Chronic effect

Chronic inhalation exposures to indium compounds can induce pulmonary toxicity and carcinogenesis in experimental animals. Indium (III) phosphide (IP) was chosen by the National Toxicology Program (NTP) for chronic toxicity studies due to its widespread use in the microelectronics industry and its potential for chronic exposure to workers (NTP 2001). Inhalation exposures of rats to IP at doses of 0, 1, 3, 

Another study has shown a significant association between the severity of pulmonary inflammation/fibrosis induced by IP, as well as other particulate compounds including nickel oxide, nickel subsulfide, cobalt sulfate, and talc, and increased incidences of adrenal pheochromocytoma in rats (Ozaki et al. 2002). The systemic hypoxemia and reduced gas exchange induced by chronic pulmonary lesions from IP exposures may result from stimulated catecholamine secretion from the adrenal medulla and this chronic endocrine hyperactivity may lead to hyperplasia and neoplasia of the adrenal gland. 

ACGIH (1996) Guide to occupational exposure values, p. 59. ACGIH Worldwide, Cincinnati. 

ACGIH (1998) TLVs and BEIs - Threshold limit values for chemical substances and physical agents, p. 43. ACGIH (American Conference of Governmental Industrial Hygienists) Worldwide, Cincinnati. 

Beckee W and Mellee J (2001) The role of nuclear medicine in infection and inflammation. Lancet Infect Dis 1 326-333. 

Certain nutrients including proteins, Ca, and vitamin C have been shown to influence the severity of F toxicity. Adverse effect of F is alleviated by these nutrients. For example, both vitamin C and Ca have been shown to decrease the toxicity in guinea pigs (Hodge and Smith 1965). Laboratory experiments showed that mice fed a low-protein (4%) diet deposited five times more F in 

Source Adapted from NRC/NAS Committee on Biologic Effects of Atmospheric Pollutants. 1971. Fluorides. National Academy of Sciences, Washington, D.C., p. 295. 

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When dispersed as a dust, adipic acid is subject to normal dust explosion hazards. See Table 3 for ignition properties of such dust—air mixtures. The material is an irritant, especially upon contact with the mucous membranes. Thus protective goggles or face shields should be worn when handling the material. Prolonged contact with the skin should also be avoided. Eye wash fountains, showers, and washing faciUties should be provided in work areas. However, MSDS Sheet400 (5) reports that no acute or chronic effects have been observed. 

Health and Safety Factors. Boron trifluoride is primarily a pulmonary irritant. The toxicity of the gas to humans has not been reported (58), but laboratory tests on animals gave results ranging from an increased pneumonitis to death. The TLV is 1 ppm (59,60). Inhalation toxicity studies in rats have shown that exposure to BF at 17 mg/m resulted in renal toxicity, whereas exposure at 6 mg/m did not result in a toxic response (61). Prolonged inhalation produced dental fluorosis (62). High concentrations bum the skin similarly to acids such as HBF and, if the skin is subject to prolonged exposure, the treatment should be the same as for fluoride exposure and hypocalcemia. No chronic effects have been observed in workers exposed to small quantities of the gas at frequent intervals over a period of years. 

The short-term or acute effects of the P-agonists may be different from chronic effects. Acute Hpolysis and glycogenolysis are not observed beyond the first day or two of treatment. Exact mechanisms of action on Hpid metaboHsm may differ among species. Chronic effects of the P-agonists reduce circulating insulin concentrations ST treatment causes an opposite change. Whereas residue levels may be of concern with adrninistration of several of the P-agonists, such is not the case for ST or GRE. 

In additional EPA studies, subchronic inhalation was evaluated ia the rat for 4 and 13 weeks, respectively, and no adverse effects other than nasal irritation were noted. In the above-mentioned NTP chronic toxicity study ia mice, no chronic toxic effects other than those resulting from bronchial irritation were noted. There was no treatment-related increase ia tumors ia male mice, but female mice had a slight increase in bronchial tumors. Neither species had an increase in cancer. Naphthalene showed no biological activity in other chemical carcinogen tests, indicating Htde cancer risk (44). No incidents of chronic effects have been reported as a result of industrial exposure to naphthalene (28,41). 

Persistent effects do not resolve, and may even become more severe after removal from the source of exposure. They can occur as a consequence of acute or repeated-exposure conditions. Thus, the use of the term persistent should be clearly differentiated from the implication of the use of the description of an effect as chronic. It should be noted, however, that some chronic effects may be persistent an example is malignant neoplasia. 

Dichloroethylene is toxic by inhalation and ingestion and can be absorbed by the skin. It has a TLV of 200 ppm (10). The odor does not provide adequate warning of dangerously high vapor concentrations. Thorough ventilation is essential whenever the solvent is used for both worker exposure and flammabihty concerns. Symptoms of exposure include narcosis, dizziness, and drowsiness. Currently no data are available on the chronic effects of exposure to low vapor concentrations over extended periods of time. 

Air-poUutant effects on neural and sensory functions in humans vary widely. Odorous pollutants cause only minor annoyance yet, if persistent, they can lead to irritation, emotional upset, anorexia, and mental depression. Carbon monoxide can cause death secondary to the depression of the respiratory centers of the central nervous system. Short of death, repeated and prolonged exposure to carbon monoxide can alter sensory protection, temporal perception, and higher mental functions. Lipid-soluble aerosols can enter the body and be absorbed in the lipids of the central nervous system. Once there, their effects may persist long after the initial contact has been removed. Examples of agents of long-term chronic effects are organic phosphate pesticides and aerosols carrying the metals lead, mercury, and cadmium. 

An exposure to a specific chemical in relatively low concentrations over a period may result in chronic effects. At higher concentrations, the effects may be acute. Some chemicals produce local damage at their point of contact with, or entry into, the body others produce systemic effects, i.e. they are transported within the body to various organs before exerting an adverse effect. 

LPG is considered to be non-toxic witli no chronic effects, but the vapour is slightly anaesthetic. In sufficiently high concentrations, resulting in oxygen deficiency, it will result in physical asphyxiation. The gases are colourless and odourless but an odorant or stenching agent (e.g. methyl mercaptan or dimethyl sulphide) is normally added to facilitate detection by smell down to approximately 0.4% by volume in air, i.e. one-fifth of the lower flammable limit. The odorant is not added for specific applications, e.g. cosmetic aerosol propellant. 

Environmental, health, or safety properties of the pollutants including their acute and chronic effects and any synergistic effects. 

Creosote is a complex mixture of toxic chemicals, which can have both immediate and chronic effects on exposed organisms. PIC of creosote are of particular concern due to long half-lives of some chemicals, and because of multiple pathways to the environment from ash and soot. 

Chronic Health Effect A chronic health effect is an adverse health effect resulting from long-term exposure to a substance. The effects could be a skin rash, bronchitis, cancer, or any other medical condition. An example would be liver cancer from inhaling low levels of benzene at your workplace over several years. The term is also applied to a persistent (months, years, or permanent) adverse health effect resulting from a short-term (acute) exposure. Chronic effects from long-term exposure to chemicals are fairly common. Recognize the PEL (permissible exposure level) for each substance in your workplace and minimize your exposure whenever possible. 

Health Hazards Information - Recommended Personal Protective Equipment Dust mask goggles or face shield protective gloves Symptoms Following Exposure Inhalation of dust irritates nose and throat. Contact with eyes causes irritation General Treatment for Exposure INHALATION move to fresh air. EYES flush immediately with physiological saline or water get medical care if irritation persists. SKIN flush with water Toxicity by Inhalation (Thresholdlimit Value) Data not available Short-Term Exposure Limits Data not available Toxicity by Ingestion Grade 1 oral LDjq 11.7 g/kg (rat) Late Toxicity Chronic effects in humans are unknown Vapor (Gas) Irritant Characteristics Not pertinent liqidd or Solid Irritant Characteristics Data not available Odor Threshold Data not available. 

Late Toxicity - Where there is evidence that a chemical can cause cancer, mutagenic effects, teratogenic effects, or delayed injury to vital organs such as the liver or kidney, a qualitative description of the chemical is given. The term implies long-term or chronic effects due to exposure to the chemical. 

In a cross-sectional study, exposure and effect are studied simultaneously. This approach contains an inherent problem because exposure must precede the effect. However, it can he used to investigate acute effects and also mild chronic effects (which do not force people to leave their jobs) if exposure has remained rather stable for a long time. When the prevalence of the effects studied are compared with the prevalence in other worker groups (controls or references) which correspond otherwise with the study group but are not exposed to the agent investigated, indicative evidence of possible causality may be obtained. For example, cross-sectional studies have been applied successfully to reveal the associations between mild neurotoxic effects and exposure to organic solvents. ... 

Toxic effects often disappear after the cessation of the exposure, but they can also be permanent. The tissue s ability to regenerate is one of the most important factors that determines the nature of toxic effects. For example, liver tissue has a remarkable capacity to regenerate, and therefore liver injur> is often reversible. On the other hand, neuronal cells do not regenerate at all, thus neuronal injury is irreversible. It is true that neuronal cells can compensate for possible losses, but only to a minor degree. In particular, chronic effects tend to be irreversible. ... 

Chronic studies Rats/inicc 1 8--14 months Chronic effects of low exposures... 

Chronic effects on mortality caused by particles IQ IQ Region.) 1. 

Chronic effects on biofilms EC50 6-25 indirect effects EC50 50-2500 direct effects Changed algal species >50 Fluvial microcosms (low P) " Experimental stream ... 

Chronic effects on biofilms 10 effects on settlement 100 biomass, change spp. Fluvial microcosms (high P)" °... 

Roberts D. 1972. The assimilation and chronic effects of sub-lethal concentrations of endosulfan on condition and spawning in the common mussel Mylitus edulis. Marine Biology 16 119-125. 

Battig K, Grandiean E. 1963. Chronic effects of trichloroethylene on rat behavior. Arch Environ Health 7 694-699. 

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