Water Pollution Diseases
According to some estimates, every year a few million Americans are made ill by polluted water. Water pollution involves the pollution of surface waters and/or groundwater, which may cause a series of diseases referred to as water pollution diseases. These could have serious health impacts. While we can control (to some extent) the water we drink, the pollution of our water streams may have long-term effects by reducing the “drinkable” water reserves of our planet. Additionally, the common filtration methods for water are not efficient for some of the new emerging contaminants – which are often not even tested for contaminants. Water pollution travels slower than air pollution but still may affect large areas.
Water may commonly be polluted by two main categories of pollutants (dissolved or suspended in water):
- Chemicals – including natural or man-made (xenobiotic) chemicals that gets into a water body (by being dissolved or dispersed in the water) and reaching concentrations that raise serious health concerns; note that, similar to the case of air pollutants, the presence of such pollutants in water is not always obvious and may not be detected by our senses. Common problematic chemicals getting into water are pesticides, chlorinated solvents, petroleum chemicals, mercury, PCBs, dioxins and other persisting organic pollutants; as well as any of the other tens of thousands of chemicals used in industrial processes.
- Living organisms (as long as they are induced by human activity; please note that some waters unaffected by human activity may still be naturally polluted with some of these organisms – in which case, the caused diseases may not be seen as pollution diseases):
- Pathogens – including a variety of living organisms (usually from animal waste) such as various species of viruses, bacteria, fungi and intestinal worms. Their presence in water, many times, remains unnoticed.
- Algae – some types of algae are toxic and may overgrow due to the presence of nitrates and phosphates in runoff water (especially agricultural runoff); such overgrowth is usually referred to as “red tides” or “brown tides”. Their toxins may affect the food chain, including fish and birds, and ultimately humans. Oxygen depletion in polluted water is another serious problem responsible for killing fish all over the world.
While the most common water pollution diseases involve poisoning episodes affecting the digestive system and/or causing human infectious diseases, water pollution may cause a large variety of health diseases including:
- Infectious diseases caused by pathogens (usually microorganisms) from animal fecal origins, of which the most common occur in developing countries, including:
- Diseases caused by polluted beach water, including:
- Stomach cramps and aches
- Respiratory infections
- Liver damage and even cancer (due to DNA damage) – caused by a series of chemicals (e.g., chlorinated solvents, MTBE)
- Kidney damage caused by a series of chemicals
- Neurological problems - damage to the nervous system – usually due to the presence of chemicals such as pesticides (e.g. DDT)
- Reproductive and endocrine damage including interrupted sexual development, inability to breed, degraded immune function, decreased fertility and increase in some types of cancers – caused by a series of chemicals including endocrine disruptors
- Thyroid system disorders (a common cause is exposure to perchlorate, which is a chemical contaminating large water bodies such as the Colorado River)
- Increased water pollution creates breeding grounds for malaria-carrying mosquitoes, which kill 1.2-2.7 million people a year
- A series of less serious health effects could be associated to bathing in contaminated water (i.e. polluted beach water) including:
- Pink eyes
Water pollution can affect us:
- Directly – through consumption or bathing in a polluted stream (such as consumption of municipal water, as well as bathing in polluted lakes or beach water).
- Indirectly – through the consumption of vegetables irrigated with contaminated water, as well as of fish or other animals that live in the polluted water or consume animals grown in the polluted water. This is many times more dangerous than being directly affected through consumption of water, because some pollutants bioaccumulate in fish and living organisms (their concentration in fish could be several orders of magnitude higher than their water concentration). Additionally, the toxins from the brown tide are strong and can travel via air, affecting homeowners close to the beach.
The most common ways of polluting the water include:
- Waste disposal:
- directly into water streams
- onto the soil from which contaminants may leak into the groundwater below
- Urban and agricultural runoff;
- Animal waste could also add dangerous pathogens (usually microbial groups, viruses and intestinal parasites) into the water;
- From air via acid rain - water can get polluted with air contaminants (that have sometimes traveled long distances – such as the case of Hg) that reach the land and water via acid rain. During precipitation, air pollutants may get dissolved in the water drops and, as a result, they may acidify the water - which is why polluted rainwater is referred to as “acid rain”.
According to a Cornell University study, water pollution accounts for 80% of all infectious diseases. According to the same study, unsanitary living conditions account for more than 5 million deaths a year!