Persistent bioaccumulative toxic substances (PBTs) are chemicals that break down slowly in the environment, accumulate in humans and other species and are toxic. Although only a limited number of PBTs are currently receiving attention, more may be identified through ongoing screening activities.
Metals, such as lead, mercury, and arsenic, are always persistent, since they are basic elements and cannot be further broken down and destroyed in the environment.
Persistence is when a chemical may last for years at a time in an organism's body, slowly breaking down by the body. Bioaccumulation is when the chemicals buildup in the body of an organism. Biological magnification is when toxic chemicals become more concentrated in organism's tissues.
In keeping with this common usage, “toxic exposure” is defined here to be a direct or an indirect contact with any natural or man-made substances or agents that can lead to deleterious changes in body structure or function, including illness or death.
Persistent toxic substances (PTS) include the Stockholm persistent organic pollutants, like dichlorodiphenyltrichloroethane, polychlorinated biphenyls, dioxin/furan, etc., and organometallic compounds, like organomercury, organotin, and organolead, which all share the same characteristics of being persistent, toxic, ...
Persistent Organic Pollutants (POPs) are toxic substances composed of organic (carbon-based) chemical compounds and mixtures. They include industrial chemicals like PCBs and pesticides like DDT. They are primarily products and by-products from industrial processes, chemical manufacturing and resulting wastes.
Persistent, bioaccumulative, and toxic (PBT) chemicals are a class of chemicals that resist degradation and persist in the environment for extensive periods. As a result of their persistence, when these chemicals are consumed, they bioaccumulate in the fat tissues, bones, and brain of organisms.
Bioaccumulation is the process by which toxins enter the food web by building up in individual organisms, while biomagnification is the process by which toxins are passed from one trophic level to the next (and thereby increase in concentration) within a food web.
Toxicity induced by metals is associated with bioaccumulation and biomagnification. Storage or uptake of metals faster than the rate at which an organism metabolizes and excretes lead to the accumulation of that metal.
Toxins from Bacteria Anthrax lethal toxin is produced by Bacillus anthracis. The anthrax toxin proteins, including anthrax lethal factor, work together to disrupt a cell's defense system. Botulinum toxin, produced by Clostridium botulinum, is one of the most poisonous substance known.
Definition of toxicity : the quality or state of being toxic: such as. a : the quality, state, or relative degree of being poisonous measuring the toxicity level of the soil The toxicity of some chemical agents degrades significantly over time, so it is unclear how lethal the stockpiles are.—
Definition of toxic adjective. of, pertaining to, affected with, or caused by a toxin or poison: a toxic condition. acting as or having the effect of a poison; poisonous: a toxic drug. causing unpleasant feelings; harmful or malicious: a toxic boyfriend who wanted complete control over her; toxic criticism.