Water quality

Water quality refers to the chemical, physical, biological, and radiological characteristics of water. It is a measure of the condition of water relative to the requirements of one or more biotic species and or to any human need or purpose. It is most frequently used by reference to a set of standards against which compliance can be assessed. The most common standards used to assess water quality relate to health of ecosystems, safety of human contact and drinking water.

Human Water Consumption

Our bodies are about 60 percent water [source: Mayo Clinic]. Water regulates our body temperature, moves nutrients through our cells, keeps our mucous membranes moist and flushes waste from our bodies. Our lungs are 90 percent water, our brains are 70 percent water and our blood is more than 80 percent water. Simply put, we can't function without it. Most people sweat out about two cups of water per day (0.5 liters). Each day, we also lose a little more than a cup of water (237 ml) when we exhale it, and we eliminate about six cups (1.4 l) of it. We also loseelectrolytes -- minerals like sodium and potassium that regulate the body's fluids. So how do we replace it?

We can get about 20 percent of the water we need through the food we eat. Some foods, like watermelon, are nearly 100 percent water. Although the amount of water that we need each day varies, it's usually about eight cups (2 l). But instead of worrying about getting in those eight cups, you should just drink when you start to feel thirsty. You can get your water by drinking other beverages -- but some beverages, like alcohol, can make you more dehydrated.

If your urine is dark yellow, you might not be drinking enough water. Of course, you need more water when you're exercising; ill with diarrhea, vomiting or fever; or in a hot environment for a long time. Most people can survive only a few days without water, although it depends on a number of factors, including their health and environment. Some have gone as long as two weeks. Followers of a Buddhist

boy meditating in Nepal claim that he has gone two years without food or water, but doctors have not been able to substantiate this [source: All Headline News].

When you don't get enough water, or lose too much water, you become dehydrated. Signs of mild dehydration include dry mouth, excessive thirst, dizziness, lightheadedness and weakness. If people don't get fluids at this point, they can experience severe dehydration, which can cause convulsions, rapid breathing, a weak pulse, loose skin and sunken eyes. Ultimately, dehydration can lead to heart failure and death.

Dehydration caused by diarrhea is a major cause of death in undeveloped countries. Nearly 2 million people, mostly children, die from it each year [source: WHO]. Consuming water polluted with biological contaminants and not having access to adequate sanitary facilities can lead to diseases like malaria and cholera and parasites like cryptosporidiosis and schistosomiasis. Water can be also be contaminated with chemicals, pesticides and other naturally occurring substances.

Water Quality Standards for Surface Waters

Highlights

Water Quality Standards protect uses of water bodies including streams and wetlands. Find out more about these types of waters here!

Streams

Wetlands

Water Quality Standards are the foundation of the water quality-based pollution control program mandated by the Clean Water Act. Water Quality Standards define the goals for a waterbody by designating its uses, setting criteria to protect those uses, and establishing provisions such as antidegradation policies to protect waterbodies from pollutants.

Drinking Water Standards are found elsewhere on our website.

Where You LiveRegional and state specific information.

Basic InformationThe importance of Water Quality Standards and how they fit into overall water quality protection. Fact sheet (PDF) (2 pp, 204K, About PDF)

Water Quality Standards Regulations and Federally Promulgated StandardsListing of federal water quality standards rules, Clean Water Act determinations and Paperwork Reduction Act information collection requests.

Policy & Guidance: Water Quality Standards HandbookThe Water Quality Standards Handbook is the central repository for policy and guidance to help states, tribes, & territories comply with federal regulations addressing water quality standards. If you are looking for a specific document related to water quality standards, try our Policy and Guidance Library.

ater quality monitoring is defined here as the sampling and analysis of water constituents and conditions. These may include:

Introduced pollutants, such as pesticides, metals, and oil

Constituents found naturally in water that can nevertheless be affected by human sources, such as dissolved oxygen, bacteria, and nutrients

The magnitude of their effects can be influenced by properties such as pH and temperature. For example, temperature influences the quantity of dissolved oxygen that water is able to contain, and pH affects the toxicity of ammonia.

Volunteers, as well as state and local water quality professionals, have been monitoring water quality conditions for many years. In fact, until the past decade or so (when biological monitoring protocols were developed and began to take hold), water quality monitoring was generally considered the primary way of identifying water pollution problems. Today, professional water quality specialists and volunteer program coordinators alike are moving toward approaches that combine chemical, physical, and biological monitoring methods to achieve the best picture of water quality conditions.

Water quality monitoring can be used for many purposes:

To identify whether waters are meeting designated uses. All states have established specific criteria (limits on pollutants) identifying what concentrations of chemical pollutants are allowable in their waters. When chemical pollutants exceed maximum or minimum allowable concentrations, waters might no longer be able to support the beneficial uses such as fishing, swimming, and drinking for which they have been designated. Designated uses and the specific criteria that protect them (along with antidegradation statements say waters should not be allowed to deteriorate below existing or anticipated uses) together form water quality standards. State water quality professionals assess water quality by comparing the concentrations of chemical pollutants found in streams to the criteria in the state's standards, and so judge whether streams are meeting their designated uses. Water quality monitoring, however, might be inadequate for determining whether aquatic life uses are being met in a stream. While some constituents (such as dissolved oxygen and temperature) are important to maintaining healthy fish and aquatic insect populations, other factors, such as the physical structure of the stream and the condition of the habitat, play an equal or greater role. Biological monitoring methods (see Chapter 4) are generally better suited to determining whether aquatic life is supported.

To identify specific pollutants and sources of pollution. Water quality monitoring helps link sources of pollution to a stream quality problem because it identifies specific problem pollutants. Since certain activities tend to generate certain pollutants (e.g., bacteria and nutrients are more likely to come from an animal feedlot than an automotive repair shop), a tentative link might be made that would warrant further investigation or monitoring.

To determine trends. Chemical constituents that are properly monitored (i.e., consistent time of day and on a regular basis, using consistent methods) can be analyzed for trends over time.

To screen for impairment. Finding excessive levels of one or more chemical constituents can serve as an early warning "screen" of potential pollution problems.

Designing a water quality monitoring program

The first step in designing a water quality monitoring program is to determine the purpose of the monitoring. This will help you select which parameters to monitor. The program steering committee should make this decision based on factors such as:

Types of water quality problems and pollution sources that will likely be encountered (Table 5.1)

Cost of available monitoring equipment

Precision and accuracy of available monitoring equipment

Capabilities of the volunteers

Chemical analysis

The simplest methods of chemical analysis are those measuring chemical elements without respect to their form. Elemental analysis for oxygen, as an example, would indicate a concentration of 890,000 milligrams per litre (mg/L) of water sample because water is made of oxygen. The method selected to measure dissolved oxygen should differentiate between diatomicoxygen and oxygen combined with other elements. The comparative simplicity of elemental analysis has produced a large amount of sample data and water quality criteria for elements sometimes identified as heavy metals. Water analysis for heavy metals must consider soil particles suspended in the water sample. These suspended soil particles may contain measurable amounts of metal. Although the particles are not dissolved in the water, they may be consumed by people drinking the water. Adding acid to a water sample to prevent loss of dissolved metals

onto the sample container may dissolve more metals from suspended soil particles. Filtration of soil particles from the water sample before acid addition, however, may cause loss of dissolved metals onto the filter.[14] The complexities of differentiating similar organic molecules are even more challenging.

Making these complex measurements can be expensive. Because direct measurements of water quality can be expensive, ongoing monitoring programs are typically conducted by government agencies. However, there are local volunteer programs and resources available for some general assessment. Tools available to the general public include on-site test kits, commonly used for home fish tanks, and biological assessment procedures.

Technological Institute of the Philippines

363 P. Casals t. Quiapo Manila

WATER QUALITY

Assignment in

Environmental Engineering

Submitted by :

Joseph Hanzal Bulanadi