Pentachlorophenol Flashcards
What are fungicides?
Chemicals used to prevent or treat fungal infections in plants
T/F: Generally, fungicides have low toxicity to animals if properly used
TRUE
Uses of pentachlorophenol (PCP)?
- Only used by certified applicators as a wood preservative (to protect limber from fungal rot and wood-boring insects)
- No longer found in wood-preserving solutions or insecticides and herbicides for home/garden use
4 sources of PCP toxicosis?
- Vapors can penetrate intact skin–dermal exposure is the most toxic route of exposure, esp to newborns
- Inhalation of toxic amounts from treated walls in sheds and barns (even if applied months-years before), esp with poor ventilation
- Licking wood treated w/ PCP
- Ingestion of contaminated feeds or water with spills of PCP
What is PCP?
Chlorinated hydrocarbon insecticide and fungicide
Solubility (salts and solution)?
- Solution not very soluble in water, but soluble in oils and organic solvents
- Salts are soluble in water
Stability?
PCP is volatile and can give off toxic vapors in toxic conc. esp. in high ambient temp
Persistence?
Not persistent in water, sewage, or soil b/c of bac. composition
Is PCP an irritant?
Yes–to mm, resp tract, and skin
What do older preparations contain?
Dioxins–carcinogenic and teratogenic
Acute oral (dermal LD50) toxicity?
Chronic toxicity?
- Acute oral in domestic animals ranges from 100-200 mg/kg
- Chronic toxicity ranges from 40-70mg/kg
Factors increasing toxicity?
- High ambient temp
- Oily or organic solvent vehicles
- Previous exposure
- Poor condition
- Newborn
- Hyperthyroidism
Factors decreasing toxicity?
- Cold temp
- Antithyroid drugs
- Presence of body fat
Where is PCP readily absorbed from? Where is it distributed?
- Readily absorbed from GI tract, by inhalation, and from intact skin
- Distributed throughout the body w/ some accumulation in body fat
Half-life?
1.5-2 days in various species
What is PCP metabolized by?
Conjugation to glucuronic acid
How is PCP excreted?
Excreted as glucuronides or unchanged in urine
Residues?
Residues in tissues and fat are depleted from the body w/in 1 week of exposure
Mechanism of action?
- Uncouples oxidative phosphorylation and blocks or decreases ATP
- Increases oxygen demand in an effort to produce ATP
- Oxygen demand > oxygen supply
- Resulting in overheating, metabolic acidosis, and dehydration
Effects on the body?
- Irritation of eye, GI mucosa, resp, and intact skin
- Decreased cellular energy may cause neurotoxic and other effects (wt. loss, dec. milk prod., repro problems)
- High exposures may lead to signs of CNS stimulation or seizures
Clinical signs of acute toxicosis?
- Onset and duration may be so fast that no signs are seen
- Hyperthermia, tachycardia, dyspnea, cyanosis, seizures, collapse, death
- Newborn pigs show hyperthermia, skin irritation, and rapid death
Clinical signs of chronic toxicosis?
- Wt. loss, dec. milk production, anemia, fetal malformations, and poss. abortions
- Fever and resp distress may be absent
What are the lesions of PCP toxicosis?
- Rapid rigor mortis
- Local irritation of skin and mm
- Pulmonary congestion and edema
- Degenerative changes in liver, kidney, and brain
- Dark blood (oxygen deprivation)
- Hyperkeratosis of skin and villous like hyperplasia of urinary bladder mucosa in chronic cases
Laboratory diagnosis: live vs. dead animal?
- Live animal–chemical analysis in blood and urine
- Dead animal–chemical analysis of kidney and skin
