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.