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Description of key information

Epidemiological study of Morfeld et al. (2011): TWA (time weighted average, 8h) of 0.06 mg/m³

other studies: acute, local, irritating effects

Additional information

One case of intoxication with Cyanuric chloride that occurred accidentally in a plant producing herbicides is reported (Catenacci et al., 1987). Irritation to the skin, eyes and pharynx followed later by a serious obstructive pulmonary syndrome with impairment of alveolar-caplillary exchanges was mentioned. The worker fully recovered from the skin, eye and lung disorders in three weeks. The effects reported demonstrate that the toxicity of Cyanuric chloride is triggered by local not by systemic effects. This conclusion is further supported by the epidemiological study of Morfeld et al. (2011) on workers where a threshold for local effects was established in the absence of systemic effects. The epidemiological study of Morfeld et al. (2011) on 394 male employees represents the most reliable study for DNEL derivation since the study comprises the worldwide most extensive data base regarding the effect of long term Cyanuric chloride exposure on human health. In this study the lung function parameters FEV1, VC or FVC and FEV1%FVC were used to assess local effects on the respiratory tract after long-term inhalation exposure. In relation to external pulmonary reference values the results indicated no abnormalities of lung function parameters. When considering models with maximum estimates of pulmonary function loss, a long-term threshold value for cumulative exposure could be identified. Using a representative model that described the estimated average loss, the result was a threshold band which offers a best value estimate of 0.3 mg/m³-years. Taking into consideration mean exposure period of 11.2 years, a tolerable additional loss of lung function of 10% of the age typical loss and a factor of two for the conversion of long-term values into an occupational exposure limit a TWA (time weighted average, 8h) of 0.06 mg/m³ was calculated. The TWA is identified as the most relevant dose descriptor and starting point for DNEL derivation. In the surveillance study of Mertschenk et al. (1998) 39 workers were subject to medical examinations. Only transient local effects due to the irritating/caustic nature of 2,4,6-trichloro-1,3,5-triazine were reported. However, due to methodological deficiencies (values for the mean concentration of 2,4,6-trichloro-1,3,5-triazine in the atmosphere at different positions of the working place are stated, no confounding factors) and the insufficient documentation (i.e. no individual data of the clinical symptoms is presented except for a respiratory parameter (forced expiration volume)) an assessment of the results is not possible. In another surveillance study it is reported that the test substance exhibits effects on the nervous system, immune system and concomitant effects on heart and blood vessels however the authors concluded that no relationship between exposure concentration and severity of response can be established (Kaskevich et al., 1984). Acute effects of Cyanuric chloride of human accidental exposure were reported by Catenacci (1987).The author reported the occures of irritation to the skin, eyes and pharynx followed later by a serious obstructive pulmonary syndrome with impairment of alveolar-capillary exchanges in case of acute occupational intoxication that occured accidentally in a plant producing herbicides. The patient fully recovered from the skin, eye and lung disorders in three weeks. Due to the insufficient documentation an assessment of the results is not possible. In one case study a non smoking 47 year old engineer with a dry cough, working occasionally at a 2,4,6-trichloro-1,3,5-triazine production plant, was tested positive for specific IgE against 2,4,6-trichloro-1,3,5-triazine (Alt and Diller, 19988). Dislocation the person from the 2,4,6-trichloro-1,3,5-triazine production plant led to complete decay of the dry cough. Under the conditions of the report by Blagodatin (1965) symptoms towards a local irritating/caustic mode of action of the test item were pointed out. However, information too limited to allow an assessment of the findings. Another report states the possibility that cyanuric chloride can cause obstructive disorders of the respiratory system and assumes a immunologic mechanism (Diller et al. 1992). An assessment of the significance of the stated results is not possible due to the lack of any individual data and the lack of information on confounding factors.