Source: Numbers for above charts are totals for Pennsylvania counties inside the Susquehanna River basin from United States Department of Agriculture, Census of Agriculture, 2012, 2007 and 2002.
Gregory Martin, a poultry expert who teaches at Penn State’s College of Agricultural Sciences, in Lancaster, Pennsylvania, the seat of Lancaster County, is skeptical that there is a connection between estrogen from agricultural pollution and intersex fish. “I just don’t see that happening,” he said. “Nice study, but I think we need to look at more of the picture.”
But Vicki Blazer, the lead author on the study, says the spike in livestock is significant.
They are “raising more animals in the same space,” she said. “As those numbers increase, obviously the nutrients and estrogens and other hormones they excrete increases as well.”
Today, Pennsylvania is the nation’s fifth-largest producer of milk, third largest of eggs and the top producer of mushrooms, according to the U.S. Department of Agriculture.
Intersex fish have been a worldwide phenomenon for two decades, and scientists have found them in the U.K., Germany, Italy, South Africa and Japan. After a massive die-off of smallmouth bass in 2003 in the Potomac River, another tributary of the Chesapeake Bay, scientists discovered that many of those ill fish were also intersex.
Most of the sickened bass found in the Susquehanna’s summertime surveys are just a few months old. Disease in fish so young suggests that their immune systems are being hurt early, scientists say. Smallmouth bass spawn in the spring, the same season when the most water runs into rivers from ranches and farms because of melting snow and heavy rains. Male bass build nests by sweeping silt off the river bottom with their fins so that females may lay their eggs. Then the eggs sit there, and often become coated with a thin layer of silt, which, the report says, contains “higher numbers and concentrations of estrogenic compounds” than the water.
“Estrogens are involved in a multitude of health and disease endpoints,” said John A. McLachlan a professor in the School of Pharmacology at Tulane University. “Not the least in immune dysfunction.”
Representatives of the agriculture industry say they have taken steps to reduce overall pollution, as mandated by state and federal laws. Also, they say, the intersex-fish report is far from conclusive.
“Studies like this have to be viewed with the understanding that correlations or associations do not necessarily equal causations,” said Richard Carnevale, vice president at the Animal Health Institute, an agricultural lobbying group.
Estrogen from human waste also enters rivers through sewage and industrial-waste treatment facilities, of which there are some 5,000 on the Ohio, Delaware and Susquehanna Rivers, according to the Pennsylvania Department of Environmental Protection. This can include synthetic estrogens from contraceptive and hormone replacement pills, which take longer to break down, scientists say. Though the water treatment process removes estrogen, there is no state standard for how much may remain, a spokeswoman from the DEP said. Also, no facilities have been upgraded to specifically remove estrogen.