INDUSTRIAL HYGIENE REPORT. Bureau of Street Maintenance

Transcription

1 INDUSTRIAL HYGIENE REPORT REPORT PREPARED FOR: Bureau of Street Maintenance Date of Surveys: NOVEMBER 28 - DECEMBER I, 1994 SURVEY PREPARED BY: Zuhdy Youssef, crn, CSP Senior Industrial Hygienist '... ",. ','. ', '.

2 .. Industrial Hygine Report Introduction The survey was conducted to evaluate employees' exposures to air pollutants emitted from crumb rubber modifier asphalt (erm asphalt) during recycling and paving operations. The survey was requested by Greg Scott, Assistant Director, Bureau of Street Maintenance. The survey was conducted at the microwave recycling plant which is operated by Cyc1ean, Inc. under a contract with the City and at the paving site. The site was on Olympic Blvd. between Indiana 51. and Calzana St. (about 4 blocks). The street surface is picked up, ground, and loaded on the trucks by a profiler machine. The ground old rubber modified asphalt is then sent to either the microwave plant or asphalt plant #} ~here it is mixed with asphalt oil that is heated either by microwave or nanial gas. This is called a wet process. The recycled asphalt is then sent to the site to be laid 0:1 the street by the paving machine. The asphalt temperature when it reaches the site is ~. The asphalt contains up to 3% rubber, and it was originally laid on the street in The paving crew consists of 8 worker~(equipment operators and street maintenance workers). The crew is involved in operating and adjusting the machine while paving. The workers sampled were the closest to the heated asphalt to evaluate the worst possible exposure. Air sampling was conducted to evaluate employees' exposures to the following: PolyneucJear Aromatic Hydrocarbons (PARs) Volatile Organic Compounds (benzene, vinyl chloride, carbon tetrachloride, styrene, toluene, and xylenes) Metals (lead, chromium, cadmium, iron, nickle, and zinc) Total particulates Sulfur dioxide, nitrogen dioxide, and carbon monoxide. The above contaminants are the common chemicals in the emission of hot asphalt containing CRM. Standards Imd Guidelines Evaluations are based on the current CaVOSHA standards, guidelines established by the American Conference of Governmental Industrial Hygienists andlor accepted state-of-the-art industrial hygiene practices to give reasonable protection to the health and well-being of City employees. MelhQds Following is the list of methods used for air sampling and analysis of chemicals under study.

3 Sampling and Analysis Methods Air Vacumm Flow Rate Collection Contaminant Source LiterlMinute Medium PAHs Gilian Pumps TeDon filters Benzo (a) Pyrene ModelHFS and Sorbent 513A Tubes Volatile Organic Gilian Pumps 0.2 Chreoal Tubes Compounds ModelHFS (except vinyl 513A chloride) Vinyl Chloride Gilian Pumps 0.2 Chrcoal Tubes Model HFS 51)A Metals GUian Pumps Mixed ModelHFS Cellulose S13A Esters Filters Total Paniculate- Gilian Pumps Pre-Weighed Model HFS PVC 513A Sulfur Dioxide Drager Pumps NA Detectror Nitrogen Oxides Tubes Carbon Monoxide Analytical Method NIaSH 5506 HPLC-UV NIaSH 1501, 100) and 1300 GC-FlD NIaSH 1007 GC-FIO P&CAMI73 ICP-AES... NIaSH0500 Gravimetric Direct Reading, Length of Stain HPLC - UV = High - pressure liquid Chromatography with UV detector GC - FID - Gas Chromatography - flame ionization detector... ICP - AES z:: Inductively coupled plasma/atomic emission spectroscopy NA"'" Not Applicable

4 The sampling pumps were calibrated before and after the sampling period. Unless otherwise stated, samples were collected in the workers' breathiong zone 10 obtain samples indicative of ac:tua1 employee exposure. All samples except those for sulfur dioxide. nitrogen dioxide, and carbon monoxid e were sent to and analyzed by EMS laboratories, in Pasadena, CaJifornia, which is accredited by the American Industrial Hygiene Association (AIHA). Samples at the recycling plant were collected in the general truck loading area, since the recycling system is fully enclosed. Ground old asphalt is dumped into a hopper to a fully enclosed conveyor to the microwave area and into a silo. The aspha1t is stored in silos until being dumped on truck beds. Results The results of air sampling are presented in Table I. The concentrations are presented in parts per million (ppm) for gases and vapors, and in milligram per cubic meter ( mglm') for particulates. Results are listed by job class, location, along with the applicable cauosha standards.

5 TABLE 1 AIR SAMPLING RESULTS Employee/Location Air TWA' CaVOSHA Job Class Contaminant Concentration PEL" Microwave Recycling Carbon Tetrachloride < 0.07 ppm 2 ppm Plant, truck loading area Benzene ppm 1 ppm '. Toluene ppm 100 ppm General area sample Methyl Butyl Ketone <0.009 ppm 5 ppm Xylenes 0.16 ppm 100 ppm. Styrene (monomer) <0.006 ppm 50 ppm Vinyl Chloride <0.08 mg/m] 1 ppm Benza (a) Pyrene ND D.2/lg/m'" Pete RiosIPaving Crew Total Paniculates 0.72 mg/m] 10 mg/m' Manuel MunozIPaving Crew Total Particulate 5.02 mglnl' 10 mg/m) Street Maintenance Worker Martin AguayolPaving Crew Total Particulate 3.00 mg/m' 10 mg/m' Manuel MunozIPaving Crew Street Maintenance Worker Pete RiosIPaving Crew Martin AguayolPaving Crew Martin Aguayo/Paving Crew Total Particulates Total Particulates Total Particulates Carbon Tetrachloride 4.72 mg/m' 10 mg/m] 1.4 mg/m l 10 mg/m l 1.2 mg/ml 10 mg/m 1 <0.006 ppm 2 ppm Benzene ppm 1 ppm Toluene ppm 100 ppm Methyl Butyl Ketone < ppm 5 ppm Xylenes 0.0)0 ppm 100 ppm S~yre r.e < ppm 50 ppm Vinyl Chloride <0.008 ppm ; 1 ppm

6 TA BLE 1 (cont.) A TR SAMPLING RESULT EmployeeJLocation Air TWA' CaVOSHA Job Class Contaminant Concentration PEL" Rudy RodriguezlPaving Crew Benzo (a) Pyrene NO 0.2 ~glm] Street Maintenance: Worker Manuel MunozIPaving Crew Iron oxide fume mglm] 5 mglm' Street Maintenance Worker Lead <0,0003 mglmj 0.05 mglm] Chromium mgfm] 0.5 mg/m] Cadmium 0,0002 mglm' 0.05 mglml Nickel < mglm' 1.0 mgfrn 1 Zinc oxide fume mg/m 1 5 mglm 1 General area around the Sulfur dioxide NO 2 ppm paving machine Nitrogen dioxide NO 1 ppm (as STEL)"""" Carbon monoxide NO 3S ppm TWA " Time-Weighted Average concentration based on an 8-haur exposure TWA concentration is essentially similar to sample concentration since exposure remains the same for the rest oflhe shift. PEL- Permissible Exposure Limit based on a full work shift NO PEL established, however. this is an advisory level established be FedJOSHA in 1 98~.... STEL- Short Term Exposure Limit (for 15 minutes) < =- Less than NO.. None Detected

7 Djscussion ;mcl Conclusjon Employees exposu re to dust was evaluated during street grinding by the profiler since dust is the major exposure during this process. Air sampling for other contaminants was done during the paving operation or at the plant during the mixing. As can be seen from the results section, employee exposures to air contaminants were wel;i below the CAIJOSHA pemussibje exposure limits (PEL), and in most cases they were below the detection limit. It should be noted that during the grinding operation employees were using dual cartridge half-face masks with HEPA filters. Since exposure did not exceed the CalIOSHA permissible exposure limit (PEL), the use of respirators should be optional.