Thoughts on Marine Debris Research Needs

Environmental remediation practitioners must assess the fate and extent of plastic garbage in marine environment. There is a an extremely vast gap in understanding where plastic debris is found, how it behaves in the ocean, and what impacts it has on aquatic ecosystems including very likely impacts to human food resources and human health outcomes.

We must endeavor to understand how marine plastic, first by its presence and by its sources and sinks, threatens ecological and economic resources. Is any part of the ocean resilient in the face of threatening and unceasing tides of plastic garbage? To understand the extent and movement of marine plastic debris, technology must be developed and refined to detect plastic debris in the ocean and tag and track it to understand its behavior and its adverse environmental impacts. While numerous studies show wide variation in plastic content in surface net trawls, a perhaps exponentially larger fraction is undetected by these conventional approaches, leaving more questions than answers. Micro plastics likely pose the greatest harm and yet at present no attempt has been made to quantify these fractions of this endless stream of garbage.

Beyond the known and yet unknown physical damages resulting from plastic contamination, plastic debris also acts as a vector for POP uptake to aquatic organisms and may have a role in contaminant fate and transport in aquatic food webs. Plastic uptake has been observed in connection with excess POP loading in fish tissue. Key food chain species are known to suffer toxic effects of contact with micro plastic particles.

To get at these questions, we must assess issues such as the role of plastic type, photo-disintegration, particle size distribution in the various marine matrices, buoyancy, and other surface and subsurface dispersion (e.g., water column, shoreline, benthic sediments).  Particular focus must be paid to the smallest, highest surface area, particles with the highest incidence of ingestion, as these may well contribute contaminants into food webs.

Research Impact on Clean Water Policy
Research and extent and impacts of plastic debris will shed light on policy short comings. When considering stormwater, non-point source, pollution policy and regulation, Federal and State authorities lack the information required on plastic fate and extent, to make informed decisions. Measuring debris quantity and other properties, while holding waste generation per capita as a constant, might highlight large differences between coastal cities pointing to their stormwater and even solid waste management strategies as possible culprits. Plastic types and even brands are important to understanding upstream sources. Data on these elements will provide information to target waste management and minimization approaches.

Likewise, plastics posing significantly greater environmental fugacity, the likelihood of distant transport of breakdown products with marine reactive qualities, could be replaced with more suitable formulations. Plastics with decreased propensity for photo-disintegration and low contaminant ad/absorption rates (Kd) may be less harmful in the aquatic environment and may be better managed on-land (recycled?) compared to highly reactive plastic formulations subject to escape disintegration and ingestion.

Research Impact on Environmental Restoration Objectives
Plastic toxicity in the environment is of great concern.  Efforts to understand plastic toxicity will include investigation of both toxic contaminants such as POPs (e.g., PCBs) and toxic plastic components or plasticizers (e.g., BDEs), but also physical location (deposition and plume migration), likelihood of aquatic organism exposure, impacts on resources at risk, and potential risk from plasticizer chemical and POP uptake.  These all have confounding effects on aquatic restoration objectives.

From Superfund to Natural Resource Damage Assessment to Endangered Species Critical Habitat and Clean Water Act Restoration needs, these issue confound high dollar cleanups and interventions often required by law and by regulators. The outcomes of these actions and policies, when confounded by the emerging role of plastic debris, may mask measurement of environmental benefit. It is imperative that we act now to take the lead in addressing the uncertainty of the impact of marine plastic debris on large risk-based cleanup decisions.

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