Biological monitoring of carbon disulphide: kinetics of urinary 2-thiothiazolidine-4-carboxylic acid (TTCA) in exposed workers

Abstract

The objectives of this study was to establish the kinetics of urinary 2-thiothiazolidine-4-carboxylic acid (U-TTCA) for workers exposed to carbon disulphide (CS2) and to investigate the effects of volume and creatinine adjustment methods for urine measurement. Ten workers in the spinning department of a rayon factory were individually monitored for airborne CS2 concentrations, with consecutive urine samples collected for 24-38 hours after termination of exposure. The U-TTCA, urine volume and creatinine level were measured for each sample. First-order and biphasic kinetics were determined using the curve-fit method, for the measurement series. For the first-order kinetics linearity fit, statistically significant correlation coefficients of 0.74-0.98 and 0.86-0.99 were derived for the volume- and creatinine-adjusted methods, respectively. For the biphasic kinetics approach, the overall correlation coefficients were 0.544-0.999 and 0.171-0.999 for the first and second phases of the creatinine-adjusted method, respectively. A post-shift U-TTCA of 3.0 mg/g Cr. equivalent, 40% below the current BEI setting at nearly PEL exposed level, was found. In conclusion, first-order kinetic response was confirmed for U-ITCA. Both volume- and creatinine-based urine adjustment are satisfactory for TTCA assessment as a biomarker of individual CS2 exposure although the correlation for creatinine-based measurement was modestly superior to the volume-based analogue. Based on the results of this study,we recommend a re-evaluation of the current biological exposure index of 5 mg/g creatinine at a CS2 exposure level of 10 ppm.

Effect of Occupational Exposure to Rayon Manufacturing Chemicals on Skin Barrier to Evaporative Water Loss

“…According to the findings in literature 29,35,36) , and in our previous studies 34,[37][38][39] , employees working in the spinning department of a rayon factory are readily exposed to considerably high levels of RMC. In the spinning department, a viscose solution containing predominantly CS 2 and minor sulfuric acid, is then pumped through a platinum nozzle into a warm viscose bath at a very high speed, and a continuous rayon thread is generated in the spinning department.…”

N–nitrosamines are associated with shorter telomere length

“…The samples were collected on Tuesdays, Wednesdays, or Thursdays. All biomarkers have short half-lives (26)(27)(28) and therefore they can be regarded to be at, or close to, steady-state already on Tuesday afternoon. Thus, the day of sampling will not affect the results.…”

Cyclic Metabolites: Chemical and Biological Considerations

“…Subsequent in vitro investigations revealed that NCQ-344 readily oxidized to a quinone (73), which could be trapped with two molecules of GSH to form a bis-adduct (74) [79]. In this study, it was also revealed that the bis-adduct underwent intramolecular cyclization whereby the -amino group of glutamic acid displaced the "doubly" activated methoxy group (adjacent to amide and present on the conjugated system) by Michael addition to form a cyclic structure (75), possibly in equilibrium with its tautomer (76). Evidence for the cyclic structure(s) was based on accurate mass tandem MS, hydrogen-deuterium exchange measurements and chemical derivatization.…”

“…The structure of TTCA was determined by GC/MS analysis while incorporation of CS 2 into TTCA was established by 13 C-NMR following dosing of N, Ndiethyl [ 13 C=S] dithiocarbamate to rats [73] . Chang and coworkers utilized urinary excretion of TTCA in workers occupationally exposed to CS 2 in a Taiwanese factory to determine total body burden of CS 2 in a biomonitoring study [76]. Fig.…”