ConcentrationIn chemistry, concentration is the abundance of a constituent divided by the total volume of a mixture. Several types of mathematical description can be distinguished: mass concentration, molar concentration, number concentration, and volume concentration. The concentration can refer to any kind of chemical mixture, but most frequently refers to solutes and solvents in solutions. The molar (amount) concentration has variants, such as normal concentration and osmotic concentration. Dilution is reduction of concentration, e.
Agricultural pollutionAgricultural pollution refers to biotic and abiotic byproducts of farming practices that result in contamination or degradation of the environment and surrounding ecosystems, and/or cause injury to humans and their economic interests. The pollution may come from a variety of sources, ranging from point source water pollution (from a single discharge point) to more diffuse, landscape-level causes, also known as non-point source pollution and air pollution. Once in the environment these pollutants can have both direct effects in surrounding ecosystems, i.
Septic tankA septic tank is an underground chamber made of concrete, fiberglass, or plastic through which domestic wastewater (sewage) flows for basic sewage treatment. Settling and anaerobic digestion processes reduce solids and organics, but the treatment efficiency is only moderate (referred to as "primary treatment"). Septic tank systems are a type of simple onsite sewage facility. They can be used in areas that are not connected to a sewerage system, such as rural areas.
DDTDichlorodiphenyltrichloroethane, commonly known as DDT, is a colorless, tasteless, and almost odorless crystalline chemical compound, an organochloride. Originally developed as an insecticide, it became infamous for its environmental impacts. DDT was first synthesized in 1874 by the Austrian chemist Othmar Zeidler. DDT's insecticidal action was discovered by the Swiss chemist Paul Hermann Müller in 1939. DDT was used in the second half of World War II to limit the spread of the insect-borne diseases malaria and typhus among civilians and troops.
Water extractionWater extraction (or water withdrawal) is the process of taking water from any source, either temporarily or permanently, for flood control or to obtain water for, for example, irrigation. The extracted water could also be used as drinking water after suitable treatment. Depending on the environmental legislation in the country, controls may be placed on extraction to limit the amount of water that can be removed. The over-extraction of water can lead to dry rivers or declining groundwater levels.
DeltamethrinDeltamethrin is a pyrethroid ester insecticide. Deltamethrin plays a key role in controlling malaria vectors, and is used in the manufacture of long-lasting insecticidal mosquito nets; however, resistance of mosquitos and bed bugs to deltamethrin has seen a widespread increase. Deltamethrin is toxic to aquatic life, particularly fish. Although generally considered safe to use around humans, it is still neurotoxic. It is an allergen and causes asthma in some people. Deltamethrin is a highly effective insecticide.
Illegal loggingIllegal logging is the harvest, transportation, purchase, or sale of timber in violation of laws. The harvesting procedure itself may be illegal, including using corrupt means to gain access to forests; extraction without permission, or from a protected area; the cutting down of protected species; or the extraction of timber in excess of agreed limits. Illegal logging is a driving force for a number of environmental issues such as deforestation, soil erosion and biodiversity loss which can drive larger-scale environmental crises such as climate change and other forms of environmental degradation.
United States Environmental Protection AgencyThe Environmental Protection Agency (EPA) is an independent executive agency of the United States federal government tasked with environmental protection matters. President Richard Nixon proposed the establishment of EPA on July 9, 1970; it began operation on December 2, 1970, after Nixon signed an executive order. The order establishing the EPA was ratified by committee hearings in the House and Senate. The agency is led by its administrator, who is appointed by the president and approved by the Senate.
