This is the water quality indicators page. This page acts as an introduction to each of the
water quality indicators. After a review of each indicator, you should
have an understanding of their importance to water quality. If you have not already noticed, there are several water quality indicators presented on this website. From this page you should go to one or all of the indicators page. You may find that some indicators are better
in their ability to measure water quality than others and that is expected.
It is for this reason that you are going to create a logarithm by
creating a system of metrics (Step 4 of the
Analytical Hierarchy Processes) and weights (see
Step 5 of the
Analytical Hierarchy Process). You can click the links at the
beginning of each paragraph to go to an indicator page. You will find as you go through each page that many of the indicators are codependent (especially the nutrient indicators--nitrogen compounds, dissolved oxygen, total phosphorous). For this reason you should not just look at one indicator but evaluate each of them for their importance with respect to the other.
A measurement of total phosphorus includes all forms
of phosphorus. Phosphorus that is attached to other particles suspended in the water is not soluble and is “particulate” in nature. The primary source of particulate phosphorus is soil loss or erosion from the land. Total phosphorus is often a problem in agricultural watersheds because total phosphorus concentrations for eutrophication control are an order of magnitude lower than those typically measured in soils used to grow crops (0.2-0.3 mg/l).
Monitoring studies conducted at national and state levels show that nitrogen (N) concentrations in groundwater exceed health standards more often than other common contaminants, such as pesticides. A nationwide survey conducted by EPA showed that 1.2 percent of community and 2.4 percent of private drinking water wells exceeded the 10 parts per million (ppm) nitrate-nitrogen (NO3-N) standard. Nitrogen is a nutrient that can encourage the growth of nuisance aquatic plants. These plants can choke up waterways and out-compete native species. High levels of nitrogen in water can be a result of runoff and leaching from agricultural land. Ideally, total nitrogen levels in water should be less than 0.5 grams per cubic meter to prevent excessive growth of nuisance plants. This project broke Nitrogenous Compounds into Ammonia Nitrogen, Total kjeldahl nitrogen (organic nitrogen plus ammonia), and Nitrate/Nitrite. From these measurements, the concentrations of organic nitrogen and of total nitrogen (comprising oxidized nitrogen, organic nitrogen and ammonia) are determined.
Arsenic is one of the most prevalent contaminants of health concern in drinking water, and is present in the tap water of over 12 million Americans at a concentration above 10 ppb. Studies have linked long-term exposure to arsenic in drinking water to cancer of the bladder, lungs, skin, kidney, nasal passages, liver, and prostate.
Dissolved oxygen is absolutely essential for the survival of all aquatic organisms ( not only fish but also invertebrates such as crabs, clams, zooplankton, etc). Moreover, oxygen affects a vast number of other water indicators, not only biochemical but esthetic ones like the odor, clarity and taste. Consequently, oxygen is perhaps the most well-established indicator of water quality.
Fecal coliforms are bacteria that live in the digestive tract of warm-blooded animals and are excreted via feces. In themselves, fecal coliforms generally do not pose a danger to people or animals but they indicate the presence of other disease-causing bacteria such as those that cause typhoid, dysentery, hepatitis, and cholera.
The next step is to click on one of the indicators above to go to an indicators webpage for a more in detail description of each indicator. The nitrogenous compounds link is an umbrella site that is divided up into three more sites. It may appear to the reader that this is becoming very complicated. This complication represents the complex nature of the AHD process. I urge you to continue on and then return from where you came to re-evaluate each attribute and sub-attribute as a part of the AHD process.