Pollution is the introduction of contaminants into the natural environment that cause adverse change. Pollution can take the form of chemical substances or energy, such as noise, heat or light. Pollutants, the components of pollution, can be either foreign substances/energies or naturally occurring contaminants. Pollution is often classed as point source or nonpoint source pollution. In 2015, pollution killed 9 million people in the world.
A polychlorinated biphenyl (PCB) is an organic chlorine compound with the formula C12H10−xClx. Polychlorinated biphenyls were once widely deployed as dielectric and coolant fluids in electrical apparatus, carbonless copy paper and in heat transfer fluids.
Indoor air quality (IAQ) is the air quality within and around buildings and structures. IAQ is known to affect the health, comfort and well-being of building occupants. Poor indoor air quality has been linked to Sick Building Syndrome, reduced productivity and impaired learning in schools.
Tetrachloroethylene, also known under the systematic name tetrachloroethene, or perchloroethylene ("perc" or "PERC"), and many other names, is a chlorocarbon with the formula Cl2C=CCl2. It is a colorless liquid widely used for dry cleaning of fabrics, hence it is sometimes called "dry-cleaning fluid". It has a sweet odor detectable by most people at a concentration of 1 part per million (1 ppm). Worldwide production was about 1 million metric tons (980,000 long tons; 1,100,000 short tons) in 1985.
Chlorine dioxide is a chemical compound with the formula ClO2. This yellowish-green gas crystallizes as bright orange crystals at −59 °C. As one of several oxides of chlorine, it is a potent and useful oxidizing agent used in water treatment and in bleaching.
Disinfectants are antimicrobial agents that are applied to the surface of non-living objects to destroy microorganisms that are living on the objects. Disinfection does not necessarily kill all microorganisms, especially resistant bacterial spores; it is less effective than sterilization, which is an extreme physical and/or chemical process that kills all types of life. Disinfectants are different from other antimicrobial agents such as antibiotics, which destroy microorganisms within the body, and antiseptics, which destroy microorganisms on living tissue. Disinfectants are also different from biocides — the latter are intended to destroy all forms of life, not just microorganisms. Disinfectants work by destroying the cell wall of microbes or interfering with their metabolism.
Oxygen saturation is a relative measure of the concentration of oxygen that is dissolved or carried in a given medium as a proportion of the maximal concentration that can be dissolved in that medium. It can be measured with a dissolved oxygen probe such as an oxygen sensor or an optode in liquid media, usually water. The standard unit of oxygen saturation is percent (%).
Orica Limited is an Australian-based multinational corporation that is one of the world's largest providers of commercial explosives and blasting systems to the mining, quarrying, oil and gas and construction markets, a supplier of sodium cyanide for gold extraction, and a specialist provider of ground support services in mining and tunnelling.
The bromate anion, BrO−
3, is a bromine-based oxoanion. A bromate is a chemical compound that contains this ion. Examples of bromates include sodium bromate,, and potassium bromate,.
Hydrogen selenide is an inorganic compound with the formula H2Se. This hydrogen chalcogenide is the simplest and most commonly encountered hydride of selenium. H2Se is a colorless, flammable gas under standard conditions. It is the most toxic selenium compound with an exposure limit of 0.05 ppm over an 8-hour period. Even at extremely low concentrations, this compound has a very irritating smell resembling that of decayed horseradish or 'leaking gas', but smells of rotten eggs at higher concentrations.
The Jilin chemical plant explosions were a series of explosions which occurred on November 13, 2005, in the No.101 Petrochemical Plant in Jilin City, Jilin Province, China, over the period of an hour. The explosions killed six, injured dozens, and caused the evacuation of tens of thousands of residents.
Total dissolved solids (TDS) is a measure of the dissolved combined content of all inorganic and organic substances present in a liquid in molecular, ionized or micro-granular suspended form. Generally the operational definition is that the solids must be small enough to survive filtration through a filter with two-micrometer pores. Total dissolved solids are normally discussed only for freshwater systems, as salinity includes some of the ions constituting the definition of TDS. The principal application of TDS is in the study of water quality for streams, rivers and lakes, although TDS is not generally considered a primary pollutant it is used as an indication of aesthetic characteristics of drinking water and as an aggregate indicator of the presence of a broad array of chemical contaminants.
Vaporized hydrogen peroxide (trademarked VHP, also known as hydrogen peroxide vapor, HPV) is a vapor form of hydrogen peroxide (H2O2) with applications as a low-temperature antimicrobial vapor used to decontaminate enclosed and sealed areas such as laboratory workstations, isolation and pass-through rooms, and even aircraft interiors.
Fish and shellfish concentrate mercury in their bodies, often in the form of methylmercury, a highly toxic organomercury compound. Fish products have been shown to contain varying amounts of heavy metals, particularly mercury and fat-soluble pollutants from water pollution. Species of fish that are long-lived and high on the food chain, such as marlin, tuna, shark, swordfish, king mackerel and tilefish contain higher concentrations of mercury than others.
The environmental impact of paper is significant, which has led to changes in industry and behaviour at both business and personal levels. With the use of modern technology such as the printing press and the highly mechanized harvesting of wood, disposable paper became a relatively cheap commodity, which led to a high level of consumption and waste. The rise in global environmental issues such as air and water pollution, climate change, overflowing landfills and clearcutting have all lead to increased government regulations. There is now a trend towards sustainability in the pulp and paper industry as it moves to reduce clear cutting, water use, greenhouse gas emissions, fossil fuel consumption and clean up its impacts on local water supplies and air pollution.
Water chemistry analyses are carried out to identify and quantify the chemical components and properties of water samples. The type and sensitivity of the analysis depends on the purpose of the analysis and the anticipated use of the water. Chemical water analysis is carried out on water used in industrial processes, on waste-water stream, on rivers and stream, on rainfall and on the sea. In all cases the results of the analysis provides information that can be used to make decisions or to provide re-assurance that conditions are as expected. The analytical parameters selected are chosen to be appropriate for the decision making process or to establish acceptable normality. Water chemistry analysis is often the groundwork of studies of water quality, pollution, hydrology and geothermal waters. Analytical methods routinely used can detect and measure all the natural elements and their inorganic compounds and a very wide range of organic chemical species using methods such as gas chromatography and mass spectrometry. In water treatment plants producing drinking water and in some industrial processes using products with distinctive taste and odours, specialised organoleptic methods may be used to detect smells at very low concentrations.
The Tianji Coal Chemical Industry Group chemical spill was a severe chemical spill that occurred in Shanxi Province, China during 2012–13. More than 39 tons of anilines leaked from a loose drainage valve at a plant owned by Tianji Coal Chemical Industry Group in the Shanxi city of Changzhi. This chemical spill contaminated the Zhuozhang River which is the source of drinking water for more than one million people, and so caused a water crisis in the downstream City of Handan, Hebei Province.
Karachi has many environmental issues, severely affecting its biophysical environment as well as human health. The industrialization as well as lax environmental oversight have contributed to the problems. The various forms of pollution have increased as Karachi which has caused widespread environmental and health problems. Air pollution, lack of proper waste management infrastructure and degradation of water bodies are the major environmental issues in Karachi.
