For ocean critters, plastic packs double whammy

January 16, 2013 by admin  
Filed under Water Quality

Products made from the particular plastic used to make water bottles (polyethylene terephthalate, or PET) might have fewer detrimental chemical impacts than products made from other types of plastic, according to the study, published online in Environmental Science Technology.

The research, conducted for 12 months at five locations in San Diego Bay, was the first controlled, long-term field experiment measuring the absorption of contaminants by the five most common plastics:

  • Polyethylene terephthalate (PET): Recycling symbol #1, like water bottles.
  • High-density polyethylene (HDPE): Recycling symbol #2, like detergent bottles.
  • Polyvinyl chloride (PVC): Recycling symbol #3, like clear food packaging.
  • Low-density polyethylene (LDPE): Recycling symbol #4, like plastic shopping bags.
  • Polypropylene (PP): Recycling symbol #5, like yogurt containers, bottle caps.

The researchers deployed pellets of each plastic type in mesh bags tied to a dock at each study site. They retrieved them periodically to measure the plastics’ absorption of persistent organic pollutants.

“Consistently in our study, we found polyethylene [HDPE and LDPE] and polypropylene [PP] absorbed much greater concentrations of contaminants than PET or PVC, and those are the most commonly mass produced and consumed plastics,” says Chelsea Rochman, a doctoral student in ecology at University of California, Davis and San Diego State University. ”They are also the most commonly recovered as marine debris.”

In 2007, HDPE, LDPE, and PP accounted for 62 percent of all plastics produced globally, while PVC and PET represented only 19 percent and 7 percent, the study says.

The data imply that products made from HDPE, LDPE, and PP may pose a greater chemical risk to marine animals that ingest plastics than products made from PET and PVC. The study notes that, although PVC did not absorb as many contaminants as did other plastics, vinyl chloride is classified as carcinogenic and toxic.

Rochman expected the pellets would absorb an increasing amount of pollutants for the first several months of the study before reaching equilibrium—the point at which they could not absorb further toxic substances.

However, Rochman found that HDPE and LDPE continued to absorb contaminants throughout the 12 months. The study estimates that, at the Shelter Island study site, it would take 44 months for HDPE and 19 months for LDPE to stop absorbing toxic substances.

“It surprised us that even after a year, some plastics would continue to take up contaminants,” Rochman says. “As the plastic continues to degrade, it’s potentially getting more and more hazardous to organisms as they absorb more and more contaminants.”

The National Science Foundation’s Graduate Research Fellowship Program funded the study, as did the Society of Environmental Toxicology and Chemistry, the San Diego State University Research Foundation, and the Padi Foundation.

Source: UC Davis

Article source: http://www.futurity.org/earth-environment/for-ocean-critters-plastic-packs-double-whammy/

G.E. Begins to Dredge Hudson for PCBs

June 4, 2009 by admin  
Filed under Protecting Habitats, Water Quality

After long battle, E.P.A. and G.E. begin a cleanup of PCB hot spots on the Hudson River. Hot spots of PCBS are mapped by GPS, and a dredge barge scoops up chunks of river mud putting it into a hopper barge, to be sent on to nearby processing facility and then, eventually, transported 2,000 mile on a train ride to a Texas hazardous waste dump.

By ANDREW C. REVKIN
Published: May 15, 2009

The Dredging of the HudsonMOREAU, N.Y. — Twenty-five years after the federal government declared a long stretch of the Hudson River to be a contaminated Superfund site, the cleanup of its chief remaining source of pollution began here Friday with a single scoop of mud extracted by a computer-guided dredge.  

Twelve dredges are to work round the clock, six days a week, into October, removing sediment laced with the chemicals known as PCBs. Mile-long freight trains running every several days will carry the dried mud to a hazardous-waste landfill in Texas. 

An estimated 1.3 million pounds of PCBs, or polychlorinated biphenyls, flowed into the upper Hudson from two General Electric factories for three decades before they were banned, in 1977, as a health threat to people and wildlife. In high doses, they have been shown to cause cancer in animals and are listed by federal agencies as a probable human carcinogen.

“Today, the healing of the Hudson begins,” George Pavlou, the Environmental Protection Agency’s acting regional administrator, said under bright skies in a riverbank ceremony here as federal, state and local officials, G.E. representatives and environmental campaigners looked on.

Those gathered scrambled from a white tent to get a good view as a blue clamshell bucket rose slowly from the riverbed holding the first five cubic yards of mud. A lone duck paddled downriver along the far bank.

The dredging operation is the first phase of an operation that, if it continues as projected through 2015, could largely eliminate the Hudson’s last significant toxic legacy from an era of unfettered industrial activity and dumping.

While the Superfund site itself is 197 miles long, stretching from Hudson Falls, N.Y., to the southern tip of Manhattan, the initial phase involves spots along a six-mile segment south of Fort Edward, the hamlet across the river from this industrial site.

G.E. is supervising and paying for the cleanup, which federal officials have estimated could cost more than $750 million. Industry experts say the ultimate cost could be many times than that, however. (G.E. declines to give an estimate.)

While most of the chemicals were dumped when such practices were legal, the Superfund law requires the responsible polluting party, when one can be pinpointed, to foot the cleanup bill.

Yet G.E has reserved the right, after a review of the operation in 2010, to reject the project’s much larger second phase. Federal environmental officials have said that if it did that, they would most likely order the cleanup to proceed and levy enormous penalties against the company.

The first phase is projected to remove 22 tons of PCBs from the riverbed; the second phase would remove 102 tons, the E.P.A. said.Even as it embarks on the cleanup, G.E. has a lawsuit challenging the constitutionality of the Superfund law working its way through federal court. (The company is a responsible party in 52 active Superfund sites across the country, according to the Environmental Protection Agency.)

Please read the rest at the NY Times website.
Source: NY Times, http://www.nytimes.com/2009/05/16/science/earth/16dredge.html