result of massive pollution these dolphins have not been sighted since 2003 and the last dolphin seen in Delhi was in 1967. Amongst other endangered animals are Chitra indica, softhead turtles, spoonbills, etc.
Mortals are solely responsible for the miserable condition of river Yamuna and the other organisms associated with it. To coexist for a sustainable future, we need to replenish the biodiversity in the river by removing its filth. In the upcoming articles, we shall highlight the government initiatives and solutions for a sustainable future.