An Evaluation of Potential Occupational Exposure to Asbestiform Amphiboles near a Former Vermiculite Mine

Table 2

PBZ data reported by activity performed, task associated with activity, PCM and TEM individual, and mean sample concentrations.

Test activity	Test activity task	Number of samples	^(a)Number of detects (PCM)	PCM conc. (fibers/mL)	^(b)Number of detects (TEM)	TEM conc. <5 𝜇m (structures/mL)	TEM conc. >5 𝜇m (structures/mL)	TEM conc. total structures (structures/mL)
Fire Line		10	10		4
	Brush Clearer			0.354		0.0277	0.0277	0.0544
				0.249		ND	0.0367	0.0367
	Chainsaw Operator			0.384		ND	ND	ND
				0.242		ND	ND	ND
	Pulaski Operator			0.438		0.0524	0.0262	0.0786
				0.410		0.0332	0.0664	0.0996
	Comby Operator			0.446		ND	ND	ND
				0.238		ND	ND	ND
	Data Recorder			0.220		ND	ND	ND
				0.117		ND	ND	ND
	Mean Concentrations			0.302		0.011	0.016	0.027
Trail Maintenance		5	5		0
	Brush Clearer			0.059		ND	ND	ND
				0.045		ND	ND	ND
				0.024		ND	ND	ND
	Chainsaw Operator			0.063		ND	ND	ND
	Data Recorder			0.015		ND	ND	ND
	Mean Concentrations			0.041		ND	ND	ND
Tree Measurement	Tree Measurer	5	5		2
				0.021		ND	ND	ND
				0.035		ND	0.0162	0.0162
				0.015		ND	ND	ND
				0.038		0.0134	ND	0.0134
				0.062		ND	ND	ND
	Mean Concentrations			0.034		0.003	0.003	0.006
^(c)Walking	Walking	4	4		0
				0.021		ND	ND	ND
				0.043		ND	ND	ND
				0.011		ND	ND	ND
				0.019		ND	ND	ND
	Mean Concentrations			0.024		ND	ND	ND

^(a)PCM Analytical Limit of Detection : (0.009−0.19 f/mL). ^(b)ND : Non detect, TEM analytical sensitivity : (0.0123−0.0367 s/mL). ^(c)One walking activity PBZ sample (not reported) revealed chrysotile asbestos, not amphibole asbestos.