Pesticides in the Environment


Pesticide Transport and Fate

Monitoring in the Environment

Methods for Measuring Human Exposure to the Agent

Exposure Pathways

Strategies for Preventing and Controlling Pesticides

Harmful Effects of Alachlor

Dose Response of Alachlor

Absorption, Distribution and Metabolism

Sites of Toxicity

Biomarkers of Disease and Molecular Mechanisms of Action

Risk Assessment

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Characteristics of Pesticides

A pesticide is a chemical, which is used to kill unwanted organisms. Pesticides often act as nerve poisons and are often hazardous to animals and humans. Some pesticides can cause nerve or liver damage, birth defects and cancer. Most pesticides are regulated by the EPA. There are many different kinds of pesticides including biopesticides, insecticides, herbicides and disinfectants, antiseptics, sterilizers and sanitizers.

Biopesticides are pesticides that come from natural sources. In 2001 there were 780 such products registered with the EPA. Biopesticides have three categories: microbial, plant-incorported-protectants (PIPs) and biochemical. Microbial pesticides are microorganisms that work to kill certain pests. These microorganisms include everything from bacteria to fungi to protozoa. PIPs are substances that result from genetic material being incorporated into a plant. Once the material has been incorporated into the plant the plant will then be resistant to that particular pest. Biochemical pesticides are naturally occurring and control pests through non-toxic routes. An example of a biochemical pesticide is a plant extract that draw insects to a trap. Because biopesticides are naturally occurring they pose much less health and environmental concerns that conventional pesticides.

Many insects have the ability to transmit diseases and pose incredible health risks to humans and animals. In addition insects can cause devastating damage to crops. Insecticides work by killing or deterring such insects. Insecticides are often used on humans in the form of bug spray, are sprayed on crops to protect them from infestation and sprayed in or around houses and commercial property to prevent entry into buildings.

A herbicide is a chemical used to kill or control the growth of plants. Some herbicides can selectively kill weeds and other plants while leaving grasses unharmed. Herbicide use has greatly increased crop yields worldwide. However, herbicides can cause severe environmental problems and are a health hazard for humans and animals.

Disinfectants, antiseptics, sterilizers and sanitizers are very similar but do slightly different things and have slightly different practical uses. They are all considered antimicrobial pesticides. Antimicrobial pesticides may not cause unreasonable health effects to human health or the environment. Disinfectants are used on hard inanimate objects and destroy microorganisms or inhibit their activity. They have two classes complete and incomplete. Complete disinfectants destroy spores and vegetative forms of microorganisms. Incomplete disinfectants affect only vegetative forms of microorganisms. Disinfectants differ from antiseptics in that antiseptics can be used safely on humans and animals. Because antiseptics are used on humans they are considered drugs and are regulated by the FDA. Sterilizers work to eliminate microorganisms like fungi, viruses and bacteria. Sterilizers are mainly used for infection control and are used most often in medical settings. Sanitizers generally only reduce microorganism growth. They are important for cleaning equipment and utensils in restaurants and food-processing plants.

All pesticides contain active ingredients and inert ingredients. The active ingredients are the substances that perform the desired effect of the pesticide. By law, all active ingredients are to be specified by name and percentage by weight on the label. Inert ingredients are mixed with the active ingredients to create the final product. These inert ingredients can have a several different purposes including increasing the effectiveness of the active ingredients, making the pesticide easier to use or apply, or allowing several active ingredients to combine into a solution. The inert ingredients can make up as much as 99% of the final product. Just because these inert ingredients don’t specifically target the pest doesn’t mean that they aren’t equally toxic as the active ingredients. The problem with the inert ingredients is that they are not required by law to be listed on the label by name, leaving consumers unaware of the exact make-up of the pesticide.