No abstract

The effect of 6 hrs single exposure to white spirit on the concentration of S‐α‐amylase, S‐cholesterol, S‐triglyceride, S‐sodium, S‐potassium, S‐creatine kinase, S‐orosomucoid, S‐urate, and S‐glucose was analysed in 12 volunteers 6 and 48 hrs after start of exposure. After exposure to 0 p.p.m. and 100 p.p.m. of each of three white spirits containing 99% paraffins or 52% paraffins and 48% naphthenes, or 57% paraffins, 25% naphthenes and 18% aromatics, respectively, the only significant changes were a decrease in S‐α‐amylase concentration and S‐Potassium concentration by 9% (P < 0.05) 48 hrs after exposure to the white spirit high in naphthenes. This type also caused the highest blood concentration. In a subsequent study on exposure to 0, 50, 100, and 200 p.p.m. of the spirit high in naphthenes the only significant dose‐response relationsship was that the concentration of S‐α‐amylase decreased 7% (P<0.05) after 6 hrs, and S‐urate decreased 4% (P<0.05%) after 48 hrs as the doses increased. No changes in subjective symptoms were found. Thus, even at low levels, white spirit high in naphthenes appears to result in subtle biological effects prior to the appearance of symptoms of poisoning.

Seven volunteers were exposed to 100 p.p.m. white spirit (99% paraffins C8‐C12) 6 hrs daily in 5 days. The mean concentration of white spirit after 5 days of exposure was 41.1 mg/kg fat (Friday afternoon). On the following Monday morning, the concentration was 31.7 mg/kg, i.e. only 23% had been eliminated during the exposure‐free weekend. The estimated mean and median half‐life was 7 and 8 days, respectively, elimination rate constant 0.0039 and 0.0036 hrs1, time to reach steady state 5 to 8 weeks, maximal and minimal steady state concentration 85 and 66 mg/kg and 66 and 52 mg/kg, respectively. The concentration of white spirit in fat found each afternoon correlated significantly with the total dose. The concentration of white spirit/kg fat correlated positively with serum triglyceride and inversely with the percentage body fat (not significantly). The concentration of white spirit in the brain at steady state was estimated to maximum 11 mg/kg, while the half‐life in the brain was estimated to maximum 18–19 hours. Minor differences occurred in the spectrometrical pattern produced by the in vivo biopsy evaporate as compared to in vitro specimens and white spirit vapours per se, thus indicating that the white spirit was slightly biotransformed or that the approximately 200 constituents of white spirit were absorbed differently. Thus, during exposure at the threshold limit value level, white spirit is accumulated in depot fat over weekends and in brain over working days. However, white spirit is almost eliminated from the brain during weekends.

This review is a critical survey and evaluation of the recent literature relevant as medical background for a discussion of hygienic threshold values for hexane. Polyneuropathy and maculopathy, as well as subclinical effects, eg, functional disturbances (conduction velocity of the motor and sensory nerves), are included.

The concentration of P-immunoglobulins (P-IgG, P-IgA, P-IgM), P-orosomucoid, S-creatine kinase (S-CK), and S-follicle stimulating hormone (S-FSH) was investigated in seven subjects exposed to 100 p.p.m. white spirit, 6 hrs daily during 5 days while 5 subjects were used as unexposed controls. The mean values for S-CK concentration in the exposed group increased significantly with 59% and 76% above the base-line (O-hr value) 96 hrs and 168 hrs, respectively, after the start of the exposure (P<0.05), while the mean values for S-FSH concentration decreased significantly to 11 YO and 9% below the base-line after 24 hrs and 96 hrs (P < 0.05), respectively. S-CK concentration and S-FSH concentration in the control group remained unchanged. A marked interindividual and intraindividual variance in S-CK concentration and S-FSH concentration was observed. No changes in the concentration of immunoglobulins and orosomucoid were observed in both groups during the experiment. The mechanisms for the changes are at present only speculative, but solvent induced changes in muscle cell membranes with subsequent enzyme leakage seem the most reasonable explanation for the increase in S-CK concentration, while an effect on the hypothalamic FSH releasing hormone may explain the decrease in S-FSH Concentration.