Water covers over two-thirds of Planet Earth and without it, life will not be possible. Pollution of water results when contaminants accumulate inside it at a rate faster than the rate at water can cleanse itself naturally. The ability of water to dissolve most solids and liquids is a major reason for its quick adulteration. Groundwater pollution is a more serious concern because unlike surface water it cannot be purified unless extracted.
Indicators of Water Pollution
Chemical and biological indicators are used for such measurement of the level of water pollution. Chemical Oxygen Demand (COD) determines if the concentration of chemicals, which cannot be biologically oxidised, in water is above the danger mark.
Biological Oxygen Demand (BOD) indicates the amount of dissolved oxygen (in milligrams) per litre of water. Greater the BOD, more is the pollution because greater concentrations of microbes have depleted dissolved oxygen.
Liquid, gaseous, and solid wastes from industries, automobiles, households, and farms are all responsible for infecting water.
Industrial discharges include:
- Untreated Waste Water i.e. water with dissolved harmful chemicals discharged directly into water bodies. It can also percolate and infect groundwater
- Oil Spills from Oil Rigs
- Thermal Pollution is the increase in temperature of water bodies when high temperature effluents are discharged
Transport can trigger water pollution as:
- Oil Spills and Leakages from Marine Tankers
- Vehicular Leakage of fuel, oils and other fluids percolating and being washed into water bodies
Chemicals such as phenols, oil, petrol, plastics, radioactive waste, garbage, lead, and mercury are the worst infectors.
Industrial Agriculture uses large doses of chemical fertilisers and pesticides that run off into surface water bodies and percolate in groundwater.
Domestic sewage and garbage accumulated on landfills can pollute surface as well as groundwater.
Species outside their natural habitat such as algae varieties in the Mediterranean have destroyed local aquatic life and created an imbalance
Flow of synthetic sediments such as construction debris, powders, soil, and rock destroy aquatic life while disruption of flow of natural sediments and chemicals into sea by dams reduces the flow of natural silts and chemicals causing coastal erosion and depletion of marine life in coastal regions.
- Water Borne Diseases such as typhoid, diarrhoea, and cholera spread as safe drinking water becomes an endangered commodity
- Harmful Algal Boom that thrive on sewage and chemicals in water bodies. These suck up oxygen from water making it difficult for native aquatic species to breathe. A dead zone where no aquatic species can survive can result as aquatic balance is disturbed. All chemical discharges, oil spills, and acid rains aid this process
- Entry of Toxins in the Food Chain through use of polluted water for farming and consumption of contaminated seafood can lead to reproductive failure in humans and wildlife, cancer, heart and kidney disease, and nervous disorders in children and foetus
- Land Pollution as land is infected with chemicals dissolved in water
- Acid Rains results from gaseous industrial and vehicular discharges getting dissolved in atmospheric moisture and condensing
- Floods from accumulation of solid wastes in river channels
- Thermal Pollution increases the BOD and species shift to cooler regions and disturb the natural balance in the destination area
The Path Ahead . . .
River valleys have always been cradles of civilisations while oceans have brought prosperity through resources and trade. Humans have, however, taken nature for granted and invited civilisational destruction. We will be condemned to repeat history unless we implement:
- Scientific Treatment of Discharges such as waste water, sewage, and garbage through sewage treatment plants, biomass processors etc.
- Use of Biodegradable Materials
- Reduce Consumption will decrease the amount of chemicals used for their production
- Soil Conservation to prevent unnatural disintegration of land and its flow into water bodies
- Prevent Obstruction of Natural Channels of Water