Acute health effects after accidental exposure to styrene from drinking water in Spain
© Arnedo-Pena et al; licensee BioMed Central Ltd. 2003
Received: 12 March 2003
Accepted: 22 May 2003
Published: 22 May 2003
We studied subjective health symptoms in a population accidentally exposed to high styrene concentrations in drinking tap water. The contamination occurred during the reparation of a water tank.
Residents of 27 apartments in two buildings using the contaminated water were contacted. A questionnaire on subjective symptoms was administered to 84 out of 93 persons living in the apartments at the time of the accident. Styrene concentration was measured in samples of water collected two days after the accident. The means of exposure associated with appearance of symptoms were examined through case-control analyses.
Styrene in water reached concentrations up to 900 μg/L. Symptoms were reported by 46 persons (attack rate 55 %). The most frequent symptoms were irritation of the throat (26%), nose (19%), eyes (18%) and the skin (14%). General gastrointestinal symptoms were observed with 11% reporting abdominal pain and 7% diarrhea. The factors most strongly associated with symptoms were drinking tap water (OR = 7.8, 95% CI 1.3–48), exposure to vapors from the basement (OR = 10.4, 2.3–47) and eating foods prepared with tap water (OR = 8.6, 1.9–40). All residents in the ground floor reported symptoms.
This accidental contamination led to very high styrene concentrations in water and was related to a high prevalence of subjective symptoms of the eyes, respiratory tract and skin. Similar exposures have been described in workers but not in subjects exposed at their residence. Various gastrointestinal symptoms were also observed in this population probably due to a local irritative effect.
Studies evaluating inhalation exposure have demonstrated that styrene is a strong irritant [1, 2]. Eye, nose and throat irritation is common at exposure levels above 50 to 100 ppm but can also occur at levels of about 20 to 30 ppm . At very high levels chronic bronchitis type symptoms and other respiratory symptoms appear. Multiple central and peripheral acute nervous system effects have been described at levels of about 100 ppm but some neurological symptoms and color vision impairment may also appear at much lower levels [4–6]. Effects on the liver (acute in animals, chronic in exposed workers), and the kidney and also genotoxic effects have been described at low levels [7, 8]. In the past, the so called "styrene sickness" was described in workers heavily exposed to styrene including nausea and vomiting, loss of appetite, and general weakness.
To our knowledge there are no previous reports of an environmental styrene contamination of water leading to health symptoms. In drinking water supplies, styrene is usually either not detected or detected at levels below 1 μg/L . We present the investigation following this accidental environmental exposure to styrene.
Among 15 subjects who reported symptoms, a sample of urine was collected on day 5 for analysis of the two main metabolites of styrene, namely mandelic and phenylglyoxylic acids (MA and PGA respectively) and of creatinine. Measurement were performed by gas chromatography at an accredited laboratory in Barcelona
The residents collected tap water samples at the second day after the accident. A more systematic sampling was done after the third day by the local health authority. Samples were analyzed by gas chromatography/mass spectrometry.
The reparation work at the firewater tank involved the application of an unsaturated polyester resin based on styrene (Aropal FS1933), followed by a cap of fiberglass mats (MAT300) containing 35% fiberglass, and then by a white gel coat based on styrene that contained a low (4–6%) proportion of a paraffin.
The sources of exposure that were associated with the occurrence of symptoms were examined through case-control analyses (10). Cases were defined as those subjects having any symptom (n = 46, mean age 30 years, range 8 months to 77 years), and the remaining subjects were defined as controls (n = 38, mean age 27 years, range 8 months to 72 years). Unconditional logistic regression was used, adjusting for age, sex, and when appropriate housing characteristics. The STATA 3.1 statistical package was used .
Styrene and toluene concentrations (μg/L) in drinking water samples
Apartment 1st floor
Apartment 3rd floor
Apartment 8th floor
Apartment 4th floor
Apartment 4t floor
Prevalence of reported symptoms by the residents of the apartments using styrene contaminated water.
Total with symptoms
Total study population
Prevalence of any reported symptom by apartment floor
Subjects with symptoms
Subjects without symptoms
Exposure after the accident associated with occurrence of symptoms in the case-control analysis
Cases (n = 46)
Controls (n = 38)
95% confidence interval
Age (mean, range)
Presence in the house between 10–13 December
Consumption of tap water
Consumption of food prepared with tap water
Direct exposure to vapors from basement
Floor of the apartment (continuous)
Name and Surname of the head of the family
Complete address and telephone ...
Each resident in the apartment should complete a separate questionnaire
Resident 1, Resident 2 etc.
Family relation (spouse, son etc)...
1. Have you been present in the apartment during the 10, 11 or 12 of the current month? Yes/No
2. Did you drink tap water during those days? Yes/No
3. How many glasses of water do you usually drink per day? Number...
4. During those days did you use tap water to prepare food? Yes/No
5. During those days did you bathe or shower at home? Yes/No
6. During those days where you exposed to gases, vapors or fumes at home? Yes/No
7. Between the 10 and the 14th of this month did you suffer from:
a. Abdominal pain
f. A feeling of bad taste in the mouth
g. Irritation in the pharynx
h. Skin eruption
i. Skin irritation
j. Nasal Irritation
k. Nasal secretion
l. Eye irritation
m. Perception of bad odors
8. Did you consult a medical doctor? Yes/No
9. If you had any symptoms how long did they last?
10. Do you have any allergies Yes/No
11. Any other observations? Specify
Cases consumed a larger quantity of tap water at home (mean = 0.72 L/day) compared to controls (mean = 0.42 L/day) but differences were not significant. Among the 26 children the two main risk factors were exposure to vapors and eating food prepared with tap water, although differences were not statistically significant.
The accidental contamination of a drinking-water tank in Castellón led to levels of styrene in tap water that were 2 to 3 orders of magnitude higher compared to the levels usually measured in drinking water . An increased prevalence of reversible health symptoms was observed in subjects using water from the contaminated tank. The close time relationship between the application of the styrene-based material and the occurrence of symptoms that can be induced by styrene in humans point to styrene as the most likely candidate for the occurrence of symptoms, although the possibility of the presence of other undisclosed contaminants cannot be entirely ruled out. The effects of styrene in humans has been studied in workers exposed to high concentrations of the solvent in air but there are no published data on subjects exposed in their residence as a consequence of water contamination. In addition to the irritative effects to the eye, skin and respiratory tract frequently reported in workers, various gastrointestinal type symptoms were observed in this population that ingested highly contaminated water.
The population involved in the accident was well defined, and the non-participation rate was low and unlikely to have modified the results. No comparison population was used, e.g., residents in neighboring buildings, and the relative increase of the prevalences is unknown. However, the prevalence of most symptoms appears high and very likely above background prevalence. The general household health survey of Spain  only includes information for wide categories of symptoms that do not exactly correspond to symptoms reported in this study. Problems in the throat, cough, simple cold or influenza that limited the free time activities during the last two weeks were reported by 2.8% of adults in Spain, headache by 2%, nausea or vomit by 0.9% and diarrhea or other intestinal problems by 0.4% .
Styrene is an environmental contaminant, and low doses have been reported in drinking water (usually 0.1–0.2 μg/l) and in some foods as beer and coffee (10–350 μg/kg) [9, 13]. Styrene concentration in water measured in our study was about two to three orders of magnitude higher. The presence of high concentration of the solvent was clearly perceived by subjects. A thin gelatinous layer on the surface of water in the tanks due to the poor water solubility of styrene  was visible, and nearly all subjects perceived the odor. The taste threshold concentration in water is around 0.7 mg/L .
Given the very high levels measured in water, it could be expected that extensive exposure of the skin and the mucosa occurred. Levels of individual exposure after the accident are, however, unknown. Mandelic and phenyglyoxylic acids were not detected in the urine samples collected at day 5. Nevertheless, this is not surprising considering that in humans the kinetics of styrene is fast, with an excretion half-time of both metabolites that is about 5–10 hours [16, 17].
The main symptoms described in the population examined are acute irritation to the eyes, nose, throat and skin. These effects are probably not related to systemic absorption, but mainly due to local contact. Usually, exposure to styrene is by inhalation and there are several studies on the kinetics of this solvent following inhalation exposure  while gastrointestinal tract exposure has not been studied in humans. Studies in animals (mainly rat and mouse) suggest that styrene is absorbed and rapidly metabolised following oral administration . The presence of symptoms of the gastrointestinal tract, such as abdominal pain and diarrhea is not among complaints usually referred by workers, even if nausea is among symptoms included in the so-called "styrene sickness" . Possibly, gastrointestinal symptoms should be considered related to the local irritant action of styrene in ingested water or foods. This is also suggested by the relation observed between symptoms and consumption of water and of food prepared with water.
The prevention measures applied should be aimed at avoiding further contact with styrene-contaminated drinking water until concentrations reached low levels. Exposure to styrene was high but was limited in time and it seems unlikely that long-term effects will occur following this accidental exposure. This accident was caused by a series of failures at various levels of control and the prevention of similar accidents requires a conjunct of measures. In the case of this residential building in a Spanish city, the drinking water tank was not isolated from the fire protection water tank, nor was it isolated from car emissions from the parking garage in the basement, nor completely isolated from possible animal contact. In the first place, the architects and constructor should not have designed and built the two communicating water tanks without adequate ventilation. Subsequently the municipality should have done a complete inspection for the building before permitting its reoccupancy. The company doing the repair was unaware of potential toxic effects of the chemicals applied, and measures should be taken to inform companies and workers on the potential toxicity of the materials used. Furthermore the type of products applied in construction and repair of drinking water tanks should be regulated and clearly labeled. Several state agencies regulate the procedures for the use of environmental contaminants and potentially toxic agents and should collaborate to inform about these risks and apply regulations. This accident highlights the precarious conditions for water safety administration in some residential areas in Spain.
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