The pollutants at the bottom of our lakes

POPs include a range of substances that include: For example, indigenous peoples may be particularly at risk because they observe cultural and spiritual traditions related to their diet. Rain and snow are considered by some individuals to be relatively "pure," yet gases and particles introduced into the atmosphere by human activities and natural phenomena, such as volcanoes, can contaminate precipitation that falls back to Earth.

Once in a lake or stream, some particles settle out of the water to become bottom sediments.

Water pollution

Domestic sewage is also a major source of plant nutrientsmainly nitrates and phosphates. Physical pollutants to lakes and streams include materials such as particles of soil that are eroded from the landscape or washed from paved areas by flowing water.

Because pathogens are excreted in fecesall sewage from cities and towns is likely to contain pathogens of some type, potentially presenting a direct threat to public health. Controlling Dioxins EPA has pursued regulatory control and management of dioxins and furans releases to air, water, and soil.

Dead zones occur worldwide; one of the largest of these sometimes as large as 22, square km [8, square miles] forms annually in the Gulf of Mexicobeginning at the Mississippi River delta.

Much of the evidence for long-range transport of airborne gaseous and particulate substances to the United States focuses on dust or smoke because they are visible in satellite images. Others have rarely or never been used locally.

Another type of physical pollutant is heat that may be discharged from an industrial source, or runoff from hot surfaces in warm weather. Intentionally produced chemicals currently or once used in agriculture, disease control, manufacturing, or industrial processes.

But in general, treatment processes remove solid material, many of the chemical pollutants, and then disinfect the treated sewage to kill disease-causing organisms before releasing the treated wastewater to the receiving waterbody.

Are used in closed-system, site-limited processes. Though the United States is not yet a Party to the Stockholm Convention, the Convention has played a prominent role in the control of harmful chemicals on both a national and global level.

If the temperature exceeds regulatory limits, the water must pass through cooling ponds or towers that lower the temperature of the water before it is discharged.

Top of page The Stockholm Convention On May 23,Christine Todd Whitman, then-EPA Administrator, signed the Convention for the United States in Stockholm, Sweden The Stockholm Convention on Persistent Organic Pollutants, which was adopted in and entered into force inis a global treaty whose purpose is to safeguard human health and the environment from highly harmful chemicals that persist in the environment and affect the well-being of humans as well as wildlife.

Sometimes, unsightly and dangerous waste materials can be washed back to shore, littering beaches with hazardous debris. When the algae die, oxygen dissolved in the water declines because microorganisms use oxygen to digest algae during the process of decomposition see also biochemical oxygen demand.

Pollution of Lakes and Streams

Several types of water pollutants are considered below. For a more-detailed treatment of toxic chemicals, see poison and toxic waste. When sequestered in these sediments, POPs can be taken out of circulation for long periods of time.

A dispersed or nonpoint source is a very broad, unconfined area from which a variety of pollutants enter the water body, such as the runoff from an agricultural area.

Occur as unintentional trace contaminants in products and articles. Top of page The Great Lakes: Many POPs were widely used during the boom in industrial production after World War II, when thousands of synthetic chemicals were introduced into commercial use.

The Great Lakes Binational Toxics Strategy, signed by the United States and Canada inwas an agreement aimed to reduce several persistent toxic pollutants, including certain POPs, in the Great Lakes Basin over a year period.

Persistent Organic Pollutants: A Global Issue, A Global Response

The strategy provided a guide for governments and stakeholders toward the virtual elimination of 12 identified. Lakes and ponds provide habitat for many plants, insects, fish, birds and other wildlife, much of our drinking water and important economic and recreational opportunities for.

Once in a lake or stream, some particles settle out of the water to become bottom sediments. Chemical pollutants adsorbed (bound) to the particles are also incorporated into the sediments, where they may be permanently buried, or be carried by the water currents to other locations.

The Great Lakes Binational Toxics Strategy, signed by the United States and Canada inwas an agreement aimed to reduce several persistent toxic pollutants, including certain POPs, in the Great Lakes Basin over a year period.

The strategy provided a guide for governments and stakeholders toward the virtual elimination of 12 identified substances through cost-efficient and expedient pollution prevention.

6 Sep., What Really is at the Bottom of our Lakes In the article Sludge William Ashworth points out that with the success of economic growth, the cost is often the environment. This is most evident in our lakes and rivers, which have served as a dumping ground whether we realized it.

Point sources of water pollution are easier to control than dispersed sources because the contaminated water has been collected and conveyed to one single point where it can be treated.

Persistent Organic Pollutants: A Global Issue, A Global Response

Pollution from dispersed sources is difficult to control, and, despite much progress in the building of modern sewage-treatment plants, dispersed sources continue to cause a large fraction of water pollution problems.

The pollutants at the bottom of our lakes
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