Maria Katerina B. Mallari, Aisha F. Subosa (March 2009)
Philippine Science High School Western Visayas Campus – Department of Science and Technology (DOST-PSHS WVC), Brgy. Bito-on, Jaro, Iloilo City 5000, Philippines
ABSTRACT
Frogs have been well-known bio indicators because of their ability to live in both water and land and their ability to absorb and concentrate toxins in their fatty tissues which make them the first to die in a polluted environment. 500 of this amphibian species are in danger of extinction due to the environmental changes and pollution.
Methamidophos and Lambda-cyhalothrin are two of the many active ingredients found in pesticides that are widely used in the Philippines. If taken in by organisms, Methamidophos can nearly paralyze them and lead to its death. Lambda-cyhalothrin may cause death because it disrupts the normal functioning of the nervous system in an organism.
This study determined the growth rate and survival percentage of Bufo marinus tadpoles exposed to Methamidophos-containing pesticides and Lambda-cyhalothrin-containing pesticide with three different levels of concentrations.
The tadpoles were randomly selected, weight initially, and exposed to different concentrations of Methamidophos-containing pesticide and Lambda-cyhalothrin-containing pesticide for a 16-day period. The samples were again weighed on the 8th and 16th day after initial exposure.
Two pesticides significantly affected the growth and survival of Bufo marinus since it produced decreasing growth rate and survival percentage. With that, both are considered to be chronically toxic and lethal.
There is a significant difference between the two pesticides. Lambda-cyhalothrin is more chronically toxic. The highest concentrations of both pesticides were proven to be the most chronically toxic and lethal.
Chronic toxicity of pesticides can be determined through the changes in the growth rate and survival percentage of Bufo marinus since they are widely-known to be good bio-indicators.