[PCOL and TOXICOLOGY] PPT Solvents and Pesticides (Part 3 of intro)

Hydrocarbons

once found wide use as industrial solvents, degreasing agents and cleaning agents

• A few examples are: • Carbon tetrachloride • Trichloroethylene • Chloroform • Tetrachloroethylene • 1,1,1-trichloroethane

Halogenated Aliphatic HC

classified as known or probable human carcinogen

Fluorinated Aliphatic

freon and closely related compounds can cause severe damage to the ozone layer

Trichloroethylene and tetrachloroethylenes

listed as reasonably anticipated to be human carcinogens

Depressants of the CNS in humans

Hydrocarbons

• Chronic workplace exposure can cause

> neurotoxicity

> impaired memory

> peripheral neuropathy

• All can cause cardiac arrythmias, hepatotoxicity in acute and chronic exposures

Neurotoxic

memory impairment

Peripheral Neuropathy

Chronic exposure to Trichloroethylene and tetrachloroethylenes can cause what

Arrhythmia

Hepatotoxicity

2 common adverse effects of exposure to

Trichloroethylene and tetrachloroethylenes HC

Dichrolomethane

a potent neurotoxin a generator of CO in humans and a probable human carcinogen

• No specific treatment

• Management depended on the organ system involved

Treatment of hydrocarbon (Dichloromethane) exposure

Aromatic Hydrocarbons

Benzene is what type of HC

Benzene

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

May be found in premium gasolines

Acute exposure to Benzene

The following are adverse effect of what:

CNS Depression, Nausea, Euphoria, Locomotor Problems and Coma; Vertigo, Drowsiness and Headache

Chronic exposure to benzene

The following are adverse effect of what:

Bone Marrow Injury

lymphomas

myelodysplastic syndrome

Benzene

a potent clastogen

A mutagen that act by causing chromosomal breakage

Suggests to have specific chromosome reorganization and genomic patterns

• Supportive treatment

• Nonspecific

two treatments of benzene exposure

Toluene and Xylene

• Does not possess the myelotoxic properties of benzene

Toluene

• Not been associated with leukemia

• Not carcinogenic but it is a CNS depressant and a skin and eye irritant

• neurotoxic and fetotoxic

• Can lead to severe over fatigue and ataxia

Toluene

Chronic effects of long term exposure has behavioral effects

Xylene

Dimethylbenzene

Has been substituted for benzene in many solvent degreasing operations

Does not possess myelotoxic properties of benzene

Not associated with leukemia

Is also a CNS depressant and skin irritant

• Chlorophenothane (DDT)

• Benzene hexachlorides

• Cyclodienes

• Toxaphenes

4 classifications of Organochlorine pesticides

Organochlorine Pesticides

• Aryl, carbocyclic or heterocyclic compounds containing chlorine substituents

• Can be absorbed through the skin, it could be inhalational or orally ingested

• Have largely abandoned because of severe environmental damage

true

t/f:

• Acute toxic properties of all the organochlorine pesticides in humans are similar

Organochlorine

• Interfere with the activation of sodium channel in excitable membranes and cause rapid repetitive firing in most neurons

• Chlorophenothane (DDT)

> Can manifest as tremors initially

Organochlorine

• Major effect is CNS stimulation

> Continuing convulsions – as the first sign of intoxication

Chlorophenothane (DDT)

Can manifest as tremors initially

Organochlorine

• Calcium transport is inhibited

> This events affect repolarization and enhance the excitability of neurons

Organochlorine Pesticides

• Considered persistent chemicals

• Slow degradation as compared with other pesticides

• Bioaccumulation in aquatic ecosystems

• Mobility depends on soil composition

• Presence of organic matter favors absorption

• Induces significant abnormalities in the endocrine balance of sensitive animal and bird species

organic matter

In organochlorine, Presence of ___ matters favors absorption

Organochlorine

Organochlorine

Organophosphorous

Useful in direct contact with insects or when used as plant systemics

Based on compounds soman, sarin and tabun (G compounds)

Developed in Germany and later weaponized for use as war gas

VX compound developed by the British which is 20x more potent than G compounds

Parathion, Malathion, Azinphos

______________ and other OP pesticides are less toxic than the military grade compounds

Organophosphates

Major effect is inhibition of acetylcholinesterase through phosphorylation of the esteratic site

Direct cholinergic activity

Physostigmine

pretreatment and other short acting antagonist compounds

may provide protection against these pesticides or war gas

Organophosphates

Can cause Altered neurologic and cognitive functions as well as psychological symptoms of variable duration

Organophosphates

Also capable of phosphorylating Neuropathy target esterase (NTE)

> Present in neural tissue

> This result in progressive demyelination of the longest nerves

> Associated with paralysis and axonal degeneration lesion (organophosphorus ester-induced delayed polyneuropathy (OPIDP)

> Delayed central and autonomic neuropathy

triorthocresyl phosphate (TOCP)

In Humans, progressive chronic axonal neurotoxicity was observed with ___________

Organophosphates

Signs and Symptoms:

• Polyneuropathy: starts with burning and tingling sensations in the feet

• Sensory and motor difficulties may extend to legs and hands

• Gait affected and ataxia may be present

> balance in walking

Organophosphates

Neuromuscular transmission failure and cardiac failure more typical on nicotinic than muscarinic poisoning

Progressive neuromuscular failure leads to weakness of the respiratory muscles then eventually death

Organophosphates