WATER POLLUTION

WATER POLLUTION

Water pollution occurs when harmful substances—often chemicals or microorganisms contaminate a stream, river, lake, ocean, aquifer, or other body of water, degrading water quality and rendering it toxic to humans or the environment. 

 

Causes of Water Pollution

Water is uniquely vulnerable to pollution. Known as a “universal solvent,” water is able to dissolve more substances than any other liquid on earth. It’s also why water is so easily polluted. Toxic substances from farms, towns, and factories readily dissolve into and mix with it, causing water pollution.

Categories of Water Pollution

1. Groundwater pollution

When rain falls and seeps deep into the earth, filling the cracks, crevices, and porous spaces of an aquifer, it becomes groundwater, one of our least visible but most important natural resources. Groundwater gets polluted when contaminants from pesticides and fertilizers to waste leached from landfills and septic systems to make their way into an aquifer, rendering it unsafe for human use.

2. Surface water pollution

Covering about 70 percent of the earth, surface water is what fills our oceans, lakes, rivers, and ponds all over the world map. Nutrient pollution, which includes nitrates and phosphates, is the leading type of contamination in these freshwater sources. While plants and animals need these nutrients to grow, they have become a major pollutant due to farm waste and fertilizer runoff. Municipal and industrial waste discharges contribute their fair share of toxins as well.

3. Point source pollution

When contamination originates from a single source, it’s called point source pollution. Examples include wastewater discharged legally or illegally by a manufacturer, oil refinery, or wastewater treatment facility, as well as contamination from leaking septic systems, chemical and oil spills, and illegal dumping.

3. Non-point source pollution

Non-point source pollution is contamination derived from diffuse sources. These may include agricultural or storm water runoff or debris blown into waterways from land.

4. Transboundary pollution

Transboundary pollution is the result of contaminated water from one country spilling into the waters of another. Contamination can result from a disaster—like an oil spill—or the slow, downriver creep of industrial, agricultural, or municipal discharge.                                                             

Types of Water Contamination

1. Agricultural

Not only is the agricultural sector the biggest consumer of global freshwater resources, with farming and livestock production using about 70 percent of the earth’s surface water supplies, but it’s also a serious water polluter. Around the world, agriculture is the leading cause of water degradation. It’s also a major contributor of contamination to estuaries and groundwater. Every time it rains, fertilizers, pesticides, and animal waste from farms and livestock operations wash nutrients and pathogens, such bacteria and viruses into our waterways.

2. Sewage and wastewater

Used water is wastewater. It comes from our sinks, showers, and toilets (think sewage) and from commercial, industrial, and agricultural activities (think metals, solvents, and toxic sludge). The term also includes storm water runoff, which occurs when rainfall carries road salts, oil, grease, chemicals, and debris from impermeable surfaces into our waterways.

3. Oil pollution

Oceans are polluted by oil on a daily basis from oil spills, routine shipping, run-offs and dumping. Vast majority of oil pollution in our seas, including oil and gasoline that drips from millions of cars and trucks, every day. Moreover, nearly half of the estimated 1 million tons of oil each year comes not from tanker spills but from land-based sources such as factories, farms, and cities.

4. Chemical waste

Detergents are relatively mild substances. At the opposite end of the spectrum are highly toxic chemicals such as polychlorinated biphenyls (PCBs).The best known example of heavy metal pollution in the oceans took place in 1938 when a Japanese factory discharged a significant amount of mercury metal into Minamata Bay, contaminating the fish stocks there. It took a decade for the problem to come to light.

5. Radioactive substances

Radioactive waste is any pollution that emits radiation beyond what is naturally released by the environment. It’s generated by uranium mining, nuclear power plants, and the production and testing of military weapons, as well as by universities and hospitals that use radioactive materials for research and medicine. At high enough concentrations it can kill; in lower concentrations it can cause cancers and other illnesses. The biggest sources of radioactive pollution in Europe are two factories that reprocess waste fuel from nuclear power plants: Sellafield on the north-west coast of Britain and Cap La Hague on the north coast of France. Both discharge radioactive waste water into the sea, which ocean currents then carry around the world. Countries such as Norway, which lie downstream from Britain, receive significant doses of radioactive pollution from Sellafield. The Norwegian government has repeatedly complained that Sellafield has increased radiation levels along its coast by 6–10 times.

Effects of Water Pollution

1. On human health 

· Water pollution caused 1.8 million deaths in 2015, according to a study published in The Lancet. Contaminated water can also make us ill. Every year, unsafe water sickens about 1 billion people.Waterborne pathogens, in the form of disease-causing bacteria and viruses from human and animal waste, are a major cause of illness from contaminated drinking water. Even swimming can pose a risk. Every year, 3.5 million people contract health issues such as skin rashes, pinkeye, respiratory infections, and hepatitis from sewage-laden coastal waters, according to EPA estimates.

2. On the environment

When water pollution causes an algal bloom in a lake or marine environment, the proliferation of newly introduced nutrients stimulates plant and algae growth, which in turn reduces oxygen levels in the water. This dearth of oxygen, known as eutrophication, suffocates plants and animals and can create “dead zones,” where waters are essentially devoid of life. In certain cases, these harmful algal blooms can also produce neurotoxins that affect wildlife, from whales to sea turtles. Chemicals and heavy metals from industrial and municipal wastewater contaminate waterways as well. These contaminants are toxic to aquatic life most often reducing an organism’s life span and ability to reproduce and make their way up the food chain as predator eats prey. That’s how fish accumulate high quantities of toxins, such as mercury.

Prevention of  Water Pollution

Some other ways to prevent water pollution are following:

• Making people aware of the problem is the first step to solving it. In the early 1990s, when surfers in Britain grew tired of catching illnesses from water polluted with sewage, they formed a group called Surfers against Sewage to force governments and water companies to clean up their act.
• Environmental laws can make it tougher for people to pollute, but to be really effective they have to operate across national and international borders.
• we have international laws governing the oceans, such as the 1982 UN Convention on the Law of the Sea (signed by over 120 nations), the 1972 London (Dumping) Convention, the 1978 MARPOL International Convention for the Prevention of Pollution from Ships, and the 1998 OSPAR Convention for the Protection of the Marine Environment of the North East Atlantic.
• Most environmental experts agree that the best way to tackle pollution is through something called the polluter pays principle. This means that whoever causes pollution should have to pay to clean it up, one way or another.
• Reduce your plastic consumption and reuse or recycle plastic when you can.
• Properly dispose of chemical cleaners, oils, and non-biodegradable items to keep them from ending up down the drain.