Threshold Limit Values TLVs TLV Definition concentrations which

Threshold Limit Values (TLVs) TLV® Definition concentrations … which it is airborne concentrations … which it is believed that nearly all workers may be repeatedly exposed … without adverse health effects believed that nearly all workers may be repeatedly exposed … without adverse

TLVs • • • How to apply… Trained professionals Guides and recommendations Not for community air pollution Not for proving disease

TLVs • • Why TLVs? OSHA Standards NIOSH RELS Other Sources

PEL Concentrations that healthy individuals can normally tolerate for eight hours a day, five days a week without harmful effects

TLVs • OSHA Standards. Permissible Exposure Limits (PELS) • Established in 1970 – 1910. 1001 Z Tables • Updated in 1989 but not since.

OSHA PELS Chemical PEL TLV (2007) • Acetylaldehyde 200 ppm 25 ppm • Acetic Acid 10 ppm • Acetone 1000 ppm 500 ppm

TLV Response LD 50 ED TWA Threshold Dose

NIOSH RELS Chemical RELs TLV (2007) • Acetylaldehyde 18 ppm 25 ppm • Acetic Acid 10 ppm • Acetone 250 ppm 500 ppm

German MAKs In the work-place environment MAK values (maximum allowable workplace concentrations) haven been fixed as time-integrated averages relatively early in order to avoid adverse health effects to workers exposed to air pollution during their working shift.

GERMAN MAKs Acetaldehyde 5 mg/m 3 Acetanilide 6 mg/m 3 Acetic acid 15 mg. m 3 Acetic anhydride 10 mg/m 3 Acetone 200 mg/m 3

TLVs Ex tra po la te d Data points Extrapolation of Data

Activity

Activity Given: 10 mg/kg LD 50 Rats for Chemical X Using Linear scaling: The LD 50 for a 2 kg rate would be 20 mg/kg For a 10 kg dog would be 100 mg What would the LD 50 for a 50 kg person be? .

Non-linear response

TLVs CH 3 • Basis: – Benzene: Leukemia – Beryllium: Lung Cancer – Toluene: Visual impairment, female reprod.

TLVs • Other Chemicals based: • Animal Studies • Epidemiology Study – Ames Study

TLVs Because of wide variations in individual susceptibility, exposure of an individual at, or even below, the TLV may result in annoyance, aggravation of a pre-existing condition, or occasionally even physiological damage.

TLVs 2007 Substance [CAS No. ] (Documentation No. ) TWA STEL NOTATION Toluene 20 ppm - A 4 BEI Time Weighted Average Not classified as Carcinogen

TLV TWA – Time Weighted Average TWA = (C 1 T 1) + (Cn. Tn) Total Time

TLV - STELS • Short Term Exposure Limits – 15 minutes – Never exceeded at any time – STEL Is the level one can be exposed to without • Irritation, chronic effects or dose related toxic effects

TLV - Ceiling • Not exceeded during any time of exposure • Sample to ensure they can not be exceeded.

Calculate TWAs Activity:

TWA • Sample 1. 100 mg/m 3 100 minutes • Sample 2. 160 mg/m 3 150 minutes • Sample 3. 200 mg/m 3 150 minutes

Extended Work Hours • Do TLVs need to be adjusted? • Why and how? • What type work would need it?

Extended Work Hours Dose • Half-Life: • Toluene: 8 hours ½ Dose 8 Hours Time

Extended Work Hours > BEI ld u Bui Purge p > 8 hrs Day 1 Day 2 Day 3 Day 4 Day 5 BEI

Biological Exposure Indices • • BEIs To control Exposure Indicators Various fluids are monitored Various Times (Critical) – What are times based on?

Biomarkers

XYLENE BEI: Methylhippuric acid in urine (Methip) Specimen collection: A post-shift urine sample (20 m. L) obtained after at least two consecutive days of exposure.

Physical Agents • • Noise RF Lasers Vibration Ultraviolet Radiation IR Heat/Cold

TLV – Physical Agents

TLV Questions?