Formaldehyde as a Chemical Agent - Essay Example

Table of Contents Case study 3 What Is Formaldehyde? 4 Where Is Formaldehyde Found? 4 What Are Routes of Exposure for Formaldehyde? 5 Who Is at Risk of Overexposure to Formaldehyde? 5 What Are Standards and Regulations for Formaldehyde Exposure? 6 What Is the Biological Fate of Formaldehyde in the Body? 7 Metabolic pathways for formaldehyde 8 Health effects 9 Acute exposure 9 Chronic exposure 9 Conclusion 11 References 12 Case study A 30 year old man works at a textile industry that uses formaldehyde-based resins as finishers so that the fabrics are resistant to creases. His symptoms began three weeks ago with gradual onset of local irritation in the eyes, nose, and upper respiratory tract. He was also experiencing shortness of breath and chest pain. He had also experienced diarrhea, nausea, vomiting and abdominal pains that had subsided after three days. The family history is unremarkable since his parents, wife and two children were perfectly in good health. Social history: The patient has been working at the manufacturing industry for almost six months. Previously he has been working as a professor in a college in New York. After being laid off from the college, he relocated with his family and sought employment at the textile manufacturing industry. The past few days he has noted increased episodes of headaches and wheezing. Vital signs showed a blood pressure was at 124/86, pulse 124 bpm and respirations 42. From the laboratory tests there were increased levels of albumin in the urine, and a high level of DNA-protein crosslinks in white blood cells. Chest radiography indicated that the lungs were hyperinflated with flattened diaphragm with significant trapping of air. The doctors concluded that the symptoms were likely to be due to asthma and it was caused from inhalation of formaldehyde at the textile manufacturing industry. The patient was a non-smoker and the area he lived with his family was rural away from air pollutants. What Is Formaldehyde? Formaldehyde is an organic compound with the formula CH2O or HCHO and a molecular weight of 30.02598 g/mol. It has a boiling point of -19.50C and a melting point of -920C. Its log octanol/water partition coefficient is -0.65.It is under aldehyde chemical family. The systematic and trade names for Formaldehyde are formalin, formolmethanal, methyl aldehyde, oxomethane, paraform and methylene oxide. It is a colorless, flammable, and strong-smelling chemical gas. Formaldehyde is soluble in alcohol, ether and acetone. It has a vapor density of 1.08 and vapor pressure of 3,890mmHG at 25 degrees celcius per 100%. A formaldehyde solution has a pH of 2.8 to 4.0. Concentrations of formaldehyde can be in ambient air and indoor air. It is a highly reactive aldehyde gas which is formed by incomplete oxidation of hydrocarbons. The compound is very hazardous and the vapor is toxic. It is classified as a volatile organic compound since it is in gaseous state at room temperature (Gonzales, Bourgkard, Courouble, Clement-Duchene, Martinet, Fevotte & Paris, 2012). Where Is Formaldehyde Found? Formaldehyde is found in many consumer goods and substances. According to the International Agency for Research on Cancer (IARC), in 2004, Formaldehyde production exceeded 46 billion pounds globally (OSHA, 2013.) It is used in several different aspects. It is utilized in producing pressed wood products such as fiberboard, particleboard, and hardwood plywood wall paneling. It is also found in furniture that made with pressed wood products. Moreover, Formaldehyde is in tobacco smoke (cigarettes). Specifically, Formaldehyde is utilized in melamine, polyacetal, and phenolic resins manufactures. It is also widely used as a preservative, a corrosion inhibitor, sterilizing agent, and in embalming fluids. Formaldehyde is found in indoor sources. It can be in paper products, pesticide, permanent press fabrics, carpets, and furniture or in cosmetic products such as lotions and shampoo, and professional keratin hair smoothing treatments therefore increasing air concentration of formaldehyde indoors. On other hand, Formaldehyde is also in outdoor sources. These are emission from fuel combustion such as motor vehicles. Industrial fuel combustion is also a source of formaldehyde outdoors. For example, power generators, automobile exhaust, forest fires and oil refining processes in petroleum industries emit Formaldehyde. However, it is rapidly broken down from the environment by sunlight or aerobic bacteria. There are quantities of formaldehyde and its adducts that are ubiquitous in the human organisms which are formed in metabolism of endogenous amino acids and is found in the blood stream concentrations of 0.1 millimolar. What Are Routes of Exposure for Formaldehyde? The main route of Formaldehyde to enter the body is via inhalation, but there are other route of exposures, which are dermal contact and water due to treatment of textiles and formation of resins and embalming of bodies by mortuary workers, and ingestion of contaminated food and water. However, ingestion of water and food are unlikely route of exposures to formaldehyde. Also, absorption of formaldehyde via body skin seems to be insignificant. In other words, the main potential routes of exposures for formaldehyde are inhalation and dermal contact, so employees might inhale formaldehyde as vapor or gas or absorb it via body skin as liquid (WHO, 2001) . Who Is at Risk of Overexposure to Formaldehyde? Formaldehyde is a chemical allergen whereby its physiological effects is elevated release of histamine and cell mediated immunity. Formaldehyde generally exists at low levels in indoor and outdoor air. Materials that contain Formaldehyde emit Formaldehyde as gas or vapor into the air, which usually be less than 0.03 PPM in normal circumstances. Human beings are at risk to expose to Formaldehyde in air. They might be exposed to Formaldehyde in homes from various consumer products such as home furnishings and building materials. Children also are at risk to expose Formaldehyde in schools. According to Environmental Protection Agency, a survey of Formaldehyde sampling in New York City demonstrated that the level of Formaldehyde in homes exceeded the outdoor air level even though those homes were nonsmoking family homes. On the other hands, the survey showed that individual in smoking family homes intake approximately from 30 to 67 μg of Formaldehyde. Formaldehyde could also be present in food naturally or a s a contamination (U.S Environmental Protection Agency, 2000) What Are Standards and Regulations for Formaldehyde Exposure? The permissible Exposure Limit (PEL) for Formaldehyde is 0.75 parts Formaldehyde per million parts of air (0.75 ppm) as an 8-hour Total Weight Average (TWA) and 2.0 parts Formaldehyde per million parts of air (2 ppm) as a 15-minute Short Term Exposure Limit (STEL). To clarify, according to 29 CFR 1910.1048(c) (1) and 29 CFR 1910.1048(c) (2), the employer shall assure that no employee is exposed to an airborne concentration of formaldehyde which exceeds 0.75 parts formaldehyde per million parts of air (0.75 ppm) as an 8-hour TWA and the employer shall assure that no employee is exposed to an airborne concentration of formaldehyde which exceeds two parts formaldehyde per million parts of air (2 ppm) as a 15-minute STEL. (OSHA, 2013). It has also been established that if formaldehyde exceed 0.1ppm, some individuals may experience burning sensations in the throat, eyes and nose to people who are sensitive to formaldehyde exposure. What Is the Biological Fate of Formaldehyde in the Body? Formaldehyde is readily to react and combine with several substances. It is also easily absorbed through the respiratory and gastrointestinal routes (Barile, 2004). First, the formaldehyde is rapidly absorbed in the respiratory and gastrointestinal tract and metabolized due to its solubility in water. However, due its rapid metabolism, exposure of human to formaldehyde by inhalation does not alter the concentration of endogenous formaldehyde in the blood. Formaldehyde reacts immediately with primary and secondary amines, hydroxyls, thiols and amides to form methylol derivatives. It acts as an electrophile and can react with macromolecules such as DNA, RNA, and protein to form reversible adducts or irreversible cross links. Absorbed formaldehyde can be incorporated into biological macromolecules via tetrahydrofolate-dependent one carbon biosynthetic pathways or can be oxidized to formate through three different pathways. Absorbed formaldehyde can be exhaled as carbon dioxide through the lungs. Small quantities may be excreted in urine as formate salts. Formate can be then oxidized to carbon (IV) oxide. Formaldehyde dehydrogenase is widely distributed in animal tissues is the major metabolic enzyme involved in the process. Formaldehyde can be incorporated into biological molecules which may form cross linkages between proteins, between proteins and single stranded DNA or enter one carbon intermediary metabolic pool by binding initially to tetrahydrofolate. Metabolic pathways for formaldehyde In the body, there is presence of formaldehyde dehydrogenase which belongs to the family of oxidoreductases, that catalyses the chemical reaction of formaldehyde to formate through three different pathways. This process is important since detoxification of formaldehyde which is toxic is important in many forms of life. In addition to formaldehyde, NAD+ and water are substrates to the enzyme while its products are formate, NADH and H+. In the formaldehyde concentration oxidation VI (H4MPT pathway) are carried out by enzymes that utilize either the cofactor tetrahydrofolate or cofactor tetrahydromethanopterin (H4MPT). Pterin cofactors tetrahydrofolate or tetrahydromethanopterin are condensed with formaldehyde that enters the cytoplasm and forms respective methylene derivative in a spontaneous or enzyme-catalyzed reaction respectively. The tetrahydrofolate pathway is a major biosynthetic pathway while the tetrahydromethanopterin pathway is used mostly for the generation of power reduction and ATP therefore have different physiological roles. 5, 10-methylenetetrahydrofolate can be metabolized when it enters the serine cycle where carbon is used for biosynthesis or may be oxidized into 5,10-methylenetetrahydrofolate, 10-formyl-tetrahydrofolate then finally to formate. Formate can be oxidized carbon (IV) oxide through the action of various formate hydrogenases. The reaction is reversible (ATSDR, 2005). Formaldehyde Health effects Exposure to formaldehyde has adverse health effects depending on the period of exposure whether acute or chronic. Body organs such as eyes, nose and throat as well as body systems such as the neurological and respiratory systems can be affected. Acute exposure There are major toxic effects caused by acute formaldehyde exposure. “Formaldehyde is mainly an irritant. Irritations of eyes, nose and throat were observed in human controlled studies after short-term formaldehyde exposures at levels starting from 0.5-1 ppm. It is a sensitizer and can cause allergic contact dermatitis and asthma.” (IARC 1995). National Institute for Occupational Safety and Health (NIOSH) states that 20 ppm of Formaldehyde is immediately dangerous to life and health (IDLH) (NIOSH, 2013). Coughing, bronchitis, wheezing and chest pains are observed from the exposure to high levels of formaldehyde. Corrosion of the gastrointestinal tract and inflammation and ulceration of the mouth, esophagus and stomach in humans after ingestion of formaldehyde. It can also lead to violent vomiting, severe abdominal pains, headache and diarrhea after ingestion. Chronic exposure The chronic effects of exposure to formaldehyde inhalation in humans has been associated with respiratory symptoms and eye, nose and irritation of the throat. Skin irritation and dermatitis in humans is a result of repeated contact with solutions of liquids with scaling, cracking and white discoloration. In experimental animal studies, there are reports that exposure to formaldehyde has effects on the nasal respiratory epithelium and lesions in the respiratory system from chronic inhalation exposure to formaldehyde. Female workers using urea-formaldehyde resins were observed to have increased incidence of menstrual disorders. However, there were confounding factors that were not evaluated in the study. According to IARC (2005), there is sufficient epidemiological evidence that formaldehyde causes nasopharyngeal cancer in humans. There is strong but not sufficient evidence for a causal association between leukemia and occupational exposure to formaldehyde, particularly myeloid leukaemia. There is only limited epidemiological evidence that formaldehyde causes of the nasal sinuses in humans. A number of studies have found associations between exposure to formaldehyde and cancer at other sites including oral cavity, oro- and hypopharynx, pancreas, larynx, lung and brain. The overall balance of epidemiological evidence did not support a causal role for formaldehyde in relation to these other cancers. There is a study that indicates workers who are exposed to formaldehyde had a higher chromosome changes in early white blood cells in the bone marrow. Methanol used to stabilize formaldehyde causes vision impairment and enlargement of the liver. In children there is an increased rate of having asthma as a result of indoor air pollution since most they spend most of their time indoors. A study showed that children who were reported to wheeze had been exposed to higher levels of formaldehyde compared to those without the symptoms therefore greater prevalence of asthma and chronic bronchitis. It has also been suggested that there were higher concentrations of formaldehyde in homes of patients with nocturnal breathlessness compared to those without the symptoms. Even at low concentration, formaldehyde found in indoor paint invokes inflammatory response in the airways of healthy children. (Rumchev, Spickett, Bulsara, Philips & Stick, 2002) Conclusion Formaldehyde is likely to cause serious health effects on people therefore workers should be protected from overexposure. The exposure limit to formaldehyde should be 0.75 ppm. Use of exterior grade pressed wood has been recommended because they emit less formaldehyde compared to urea resins. People are advised to inquire about the levels of formaldehyde in content before buying. It is also important to ensure adequate ventilation, moderate temperatures and reduced humidity levels so as to reduce References Agency for Toxic Substances and Disease Registry (ATSDR). (2008). Toxicological Profile for Formaldehyde. Atlanta, GA: U.S. Department of Health and Human Services, Public Health Service IARC Monograph (1995). Formaldehyde. monographs.iarc.fr Accessed on Tuesday 18th November 18, 2014 Occupational Safety and Health Administration (OSHA) (2011). Formaldehyde. www.osha.gov accessed on Tuesday 18th November, 2014 Rumchev, K.B., Spickett, J.T., Bulsara, M.K., Philips, M.R., Stick, S.M. (2002).Domestic exposure to formaldehyde significantly increases the risk of asthma in young children. European Respiratory Journal, 20(2): 403-8. Toxicokinetics and Modes of Action of Formaldehyde." Review of the Environmental Protection Agencys Draft IRIS Assessment of Formaldehyde . Washington, DC: The National Academies Press, 2011 . U.S. Environmental Protection Agency (2000). Health and Envrironmental Effects Profile for Formaldehyde. Environmental Criteria and Assessment Office, Ofiice of Health and Environmental Assessment, Ofiice of Research and Development, Cincinnati, OH. Wild, P., Gonzalez, M., Bourgkard, E., Courouble, N., Clement-Duchene, C., Martinet, Y., Fevotte, J., & Paris, C. (2012). Occupational risk factors have to be considered in the definition of high-risk lung cancer populations. British Journal of Cancer 106,1346-1352 World Health Organization (WHO) (2001). Formaldehyde. WHO Regional Office for Europe Copenhagen, Denmark. Read More