(NaturalNews) An infertility crisis on Spanish pig farms has been linked to endocrine-disrupting plastic chemicals also found in human food products, in a study conducted by researchers from the University of Zaragoza and published in the journal Scientific Reports in May.
The study marks "the first time that the correlation between reproductive failures and compounds migrating from plastic materials [has been] studied and demonstrated," lead researcher Cristina Nerin said.
Semen bags contaminated
In the spring of 2010, sows on 41 separate pig farms across Spain abruptly stopped bearing young or began producing smaller-than-normal litters. Researchers examined both the sows and the semen that had been used to artificially inseminate them but found no abnormalities or evidence of disease and no evidence of feed or water contamination.
They did eventually discover, however, that all the semen used in inseminating sows on the farms had been originally refrigerated in bags that came from the same company.
Nerin, an expert in food packaging, was called in by the bag-making company to solve the mystery. Her preliminary tests identified several chemicals in the bags that have been linked to endocrine (hormone) disruption and reproductive problems, most notably cyclic lactone and BADGE.
Cyclic lactone is commonly used in the adhesives used to seal food bags, such as bags of potato chips or sliced meat. It was among the chemicals found at highest concentrations in the semen bags. BADGE, a byproduct of the notorious chemical bisphenol A (BPA), was also found at high levels.
BPA and BADGE are both found in high levels not just in hard plastics but also in the linings of 95 percent of food and beverage cans on the market. BADGE is also found in household dust.
Both cyclic lactone and BADGE have been shown, in prior studies, to migrate from packaging into food. A recent study by the New York State Department of Health found BADGE in 100 percent of urine samples collected in the United States and China.
In the case of the pigs, the chemicals appear to have come from accidental contamination of the adhesive glue used to keep the semen bags sealed.
Sperm damaged, misdirected
In order to confirm that cyclic lactone and BADGE were behind the pigs' fertility problems, researchers inseminated sows with two new batches of semen that had not been stored in bags. One batch had been treated with the two chemicals. The researchers found that only 58 percent of sows inseminated with the chemical-treated semen conceived, compared with 84 percent of those inseminated with untreated semen.
Notably, the researchers found no evidence that BADGE was actually functioning as an endocrine disruptor at the concentrations found in the semen bags. Other studies have suggested, however, that BADGE may also act as a mutagen. Nerin believes that this property may be behind the pigs' fertility problems: BADGE caused mutations in the DNA of the pig sperm, leading to lower insemination rates and more non-viable embryos.
Another recent study, conducted by researchers from the Center of Advanced European Studies and Research in Bonn, Germany, indicated some other ways that endocrine disruptors might affect male fertility. The researchers exposed human sperm cells to 96 separate known endocrine disruptors which they described as "omnipresent in food, household, and personal care products."
One-third of the chemicals tested produced disruption to a cell-signaling pathway known as the "calcium channel," which induces sperm to swim toward and penetrate the egg.
"The sperm cells may have more difficulty in sensing where the egg is," researcher Niels Skakkebaek said. "They could also be swimming in the wrong direction, because they had wrong signals on the way."
The most potent sperm disruptors were found in sunscreens, phthalates (plastic-softening chemicals) and antibacterial and antifungal chemicals, including the triclosan used in antibacterial soap.