Acrylonitrile Fact Sheet WHAT IS ACRYLONITRILE ? Also known as: 2-propenenitrile, vinyl cyanide, cyanoethylene Chemical formula and structure: C 3H3N Physical properties : colorless to pale yellow liquid, with a garlic- or onion-like odor Chemical properties: volatile, flammable liquid (explosive if exposed to flame), soluble in water and most organic solvents; reactive, polymerizes spontaneously with heat or strong alkali. CAS #: 107-13-1. Uses: Used extensively in the manufacture of acrylic and modacrylic fibers (fabrics used in textiles), acrylonitrile-butadiene-styrene (plastics used in business machines, luggage, and construction material), styrene-acrylonitrile (plastics used in automotive and household goods, and in packaging material), and adiponitrile (a chemical used to make nylon). A mixture of acrylonitrile and carbon tetrachloride was used as a pesticide in the past; however, all pesticide uses have stopped . WHERE DOES ACRYLONITRILE COME FROM ? Sources: Acrylonitrile does not occur naturally. Sources of release of acrylonitrile to the environment include fugitive emissions from facilities producing, processing, and using the chemical in the manufacture of acrylic and modacrylic fibers, resins, adiponitrile, acrylamide, and other resins and chemicals. Other sources of acrylonitrile include landfills, cigarette smoke, auto exhaust, and the incineration of sewage sludge. It may also be released from polyacrylic fibers and plastics. What is the statewide inventory for acrylonitrile? Approximately 170,000 pounds of acrylonitrile were emitted into the air in California in 2002. Acrylonitrile is a product of incomplete combustion and is emitted from cars and trucks (mobile sources). Acrylonitrile is also emitted directly from stationary sources. According to our estimates, the most significant stationary sources are landfills (46%), the chemical industry (33%), other industrial processes (10%), and petroleum marketing (7%). There are no known natural sources of acrylonitrile. [Note: The emission estimates for landfills are not consistent between local air districts, and it is unclear if the emission estimates are accurate.] What do future projections of acrylonitrile emissions show? Acrylonitrile emissions from motor vehicles will continue to decrease as more stringent controls are required for passenger cars and other mobile sources. It is unknown to what extent acrylonitrile emissions from stationary sources will decrease in the near term. HOW IS ACRYLONITRILE MEASURED ? Monitoring methodology: A Xontech 910A sampler is used to collect the sample into a SUMMA stainless steel canister. Samples are extracted in the MLD lab and undergo preconcentration on a three bed adsorbent trap, thermal desorption to a cryofocuser at the GC injector, separation using a DB-624 column, and detection by mass spectrometry. Level of Detection (LOD) for acrylonitrile: 0.3 ppb. % of samples above the LOD? Slightly more than 75% of samples have produced values above the LOD. Sampling frequency and averaging time: 24-hour (midnight-to-midnight) acrylonitrile samples are collected once every 12 days. Monitoring locations: 17 sites in California (and 2 in Mexico) monitor acrylonitrile. California sites are Azusa, Bakersfield-5558 California Avenue, Burbank-W Palm Avenue, Calexico-Ethel Street, Chico- Manzanita Avenue, Chula Vista, El Cajon-Redwood Avenue, Fremont-Chapel Way, Fresno-1st Street, Los Angeles-North Main Street, North Long Beach, Riverside-Rubidoux, Roseville-N Sunrise Blvd, San Francisco-Arkansas Street, San Jose-Jackson Street, Simi Valley-Cochran Street, and Stockton-Hazelton Street. Mexico sites are Mexicali-Calzada Benito Juarez and Rosarito. How much data are available? Acrylonitrile data are available starting July 2003 and currently through January 2005. Monitoring is ongoing. 1 ARB/PTSD/AQDB/5-19-05 Do the ambient data show any trends? There isn't enough data for temporal trends to be evaluated. There does not appear to be any geographical pattern to the data. WHAT HAVE WE LEARNED FROM ACRYLONITRILE MEASUREMENTS? Levels observed: In 2004 (the only year with complete data), the statewide annual average concentration was 0.48 ppb, which corresponds to an estimated risk of 299 cancer cases per million population. Daily measurements ranged from below-the-LOD (0.3 ppb) to a high of 2.0 ppb. Fremont-Chapel Way and Los Angeles have observed the highest concentrations; Fresno-First Street and San Jose-Jackson have observed the lowest concentrations. Are there daily, monthly, or seasonal variations? Since measurements are made over 24 hours, it's not possible to assess diurnal variations. There is no discernable trend in monthly or seasonal levels, however the limited data record makes this determination inconclusive. Geographical variation: There is no clear geographical pattern in the acrylonitrile measurements. However, there are contrasts between neighboring sites: In the San Francisco Bay Area, Fremont-Chapel Way is the highest site in the network, whereas San Jose-Jackson Street is one of the lowest; similarly in San Diego County, El Cajon-Redwood Avenue is among the higher sites while nearby Chula Vista is one of the lowest. Hot spots: The ambient data don't have sufficient spatial resolution to allow us to discern hot spots. An analysis of emission patterns is needed to investigate hot spots. Global background: Pending. WHAT ENVIRONMENTAL PROBLEMS DOES ACRYLONITRILE POSE ? Environmental fate of airborne acrylonitrile: The half life for acrylonitrile is on the order of 5 to 50 hours. EPA suggests that this is long enough for dispersion to be likely. Acrylonitrile reacts readily with oxygen and hydroxyl radicals in the atmosphere to form formaldehyde, formic acid and formyl cyanide. In soil and water, acrylonitrile is most likely to volatilize into the atmosphere, though bacteria in soil and surface water metabolize acrylonitrile. Does acrylonitrile contribute to any criteria pollutant problems? Acrylonitrile can contribute to the formation of photochemical smog when it reacts with other volatile organic compounds (VOCs) in the air. Multimedia effects: Acrylonitrile is not typically found in soil or water, either because it volatilizes, leaches into groundwater, is transported by water runoff, or is broken down by bacteria. WHAT ARE THE HEALTH EFFECTS OF EXPOSURE TO ACRYLONITRILE ? How are people exposed to acrylonitrile? Acrylonitrile enters the body when people breathe air, consume water or food contaminated with it, or in some instances via absorption following skin contact. Exposure can occur in the workplace or in the environment following releases to air, water, land, or groundwater. Exposure can also occur when people smoke cigarettes or breathe automotive exhaust. It doesn’t remain in the body due to break down and removal. What are the symptoms associated with exposure to acrylonitrile? Liquid to skin contact causes skin redness and blisters. Acute exposure to high concentrations can cause nose and throat irritation, tightness in the chest, difficulty breathing, nausea, dizziness, weakness, headache, impaired judgment, and convulsions. These symptoms abate when exposure is terminated. Animal studies suggest that decreased fertility and birth defects may result from exposure to high concentrations. It appears that children are much more sensitive to acrylonitrile exposure than are adults. Is there a medical test to determine if someone has been exposed to acrylonitrile? Yes. A blood test (not routinely available) can detect acrylonitrile. A urine test is also available, but it is not conclusive, since it tests for metabolites, which may derive from other sources. Is acrylonitrile a carcinogen? Yes. OEHHA has determined that it is related to human respiratory tract cancer and given it a unit risk factor of 0.00029 ug/m 3. Cancer occurs primarily in the respiratory tract. Studies have also shown that repeated exposure to acrylonitrile adversely affects the respiratory and central nervous systems. 2 ARB/PTSD/AQDB/5-19-05 What levels of acrylonitrile pose adverse health effects in people? Breathing acrylonitrile for short periods of time adversely affects the nervous system, the blood, the kidneys, and the liver; these effects subside when exposure stops. Nervous system effects range from headaches, dizziness to irritability, rapid heartbeat, and death. Symptoms of acrylonitrile poisoning may occur quickly after exposure or after levels of breakdown products like cyanide build up in the body. Direct contact with liquid acrylonitrile severely damages the skin. Its vapor causes eyes, nose, and throat irritation. These effects are not likely to occur at levels normally found in the environment. How does the risk of exposure to acrylonitrile compare with other TACs? The ambient data suggest that acrylonitrile is pervasive in the atmosphere. While exposure to other substances might be related to proximity to specific sources (benzene and 1,3-butadiene from motor vehicles, for example), there's no evidence -- yet -- that this applies to acrylonitrile. The unit risk factor for acrylonitrile is about 1.5 times that of 1,3-butadiene, and more than six times that of benzene. [Incomplete – need to say something about the risk due to acrylonitrile compared to diesel and other TACs] Does acrylonitrile have synergistic effects with other pollutants or toxics? Unknown. Is indoor exposure to acrylonitrile of concern? Canadian research has shown that tobacco smoke appears to be a source of acrylonitrile in indoor air. Acrylonitrile was found in 4 of 47 houses sampled in 1990, and the mean concentration from these 4 samples was 9.1 micrograms per cubic meter (4.2 ppb). Sources: 1. nsc.org: http://www.nsc.org/library/chemical/acryloni.htm 2. atsdr.cdc.gov: http://www.atsdr.cdc.gov/tfacts125.html 3. epa.gov: http://www.epa.gov/opptintr/chemfact/acry-sd.txt 4. Technical Support Document for Describing Available Cancer Potency Factors, December 2002 5. ec.cg.ca: http://www.ec.gc.ca/NOPP/DOCS/P2Plans/ACN/en/faq.cfm 6. Toxic Air Contaminant Identification List Summaries - ARB/SSD/SES September 1997 3 ARB/PTSD/AQDB/5-19-05 .