When we consider what the factors are that affect water quality I am often reminded of the observation made by Walt Kelly’s cartoon character Pogo to his friend Porky as they stand in a trash filled swamp – “we have met the enemy and they are us”. Though there are natural conditions that effect water quality it often appears that humans pose the greatest threat to that most essential element needed to sustain life.
According to the U.S. Geological Survey, water quality is considered “a measure of the suitability of water for a particular use based on selected physical, chemical, and biological characteristics.” Those “particular uses” consist of drinking water, recreational water, water that is safe to use for agricultural and water that sustains aquatic life. What are the factors that determine each?
The human body is about 70% water. The water within us transports nutrients and oxygen to body parts and regulates body temperature. For every pound you weigh you will need a half ounce of water to sustain your body functions and promote good health. Without potable water – water that is essentially free from pollution, harmful organisms and impurities – humans cannot endure. All drinking water has some contaminants in it like mercury, arsenic, selenium and chromium but at levels that nullify their toxicity. However, these and other natural contaminants will affect taste, smell, or clarity of water.
It is the responsibility of the 155,000 public water systems across the country to insure that the public drinking water does not exceed the EPA “action levels” for contaminants in drinking water. Factors that contribute to public drinking water supply quality are ground water washing surface contaminants like fertilizers, pesticides and organic chemicals from industrial processes or petroleum use into public storm drains and surface water supplies like lakes and reservoirs. Many of these contaminants can also affect water’s ph levels, making alkaline-weak waters more acidic.
Sewer lines that bust or septic systems that leak will seep into water supplies, affecting water quality. Climatic conditions like flooding can also contribute to water quality by inundating a system and mix sewage components and toxic chemicals with public water supplies. Certain additives actually enhance water quality, like chlorine. At very low levels chlorine safely disinfects drinking water. Supplies that are devoid of chlorine, as in most 3rd world countries, often allow water borne diseases like cholera and typhoid, killing thousands around the world on a daily rate
The EPA informs us that contaminants not previously detected in water supplies, “contaminants of emerging concern” (CECs) like pharmaceuticals and personal care products, are beginning to surface in water analyses. Each year by July 1st customers should receive an annual water quality report (Consumer Confidence Report) in an e-mail from your water supplier that tells you where your water comes from and what’s in it. The EPA’s Local Drinking Water Informationwebsite will provide this information for you if you sent that e-mail to the junk site without reading it.
Rainfall and temperatures are factors in recreational water. Public pools maintained by professional staff and kept disinfected with chlorine are usually not impacted by environmental concerns and toxic runoffs. Lakes, beaches and sporting domains for fishers and scuba divers are. Excessive heat can dry up natural sources of recreational water or rob it of oxygen and severe climate activity, like flooding, can pollute them.
Non-climatic factors that affect water quality in this category are chemical compounds that can leach into lakes and streams such as the nitrates and nitrites from fertilizers from farms and home lawns. As a natural element nitrates exists in all living organisms but when conditions are created, naturally or anthropogenically, in inordinate amounts, they effect bad health and become life-threatening. If nitrites are consumed and get into the blood stream they can react directly with hemoglobin and produce methemoglobin, which destroys the ability of blood cells to transport oxygen Ammonia is a nitrate chemical (NH3) and as a popular commercial and residential cleaning agent it gets mixed into recreational water like lakes that also serve as water supplies for public consumption.
Another friendly chemical that serves human needs can also become deadly when it exists in certain states and combines with other elements. Chlorine, in its “free” state (chlorine gas dissolved in water), can combine with decaying materials like plants and fish to form compounds called trihalomethanes or THMs, which in high concentrations are carcinogenic to humans. THMs can get absorbed through the skin when we unknowingly swim in natural bodies of recreational water with high concentrations of this chemical compound.
Alkalinity, a total measure of the substances in water that have “acid-neutralizing” ability, will determine water’s ph balance. The alkalinity of a body of water like a lake can be determined by the local minerals that reach it. Limestone is rich in carbonates so water that flows over limestone and reaches this body of water gives it greater ability to buffer high acid levels. Conversely, granite-filtered water has the opposite effect. Rivers and streams with poor alkalinity can allow high levels of acid to form, making it uninhabitable for fish and thus negatively impacting recreational and sport fishing.
Finding adequate uncontaminated water resources for agricultural processes is becoming more and more difficult as agribusinesses compete with urban needs for dwindling water resources. According to the World Bank’s Developmental Education Program, “agriculture consumes 60 to 80 percent of the fresh water resources in most countries”. In areas that suffer frequent drought conditions, resources are stretched even more often pitting the forces that need water for basic human consumption and those that needed it to sustain them economically.
Ironically, water that can be harmful for agricultural purposes is generated by the use of agricultural nitrogen-based fertilizers. As rainfalls wash this necessity for crop production into streams and river basins it contaminates water that farmers require for their livelihood. It can also leach into well water used for drinking and as mentioned above can cause methemoglobin, which when consumed by infants can poison them since they are more susceptible to the adverse affects of this condition. Factors that can alter agricultural water for the good would be to employ practices that use more natural means of fertilizers like manure from the factory meat farms, reduce their dependency on pesticides and get away from single cash crops that allow for easier erosion from over plowing the soils.
WATER THAT SUSTAINS AQUATIC LIFE
Of all the factors that impact water quality for humans mentioned earlier, it is dealt out in spades for marine life. Perhaps the best case that can be made for this is one of the world’s largest “dead zones” at the mouth of the Mississippi River. Stretching nearly 7000 square miles along the continental shelf from Louisiana to the northern coast of Texas are vast pockets of water made uninhabitable due to the run-off of every chemical man leaves exposed to the elements.
The branch lines that feed the Mississippi run as far north as Minnesota and as far east and west as Pennsylvania and Montana. Along this water system are a multitude of businesses, agricultural and commercial, along with residential developments that dump hazardous waste into them every single day. It all wounds up where the mighty Mississippi feeds into the Gulf of Mexico. The nitrates from fertilizers along with carbon-based petro-chemicals over-burden the eco-systems in this area. Oxygen becomes depleted, killing many bottom dwellers like shrimp, oysters and crabs that are least likely to escape these adverse conditions. Industrial waste products also affect the alkalinity of these waters, offsetting the ph balance needed to sustain life there.
Climate conditions can also be a detrimental factor to water quality as rivers flood and wash over more land covered with pesticides and herbicides that ultimately flow into estuaries and marshes that produce high levels of aquatic life that many fishermen rely on for their livelihoods. Hurricanes, earthquakes and tornadoes can damage man-made water supplies by destroying pipes and storage facilities that move and store potable water and keep it separate from sewage. As this occurs it spills into rivers, lakes and ocean habitats where marine life dwells.
As populations increase along with the demand to sustain quality water supplies, the need for people to re-think how they take water for granted will need to change. Clearly we must end those practices that threaten our water resources or find ways to counter act them without adding to the problem. Conscientious people in private and public sectors must work to educate the general public about the severity we face with adequate H2O resources for the future. The prospect that renewable energy sources brings with it is one area of focus that can benefit this effort but we must get past our dependency on fossil fuels to achieve this.
A primer on water quality
Important Water Quality Factors