What is a pesticide? Pesticides and Herbicides are commonly used to kill off unwanted organisms, most particularly in agriculture. Pesticides are large molecules that have been intentionally released to increase the time of crops in the fields, and reduce crop depletion by bugs and other organisms. Herbicides typically target plants, not bugs or mammals, so weeds and types of grasses. Unlike other pollutants, like NOx, VOCs, CFCs, and CO, pesticides were intentionally made and released into the environment. Pesticides can have human, animal, and plant health effects. 

Sarin was a pesticide developed in the 1930s. Sarin is now considered a chemical weapon after the German government discovered its uses as a nerve agent against other soldiers during World War II. Just because some pesticides and herbicides are not extremely toxic to humans does not mean that they do not have grave environmental impacts. Pyrethrins are hypothesized to be interfering with the bee population, which in turn affects pollination rates in the world. 

Most modern-age pesticides have been made to have specific shapes to interfere with enzyme function and cellular communication. The specificity of pesticides is very important in determining the health effects of the pesticide on the overall environment. When a pesticide has a high specificity, they are specific for a certain type of organism. An example of this is using insect pheromones to trap and kill specific bugs that are a problem for your crops. This avoids hurting other non-problematic organisms while solving your crop depletion problem. Low specificity means that the pesticide is toxic towards a large range of organisms, like Arsenic, which is poisonous to many organisms, including humans. 

LD50 measurements are a great way to tell how lethal a dose of a chemical is for mammals. LD50 measures the lethal dose for 50% of the individuals in the study, so when half of the testing population dies. The lower the LD50, the higher the toxicity, which means the less a mammal is able to intake before lethal levels are reached. While LD50 is specifically for animals, like mammals, it is a good indication in determining the general effect on the environment around. The more toxic the chemical, the lower the LD50, and the more plants and animals are impacted negatively. Pesticides can be useful in agriculture to prevent crop depletion by insects and other organisms, but the health and environmental impacts can be very severe. Determining a new type of pesticide that can be used with low specificity and a higher LD50 would be very beneficial to environmentally friendly agriculture practices.