Toxins, Pesticides and Solid Waste Notes Series for Environmental Science

Pesticide Definition A pesticide is any substance or mixture of substances intended for: preventing,destroying, repelling, or mitigating any pest. (US EPA – Pesticides)

Major Types of Pesticides Category Persistence Category Persistence Insecticides High Herbicides Low Fungicides Low Fumigants High

Pesticide Types Organophosphate Pesticides – Affect the nervous system as insecticides Carbamate Pesticides – Affect the nervous system Organochlorine – removed from the market (DDT and chlordane) Pyrethroid – synthetic version of pyrethrin (in chrysanthemums).

Pesticides in Food Tolerance levels in foods (pesticides) was addressed in 1996 with the Food Quality Protection Act (FQPA). There was a revisit of the tolerance levels in August 2006 by the US EPA. The FQPA amended many acts and has become the major driving force for pesticide control.

Plant Incorporated Protectants Plant Incorporated Protectants (PIPs) Plant Incorporated Protectants (PIPs) – are genetic modifications to code for pesticidal proteins. Plant Incorporated Protectants (PIPs) For example – the proteins & its genetic material are regulated by EPA genetic material are regulated by EPA Plants are regulated by US Department of Agriculture

Biopesticides Microbial Pesticides – microorganisms as active ingredients (bacterium, fungus) Plant-pesticides – PIPs Plant-pesticides – PIPs Biochemical pesticides – naturally occurring by non-toxic mechanisms (sex pheromones

Pesticide and EPA

Why Pesticides? Increase the amount of crops harvested per acre Improve human health from malaria, encephalitis, etc… New generation pesticides are target specific (narrow range)

2006 Reports of West Nile Virus Activity

2006 West Nile Virus Human Neuroinvasive Disease Incidence in the United States (Reported to CDC as of March 6, 2007)

Highly Toxic Defined by OSHA (Ocupational Safety and Health Administration) as: Defined by OSHA (Ocupational Safety and Health Administration) as: “A chemical that has a median lethal dose (LD50) of 50 milligrams or less per kilogram of body weight when administered orally to albino rats weighing between 200 and 300 grams each.” “A chemical that has a median lethal dose (LD50) of 50 milligrams or less per kilogram of body weight when administered orally to albino rats weighing between 200 and 300 grams each.” A chemical that has a median lethal concentration (LC50) in air of 200 parts per million by volume or less of gas or vapor, or 2 milligrams per liter or less of mist, fume, or dust, when administered by continuous inhalation for one hour (or less if death occurs within one hour) to albino rats weighing between 200 and 300 grams each.

Lethal Dose 50 The dose at which 50 percent of the organisms die when exposed to a specified concentration (LD 50 ) Toxic substances have this amount and dosage listed If it is a gas, it would be LC 50

Measurement of Acute Toxicity Classification LD 50 -Wt/Kg Single Oral Dose Rat LC 50 -PPM 4 Hr Inhalation Rat Extremely Toxic5-50 mg or less<10 Highly Toxic5-50mg1-100 Moderately Toxic mg100-1,000 Slightly Toxic0.5-5grams,1,000-10,000 Practically Non- toxic 5-15 grams10, ,000 Relatively Harmless 15 grams or more>100,000