BENZENE-SOLUBLE & TOTAL PARTICULATE (ASPHALT FUME): METHOD 5042, Issue 1, dated 15 January 1998 - Page 7 of 7
ratio of benzene-soluble mass to total particulate was 106% (S r = 7.80%). In other experiments, three of 60 field blanks (three sets of 20 field blanks each) had a significantly higher than expected benzene-soluble fraction when compared with the other field blanks [6]. This event had two undesirable consequences: (1) Because the average weight of the field blanks was increased, the field samples were over corrected, and (2) the standard deviation of the field blank weights was increased resulting in higher LOD and LOQ values. For example, if the set of twenty field blanks with one high result is randomly assigned to groups of three (repeatedly), the standard deviation of the groups with the high result could exceed the standard deviation of the other groups by more than 1.6 times. Since this event also may occur with field samples, these elevated results were not excluded when the data were evaluated. Although these events were observed with a syringe type clarification unit and not the recommended clarification unit, the cause of this event was not determined. Therefore,it is important to collect as many field blanks as is reasonable (five blanks per day); also, it may be advisable to establish a monitoring program to track the occurrence of elevated field blanks and, if possible, to identify and eliminate the cause(s). In another experiment, the recommended clarification unit (PTFE-treated reservoir and a PTFE filter) was evaluated along with three syringe type clarification units [6]. The recommended clarification unit gave lower average extractable material than the syringetype clarification units; also, the recommended clarification unit did not release increasing amounts of extractable material upon prolonged contract with solvent. Prerinsing the recommended clarification unit appeared to lower the average amount of extractable material. Additionally, the recommended clarification unit eliminated the need for using a glass syringe and was more convenient to use than the syringe type clarification units. In a preliminary asphalt fume spiking experiment, benzene and methylene chloride were evaluated as extraction solvents [6]. Asphalt fume [5] was spiked on tared PTFE filter media at the following concentrations: 3.38, 0.68, 0.14, and 0.034mg per filter. Benzene gave recoveries greater than 100% for all concentrations of asphalt fume spiked on PTFE filters. While methylene chloride gave recoveries greater than 96% for the two highest levels spiked, at the two lower levels the recoveries were less than 67%.
REFERENCES: [1] NIOSH [1994]. Particulate not otherwise regulated, total: Method 0500. In: Eller PM, Cassinelli ME, ® eds. NIOSH Manual of Analytical Methods (NMAM ), 4th ed. Cincinnati, OH: National Institute for Occupational Safety and Health, DHHS (NIOSH) Publication No. 94-113. [2] NIOSH [1998]. Polycyclic aromatic compounds: Method 5800. In: Eller PM, Cassinelli ME, eds. NIOSH Manual of Analytical Methods (NMAM®), 4th ed., 2nd Supplement. Cincinnati, OH: National Institute for Occupational Safety and Health, DHHS (NIOSH) Publication No. 98-119. [3] NIOSH [1998]. Benzothiazole in asphalt fume: Method 2550. In: Eller PM, Cassinelli ME, eds. NIOSH Manual of Analytical Methods (NMAM®), 4th ed., 2nd Supplement Cincinnati, OH: National Institute for Occupational Safety and Health, DHHS (NIOSH) Publication No.98-119. [4] NIOSH [1992]. NIOSH recommendations for occupational safety and health, compendium of policy documents and statements. Cincinnati, OH: National Institute for Occupational Safety and Health, DHHS (NIOSH) Publication No. 92-100. [5] Sivak A, Niemeier R, Lynch D, Beltis K, Simon S, Salomon R, Latta R, Belinky B, Menzies K, Lunsford A, Cooper C, Ross A, Bruner R [1997]. Skin carcinogenicity of condensed asphalt roofing fumes and their fractions following dermal application to mice. Cancer Letters 117:113-123. [6] NIOSH [1998]. NIOSH backup data report for total particulate and benzene-soluble fraction (asphalt fume), NIOSH Method 5042 (unpublished).
METHOD WRITTEN BY: Larry D. Olsen (Team Leader), Barry Belinky, Peter Eller, Robert Glaser, R. Alan Lunsford, Charles Neumeister, Stanley Shulman, NIOSH/DPSE.
NIOSH Manual of Analytical Methods (NMAM), Fourth Edition
