YSI has been in the water quality business for decades (65+ years), and because of our instruments, and instruments like ours, professionals all over the world have been able to monitor the quality of their water. With this being said, it is apparent that water quality concerns have changed over the years and will continue to change over time.
The quality of any body of surface or groundwater is a function of either both natural influences and human influences.
Without human influences water quality would be determined by the weathering of bedrock minerals, by the atmospheric processes of evapotranspiration and the deposition of dust and salt by wind, by the natural leaching of organic matter and nutrients from soil, by hydrological factors that lead to runoff, and by biological processes within the aquatic environment that can alter the physical and chemical composition of water.
Typically, water quality is determined by comparing the physical and chemical characteristics of a water sample with water quality guidelines or standards. Drinking water quality guidelines and standards are designed to enable the provision of clean and safe water for human consumption, thereby protecting human health. These are usually based on scientifically assessed acceptable levels of toxicity to either humans or aquatic organisms.
Declining Water Quality
Declining water quality has become a global issue of concern as human populations grow, industrial and agricultural activities expand, and climate change threatens to cause major alterations to the hydrological cycle.
Globally, the most prevalent water quality problem is eutrophication, a result of high-nutrient loads (mainly phosphorus and nitrogen), which substantially impairs beneficial uses of water. Major nutrient sources include agricultural runoff, domestic sewage (also a source of microbial pollution), industrial effluents and atmospheric inputs from fossil fuel burning and bush fires. Lakes and reservoirs are particularly susceptible to the negative impacts of eutrophication because of their complex dynamics, relatively longer water residence times and their role as an integrating sink for pollutants from their drainage basins. Nitrogen concentrations exceeding 5 milligrams per litre of water often indicate pollution from human and animal waste or fertilizer runoff from agricultural areas.
An emerging water quality concern is the impact of personal care products and pharmaceuticals, such as birth control pills, painkillers and antibiotics, on aquatic ecosystems. Little is known about their long-term human or ecosystem impacts, although some are believed to mimic natural hormones in humans and other species.
Poor water quality has a direct impact on water quantity in a number of ways. Polluted water that cannot be used for drinking, bathing, industry or agriculture effectively reduces the amount of useable water within a given a area.
It is safe to say water quality is always changing, and monitoring these changes and reacting to them appropriately is a necessity. YSI has a passion to keep providing the best in class water monitoring instrumentation to meet those needs, and that is something that will never change.
Sources: Policy Brief on Water Quality. UN-Water, March 2011 Water Quality for Ecosystems and Human Health. 2nd edition. UNEP, ERCE, UNESCO. 2008 World Water Development Report 3 'Water in a Changing World'. WWAP, 2009 Vital Water Graphics. UNEP
Additional Blog Posts of Interest:
Oregon's Tualatin River: America's Early TMDL Case Study
Lakes Recovering from Acid Rain | Water Quality Improvements Are Proof
Watershed Partnership Addresses Concerns in a Rural Watershed
Southeastern Estuarine Research Society Meeting fDOM Sensor Research