Pig farmers in Spain noticed a worrisome problem in 2010. Their pigs weren’t producing offspring anymore — or if they were, the litters were decidedly smaller. The disturbing reason for this phenomenon may give you pause.
It began happening in the spring of 2010. On 41 farms around Spain, the size of pig litters took an unnatural nosedive between April and June. Many sows couldn’t produce any piglets at all. These were large-scale farms, having between 800 and 3,000 pigs apiece.
It was no small problem and it threatened the farmer’s livelihoods. They scratched their heads in confusion. What was going on?
Investigating Pig Reproductive Failure Across Spain
The farmers called in investigators to find out. They examined everything, looking for a common denominator. Nothing was wrong with what the pigs were eating and drinking. They weren’t infected and hadn’t ingested any toxins. They even tested the boar semen used to impregnate the sows. Everything seemed perfectly fine.
The investigators delved deeper and looked at how the semen was being stored. These farms bred 100 percent of their sows via artificial insemination — a process routinely requiring that extracted semen be stored for future use.
Farmers stored semen doses collected from the boars at 17 degrees Centigrade in plastic bags for between 24 hours and approximately one week, according to a new study that examined this situation. As they reviewed these practices, investigators realized that every one of the farms experiencing this sudden breeding decline stored boar semen in the same type of plastic bag.
As it turned out, chemical compounds in adhesives within the Chinese-manufactured plastic were leaching into the semen, damaging the sperm’s DNA. This was happening despite the fact that the semen was stored only for a few days. That’s just scary.
Cristina Nerin, an analytical chemist at Spain’s University of Zaragoza, studies packaging materials. The company that sold these bags to the Spanish farmers reached out to Nerin to request that she help them find out why these particular bags caused this problem.
“They were desperate,” she told National Geographic, “because they didn’t find a reason why reproduction failed.” Nerin’s research team looked at what was going on and came up with some sobering realizations. They believe the adhesive compounds used to create these multilayer plastic bags were the culprits.
“This is the first described relationship between reproductive failure and toxic compounds released from plastic bags,” reported the team in its newly released study, published in the journal Scientific Reports.
Why You Should Care About Problems with Pig Semen Bags
Here’s why this story should matter to you. Some of the same chemicals found in the pigs’ semen storage bags are — wait for it — also in the plastic you’re probably using to store food. They are chemicals known to migrate from plastic to food. Not so appetizing, is it?
The study “provides evidence of the risk we [are] facing, and it emphasizes the importance of adhesive control in packaging.”
Adhesive compounds found in the multilayer plastic bags included:
- Cyclic lactone - According to National Geographic, this compound is “a common by-product in adhesives used in potato chip bags and sliced meat packages.”
- BADGE (bisphenol A diglycidyl ether) - A derivative of BPA. You remember our friend BPA, don’t you? It’s the substance we’re all trying to avoid in our plastic bags, bottles, food containers and elsewhere, though it reportedly lines 95 percent of the food and drink cans in the entire U.S. BPA is suspected to negatively affect the brain, behavior and even prostate glands of children, babies and fetuses.
Consider this finding: the pigs’ sperm cells behaved normally, moving as they should and entering eggs as they always do. Despite this, fertilized embryos failed to develop and would not implant themselves in the uterus. The pregnancies wouldn’t “take” — apparently because the damage done by these compounds had reached into the very DNA of the sperm and damaged it.
When the farmers switched to a different type of bag, the problem resolved itself, but the concern remains. Food contact materials (FCMs), including plastics, contain harmful properties like formaldehyde, endoctrine distruptors, BPA, mutagens and more. These same compounds are in all sorts of packaging for everything from toothpaste to toys.
Scientists recently opined in the Journal of Epidemiology and Community Health that the lifelong risks of ingesting foods stored in FCMs is not yet documented. They noted:
Whereas the science for some of these substances is being debated and policymakers struggle to satisfy the needs of stakeholders, consumers remain exposed to these chemicals daily, mostly unknowingly.
Studying the effects of such exposure may well be impossible, they say. There really aren’t any unexposed populations they could use as a control group.
Other scientists feel this concern is overblown. “[H]igh levels of fat, sugar and salt in a lot of today’s processed food are more of a health concern than any migration of chemicals from the packaging,” Dr. Oliver Jones of Melbourne, Australia’s RMIT University told the BBC.
That’s probably true. Now you feel better, right? Right?
Photo credit (all images): Thinkstock