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Children and Solvents Amber E. Barnato, MD, MPH
Solvents are pervasive in manufacturing processes, and the majority of environmental contamination results from releases by industry. The majority of personal human exposure to solvents, however, comes from indoor sources such as household cleaners, recently dry-cleaned clothes, insecticides, paints, glues, and fuels. Solvents also are commonly abused as inhalants. Acute health effects include CNS depression, skin and mucous membrane irritation, and risk of myocardial sensitization. Treatment is primarily supportive and prevention should be emphasized. The materials in this module are appropriate for use in a didactic noon conference or for problem-based learning which uses case histories. Cases and tables are included as handouts and visual aids. Learning Objectives At the completion of this teaching module, pediatric, family practice, and nursing faculty will be able to teach students to:
General Principles of Solvent Toxicity Introduction A solvent is a liquid used to dissolve other substances. Not all solvents pose health risks: water, for example, is a solvent. This module, however, will refer to solvents that are extracted or manufactured for chemical use. Many commonly used substances, such as gasoline, white spirit, kerosene, and jet fuel, are mixtures of solvents and other chemicals. Most solvents are colorless liquids at room temperature that volatilize easily and have sweet odors. They are usually lipophilic, but some are water-soluble. These compounds may be referred to as volatile organic compounds (VOCs) (in reference to their physiochemical properties), or as hydrocarbons (in reference to their chemical structure). They are widely used for manufacturing, degreasing and other cleaning, and as carrying agents (or "inert" ingredients) in products ranging from insecticides to glues and paints. There is little information in animals or humans regarding the health effects of chronic low-dose exposure, which is more common than high-dose exposure in children and adults.1 Much of the data on health effects comes from case series data from children who abuse solvents, along with epidemiological data from adults who suffer acute occupational exposure. Similarly, animal data focus on the correlation of high-dose solvent exposure with acute and chronic morphological, biochemical, neuropsychologic and pathophysiologic effects. Information on the health risks of solvent exposure may change over time as research better defines this area of environmental health. This teaching module focuses on unintentional solvent exposure among children. However, sniffing or "huffing" abuse of solvents by children and adolescents poses a significant public health burden.2 Young "huffers" show the most severe effects of solvent exposure. What are the sources and uses of solvents? The many household and industrial uses of solvents are shown below.3 In general, volatile organic solvents are used as intermediates in the manufacture of other chemical compounds, rubber, and plastics, as degreasing and cleaning agents, as carriers for pigments in paint and ink, as adhesives in glue, as paint and varnish strippers, and as fuels. Products containing almost 100% solvents include paint thinner, furniture stripper, dry-cleaning fluid, spot remover, degreaser, turpentine, and nail polish remover. Products that are composed partially of solvents include furniture oil, glues, aerosol sprays, shoe care products, rug cleaners, and oil-based paints.4
How are solvents distributed in the environment? Solvents can be released into the environment during their production, storage, transportation, and use. Because of their volatility, solvents quickly evaporate into the air and can be found in high concentrations when used in poorly ventilated indoor spaces. Once released into the atmosphere, these compounds are photo-oxidized, either rapidly or slowly depending on the compound. Some solvents create free radicals that contribute to the depletion of atmospheric ozone. When released onto the soil, these compounds evaporate or are slowly biodegraded. If released to surface water, they similarly evaporate. However, most volatile organic compounds are virtually impossible to remove once they have permeated ground water. Solvents cannot, for example, be removed effectively by filtration devices or water treatment plants from ground water that is used as a household water supply. They are volatilized during activities that utilize hot water, such as showering, cooking, or laundering. How are solvents absorbed by and excreted from the body? Solvents are most commonly inhaled in their volatilized form and absorbed via the respiratory tree directly from solvent-containing liquid products such as paints, and from solvent-contaminated water through off-gassing during hot showers, cooking, and laundering. Some of the inhaled dose that is not absorbed is exhaled. Significant doses of solvents may occur through skin exposure and absorption.5 Since most solvents are lipophilic, they can be excreted in breast milk and ingested by nursing infants and children. Finally, unintentional ingestion of liquid solvents or solvent-contaminated food and water results in absorption through the gastrointestinal tract. Among young children, accidental ingestion or dermal contact with solvents is the most commonly reported mode of exposure. Accidental ingestion of solvents comprises 5% of all accidental poisonings in children under age five. Solvent exposures via indoor and outdoor air Extensive data on exposure to environmental pollutants comes from the Environmental Protection Agency's Total Exposure Assessment Methodology (TEAM) Study. In direct measurements (outdoor air sampling, personal air samplers, and exhaled air analysis), persons aged 7-78 in five geographically diverse cities were assessed for exposures to a number of toxicants, including solvents. In an industrial city, solvent exposure did not correlate with residence near a source of industrial solvent emissions.6 In all communities, personal exposure to solvents (as measured by personal sampling in the breathing zone) were at least three times higher than concurrent outdoor concentrations of the solvents. In this study, the majority of children's solvent exposures came from indoor sources, such as second-hand cigarette smoke and newly dry-cleaned clothes, rather than from outdoor pollution.7, 8 Recent studies using biologic markers to study exposure in populations living near solvent sources have produced variable results. A community study of persons aged 8-75 living near a hazardous waste site, which measured blood levels of 31 volatile organic compounds, found that only acetone levels were significantly elevated when subjects were compared both to residents living at a greater distance from the site and to a national reference population.9 A study of residents living near a polyurethane manufacturing plant that emitted toluene diisocyanate found antibodies to the compound in 9% (10 persons) of those studied. Only 3 of the 10 positives had occupational or vocational exposures to the chemical, suggesting that ambient air may have been a source of exposure to toluene diisocyanate.10 A European study of residents living near 12 dry-cleaning shops demonstrated higher perchloroethylene concentrations in exhaled air samples taken from those living closer to the shops.11 A more recent study conducted among New York City residents who lived in buildings with dry-cleaning establishments on the ground floor demonstrated elevated biomarkers of exposure to perchloro-ethylene, particularly among those spending a great deal of time at home, such as infants, children, pregnant women, lactating mothers, and the elderly.12 Health Effects of Solvents Animal studies in the toxicology literature emphasize the role of solvents as neuro-toxins.13 Solvents that act primarily on the central nervous system ó including toluene, xylene, and styrene ó have been demonstrated in many animals to cause morphological and biochemical changes in the brain that, in turn, produce neuropsychological, motor, and behavioral effects. Solvents that act as peripheral nervous system toxins have been shown in animals to damage axons, myelin, and the function of axonal transport. Studies have not been conducted on the effects of solvent exposure in children. Findings reported in case studies of young solvent abusers, however, are consistent with the health effects reported from acute and chronic high-dose solvent exposures in the workplace. Some of the human health effects are listed below. Neurotoxicity The majority of solvents are central nervous system depressants and some have long-term neuropsychological effects, including chronic toxic encephalopathy.14 Long-term exposure to n-hexane, methyl butyl ketone, or methyl ethyl ketone is associated with peripheral neuropathy.15 Some case-control studies have found an association between exposure to organic solvents and multiple sclerosis, while others have not.16 In adults, the following neurobehavioral problems resulting from chronic solvent exposure have been recorded in the literature:
Carcinogenicity Many solvents are considered by the EPA to be suspected or confirmed carcinogens.17, 18 Known human carcinogens:
Suspected carcinogens:
Liver and Kidney Effects Solvents, particularly toluene and chlorinated solvents, can cause permanent damage to the liver and kidney.19, 20 Respiratory Effects Pulmonary sensitization to solvents can lead to asthma.21 In addition, aspiration after ingestion may cause a chemical pneumonitis that can be profound and fatal (see case 1, below). The lower the viscosity of the compound, the higher the likelihood of chemical pneumonitis. Some solvents are also thought to cause apnea and respiratory irritation.22 Cardiac Effects Animal studies have demonstrated that toluene exposure can produce high degree AV block and SA node suppression, and that fluorocarbons can produce bradycardia and lower escape rhythms resulting in ventricular fibrillation or asystole.21 Benzene, heptane, chloroform, and TCE are potent cardiac sensitizers, carbon tetrachloride and halothane are moderate cardiac sensitizers, and ethane, propane, propylene, n-butane, acetylene, spiropentane, isobutane, butene, cyclobutene, isopentane, dimethylbutane, dimethylether, and methyl cyclobutanes are weak cardiac sensitizers.21 Sudden death has been reported from inhaling typewriter correction fluid containing 1,1,1-tricholorethane.23 Dermal Effects Sustained or chronic dermal contact with solvents can result in defatting of the dermis and in chemical burns. Exposure can result in eye and mucous membrane irritation. Fetal health effects Some data suggests that the risk of spontaneous abortion is increased in women occupationally exposed to perchloroethylene, trichloroethylene, paint thinners (white spirit),24 or toluene.25, 26 Mental retardation has been observed more frequently in the offspring of women exposed to organic solvents in late pregnancy.27 Since 1979, evidence has mounted that the constellation of facial dysmorphology, small head size, and low birth weight sometimes seen in children born to women who abused toluene during pregnancy represents a clinical entity, fetal solvent syndrome. The pathology is similar to that observed in fetal alcohol syndrome.28,29 Renal tubular acidosis can be seen in the newborns of women who abused toluene during pregnancy.30 Health effects in children Other than accidental ingestion, there is scant data beyond case reports in the literature on the health effects of unintentional solvent exposure in children (see case 2, below). One study attributed low-level exposures to a combination of solvents in drinking water to a childhood leukemia cluster in Woburn, MA.31 The study was criticized on methodological grounds, however, and other investigations have failed to replicate the findings. Further epidemiological studies and research in animal models is needed to determine the health effects of chronic, lowlevel exposure to mixtures of solvents, which may occur in home environments. Clinical Recognition of Solvent Poisoning As described above, the most common signs of solvent exposure are central nervous system depression, which can include such non-specific symptoms as headache, dizziness, irritability and fatigue. Eye, mucous membrane, and respiratory tract irritation, and nausea may also be present. A patient or caretaker may note symptom onset in association with a sweet odor, but not all solvents are detectable by odor at toxic thresholds. Chronic toxicity may be even more difficult to identify. The most important rule of thumb is to consider exposure to toxicants, including solvents, in the differential diagnosis when evaluating children with puzzling symptoms. Clinical uses of biomarkers Many solvents remain in steady state between blood and alveolar air, and are measurable in the blood and in exhaled air, particularly at end-expiration. Metabolites from liver oxidation or conjugation can be measured in the blood and urine. In some cases, the solvent metabolite is more toxic than the parent compound.32 Though solvents and their byproducts can be measured in blood, urine, or expired air, the half-life is usually very short, making measurement difficult. In addition, tests for biologic markers of solvent exposure generally are not clinically available to child health providers. Such tests may be available through consultation with an occupational health practitioner. Treatment In the case of acute intoxication secondary to inhalation of solvent fumes, removal from the source to an area with open ventilation and supportive measures are indicated. There are no antidotes for solvent exposure and plasmapheresis has not shown any benefit. Supplemental oxygen, assisted ventilation as necessary, and cardiac monitoring are used in the hospital setting. In the case of aspiration and chemical pneumonitis, it is important to avoid fluid overload. Aspiration, which may result in vomiting and seizures, is a risk with acute intoxication. Risk of aspiration may be increased by gastric lavage.33 Therefore, gastric emptying is not recommended when the ingestion poses little threat of systemic toxicity through gastrointestinal absorption (such is the case with kerosene, naphtha, gasoline, and mineral spirits). Gastric lavage may be indicated for those compounds that do pose a significant threat of systemic toxicity from gastrointestinal absorption (such as aromatic hydrocarbons such as benzene, toluene, and xylene, solvents such as chlordane, and carbon tetrachloride, or hydrocarbon-pesticide mixtures such as organophosphates in kerosene). However, the use of gastric emptying for this purpose is highly controversial. All patients with signs and symptoms of possible aspiration (coughing, choking, gasping, and vomiting) should be brought into an emergency department for evaluation. Those with clear signs and symptoms of aspiration or with respiratory compromise should be admitted for supportive treatment. If the ingestion patient demonstrates no signs and symptoms and the chest X-ray is negative, 6-8 hours of observation followed by discharge is considered appropriate.33 In older children, suicidal intent should be explored. In the case of dermal contact, clothing should be removed and placed outdoors or bagged, and skin should be washed with soap and water to prevent dermatitis and chemical burns (see case 3, below). Eyes should be irrigated for 10-15 minutes. The regional poison control center can play an important role in managing these cases in the home, clinic, or hospital setting. Prevention Prevention entails keeping all cleaning agents, gasoline, paints, glues, thinners, and other household products in locked or inaccessible cabinets. These products should never be used in closed spaces, and areas should be extensively aired out after product use. Even with adequate room ventilation, it is probably prudent to avoid exposing children altogether (see case 4, below). Tell parents to avoid bringing children to nail salons and to keep children out of newly remodeled rooms that may be off-gassing solvents from carpet and wallpaper glues. Dry-cleaning should be aired out in the yard or an open garage for one day before being brought into the house, and car windows should be open when transporting freshly dry-cleaned clothes. The dangers of gasoline siphoning and gasoline ingestion should be made clear to young people and their parents (see case 5, below). As in the home, art supplies used at school should be nontoxic. "Acceptable Children's Art and Craft Materials," a list of 2,500 nontoxic art materials, is available from the California Department of Health Services.34 Clinicians must be alert to parents who might be exposing their children to solvents in the home though a number of hobbies, including silk-screening, furniture restoration, model building, and illegal drug labs (an increasing problem in certain communities).35 Finally, children should be screened during the well-child interview for any drug abuse, including the use of "legal" substances such as solvents. The best way to dispose of solvents is to use them up as intended. Otherwise, solvents should be treated as hazardous waste and disposed through a licensed hazardous waste handler.36 Learning Methods The best format for presenting this information to busy students or residents is during a teaching conference. This material can be covered in one hour; the cases found at the end of this module can be used as a starting point or incorporated into the body of the lecture. Each case should be broken down into parts, with each participant getting case clues a few sentences at a time. The participants can ask for elements of the history and physical and the session leader can mete out answers and further clues. The focus should be on differential diagnoses that include environmental or toxic exposures. The session leader can use the text material as background for teaching salient points as participants discuss the case(s). Evaluation Methods Fulfillment of the learning objectives can be determined by completion of a brief post-test. Visual Aids: Cases And Tables Show one or more case studies at the beginning of the teaching conference or during presentation of the relevant topics as indicated in the text, or use them as discussion tools in small group sessions. Case Studies Case 1 37 A 16-year-old boy is brought into the emergency department with recurrent generalized seizures and vomiting of 1 hour's duration. There is no significant PMH. A search of the boy's pants pockets reveals several magazine photographs of movie stars and a note from a girl inviting him on a date. The child is afebrile, p 100/reg; blood pressure 90/60 mmHg. The cardiac exam is normal but there is decreased air entry in the left lower lung field. His breath smells of turpentine and questioning reveals ingestion of 200 ml of turpentine 1.5 hours before hospital admission. The labs are all within normal limits; a chest X-ray shows haziness in the LLL. Gastric lavage with saline and sodium bicarbonate is performed. The boy's respiratory status deteriorates, requiring intubation. He is managed with IV fluids, antibiotics, corticosteroids, diazepam, and atropine. The patient dies within 4 hours of hospitalization. An autopsy reveals the presence of food particles in the stomach with a sweet odor and mucosa with punctate bleeding; the lungs and kidneys are congested; the meninges and cortical surfaces of the brain demonstrate multiple small bleeding points. Case 2 38 A teenage boy is brought into the ED intubated, unresponsive, pulse 88, pressure 90/palp, in sinus rhythm with occasional PVCs and a normal QT interval. His pupils are fixed and dilated. The paramedics report that they were called to the scene by parents who found the child unresponsive in a sleeping bag on the floor. The patient was resuscitated from full arrest with a time of hypoxia of at least 15 minutes. There was a plastic dry-cleaning bag near the sleeping bag, which had just been brought home from the cleaners; however, the bag was not on the teenager's head when his parents found him. The child had no history of depression or known substance abuse and no empty bottles were found at the scene. Case 3 You are paged in the evening by the mother of an 8-month old girl. She explains that about 20 minutes previously the child had crawled into a room that was used for furniture refinishing, the father's hobby, and had spilled paint thinner on herself. The mother has washed the baby's chest and face with soap and water, and irrigated the eyes. She notes that an area under the child's diaper, that appears to be wet from the spill, has become red. On questioning, she responds that the child is crying and irritated, but does not seem to be lethargic nor is she coughing or vomiting. Case 4 A 15-month-old boy is brought to your urgent-care clinic with a 3-hour history of lethargy and vomiting. The mother is worried that he may have the flu. On physical exam you note a lethargic toddler with reactive pupils, no fever, pulse 110, blood pressure 96/66, good skin turgor and color, and no rash. Concerned about poisoning, you ask the mother if there is any chance the child could have "gotten into anything?" She says no because she kept him in his playpen all morning while she painted the living room, to be certain he stayed away from the paint cans. Case 5 39 A 9-year-old girl is brought into the ED with no pulse or pressure. Paramedics coded her for 35 minutes at the scene and enroute. She was found in asystole at the scene. At the hospital, further resuscitation efforts are unsuccessful and the child is pronounced dead. On questioning, her mother reports that she had asked the child to siphon gas from the car into a container to use in the lawn mower. The child had run down the hill to the car, siphoned the gas, and run back up the hill, dropping unconscious and unresponsive next to the lawn mower. At autopsy, no anatomical cause of death is found. Other Information Resources Your Regional Poison Control Center Your State Environmental Health Department Your State Health Department Agency for Toxic Substances and Disease Registry
National Institute for Environmental Health Sciences
United States Environmental Protection Agency, Office of Children's Health Protection
National Institute for Occupational Safety and Health
References 1 Ott WR, Roberts JW. Everyday exposure to toxic pollutants. Scientific American 86-91 (1998). 2 Henretig F. Inhalant abuse in children and adolescents. Ped Annals 25(1):45-54 (1996). 3 Human Toxic Chemical Exposure ñ Organic Solvents. Technical bulletin published by Pacific Toxicology Laboratories, Woodland Hills, CA. 1990-1999. 4 Orientation to Indoor Air Quality. US EPA 3/23/99; http://www.epa.gov/grtlakes/seahome/housewaste/house/solvent.html 5 Brown HS, Bishop DR, Rowan CA. The role of skin absorption as a route of exposure for volatile organic compounds in drinking water. Am Jrnl of Pub Hlth 74:479-484 (1984). 6 Wallace LA. Human exposure to environmental pollutants: a decade of experience. Clinical and Experimental Allergy 25:4-9 (1995). 7 Wallace LA, et al. The TEAM Study: personal exposures to toxic substances in air drinking water and breath of 400 residents of New Jersey, North Carolina, and North Dakota. Environmental Research 43:290-307 (1987). 8 Wallace LA, Pellizzari ED, Hartwell TD, Whitmore R, Zelon H, Perritt R, Sheldon L. The California TEAM Study: breath concentrations and personal exposures to 26 volatile compounds in air and drinking water of 188 residents of Los Angeles, Antioch, and Pittsburgh, CA. Atmospheric Environment 22(10):2141-2163 (1988). 9 Hamar GB, McGeehin MA, Phifer BL, Ashley DL. Volatile organic compound testing of a population living near a hazardous waste site. J of Ex Anal and Env Epi 6(2): 247-255 (1996). 10 Darcey D, Lipscomb H, Cherry L, Cooper M, Pate W, Smith CG. Community exposure to toluene diisocyanate from a polyurethane foam manufacturing plant ñ North Carolina. MMWR 47(22):455-457 (1998). 11 Verberk MM, Scheffers TML. Tetrachloroethylene in exhaled air of residents near dry cleaning shops. Environmental Research 21:432-437 (1980). 12 Schreiber J, Hudness K, Parker J. Assessing residential exposure to tetrachloroethylene using biomarkers and visual system testing in populations living above dry cleaning facilities. In Press. 13 Arlien-Soborg P. Solvent Neurotoxicity. Boca Raton: CRC Press, 1992;211-226. 14 Tsai SY, Chen JD, Chao WY, Wang JD. Neurobehavioral effects of occupational exposure to low level organic solvents among Taiwanese workers in paint factories. Environmental Research 73:146-155 (1997). 15 Mortensen JT, Bronnum Hansen H, Rasmussen K. Multiple sclerosis and organic solvents. Epidemiology 9:168-171 (1998). 16 Human Toxic Chemical Exposure ñ Organic Solvents. Technical bulletin published by Pacific Toxicology Laboratories, Woodland Hills, CA. 1990-1999. 17 Human Toxic Chemical Exposure ñ Organic Solvents. Technical bulletin published by Pacific Toxicology Laboratories, Woodland Hills, CA. 1990-1999. 18 ATSDR. Case Studies in Environmental Medicine (Toluene Toxicity, Trichloroethylene Toxicity, Tetrachloroethylene Toxicity, Benzene Toxicity, 1,1,1 Trichloroethane, Gasoline Toxicity, Jet Fuel Toxicity, and Stoddard Solvent Toxicity). U.S. Department of Health and Human Services, Public Health Service, Washington D.C. 19 Gist GL, Burg JR. Trichloroethyleneóa review of the literature from a health effects perspective. Toxicology and Industrial Health 11(3):253-307 (1995). 20 Mutti A, et al. Nephropathies and exposure to perchloroethylene in dry-cleaners. The Lancet 340:189-93 (1992). 21 Bernstein JA. Overview of diisocyanate occupational asthma. Toxicology 111:181-185 (1996). 22 ATSDR: Case Studies in Environmental Medicine (Toluene Toxicity, Trichloroethylene Toxicity, Tetrachloroethylene Toxicity, Benzene Toxicity, 1,1,1 Trichloroethane, Gasoline Toxicity, Jet Fuel Toxicity, and Stoddard Solvent Toxicity). U.S. Department of Health and Human Services, Public Health Service, Washington D.C. 23 King, GS. Sudden death in adolescents resulting from the inhalation of typewriter correction fluid. JAMA 253: 2604-1606 (1985). 24 Windham GC, Shusterman D, Swan SH, Fenster L, Eskenazi B. Exposure to organic solvents and adverse pregnancy outcomes. Am Jrnl of Indus Med 20:241-259 (1991). 25 Lindbohm ML, Maskinen H, Sallmen M. Spontaneous abortions among woman exposed to organic solvents. Am Jrnl of Indus Med 17:449 (1990). 26 Taskinen H, Kyyronen P, Hemminki K. Laboratory work and pregnancy outcome. Jrnl of Oc Med 36:311 (1994). 27 Roeleveld N, Zielhuis, Gabreels F. Mental retardation and parental occupation: a study on the applicability of job exposure matrices. British Jrnl of Indus Med 50:945-954 (1993). 28 Jones HE, Balster RL. Inhalant abuse in pregnancy. Ob and Gyn Clin of North America 25(1):153-167 (1998). 29 Arnold GL, Kirby RS, Langendoerfer S, Wilkins-Huang L. Toluene embryopathy: clinical delineation and developmental follow-up. Pediatrics 93(2):216-220 (1994). 30 Erramouspe J, Galvez R, Fishel DR. Newborn renal tubular acidosis associated with prenatal maternal toluene sniffing. Jrnl of Psychoactive Drugs 28(2)201-204 (1996). 31 Lagakos S, Wessen B, Zelen M. An analysis of contaminated well water and health effects in Woburn, Massachusetts. Jrnl of the Am Stat Assoc 81:583-596 (1986). 32 Arlien-Soborg P. Solvent Neurotoxicity CRC Press, Boca Raton, FL, 1992; 211-226. 33 Litovitz T, Greene A. Health implications of petroleum distillate ingestion. Oc Med 3:555-567 (1988). 34 Spandorfer M, Curtiss D, Snyder J. Making Art Safely. New York: Van Nostrand Reinhold, 1993. 35 The threat of meth. Envir Hlth Perspec 106(4):2-3 (1998). 36 Orientation to Indoor Air Quality. US EPA 3/23/99; http://www.epa.gov/grtlakes/ seahome/housewaste/house/solvent.html 37 Pande TK, Pani S, Hiran S, Rao VVB, Shah H, Vishwanthan KA. Turpentine poisoning: a case report. Forensic Sci Intl 65:47-9 (1994). 38 Barcelouz DG, Rosenberg J. Trichloroethylene Toxicity. ATSDR Case Studies in Environmental Medicine. U.S. Department of Health and Human Services, Public Health Service, Washington D.C., January 1992. 39 Bass M. Death from sniffing gasoline, letter to the editor. N Eng Jrnl of Med 299(4):203 (1978).
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