The fish were collected in 2003 a few miles offshore in multiple locations as part of research to determine whether ocean life is harmed at the outfalls. At the time, 11 of 64 male turbot and sole caught near the outfalls were marked positive as having eggs, while none were found farther away. The locations fit the hypothesis that the estrogenic pollutants in the wastewater could alter fish sex organs. “All of them were near an outfall site so the pattern we saw made sense,” Bay said.
The scientists originally discussed their findings of feminized fish at a 2005 toxicology conference in Baltimore, and the Los Angeles Times published a story on it then. “At the time, we felt these were real findings,” Bay said.
“It was depressing” to find the error, Bay said. “But thank god we didn’t write a paper on it.” Since the data were preliminary, the scientists hadn’t submitted anything to a journal for publication. The authors acknowledged the error in December in a report in the journal Environmental Toxicology and Chemistry.
Bay said the mistake came when his team saw in the pathology report that 11 male samples were checked positive for eggs but failed to notice the eggs’ location; the pathologist had noted the eggs were outside the testes. When the same slides were retested three months ago, three of the turbot and all six English sole had no eggs, and two other turbot had “minimal testis-ova,“ likely due to contamination during dissection or processing, Bay said.
Errors "a rarity"
Founded in 1969, the Southern California Coastal Water Research Project is a public agency funded by the U.S. Environmental Protection Agency, state environmental agencies and county and city sanitation agencies. It is well known and its science is highly regarded, although they are not specialists in hormone disruption. The private Virginia-based lab, Experimental Pathology Laboratories, that analyzed the tissues is considered among the most experienced animal pathology labs in the country. The company's pathology supervisor, contacted by EHN, declined to comment, citing client privacy.
Steve Weisberg, executive director of the Southern California institute, called the errors “a rarity."
Elsewhere, feminized fish have been discovered, and confirmed, in many rivers, estuaries and lakes contaminated by sewage treatment plants or industries, including ones in England, Canada, the Mediterranean Sea and the Potomac River.
During its expanded testing, the Southern California scientists found no intersex fish out of 373 males caught in 2006. However, they did find subtle changes in their hormones.
For example, male hornyhead turbot had very high estrogen levels, higher than the females, regardless of where they were caught. It may be a natural oddity of the species. But both male and females near the outfalls had about half the estrogen found in the ones near uncontaminated sites, according to their December report. Anti-estrogenic chemicals near the outfalls could be the cause, the report says. Stress and thyroid hormones also were different in the fish near the outfalls, indictating an effect on their physiology.
However, hornyhead turbot, chosen for study because they are bottom-dwellers and are fairly sedentary, are abundant, and there seem to be no overall effects on their populations or reproductive organs. “We know that populations of the fish seem to be healthy. We don’t see declines,” Bay said.