The most water polluting sectors

Water pollution is the contamination of water bodies. These water bodies can include lakes, rivers, groundwater, oceans, etc. Water pollution occurs when unfiltered wastewater is released into the water system, or when water systems merely become a waste dumping ground for unscrupulous parties. Considering the amount of biodiversity found in the various water systems on earth, the effects of water pollution may cause a domino effect in the water ecosystem.   

There are three sources where water pollution can occur; point sources, where the water pollution occurs from a single source that is easily identifiable, like ditches and pipes. Non-point source pollution is the cumulative effect that occurs after small amounts of contaminants from various sources gather in one area. The source is discrete and not easily identifiable. Groundwater contamination occurs when non-surface water sources are indirectly impacted by external pollutants via seepage.   

Some of the sectors that are the most water-polluting are listed below:  

1.  Small and large industries - A lot of industries produce a high amount of industrial waste which is not disposed of properly. A lot of these wastes contain toxic pollutants that are very damaging to the environment. Some industries do not filter out their waste properly, and as a consequence, the unfiltered waste gets into the waterways, increasing the amount of nutrients which leads to the eutrophication of the water body the waste is released into, causing algal blooms. This in turn can reduce the amount of dissolved oxygen in the water, which then affects the temperature of the water, the biodiversity of the organism, and the overall water quality index.   
2.  Sewage - In many households, the wastewater and sewage that is expelled are chemically saturated, which are then released into the sea. Besides carrying toxic chemicals, the sewage water is also home to many bacteria and pathogens. These can infect many water-dwelling flora and fauna, which can then act as carriers, infecting other organisms that come into contact or ingest them. One example is the cycle of infection of tapeworm, which is found in raw or undercooked fish, and these parasites complete their life cycle in the human intestines and bowels, passing out in human excreta. When wastewater is not treated properly, the tapeworm larvae will then use fish as intermediate hosts until the fish is ingested.   
3.  Agriculture - Many modern farmlands these days encourage the robust growth of their produce by means of chemical fertilizers and pesticides. While they are great to boost the fitness of the plants, the over use of these products often result in the excess being mixed up in rainwater, resulting in chemical runoffs that affect waterways. When the runoff pollutes the waterways, these chemicals harm the aquatic biota, leading to a loss of biodiversity and eutrophication.   

There are many efforts being made, both locally and internationally, to keep Earth’s water systems clean. However, the reality of the situation is severe, and it takes the conscious effort of the collective community to keep our waterways clean. Currently, scientists have found many parts of the Australian Great Barrier Reef dead, which is a big blow to the environmental fitness of Earth. If an effort is not made right now to stop polluting our waterways, we may be observing the collapse of the ecosystem on a large scale in the not too distant future.