The uptake of substances by an organism across membranes (e.g., cell wall, gill, intestine).

One dose or multiple doses of a stimulus occurring within a short time period (e.g., 96 hours or less for aquatic life, less than 14 days for human health).

A hydrocarbon group such as methyl, butyl, octyl, etc.

Organotins containing alkyl groups: methyltins, butyltins and octyltins.

Coatings applied to the portion of a hull below the waterline to discourage marine animals and plants that would otherwise adhere to it.

General name for any substance that kills or inhibits the growth of microorganisms such as bacteria, molds, slimes, fungi, etc.

One type of tin stabilizer, made up of one butyl group (monobutyl) or two butyl groups (dibutyl) bonded to the tin atom. Used in rigid applications such as pipe, siding and profiles. In the United States and Canada, butyltin stabilizer formulations are also approved for drinking water pipe.

Causing or promoting cancer.

Multiple exposures occurring over an extended period of time (e.g., >3 months) or a significant fraction of an animal's or human's lifetime.

The lowest amount of substance that can be distinguished from the noise of an analytical instrument or method for a "clean" sample of a particular matrix.

Organotins containing two alkyl groups bonded to the tin atom.

Compounds containing two organic groups bonded to the tin atom. Dialkyltins are one type of di-organotins.

The United States Environmental Protection Agency, an agency of the federal government established in 1970 to protect human health and safeguard the natural environment. The EPA is headed by an administrator who is appointed by the President of the United States.

Contact of an organism with a chemical or physical agent. Exposure is quantified as the amount of the agent available at the exchange boundaries of the organism (e.g., skin, gills, lungs or gut) that is available for absorption.

The course a chemical or physical agent takes from a source to an exposed organism. An exposure pathway describes a unique mechanism by which an individual or population is exposed to chemicals or physical agents at or originating from a site.

The U.S. Food and Drug Administration, an agency within the Department of Health and Human Services of the federal government, established to promote and protect the public health.

The transfer of food, energy, and certain chemicals when one organism is eaten by another.

See stabilizers.

High Production Volume chemicals. Several tin stabilizers and their precursors are listed on the HPV lists of EPA and the Organization for Economic Cooperation and Development (OECD) for which industry is voluntarily participating in an extensive testing program.

International Maritime Organization, an international body established by the United Nations to promote maritime safety.

The process by which one substance is released from another substance in which it is contained.

The difference between the estimated chronic dose and safe dose of a substance. The greater the difference, the greater the margin of safety.

Marine Environmental Protection Committee (a work group of the IMO)

A sulfur-containing compound that reacts with the chloride in PVC to reduce decomposition. (Also called thiols.)

Descriptive of a type of stabilizer incorporating mercaptans.

One type of tin stabilizer made up of one methyl group (monomethyl) or two methyl groups (dimethyl) bonded to the tin atom. Some formulations (mercaptides) have been approved for food contact applications.

The process by which a chemical or substance changes position and moves within a compound in which it is contained, usually moving toward a boundary layer or surface.

Organotins containing one alkyl group bonded to the tin atom.

Compounds containing one organic group bonded to the tin atom. Monoalkyltins are one type of mono-organotin.

National Sanitation Foundation International, an independent, not for profit organization that develops voluntary consensus standards, product testing procedures and certification services in the areas of public health, safety and the environment.

One type of tin stabilizer made up of one octyl group (monooctyl) or two octyl groups (dioctyl) bonded to the tin atom. Some octyltin stabilizer formulations are approved for food contact applications by most regulatory agencies worldwide, including the FDA.

Compounds containing at least one bond between tin and carbon.

Organotin compounds used in the stabilization of PVC.

Organotin Environmental Programme Association, and international non-profit organization representing producers of organotin compounds. The organization is headquartered in The Netherlands.

Occupational Safety and Health Administration, a division of the U.S. Department of Labor responsible for ensuring safe workplaces in America.

Resisting natural degradation and therefore building up over time in the environment.

Part per billion. The equivalent of about 1 second in 31 years.

Part per million. The equivalent of about 1 second in 12 days.

Part per trillion. The equivalent of about 1 second in 31,000 years.

Daily intake for humans that is expected to be without effect over a long-term (chronic) exposure.

Polyvinyl Chloride, commonly known as vinyl.

The amount of a substance that is likely to be without appreciable risk of deleterious effects to an organism during a lifetime.

The matter remaining after evaporation, combustion, etc.

The likelihood of adverse effects arising from exposure to a hazard.

The methodical determination of the likelihood of adverse effects arising from exposure to a hazard.

A mathematical expression used in risk assessments to increase the margin of safety. Such factors are applied to the measured toxicology effects to account for uncertainty in those tests and thereby ensure protection of people and the environment.

Matter that settles to the bottom of a river, stream, or the ocean.

Any substance which tends to keep a compound or mixture from changing its form or chemical nature. Heat stabilizers are utilized for processing polyvinyl chloride (PVC). The primary purpose of these stabilizers is to reduce the polymer backbone degradation of the PVC. They do this by scavenging the HCl lost during processing at high temperatures and stabilizing the unstable chloride sites in the PVC molecule.

Tributyltin. Used throughout the world in antifouling paints for marine applications, TBT is not used as a stabilizer.

Tolerable Daily Intake. The tolerable daily consumption for humans of a particular compound. This amount is unlikely to cause harm to human health if ingested on a regular (i.e., daily) basis over a lifetime.

Organotins containing three alkyl groups bonded to the tin atom.

Tin Stabilizer Association, a nonprofit organization in North America formed to promote the use of tin stabilizers in vinyl (polyvinyl chloride or PVC) applications. TSA works to provide accurate information about the quality and safety of tin stabilizers and to differentiate the use of tin stabilizers from other applications. TSA also cooperates with other organizations throughout the world to promote product stewardship, conduct scientific studies and enhance communications related to the product.

Vinyl Council of Canada, a trade group representing more than 20 Canadian companies, including vinyl resin and additive producers and processors. The VCC is a council of the Canadian Plastics Industry Association.

The Vinyl Institute, a U.S. trade association representing the leading manufacturers of vinyl, vinyl chloride monomer, vinyl additives and modifiers, and vinyl packaging materials.

Usually refers to PVC.

Volatile Organic Compound. Organic chemicals used as solvents, degreasers, fumigants and dry cleaning chemicals. They tend to evaporate readily. Some of these compounds are associated with carcinogenic and chronic toxicity.

The concentration of a substance that will protect an organism, a community of species, or a prescribed water use from adverse effects of safety.