Toxicology long-term effects

Workers in the metals treatment industry are exposed to fumes, dusts, and mists containing metals and metal compounds, as well as to various chemicals from sources such as grinding wheels and lubricants. Exposure can be by inhalation, ingestion, or skin contact. Historically, metal toxicology was concerned with overt effects such as abdominal coHc from lead toxicity. Because of the occupational health and safety standards of the 1990s such effects are rare. Subtie, chronic, or long-term effects of metals treatment exposure are under study. An index to safety precautions for various metal treatment processes is available (6). As additional information is gained, standards are adjusted. 

The necessary containment or transport capability of a local ventilation sy stem depends on the type of contaminant present and its health risks. There could be different demands for gases and particles, for contaminants that have immediate health risks and those that have long-term effects, for contaminants that affect the breathing system and those that affect the skin and eyes, for infectious contaminants, fot contaminants that follow the air streamlines closely and those that fall out on floor and work surfaces, etc. (See Chapter 5 for physiological and toxicological considerations.)... 

Sanotskii IV Aspects of the toxicology of chloroprene Immediate and long-term effects. Environ Health Perspea 17 85-93, 1976... 

The principles of toxicology, dose - response and individual sensitivity, are well illustrated by the metals. Historically, most of the interest and concern was with the obvious effects of metal toxicity such as colic from lead or symptoms of the Mad Hatter from mercury. The emphasis has changed to the more subtle and long-term effects and concern for potentially sensitive individuals. It is now well documented that children exposed to even low levels of lead will have a lowered IQ and other learning difficulties. This knowledge has resulted in significant changes in our use of metals. 

UV radiation illustrates the basic principles of toxicology in that individual sensitivity varies greatly, and it is best to limit your dose (exposure) to control your response. The challenge is to understand and manage the risk and benefits of our individual exposure and resulting acute and long-term effects. 

The toxicological data should provide evidence of adverse effects to humans. The acute oral, dermal or inhalation toxicity is characterized by the LD50 or LC50 (lethal dose or lethal concentration). In addition to the acute toxicity, possible long-term effects are reported, such as mutagenic, carcinogenic, or teratogenic effects. 

At the request of the Department of the Army, the Committee on Toxicology in the Board on Toxicology and Environmental Health Hazards of the National Research Council s Commission on Life Sciences undertook a study to investigate possible delayed and long-term effects of experimental chemicals administered to soldiers at the U.S. Army Laboratories, Edgewood, Maryland. A total of 6,720 soldiers volunteered, of whom 4,826 were exposed to some experimental chemicals. 

For the next 20 years from 1964 to 1984 no follow-up of these studies was done. The world had to have its worst industrial disaster in the last month of 1984 to prompt a renewed interest in the toxicology of MIC this provoked The Lancet (Editorial, 1984) to comment In a year s time we will have learned a lot more about methyl isocyanate - at an appalling price. It is to the credit of Kimmerle and Eben (1964) that their stringent observations were confirmed by all the studies since 1984. On the other hand, acute toxicity studies are not predictors of long-term effects (Salmon,... 

Schwerdt G, Flolzinger FI, Sauvant C, Konigs M, Flumpf FlU, and Gekle M. Long-term effects of ochratoxin A on fibrosis and cell death in human proximal tubule or fibroblast cells In primary culture.Toxicology 232 57-67, 2007. 

Toussaint O, Dumont P, Dierick JF, Pascal T, Frippiat C, Chainiaux F, Magalhaes JP, Eliaers F, Remade J. Stress-induced premature senescence as alternative toxicological method for testing the long-term effects of molecules under development in the industry. Biogerontology 2000 l(2) 179-83. 

Bell FP, Iverson F, Arnold D, et al. 1994. Long-term effects of Aroclor 1254 (PCBs) on plasma lipid and carnitine concentrations in rhesus monkey. Toxicology 89(2) 139-153. 

National Research Council (Committee on Toxicology), Possible Long-Term Effects of Short Term Exposure to Chemical Agents. Vol. 3. Final Report. Current health status of test subjects. NTIS AD-A163 614, 1985. 

IRPTC cooperates with the Commonwealth of Independent States Committee for Science and Technology and its successor body to produce an extensive series of mtxiographs which review the scientific literature in Russian on selected hazardous chemicals. Many titles deal with pesticides. A small number of specialised publications have been produced as a result of this cooperation, for example. Long Term Effects of Chemicals and Principles of Pesticide Toxicology. 

ECETOC) (1998). Organophosphorus pesticides and long-term effects on the nervous system, European Center for Ecotoxieology and Toxicology technical report No. 75. ECE-TOC, Brussels. 

In the US, a request to authorize a new food additive is presented to the FDA. A petition for an additive or a colorant must include data pertaining to the toxicity of the additive accompanied by toxicological tests on animals and even on humans. To evaluate whether an additive should be approved, the agency first considers the composition and attributes of the substance, the probable amount that will be ingested, the possible long-term effects on consumers and various additional safety factors. If the additive is approved, the FDA publishes regulations that may include the types of foods in which it can be used, the maximum quantities that can be added, and how it should be identified in the food labels. 

Sicko-Goad, L. and Andersen, N. A. (1993b) Effect of diatom lipid composition on the toxicity of trichlorobenzene II. Long-term effects of 1,2,3-trichlorobenzene. Archives of Environmental Contamination and Toxicology, 24, 243-8. 

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