Fundamentals of Industrial Hygiene

6th Edition

Part III: Recognition of Hazards

Chapter 6:

Industrial Toxicology

Compiled by Allen Sullivan,

Assistant Professor, Safety and Health ManagementCentral Washington University

Definitions

• Definitions• toxic effect• toxicity• dose• hazard

• route of entry (inhalation, dermal, ingestion)• quantity of exposure (amount and duration)• characteristics of substance (physical state, size, pH)• physiological state (state of health, pre-existing conditions)• environmental variables (presence of other substances)

Route of Entry

• Inhalation• upper respiratory tract• lower respiratory tract

• Skin Absorption• skin thickness• temperature• perspiration

• Ingestion• Injection

Dose–Response Relationship

• Dose C T = K• concentration (C)• time duration (T)• constant (K)

• Response• threshold concept• potency• toxicity• cumulative effects• exposure thresholds

• NOAEL (No Observable Adverse Effect Level)• LOAEL (Lowest Observed Adverse Effect Level)

Lethal Dose (LD)

• Lethal Dose• bell-shaped Curve

• LD50

• LD0

• LD100

• usually mg/kg

• Lethal Concentration (LC)• airborne• usually mg/m3 or ppm

• Evaluation

Timing: Exposure and Effect

• Acute Effects and Acute Exposures• rapid onset• short duration• rapid absorption

• Chronic Effects and Chronic Exposures• slow to develop• long duration and/or frequent recurrence

Airborne Contaminant Exposure

• Irritants• primary irritant• secondary irritant

• Allergens• hypersensitivity v. hypersusceptibility

• Systemic Toxins• Asphyxiants

• simple asphyxiants• chemical asphyxiants

Airborne Contaminant Exposure (cont.)

• Organ-Specific Effects• central nervous system

depressants• cardiac sensitization• neurotoxic effects• pulmonary effects

• particulates not otherwise specified (PNOS)

• heavy metals

• carcinogenesis• carcinogen• carcinogenic potential

Airborne Contaminant Exposure (cont.)• mutagenesis• reproductive toxicity

• teratogenesis• pregnant women in the workplace

Basis for Workplace Standards

• Chemical Analogy• Animal Experimentation

• exposure standards• screening procedures• problem areas

• In-vitro Testing• Human Epidemiological Studies

• descriptive studies• retrospective studies• prospective studies

Federal Regulations

• Occupational Safety and Health Act of 1970 (OSHAct)• right-to-know regulation• permissible exposure limits (PELs)• toxic substances list

• Toxic Substances Control Act of 1976 (TSCA)• NIOSH Standards

• criteria documents• recommended exposure levels (RELs)• current intelligence bulletins (CIBs)

• OSHA Standards

American Conference of Governmental Industrial Hygienists (ACGIH)

• Threshold Limit Values (TLV®)• limitations of TLVs (OELs)• time-weighted average

• ceiling values• STELs• mixtures

• antagonistic

• potentiation (synergistic)• carcinogens (carcinogenic potential)• physical factors (judgment)• unlisted substances

• Selection of TLVs (OELs)

CaTa + CbTb + … CnTn = TWA 8

C1 + C2 + C3 + ... = 1 T1 T2 T3

• Biological Testing• biological analysis

• body burden• amount in circulation• amount excreted

• benefits of biological analysis over air sampling• types of biological analyses

• unchanged substances• metabolites• levels of naturally occurring substances

• urine, blood, and breath analyses

Biological Testing