Expt. 4 - Pesticides

Pesticides

• numerous and diverse group of chemical compounds

• Used to eliminate pests in an agricultural setting and households

• Enable the quantity and the quality of crops and food to be controlled and help limit many human diseases transmitted by insects or rodent vectors

• Some of the most toxic and mobile substances in the environment

• organic

• inorganic

2 divisions of pesticides

• organophosphorus

• organonitrogen

under organic compounds (2)

• arsenic

• fluoride

under inorganic compounds (2)

Organophosphorus pesticides (OPPs)

• principal group of compounds used to protect plants

• Usually have ester structure decomposing fairly easily on the surfaces and interiors of plants in the soil

• parathion

• malathion

examples of Organophosphorus pesticides (2)

• phenylureas

• carbamates

• triazines

organitrogen pesticides (OPNs) include (3)

Lassaigne’s Test / Sodium Test

General test to detect the presence of elements common in pesticides

• dimethyl sulphoxide

• aniline

• chlorobenzene

Lassaigne’s Test or Sodium Test is used to detect (3)

• herbicides

• fungicides

• rodenticides

• insecticides

classification of pesticides

Herbicides

Chemicals that kill or control unwanted plants, especially weeds that compete with crops or harm ecosystems.

Fungicides

Are chemicals that kill or stop fungi from harming plants, animals, or humans

Rodenticides

• Chemicals made and sold for the purpose of killing rodents. While commonly referred to as "rat poison"

• also used to kill mice, squirrels, woodchucks, chipmunks, porcupines, nutria, beavers, and voles

Insecticides

Are pesticides that are formulated to kill, harm, repel, or mitigate one or more species of insects like bedbugs, houseflies, clothes moths, and Japanese beetles.

LD50 of 0.26 - 1.125 mg/kg

toxic dose of rodenticides

LD50 of 639 - 1646 mg/kg

toxic dose of herbicides

LD50 of 8,400 mg/kg

toxic dose of fungicide

LD50 of 1,494 mg/kg

toxic dose of insecticide

• mouth

• skin

• lungs

3 ways pesticides can enter the body