Ambient monitoring and biomonitoring of workers exposed to N-methyl-2-pyrrolidone in an industrial facility

Abstract

Objectives: The exposure of seven workers and three on-site study examiners to N-methyl-2-pyrrolidone (NMP) was studied in an adhesive bonding compound and glue production facility. Methods: Airborne NMP was analysed by personal and stationary sampling on activated charcoal tubes. NMP and its main metabolites, 5-hydroxy-N-methyl-2-pyrrolidone (5-HNMP) and 2-hydroxy-N-methylsuccinimide (2-HMSI), were analysed in pre-shift and post-shift spot urine samples by gas chromatography-mass spectrometry. The workers were examined with respect to irritation of the eyes, the mucous membranes and the skin, and health complaints before and after the work-shift were recorded. Results: The timeweighted average concentration of NMP in most work areas varied between 0.2 and 3.0 mg/m 3 . During the manual cleaning of stirring vessels, valves and tools, 8-h TWA exposures of up to 15.5 mg/m 3 and single peak exposures of up to 85 mg/m 3 were observed. NMP and its metabolites were detected in two pre-shift urine specimens. NMP and 5-HNMP concentrations in post-shift urine samples of five workers and three on-site study examiners were below 125 lg/g creatinine and 15 mg/g creatinine, respectively, while two vessel-cleaning workers showed significantly higher urinary NMP concentrations of 472 and 711 lg/g creatinine and 5-HNMP concentrations of 33.5 and 124 mg/g creatinine. 2-HMSI was detectable in four post-shift samples (range: 1.6-14.7 mg/g creatinine). The vessel cleaner with the highest NMP exposure reported irritation of the eyes, the upper respiratory tract and headaches. Conclusions: The results of this study indicate a relatively low overall exposure to NMP in the facility. An increased uptake of NMP occurred only during extensive manual vessel cleaning. Health complaints associated with NMP exposure were recorded in one case and might be related to an excessive dermal exposure due to infrequent and inadequate use of personal protective equipment.

Human volunteer study on the influence of exposure duration and dilution of dermally applied N-methyl-2-pyrrolidone (NMP) on the urinary elimination of NMP metabolites

“…While the occupational-medical Weld studies and workplace surveillance data available at the moment (Anundi et al 1993(Anundi et al , 2000Hervé-Bazin 1997;HSE 1997;Langworth et al 2001;Bader et al 2005b) pointed out that the concentration of airborne NMP typically accounts for only some percent of the workplace limit values, the dermal route may turn out to play the major role in the overall uptake of NMP. Especially laborious manual work under unfavourable working conditions and infrequent or improper use of personal protective equipment may easily result in a contamination of the human skin and thereby in the uptake of signiWcant amounts of the solvent.…”

“…The samples were stored at ¡28°C before analysis. Urinary creatinine was analysed photometrically according to the JaVé reaction to correct for diuretic variance as described by Bader et al (2005b).…”

Comparative developmental toxicities of the three major metabolites of N‐methyl‐2‐pyrrolidone after oral administration in rats

“…Thus, NMP is metabolised to 5-hydroxy-N-methyl-2-pyrrolidone (5-HNMP), N-methylsuccinimide (MSI), 2-hydroxy-Nmethylsuccinimide (2-HMSI) and 2-pyrrolidone (2-P). However, there were some differences, especially, 2-HMSI was more abundant in humans than in rats (Akesson and Jönsson, 2000;Anundi et al, 2000;Akesson, 2001, 2003;Bader et al, 2005aBader et al, , 2005bCarnerup et al, 2005Carnerup et al, , 2006Keener et al, 2007).…”

“…Nevertheless, several factors may affect NMP blood levels in humans, including co-exposure with other solvents, exposures to both the inhalation and dermal routes, and toxicokinetic genetic polymorphisms (Ligocka et al, 2003). It should be noticed that NMP concentrations (8-h time-weighted average, TWA) ranging from 0.03 to 15.5 mg m −3 were measured in working areas (Anundi et al, 2000;Bader et al, 2005b). An occupational exposure limit (8-h TWA) of 40 mg m −3 (10 ppm) was recently recommended in the European Union (European Commission, 2005).…”

Richtwerte für 1-Methyl-2-pyrrolidon in der Innenraumluft

“…In einer weiteren Studie derselben Arbeitsgruppe wurde die Ausscheidung von NMP und Metaboliten im Urin von 56 Personen (31 Frauen,25 Männer, Alter 18-64 Jahre) ohne bekannte Exposition gegenüber NMP untersucht [9]. In fast allen Proben (> 96 %) lag die Konzentration an 5-HNMP und 2-HMSI über der Nachweisgrenze, für 5-HNMP wurden Median-, 95.…”