There are more than 80,000 chemicals in use in the United States. These chemicals occur in industrial, agricultural and consumer products. The DEQ laboratory analyzes for a small sub-set (approximately 400) of these in seven major categories:
Consumer product constituents
Consumer product constituents include fragrances, pharmaceuticals, insect repellants and other products found in every-day household chemicals, cleaning products, beauty products, clothing and medications. Examples of commonly detected consumer products include the insect repellant DEET, the stimulant caffeine, and the antibiotic sulfamethoxazole. These constituents likely make their way into the water through wastewater discharges and septic systems.
Plant or animal sterols, a sub-set of this category shown separately in the chart, exist both naturally in the environment as products of digestion (such as cholesterol and coprostanol) and may also be present in industrial processes (wood pulping, food oils) and certain dietary supplements (such as beta-sitosterol).
Current-use pesticides
Current-use pesticides include insecticides, herbicides, fungicides and others. Use of these products occurs on agricultural lands, public right-of-ways, managed forest areas and residential properties. Some examples of current-use pesticides are: diuron –herbicide used for roadside weed control as well as on varied agricultural lands; carbaryl - insecticide used on forests, fields, homes and a variety of crops; and propiconazole – fungicide used on food crops as well as ornamental plants. Detections of this group of chemicals are common in this monitoring program. Research indicates current-use pesticides may affect salmon and other fish species.
Legacy pesticides
Legacy pesticides include pesticides that are banned from use in the United States. In some cases, these chemicals continue to be used in other parts of the world. Due to their environmental persistence, they remain in parts of the environment. These chemicals often bind to sediment and, thus, runoff from historically treated areas is a source of these chemicals to aquatic systems. In addition, because of their chemical nature, these compounds bioaccumulate in organisms and pose a risk to these organisms, wildlife and, ultimately, human health.
Flame retardants
Flame retardants or polybrominated diphenyl ethers (PBDEs) are chemicals which are added to a variety of products. Prevalent in items such as laptops, automobiles, furniture and textiles, these chemicals tend to leach out of these products and enter the environment. Similar in structure to polychlorinated biphenyls (PCBs), they persist in the environment and tend to bioaccumulate in organisms. Concern over the potential toxicity of this group of chemicals prompted several states and countries to pass legislation banning their manufacture and use.
Combustion byproducts
This group includes polycyclic aromatic hydrocarbons. These combustion byproducts make their way into the aquatic environment through a variety of routes. Since these chemicals are a product of automobile combustion, forest fires and incineration of industrial and municipal wastes, air deposition is a major source. Another large source is stormwater runoff, especially from urban and impervious surfaces.
This group also includes the family of chemicals known as dioxins and furans. These chemicals are not produced intentionally but rather are a byproduct of industrial activities (paper bleaching, industrial production) and fossil fuel combustion from sources such as incineration, wood stoves and forest fires. These chemicals persist in the environment, bioaccumulate in organisms, and are toxic to humans and wildlife.
Metals
Stormwater runoff, industrial processes and consumer products are all sources of metals to the environment. In addition, metals occur naturally in the earth’s crust and enrichment of certain metals in rocks varies based on the makeup and source of the rocks. This group includes metals such as copper and lead that may reach the environment from cars; silver, which is found in x-rays and photography, jewelry and electronics; and arsenic used in some pesticides and semi-conductors. This group also includes mercury and methylmercury. Atmospheric deposition from coal-burning and other activities is a major source of mercury, but it is also found in dental amalgams and is naturally occurring. Mercury bioaccumulates in organisms. Fish consumption advisories exist for mercury in Oregon and around the world.
Industrial intermediates
This category includes the industrial chemicals known as polychlorinated biphenyls or PCBs. Most commonly used historically as an electrical insulating fluid, old transformers and capacitors are a common source. However, additional uses existed, including use of PCBs in adhesives, sealants, paints and pesticides. Because of their persistence in the environment, toxicity to humans and possible links to cancer, the United States banned manufacture and use of these chemicals. Similar to legacy pesticides, these chemicals persist in the sediment of aquatic systems. Sources still exist from improper disposal of transformers and other PCB-containing items. Because of their chemical nature, they bioaccumulate in organisms and pose a risk to humans through fish consumption. Several fish consumption advisories exist in Oregon for PCBs.