toxicology

OCCUPATIONAL TOXICOLOGY

Deals with the effects of chemicals found in the workplace

Occupational Safety and Health Administration (OSHA)

Promulgates standards for specific materials of particularly serious toxicity

Permissible Exposure Limits (PELs)

Used to establish safe ambient air concentrations for many chemicals found in the workplace

8 HOURS

How many hours of workday to which workers may be repeatedly exposed without adverse effects

Threshold Limit Values (TVLs)

Useful as reference points in the evaluation of potential workplace exposures in the absence of OSHA requirements

ENVIRONMENTAL TOXICOLOGY

Concerned with the toxic effects of chemical and physical agents on populations and communities of living organisms within defined ecosystems

ENVIRONMENTAL TOXICOLOGY

Also called as "Ecotoxicology"

ENVIRONMENTAL TOXICOLOGY

Deals with the deleterious impact of chemicals, present as pollutants in the environment, on living organisms

Traditional toxicology

concerned with toxic effects on individual organisms

Acceptable Daily Intake (ADI)

Denote the daily intake of a chemical from food that appears to be without appreciable risk.

Food and Drug Administration (FDA) and the Department of Agriculture

ADI is regulated by

Hazard

ability of a chemical agent to cause injury in a given situation or setting

Risk

expected frequency of the occurrence of an undesirable effect arising from exposure to a chemical or physical agent

Inhalation

major route of entry in the industrial setting

Inhalation and dermal contact

Atmospheric pollutants

Inhalation, ingestion, and dermal contact

Water and soil pollutants

Inhalation, Transdermal, Oral ingestion

Routes of Exposure

Acute exposure

single or multiple exposures from seconds to 1-2 days

Rhodanese

A mitochondrial enzyme that detoxifies cyanide to nontoxic thiocyanate.

Chronic exposure

single or multiple exposures over a longer period of time

BIOACCUMULATION

Intake of a long-lasting contaminant by an organism exceeds the latter's ability to metabolize or excrete the substance, the chemical accumulates within the tissues of the organism

Polychlorinated biphenyls (PCBs)

Example of BIOMAGNIFICATION

NITROGEN OXIDES, OZONE, SULFUR DIOXIDE,CARBON MONOXIDE

AIR POLLUTANTS

NITROGEN OXIDE

Mixed up the majority of the air pollutants around 52%

CARBON MONOXIDE

Colorless, tasteless, odorless, and nonirritating gas

CARBON MONOXIDE

Byproduct of incomplete combustion

0.1 ppm

Average concentration of CO in the atmosphere

50 ppm

PEL OF CARBON MONOXIDE

Carboxyhemoglobin

The by product of Carbon monoxide and hemoglobin

high flow oxygen

TREATMENT for CARBON MONOXIDE

SULFUR DIOXIDE

Colorless irritant gas generated primarily by the combustion of sulfur-containing fossil fuels

5 ppm

PEL of Sulfur Dioxide

no specific treatment

TREATMENT FOR SULFUR DIOXIDE

200 g SO2 /L of water

solubility of SO2

sulfurous acid

What will form/happen when SO2 contacts moist membranes?

SULFUR DIOXIDE

severe irritant effects on the eyes, mucous membranes, and skin

SULFUR DIOXIDE

If it is inhaled it can cause bronchoconstriction (asthma) and pulmonary edema

NITROGEN OXIDE

Brownish irritant gas

NITROGEN OXIDE

Seen in Fires, automobile, and truck traffic emissions

NITROGEN OXIDE

Associated with Silo-filler's disease

Silo gas

a combination of nitrogen oxide and carbon dioxide

Nitric Acid

In Silo-filler's disease the nitrogen dioxide will combine with water in your lungs to form?

5 PPM

PEL of NITROGEN OXIDES

NITROGEN OXIDE

MOA : decrease of lung surfactant

affect type 1 alveoli

CLINICAL EFFECTS OF NITROGEN OXIDES: Low to moderate inhalation exposure

affect type 1 and type 2 alveoli

CLINICAL EFFECTS OF NITROGEN OXIDES: High exposure

Cardio Vascular disease and stroke

CLINICAL EFFECTS OF NITROGEN OXIDES: Chronic exposure

irritating to some individuals

CLINICAL EFFECTS OF NITROGEN OXIDES: 25 ppm

pulmonary edema and death

CLINICAL EFFECTS OF NITROGEN OXIDES: 100 ppm

irritating to the eyes and nose

CLINICAL EFFECTS OF NITROGEN OXIDES: 50 ppm

pulmonary edema and subacute or chronic pulmonary lesions

CLINICAL EFFECTS OF NITROGEN OXIDES: Exposure for 1 hour at 50 ppm

no specific treatment

TREATMENT for NITROGEN OXIDES

OZONE

a bluish irritant gas found in the earth's atmosphere, where it is an important absorbent of ultraviolet light at high altitude.

OZONE

MOA: irritant of mucous membranes

OZONE

PEL is 0.1 ppm

OZONE

CLINICAL EFFECTS: pulmonary edema, bronchoconstriction, chronic bronchitis, bronchiolitis, fibrosis, and emphysematous changes

irritation and dryness of the throat

CLINICAL EFFECTS OF OZONES: 0.1 ppm O3 for 10-30 minutes

changes in visual acuity, substernal pain, and dyspnea

CLINICAL EFFECTS OF OZONES: above 0.1 ppm

pulmonary function is impaired

CLINICAL EFFECTS OF OZONES: exceeding 0.8 ppm

no specific treatment

TREATMENT FOR OZONE

HALOGENATED ALIPHATIC HYDROCARBONS, AROMATIC HYDROCARBONS

SOLVENTS

HALOGENATED ALIPHATIC HYDROCARBONS

also called as "Halohydrocarbons"

HALOGENATED ALIPHATIC HYDROCARBONS

Human carcinogens

HALOGENATED ALIPHATIC HYDROCARBONS

Lungs: Least affected

Trichloroethylene

Associated with Renal cancers and non-Hodgkin lymphomas

dichloromethane,
Trichloroethylene
tetrachloroethylene

Associated with Renal, prostate, and testicular cancer

CLINICAL EFFECTS AND MECHANISM OF ACTION OF HALOGENATED ALIPHATIC HYDROCARBONS

CNS depression, liver injury, kidney injury, and cardiotoxicity/cardiac arrhythmia

no specific treatment

TREATMENT FOR HALOGENATED ALIPHATIC HYDROCARBONS

BENZENE

An important component of gasoline

BENZENE

used for its solvent properties and as an intermediate in the synthesis of other chemicals

BENZENE

MOA: chromosomal breakage, chromosome reorganization

1 ppm

PEL OF BENZENE: AIR

5 ppm

PEL OF BENZENE: SKIN

CNS depression

CLINICAL EFFECTS OF BENZENE: Acute toxic effect

euphoria, nausea, locomotor problems, and coma

CLINICAL EFFECTS OF BENZENE: Acute toxic effect- \>3000 ppm:

vertigo, drowsiness, headache, and nausea

CLINICAL EFFECTS OF BENZENE: Acute toxic effect- 250-500 ppm:

bone marrow injury (aplastic anemia, leukopenia, pancytopenia, thrombocytopenia, leukemia, lymphomas, myeloma, and myelodysplastic syndrome)

CLINICAL EFFECTS OF BENZENE: Chronic exposure

BENZENE

may be found in premium gasolines at concentrations of about 1.5%

TOLUENE

CNS depressant, eye irritant, neurotoxic, fetotoxic

methylbenxene

200 ppm

PEL OF TOLUENE:

Severe fatigue and ataxia

CLINICAL EFFECTS OF TOLUENE: 800 ppm

rapid loss of consciousness

CLINICAL EFFECTS OF TOLUENE: 10,000 ppm

XYLENE

CNS depressant, skin irritant

dimethylbenzene

100 ppm

PEL OF XYLENE:

Organochlorine pesticides
Organophosphorous pesticides
Carbamate pesticides
Botanical pesticides

PESTICIDES

ORGANOCHLORINE PESTICIDES

Bioaccumulation due to slow degradation

ORGANOPHOSPHOROUS PESTICIDES

Useful pesticide when indirect contact with insects or when used as plants systemics

Triorthocresyl phosphate (TOCP)

noninsecticidal organophosphorus compound.

ORGANOCHLORINE PESTICIDES

CLINICAL EFFECTS: CNS stimulation & Endocrine pathway disruption

TCDD

Associated w/ non-Hodgkin's lymphoma, soft tissue sarcomas, lung cancer, Hodgkin's lymphomas, and others

Ivermectin, pentobarbital, mephenesin

Management of Pyrethrum toxicity

TOCP

associated with progressive chronic axonal neurotoxicity

ORGANOPHOSPHOROUS PESTICIDES

MOA: inhibition of acetylcholinesterase and phosphorylation of neuropathy target esterase (NTE)

Pralidoxime

TREATMENT FOR ORGANOPHOSPHOROUS PESTICIDES

CARBAMATE PESTICIDES

Spontaneous reactivation of cholinesterase is more rapid

CARBAMATE PESTICIDES

CLINICAL EFFECTS: SHORTER DURATION

Nicotine

CNS stimulation

suppression of convulsions

Treatment for Nicotine:

Rotenone

GI irritation, conjunctivitis, dermatitis, pharyngitis, and rhinitis

Pyrethrum

eye irritation, asthma, CNS excitation, convulsions, and tetanic paralysis