Chemicals leached into waterways from commonly used plastics and detergents may be making the lobsters in Long Island Sound and elsewhere in southern New England more susceptible to a bacterial infection known as shell disease, a University of Connecticut researcher has found.
Among the chemicals studied is bisphenol A, also called BPA and the subject of recent concern and controversy about its presence in plastic baby bottles and other products and possible harmful effects on children's development.
Hans Laufer said Monday that the research findings are the first to connect plastics chemicals with the shell disease, which leaves lobsters with weakened shells with dark lesions that can eventually break through and allow them to succumb to bacterial infections. He will present his findings at a two-day symposium today and Wednesday at the University of Rhode Island.
Earlier this year, the U.S. Food and Drug Administration raised concerns about BPA's effects on developing fetuses and infants, and in Connecticut a ban on BPA in children's products will take effect in the fall.
Laufer said he believes BPA and the three other alkylphenols he studied are a serious threat to human health, as well as to lobsters and other marine animals. He advocated reduced use of plastics and more recycling.
"We need to reuse plastics instead of throwing them away and increase our use of plastic substitutes like cardboards and glass bottles," he said.
Laufer's research is also significant because of recent debate over a proposal under consideration by regional fisheries regulators over whether the lobster fishery in southern New England should be closed because stocks depleted for the past decade have failed to recover.
Penny Howell, fisheries biologist with the state Department of Environmental Protection and a member of a regional fisheries regulatory panel, said Monday that Laufer's research could lead the panel to conclude that near-term recovery is unlikely and that a closure of the fishery would be prudent.
"But we would have to look at his data very carefully," said Howell, who is a member of one of the panels scheduled for the URI symposium.
Lobsters studied by Laufer and his colleagues came from Long Island Sound as well as southern Massachusetts, Cape Cod Bay and offshore Rhode Island. More than half of the more than 950 lobsters, eggs and larvae studied through blood and tissue samples had high concentrations of one or more of the chemicals.
The chemicals find their way into waterways from landfills and sewage plants, which are not equipped to remove them during the treatment process. Laufer said about 60 percent of the 1 million tons of BPA produced annually ends up in the ocean, most of it in marine sediments where lobsters spend much of their time. The lobsters ingest the chemical when they eat sediment-dwelling animals such as clams and mussels.
Laufer's research also found that the chemicals impede hormones that promote the growth and development of young lobsters, interfere with shell hardening and cause females to molt when carrying eggs, effectively killing them. The four chemicals studied are alkylphenols, including bisphenol A.
"I'm most interested in the effects on larval lobsters," Howell said, noting that surveys done in Rhode Island and Connecticut waters have shown the steepest declines in larval lobster populations. "That's our biggest concern," she said.
The surveys Howell cited also showed that about one third of the lobsters from eastern Long Island Sound had the shell disease, with lower rates in the central and western Sound.
Laufer's study, however, showed a seemingly contradictory finding that demonstrates that a complex and not yet fully understood convergence of factors has caused the steep lobster declines, Howell said.
The chemicals were most prevalent in lobsters from the western Sound, the south shore of Massachusetts and Cape Cod Bay. Howell said one possible explanation is that the bacteria associated with shell disease is more widespread in the eastern Sound, so exposure to the chemicals there is more likely to leave lobsters susceptible to it. Warmer water temperatures and more competing bacteria in some areas may be keeping the shell disease bacteria at bay there, she said.
Laufer said the lobster die-off of the mid-1990s was most likely due to warmer-than-normal water temperatures, but that shell disease is a likely culprit in the lack of recovery since then.
"They're a cold-water animal," he said.
Laufer, a professor emeritus in UConn's Department of Molecular and Cellular Biology, conducted his research with colleagues at UConn, the Woods Hole Oceanographic Institute and Biological Laboratory, and the University of Massachusetts. It was funded by the state Department of Environmental Protection and the Connecticut and Rhode Island Sea Grant programs.
Laufer said he suspects all of the alkylphenols studied are hazardous to humans as well as lobsters, and that given their widespread distribution in the environment, many people are also contaminated by the chemicals.
"This is as big a threat to human health as tobacco," he said. "Many companies are saying they're safe, but they're not."
Percent of lobster samples tested that had chemical contamination:
Western Long Island Sound: 55
Southern Massachusetts: 52
Cape Cod Bay: 50
Narragansett Bay: 38
Eastern Long Island Sound: 35
Southern Long Island Sound: 22
Central Long Island Sound: 19
Total number tested: 985
Source: UConn Prof. Hans Laufer and colleagues