Emily E. Peacock

Plastic accumulation in the North Atlantic subtropical gyre.

Sea of Plastic Plastics are highly resistant to degradation and persist in the environment after being discarded. Notoriously, plastics accumulate within ocean gyres, where patterns of surface circulation concentrate them into specific regions. One area of plastic buildup lies in the middle of the North Atlantic Gyre. Law et al. (p. 1185; published online 19 August) report results from 22 years of plankton tows in the North Atlantic that showed the pattern of plastics accumulation was indeed as predicted by theories of ocean circulation, but, despite the steady increase in plastic production and disposal, the concentration of plastic debris had not increased. The amount of plastic debris in the surface waters of the western North Atlantic Ocean has plateaued over the past 22 years. Plastic marine pollution is a major environmental concern, yet a quantitative description of the scope of this problem in the open ocean is lacking. Here, we present a time series of plastic content at the surface of the western North Atlantic Ocean and Caribbean Sea from 1986 to 2008. More than 60% of 6136 surface plankton net tows collected buoyant plastic pieces, typically millimeters in size. The highest concentration of plastic debris was observed in subtropical latitudes and associated with the observed large-scale convergence in surface currents predicted by Ekman dynamics. Despite a rapid increase in plastic production and disposal during this time period, no trend in plastic concentration was observed in the region of highest accumulation.

The size, mass, and composition of plastic debris in the western North Atlantic Ocean.

This study reports the first inventory of physical properties of individual plastic debris in the North Atlantic. We analyzed 748 samples for size, mass, and material composition collected from surface net tows on 11 expeditions from Cape Cod, Massachusetts to the Caribbean Sea between 1991 and 2007. Particles were mostly fragments less than 10mm in size with nearly all lighter than 0.05 g. Material densities ranged from 0.808 to 1.24 g ml(-1), with about half between 0.97 and 1.04 g ml(-1), a range not typically found in virgin plastics. Elemental analysis suggests that samples in this density range are consistent with polypropylene and polyethylene whose densities have increased, likely due to biofouling. Pelagic densities varied considerably from that of beach plastic debris, suggesting that plastic particles are modified during their residence at sea. These analyses provide clues in understanding particle fate and potential debris sources, and address ecological implications of pelagic plastic debris.

Organic micropollutants in marine plastics debris from the open ocean and remote and urban beaches

To understand the spatial variation in concentrations and compositions of organic micropollutants in marine plastic debris and their sources, we analyzed plastic fragments (∼10 mm) from the open ocean and from remote and urban beaches. Polychlorinated biphenyls (PCBs), polycyclic aromatic hydrocarbons (PAHs), dichloro-diphenyl-trichloroethane and its metabolites (DDTs), polybrominated diphenyl ethers (PBDEs), alkylphenols and bisphenol A were detected in the fragments at concentrations from 1 to 10,000 ng/g. Concentrations showed large piece-to-piece variability. Hydrophobic organic compounds such as PCBs and PAHs were sorbed from seawater to the plastic fragments. PCBs are most probably derived from legacy pollution. PAHs showed a petrogenic signature, suggesting the sorption of PAHs from oil slicks. Nonylphenol, bisphenol A, and PBDEs came mainly from additives and were detected at high concentrations in some fragments both from remote and urban beaches and the open ocean.

The M/V Cosco Busan spill: source identification and short-term fate.

Understanding the fate of heavy fuel oils (HFOs) in the environment is critical for sound decisions regarding its usage and spill cleanup. To study weathering of HFOs, we examined the M/V Cosco Busan spill (November 2007; San Francisco Bay, CA, USA). In this baseline report, we identified which ruptured tank (port tank 3 or 4) was the source of the spilled oil and characterized changes in the oil composition across location and time. Samples from three impacted shorelines, collected within 80 days of the spill, were analyzed using one- and two-dimensional gas chromatography (GC and GC × GC, respectively). Weathering varied across sites, but compounds with GC retention times less than n-C(16) were generally lost by evaporation and dissolution. Changes in n-C(18)/phytane and benz[a]anthracene/chrysene ratios indicated some biodegradation and photodegradation, respectively.

The West Falmouth Oil Spill: ∼100 Kg of Oil Found to Persist Decades Later

In order to investigate the long-term fate of petroleum hydrocarbons in salt marsh sediments in Wild Harbor (West Falmouth, MA) impacted by the Florida spill of 1969, 26 sediment cores were collected and analyzed for total petroleum hydrocarbons (TPH). The results from this effort indicate that the distribution of petroleum hydrocarbons is spatially heterogeneous, oil compounds are generally located at sediment depths of 4 to 20 cm in areas closest to the banks of the marsh, and ∼ 100 kg of petroleum residues can be found to persist in intertidal sediments that were originally the most impacted.

Tracking and Modeling the Degradation of a 30 Year Old Fuel Oil Spill with Comprehensive Two-Dimensional Gas Chromatography

ABSTRACT On October 9, 1974, the barge Bouchard 65, carrying 12 million liters of No. 2 fuel oil, spilled an undetermined amount of oil off the west entrance of the Cape Cod Canal in Buzzards Bay, Massachusetts, USA. Wind patterns and currents caused significant oiling of the nearby Winsor Cove salt marsh. Fortunately, an original Bouchard 65 cargo oil sample was retained from the spill which offers a unique opportunity to compare in vitro weathering experiments with petroleum that has been weathered naturally for over thirty years. Samples of the original product were bio-weathered in the lab over a period of days, and then these samples, plus a contemporary sample from Winsor Cove, were analyzed by Comprehensive two-dimensional gas chromatography with Time of Flight Mass Spectrometry detection (GC×GC-MS). The data from the laboratory experiment was used to create a Principal Components Regression model to predict amount of weathering. The environmental sample was projected onto the regression model and ...