Acrylonitrile exposure

There is a test that can detect acrylonitrile in blood. In addition, the major breakdown products of acrylonitrile by the body (termed metabolites) can be measured in urine. Some breakdown products that can be measured are specific to acrylonitrile. However, one breakdown product of the body (cyanide) that is commonly measured is not specific to acrylonitrile exposure, and the results can be affected by cigarette smoking. Because special equipment is needed, these tests cannot be performed routinely in your doctor s office. There is not enough information at present to use the results of such tests to predict the nature or severity of any health effects that may result from exposure to acrylonitrile. Further information on how acrylonitrile can be measured in exposed humans is presented in Chapters 2 and 6. 

Additional follow-up will be necessary to determine whether death can be associated with cancers resulting from acrylonitrile exposure. 

Epidemiology studies have also suggested a possible association between acrylonitrile exposure and prostate cancer (Chen et al. 1987 O Berg et al. 1985), but the data are too limited to warrant any firm conclusion. Collins et al. (1989) found no increase in prostate cancer in acrylonitrile-exposed workers, but again the data are too limited to be meaningful. 

In animals, the hemorrhagic effects of acrylonitrile exposure on the adrenals may be reduced by prior exposure of the animals to adrenergic blockers or chemicals that deplete the adrenal cortex of catecholamines (Silver et al. 1987 Szabo et al. 1980). It is difficult to judge whether adrenergic antagonists would have a similar protective effect in humans, because effects of acrylonitrile on the adrenal have not been described in humans. 

Neurotoxicity. Clinical signs indicative of disturbances of the nervous system in exposed humans have been well documented in short-term studies at high doses and appear to be reversible. These effects are characteristic of cyanide toxicity. Animal studies confirm findings in humans. In longer-term studies, effects on the nervous system have also been reported, but it is not certain if these effects are permanent or reversible following termination of acrylonitrile exposure. 

Epidemiological and Human Dosimetry Studies. There are studies on the adverse effects of acrylonitrile in humans. These studies link acrylonitrile exposure and lung cancer. It has also been suggested that acrylonitrile may have the potential to cause prostate cancer. Many of the studies have major limitations including insufficient quantification of exposure, short follow-up, small study population, and inadequate evaluation of confounding associations. Additional studies would be useful in clarifying the cancer risk and estimating the exposure levels that lead to these effects. 

Biomarkers of Exposure and Effect. The presence of thiocyanate and 2-cyanoethyl mercapturic acid have been monitored in urine as indicators of acrylonitrile exposure. 

Immunological and histological studies on brain tumors following acrylonitrile exposure NCI... 

Studies using radioactivity-labeled acrylonitrile indicate that acrylonitrile or its metabolites form covalent adducts with cellular macromolecules in most tissues. Studies to develop chemical or immunological methods for measuring these adducts would be especially valuable in detecting and perhaps even quantifying human exposure to acrylonitrile. Adverse health effects demonstrated following exposure to acrylonitrile, particularly acute exposures, were characteristic of cyanide toxicity. Because these effects are also indicative of exposure to many other toxicants, additional methods are needed for more specific biomarkers of effects of acrylonitrile exposure. 

Cote IL, Bowers A, Jaeger RJ. 1983. Induced tolerance to acrylonitrile toxicity by prior acrylonitrile exposure. Res Commun Chem Pathol Pharmacol 42 169-172. 

Fanini D, Trieff NM, Sadagopa Ramanujam VM, et al. Effect of acute acrylonitrile exposure on metrazol induced seizures in the rat. Neurotoxicology 6 29-34. 

Mortality associated with acrylonitrile exposure was evaluated as part of a study of 15 643 male workers in a rubber plant in the United States (Akron, Ohio) (Delzell Monson, 1982). Included in the analysis were 327 workers who were employed for at least two years in the plant between 1 January 1940 and 1 July 1971, and who had worked in two departments where acrylonitrile was used, i.e., 81 worked only in the nitrile rubber manufacturing operation where exposures to 1,3-butadiene (see this volume), styrene (lARC, 1994a) and vinylpyridine also occurred and 218 only in the department where the latex was coagulated and dried. [No information on levels of exposure to acrylonitrile was provided ] Mortality among these workers was assessed through 1 July 1978 and compared with age- and calendar-time-specific rates for white men in the United States. SMRs were 0.8 ( = 74 95% CI, 0.7-1.0) for all causes of death, 1.2 ( = 22 95% CI, 0.8-1.9) for all cancers combined, 1.5 ( = 9 95% CI, 0.7-2.9) for lung cancer, 4.0 ( = 2 95% CI, 0.5-14.5) for urinary bladder cancer and 2.3 ( = 4 95% CI, 0.6-5.8) for cancers of the lymphatic and haematopoietic system. SMRs for lung cancer by duration of employment were [1.0] (4 observed, 3.8 expected) [95% CI, 0.3-2.7] for < 5 years, and [3.3] (5 observed, 1.5 expected) [95% CI, 1.1-7.8] for 5-14 years. No case was observed with duration > 15 years. 

In a study of 102 workers from acrylic fibre factories in Japan, Sakurai et al. (1978) did not find any significant abnormality in liver function tests related to acrylonitrile exposure. 

Starr TB, Cause C, Youk AO, Stone R, Marsh GM, and Collins JJ (2004) A risk assessment for occupational acrylonitrile exposure using epidemiology data. Risk Analysis 24(3) 587-601. 

Internet search are Legionnaires disease, Agent Orange, breast cancer and silicone implants, thalidomide, and Bendectin. The National Cancer Institute has many fact sheets on a wide range of topics related to cancer at http //www.cancer.gov/cancertopics/factsheet/Risk. Two other examples are a false positive in early studies of breast cancer associated with serum level of DDE [l,l-dichloro-2,2-bis(p-chlorophenyl)ethylene] and a false positive between acrylonitrile exposure and lung cancer in occupational settings. 

Central nervous system dysfunction. Acute effects of exposure to acrylonitrile generally involve the central nervous system. Symptoms of acrylonitrile exposure include headache, nausea, dizziness, and general weakness. The animal studies cited above suggest possible carcinogenic effects of acrylonitrile on the central nervous system, since rats exposed by either inhalation or ingestion have developed similar CNS tumors. 

---