Cotton dust measurements revealed that most levels in all work areas exceeded the current Occupational Safety and Health Administration permissible exposure limit of 0.2 mg/m 8-h time-weighted average dust (Table 1). Median concentrations for dust ranged from 0.24 mg/m in fine spinning to 1.73 mg/m in cleaning. Canadian family pharmacy Click Here Endotoxin concentrations ranged from 0.004 Mg/m in fine spinning to 0.75 Mg/m in the drawing area. When dichotomized into exposure areas as just described, about half the cotton areas and a third of the endotoxin areas were in the lower category. There was moderately high correlation (Spearman’s test) between airborne VE dust and VE endotoxin levels (rs=0.66 for mill 1, p<0.01; rs=0.79 for mill 2).
Overall, dust levels remained relatively stable over the 5 years between surveys with the exception of the drawing area of one mill which was higher at the second survey. Since workers remained in the same work areas throughout their employment at the mills, there was little change in the personal assignments of dust or endotoxin levels from survey to survey. mill 2). Overall, dust levels remained relatively stable over the 5 years between surveys with the exception of the drawing area of one mill which was higher at the second survey. Since workers remained in the same work areas throughout their employment at the mills, there was little change in the personal assignments of dust or endotoxin levels from survey to survey. Symptom Prevalence: The prevalence of all chronic respiratory symptoms, except dyspnea which increased, was similar at the time of the second survey. Overall, there was a low prevalence of byssinosis. At most, only 10 percent consistently reported the presence of specific symptoms (Fig 1), while the majority (two thirds) of subjects ever reporting symptoms were inconsistent in their responses.
Table 1—Cotton Dust and Endotoxin Concentrations in Area Samples
|Dust (mg/m)||Endotoxin (Mg/m)|
|Mill 1||Mill 2||Mill 1||Mill 2|
|Opening||1.69t (0.97-2.36)1||1.27 (0.42-2.89)||0.33 (0.13-0.80)||0.22 (0.05-0.45)|
|Cleaning||1.17 (0.59-2.32)||1.73 (1.09-2.93)||0.36 (0.20-0.92)||0.58 (0.03-1.34)|
|Carding||1.29 (0.65-2.26)||1.52 (0.48-2.58)||0.48 (0.17-0.78)||0.35 (0.04-1.70)|
|Drawing||0.69 (0.22-3.75)||1.52 (0.46-2.32)||0.43 (0.02-1.46)||0.75 (0.52-1.20)|
|Combing||0.44 (0.12-1.11)||0.39 (0.09-0.98)||0.64 (0.27-1.53)||0.08 (0.07-0.67)|
|Roving||0.33 (0.14-0.72)||0.45 (0.31-0.67)||0.99 (0.15-1.06)||0.04 (0.02-0.11)|
|Spinning||…I||0.24 (0.04-0.80)||…I||0.004 (0.001-0.14)|
Figure 1. Long-term (5-year) consistency of respiratory symptoms. CTW, chest tightness at work; CB, chronic bronchitis; CC, chronic cough; DYS, dyspnea.