Boaters had a scare a couple of years ago, when a District Court judge ruled that terms of the National Pollutant Discharge Elimination System (NPDES) applied to small boats. After the Environmental Protection Agency (EPA) lost its appeal of this decision, Congress passed a two year moratorium for this requirement in its Clean Boating Act of 2008 (PL 110-288) and directed the EPA to develop best management practices to help mitigate these discharges and craft performance standards for these practices.
The EPA has released the first of the studies required to meet their commitments as defined under the new clean boating laws. The study is titled Study of Discharges Incidental to Normal Operation of Commercial Fishing Vessels and Other Non-Recreational Vessels Less than 79 Feet and the full text of the report can be downloaded from the agency’s website.
Study Design
This study was designed to characterize the discharges coming from commercial fishing and other non-recreational vessels that are under 79 feet in length. A determination needed to be made of the volumes and locations of discharges coming from these boats. After looking at what was being discharged from the vessels, the EPA needed to quantify the environmental effects caused by these boat discharges.
Boats can and do discharge a variety of substances into the marine environment. Among these discharges are effluent from engine operations, liquid graywater wastes generated by laundry, galley and shower use, and washdown water from cleaning decks, bilges and fish holds. The Agency estimates some 140,000 boats addressed in this study are subject to the NPDES permit moratorium.
The EPA sampled wastewater discharges coming from 61 vessels in nine boat classes. Vessels selected for sampling came from varied geographical regions across the United States.
Study Results
The Agency study found that the discharges coming from deck washdown, effluent from fish holds, bilges and graywater generation posed the greatest risks to the environment. Water coming from the washdown of decks was found to have high levels of aluminum. Effluent from fish holds significantly increased biological oxygen demand (BOD) and chemical oxygen demand (COD) in waters where is is discharged. Graywater from laundry and sinks contains food waste, fecal coliform bacteria, and detergents. Bilge spaces contributed fuel, oil, sewage and dissolved metal contamination to vessel discharge streams.
The EPA also looked at the effects of anti-fouling bottom paints. The most commonly used biocide used in these paints is cuprous (copper) oxide. Copper from bottom paint enters the environment by leaching and underwater hull cleaning. After looking at all of the vessel discharge streams, the EPA concluded that arsenic and copper represent the greatest environmental impact of concern to the Agency. There were other notable pollutants, coming mainly from fish holds, which worsens eutrophication (increase in nutrients that stimulates excessive plant growth in the water) of small bodies of water like bays and harbors.
Conclusion
The EPA showed that smaller, non-recreational vessels produced discharges that can impact the marine environment. Incidental discharges from these vessels into large bodies of water are not likely to cause water quality problems. Where vessels might become more concentrated in smaller areas, local problems with water quality could be seen. Among all the potential discharge streams, dissolved copper has the greatest chance of causing violations of water quality standards, especially in waters that already have a high background level of the dissolved metal.
It is likely that the EPA moving forward will craft best management practices for non-recreational vessels that seek to reduce these harmful discharges into the environment. Banning the practice of in-water hull cleaning might be an example. Guidelines are more likely to be imposed where large numbers of boats are concentrated near sensitive marine habitat. Crowded commercial boat harbors will see changes in vessel regulations first.
It will pay vessel owners and operators to follow the progress of the EPA as it tries to comply with the Clean Boating Act of 2008.
Copyright © 2010 by Alan Sorum
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