- PPM-Parts per million (1 in per 1,000,000,10-6)
- PPB-Parts per billion (1 part in 1,000,000,000,10-9)
- PPT-Parts per trillion (1 in 1,000,000,000,000,10-12)
- One part per million is 1 inch in 16 miles
- 1 mim in 2 yrs
- 1cent in $10,000
- 1 ounce of salt in 31 tons of potato chips
- 1 bad appple in 2,000 barrels of apples
- 1 part per billion is 1 inch in 16,000 miles
- 1sec in 32 yrs
- 1 cent in $10,000,000
- 1 pinch of salt in 10 tons of potato chips
- 1 lob in 1.200,000 tennis matches
- 1 bad apple in 2,000,000 barrels of apples
- Left side of the decimal point:
- 1 trillion is bigger than 1 billion
- 1 billion is bigger than 1 million
- 1 million is bigger than 1 thousand
- Right side of the decimal point:
- 1 part per triliion is smaller than 1 part per billion
- 1 part per billion is smaller than 1 part per million
- 1 part per million is smaller than 1 per thousand
- Water at STP (standard temperature 23C and pressure 15 psi): 1cc=1ml-1g
- Toxicity of chemicals is determined in the laboratory
- The normal procedure is to expose test animals
- Toxicity is measured as clinical"endpoints"
- include mortality, teratogenicity, carcinogenicity, mutagenicity
- LD50 is the amount of the chemical which produces death in 50% of a population of test animals to which it is administered by any of a variety of methods
- LC50 is the concentration of a chemical in an environment(generally air or water) which produces death in 50% of an exposed population of test animals in a specified time frame
- 3 primary routes by which organisms are exposed to pesticides is oral, dermal, inhalation
- Taken in through the mouth & passes through the gastrointestinal tract
- During oral exposure, although carried within the body, the pesticide is still outside of the body proper until it passes through epithelial cellular membranes
- proper hygiene this type of exposure is
- generally not serious unless there is a specific, rapid toxicological efect (often eye efects) which is of concern
- beathed into the
- lungs through the nose or mouth
- Not of toxicological concern until it crosses from the lung into the body (unless the chemical is corrosive)
- Acute ~ single exposure of short
- duration
- Chronic ~ repeated long-term contact
- Subchronic ~ repeated exposure over
- Expression of toxic symptoms only after repeated exposure to a chemical in doses regularly applied to the organism for a time greater than half of its life-expectancy
- Toxic symptoms are expressed after repeated applications for a timeframe less than half the life expectancy of the organism
- more often than a single dose or multiple doses applied for only a short time
- The less you need to cause a toxic efect – the more toxic the substance is
- “Warning” reflects an intermediate degree of relative toxicity
- “Danger” reflects the highest degree of relative
- toxicity