Cadmium is a chemical element; it has symbol Cd and atomic number 48. This soft, silvery-white metal is chemically similar to the two other stable metals in group 12, zinc and mercury. Like zinc, it demonstrates oxidation state +2 in most of its compounds, and like mercury, it has a lower melting point than the transition metals in groups 3 through 11. Cadmium and its congeners in group 12 are often not considered transition metals, in that they do not have partly filled d or f electron shells in the elemental or common oxidation states. The average concentration of cadmium in Earth's crust is between 0.1 and 0.5 parts per million (ppm). It was discovered in 1817 simultaneously by Stromeyer and Hermann, both in Germany, as an impurity in zinc carbonate.
Paint is a material or mixture that, when applied to a solid material and allowed to dry, adds a film-like layer. As art, this is used to create an image or images known as a painting. Paint can be made in many colors and types. Most paints are either oil-based or water-based, and each has distinct characteristics.
A pigment is a powder used to add color or change visual appearance. Pigments are completely or nearly insoluble and chemically unreactive in water or another medium; in contrast, dyes are colored substances which are soluble or go into solution at some stage in their use. Dyes are often organic compounds whereas pigments are often inorganic. Pigments of prehistoric and historic value include ochre, charcoal, and lapis lazuli.
Toxic waste is any unwanted material in all forms that can cause harm. Mostly generated by industry, consumer products like televisions, computers, and phones contain toxic chemicals that can pollute the air and contaminate soil and water. Disposing of such waste is a major public health issue.
Titanium dioxide, also known as titanium(IV) oxide or titania, is the inorganic compound derived from titanium with the chemical formula TiO
2. When used as a pigment, it is called titanium white, Pigment White 6 (PW6), or CI 77891. It is a white solid that is insoluble in water, although mineral forms can appear black. As a pigment, it has a wide range of applications, including paint, sunscreen, and food coloring. When used as a food coloring, it has E number E171. World production in 2014 exceeded 9 million tonnes. It has been estimated that titanium dioxide is used in two-thirds of all pigments, and pigments based on the oxide have been valued at a price of $13.2 billion.
Saponification is a process of cleaving esters into carboxylate salts and alcohols by the action of aqueous alkali. Typically aqueous sodium hydroxide solutions are used. It is an important type of alkaline hydrolysis. When the carboxylate is long chain, its salt is called a soap. The saponification of ethyl acetate gives sodium acetate and ethanol:
Cadmium pigments are a class of pigments that contain cadmium. Most of the cadmium produced worldwide has been for use in rechargeable nickel–cadmium batteries, which have been replaced by other rechargeable nickel-chemistry cell varieties such as NiMH cells, but about half of the remaining consumption of cadmium, which is approximately 2,000 tonnes annually, is used to produce colored cadmium pigments. The principal pigments are a family of yellow, orange and red cadmium sulfides and sulfoselenides, as well as compounds with other metals.
Oil paint is a type of slow-drying paint that consists of particles of pigment suspended in a drying oil, commonly linseed oil. For several centuries the oil painting has been perhaps the most prestigious form in Western art, but oil paint has many practical uses, mainly because it is waterproof.
White spirit (AU, UK and Ireland) or mineral spirits (US, Canada), also known as mineral turpentine (AU/NZ/ZA), turpentine substitute, and petroleum spirits, is a petroleum-derived clear liquid used as a common organic solvent in painting. There are also terms for specific kinds of white spirit, including Stoddard solvent and solvent naphtha (petroleum). White spirit is often used as a paint thinner, or as a component thereof, though paint thinner is a broader category of solvent. Odorless mineral spirits (OMS) have been refined to remove the more toxic aromatic compounds, and are recommended for applications such as oil painting.
Ethylbenzene is an organic compound with the formula C6H5CH2CH3. It is a highly flammable, colorless liquid with an odor similar to that of gasoline. This monocyclic aromatic hydrocarbon is important in the petrochemical industry as a reaction intermediate in the production of styrene, the precursor to polystyrene, a common plastic material. In 2012, more than 99% of ethylbenzene produced was consumed in the production of styrene.
Zinc white is an inorganic pigment composed of zinc oxide that has been used by painters since the late eighteenth century. Alongside lead and titanium white, it is among the three most prominent white pigments that are commercially available today. Its primary advantages are its low toxicity and the cool clarity of its color. It was initially developed in the 1780s by the French chemist and magistrate Louis-Bernard Guyton de Morveau, who struggled to popularize its use. The French Academy of Sciences approved of the invention in 1782, but artists from the French Royal Academy of Painting and Sculpture expressed skepticism. Initially, zinc white pigment was more costly to produce than lead white, but its price diminished as production methods improved over the course of the nineteenth century. While the superior safety of zinc white had been established by the end of the eighteenth century, manufacturers of lead white downplayed these differences, and lead continued to dominate the market for white paint until the early twentieth century.
White lead is the basic lead carbonate 2PbCO3·Pb(OH)2. It is a complex salt, containing both carbonate and hydroxide ions. White lead occurs naturally as a mineral, in which context it is known as hydrocerussite, a hydrate of cerussite. It was formerly used as an ingredient for lead paint and a cosmetic called Venetian ceruse, because of its opacity and the satiny smooth mixture it made with dryable oils. However, it tended to cause lead poisoning, and its use has been banned in most countries.
Fateful Harvest: The True Story of a Small Town, a Global Industry, and a Toxic Secret is a nonfiction book written by Duff Wilson, who was a reporter for the Seattle Times. The book began as a series of newspaper reports, which made the issue a "national focus".
Lead-based paint was widely used in the United States because of its durability. The United States banned the manufacture of lead-based house paint in 1978 due to health concerns.
The environmental impact of paint can vary depending on the type of paint used and mitigation measures. Traditional painting materials and processes can have harmful effects on the environment, including those from the use of lead and other additives. Measures can be taken to reduce its environmental effects, including accurately estimating paint quantities so waste is minimized, and use of environmentally preferred paints, coating, painting accessories, and techniques.
Most lead-based paint in the United Kingdom were banned from sale to the general public in 1992, except for specialist uses. Prior to this, lead compounds had been used as the pigment and drying agent in different types of paint, for example brick and some tile paints. Lead-based paint has been an important cause of lead poisoning.
British Titan Products was the manufacturer of Tioxide, a brand of white yet opaque pigment and whitening agent made from titanium dioxide. It was initially organised to replace titanium dioxide supplies that British paint manufacturers imported from Germany. This British industry was established as a joint venture in 1934 by two of the world's major mining and chemical businesses in conjunction with a major industrial consumer and a distribution business.
Lead contamination in Oakland represents a serious and persistent public health threat. Lead contamination in modern Oakland comes from three primary sources: remnants from previous industry, deposits from leaded gasoline, and paint chips from leaded paints. Significant portions of the City of Oakland, California have soil lead levels far in excess of 400 ppm, the level at which the US EPA suggests remedial action be taken, and far higher than 80 ppm, the level at which California’s Office of Environmental Health Hazard Assessment suggests action should be taken. Not all areas of Oakland are affected equally: West Oakland's contamination is especially severe, particularly near the former Oakland Army Base, and many of Oakland's poorer neighborhoods also suffer disproportionately.
Lead abatement is an activity to reduce levels of lead, particularly in the home environment, generally to permanently eliminate lead-based paint hazards, in order to reduce or eliminate incidents of lead poisoning.
