EPA to consider treatment of ballast water in ships

Ships may be forced to treat ballast water before it is discharged into US coastal waters in order to prevent the introduction of aquatic nuisance species (ANS), such as zebra mussels, the US Environmental Protection Agency (EPA) has announced.

The EPA has published a draft report, Aquatic Nuisance Species in Ballast Water Discharges: Issues and Options, in response to a petition from the Pacific Environmental Advocacy Center on behalf of a number of NGOs and state and tribal governmental organizations, and following an enquiry by 18 members of Congress into how the effects of seagoing ships, such as tankers which can carry around 28 million gallons of ballast water, can be mitigated.

It is estimated that more than 10,000 marine species each day around the world are being transported in ballast water, causing problems such as out-competing native species, or even being a detriment to human health, with growing concern over the movement of pathogens such as cholera. Ships have been described as ‘biological islands’, with the organisms that live aboard able to depart, or disperse eggs of young at any port of call, resulting in the dispersal of many marine, estuarine and even terrestrial species around the world for thousands of years. Many species in the US that are often considered to be native in the US are actually the result of anthropogenic introductions by ships over the last 500 years, says the report.

The greatest impediment to effective control of ANS introductions is the lack of technical solutions to remove them from discharge water, says the EPA report. The exchange of ballast water in mid-ocean may offer some relief, but this is not effective in removing 100% of organisms and can involve significant safety risks to vessels during bad weather. Neither can it be practically applied to most domestic US traffic and is difficult to inspect for compliance, according to the EPA.

However, there are a number of actions that can be taken, says the report. These include the promotion of the development of effective ballast water treatment technologies by the EPA through measures such as work with the ANS Task Force, and the promotion of its Small Business Innovative Research programme. The EPA could also encourage education and outreach programmes, and should work with the US Coast Guard to maximize compliance with its regulations, says the report.

The problem of ANS being introduced by the discharge of untreated ballast water occurs all around the world, for example in Australian coastal waters where the New Zealand screw shell, a species of marine shellfish, is driving out native screw shell species and scallops, also affecting the species further up the food chain that depend on them (see related story).

The EPA is seeking information and comments on the report, and these should be sent by 11 January 2002 to Ballast.Water@epa.gov, or sent by post to: Marine Pollution Control Branch, ATTN: Ballast Water, US Environmental Protection Agency (4504F), 1200 Pennsylvania Avenue, NW, Washington, DC, 20460. Respondents should include their name, affiliation, address, telephone number and email address.

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