Discipline: Veterinary Medicine
Experiments were conducted to determine contamination of Laguna de Bay in the Philippines with estrogenic endocrine disrupting compounds and to examine their impact on introduced fish. Results revealed 17ß- estradiol (E2) levels in water samples ranging from 0.29±0.07 μg/L to 0.40±0.16 μg/L. Caging of adult male common carp (Cyprinus carpio Linnaeus) in the east and west bays of the lake induced production of the egg-yolk protein precursor vitellogenin (8.33±0.40 to 8.77±0.60 μg/ml) and mild to moderate lesions in the testis that are consistent with estrogenic exposure. In general, the results validate pollution of the lake with estrogenic substances. Whether or not the obtained E2 levels could elicit biologic effects that can compromise reproduction and population dynamics in fish and in higher vertebrates should be a subject of future research endeavors. Given the current weight of evidence on the adverse effects of endocrine disruption by environmental estrogens, the implementation of measures that could prevent the discharge of these compounds in the lake watershed is recommended.