Occurrence and distribution of hormones and bisphenol A in Laguna Lake, Philippines.

The occurrence of hormones and hormone-like compounds in water has been regarded as an emerging environmental concern. These water contaminants are known to cause endocrine disruption that may affect aquatic organisms. In this study, hormones and phenolic xenoestrogens were investigated and measured in the surface waters of Laguna Lake, Philippines. Laguna Lake is the largest lake in the country that has many uses including fish cultivation and source for potable water production. The hormones estrone, 17-beta-estradiol, 17-alpha-ethynylestradiol, progesterone and testosterone as well as the plasticizer bisphenol A in the lake water were determined by solid phase extraction and LC-MS/MS. The extraction method exhibited good recoveries (75-90% in spiked lake water) while the instrumental method of analysis has low detection limits (0.01-0.24 μg/L) and good linear response (>99% in the 0-50 μg/L concentration range). In the nine sampling sites across the lake, estrone was found in concentrations between 0.03 and 0.30 ng/L. 17-Beta-estradiol, testosterone and progesterone were detected in some of the sites in concentrations up to 0.36, 0.22, and 2.05 ng/L, respectively. Bisphenol A was detected in all sites in higher concentrations of 0.71-47.40 ng/L. Although there are no local guidelines yet, the determination and monitoring of these emerging water contaminants are important because of their potential environmental impacts. Further to this initial study, investigations on point sources spanning the tributary rivers, long-term determination of locational and temporal variations, and assessment of ecotoxicological risks are needed. These are crucial in the regulation and mitigation of discharges into the lake.