Justificación del estudio

The Phantom algae Pfiesteria piscicida has not yet been found in European waters, but was recently introduced into the Chesapeake Bay. It is believed that this species may be transported and subsequently introduced via ballast water or tank sediment (Macdonald per. comm.).

P. piscicida and are dinoflagellates that have been made responsible for recent estuarine fish

kills on the U.S. eastern seaboard (see below) and have also been reported to be associated with human illness. These dinoflagellates appear similar under light microscopy and require scanning electron microscopy for definitive identification. Pfiesteria piscicida is known in 24 different forms and is able to produce dormant cysts that may remain for years. The dinoflagellate feeds on fish body fluid. The waste from fish swimming above resting stages of the dinoflagellate in the sediments makes the cysts change to a toxic life form. These migrate towards the water surface and anaesthetise the fish with their poison and start to feed on the fish fluids from the body tissue after the have bored in. After the fish died, Pfisteria piscicida starts to reproduce and the next generation of cysts return to the bottom waiting for their prey. Human Health Impacts

Thirteen people who worked with dilute toxic cultures of Pfiesteria sustained mild to serious adverse health impacts through water contact or by inhaling toxic aerosols from the cultures. These people generally worked with the toxic cultures for 1-2 hours per day over a 5-6 week period. The effects include a suite of symptoms such as narcosis (a "drugged" effect), confusion, development of acute skin burning (in areas that directly contact water containing toxic cultures of P. piscicida, and also on the chest and face), uniform reddening of the eyes, severe headaches, blurred vision, nausea / vomiting, sustained difficulty breathing (asthma- like effects), kidney and liver dysfunction, acute short-term memory loss, and severe cognitive

impairment (= serious difficulty in being able to read, remember one's name, dial a telephone number, headaches, skin rash, eye irritation, upper respiratory irritation, muscle cramps, and gastrointestinal complaints (i.e., nausea, vomiting, diarrhoea, and / or abdominal cramps). Most of the acute symptoms proved reversible over time, provided that the affected people were not allowed near the toxic cultures again. Some of these effects have recurred (relapsed) in people following strenuous exercise, thus far up to six years after exposure to these toxic fish-killing cultures. The first known fish kills in adjacent waters to the Atlantic Ocean caused by Pfisteria were documented in 1988 in fish culture sites of North Carolina (USA). Fish kills and fish disease events linked to Pfiesteria can extend for 6-8 weeks in North Carolina's estuaries (Pamlico Sound region), thus potentially providing the circumstances for humans in field settings to be hurt due to this dinoflagellate toxins. Since 1991 a billion fish have been killed by Pfisteria in eastern U.S. waters. Most recently un-confirmed findings of Pfiesteria were noted from the Chesapeake Bay region (USA). However, it will not be possible to determine the extent to which people in European estuaries are being affected by Pfiesteria toxins, or whether it is safe to consume fish from toxic outbreak areas, until we have a way to diagnose the presence of these toxins. That will require identification of the chemical toxins produced by Pfiesteria, which is the subject of intensive research.

Lung disease

In Asia a fatal lung disease caused by the parasite Paragonimus westermani (Trematoda) results in cough, peritonitis and pneumothorax (Ichiki et al. 1989) such threatening mammals as rats, dogs, pigs and humans (Davis 1986). The life cycle of this parasite includes two intermediate hosts, the gastropod Thiara granifera and the crab Eriocheir spp. The gastropod was introduced to the USA (Florida and Texas )(Abbott 1950), and the crab as second intermediate host as well (occasional findings in the Great Lake area and established in San Francisco Bay) (Nepszy & Leach 1973, Cohenet al. 1995, Cohen & Carlton 1997). If both the introduced intermediate hosts will spread and become common in overlapping areas this would complete the life cycle of the parasite. Therefore, it could happen that the lung disease will introduce to the USA.

Cholera

A Cholera epidemic (disease agent: Vibrio cholerae) commenced in Easern Celebes (Indonesia) during 1961 and finally completed its encirclement of the globe in 1991. In South

America the epidemic wave started on the coasts of Peru and was documented later from several ports of Latin America. Therefore, it is believed that the Cholera had been introduced by maritime traffic (Epstein 1993). In November 1991 and June 1992 the USA documented the detection of active Cholera bacteria in ballast water of vessels coming from South America (McCarthy & Khambathy 1994). Therefore Australia introduced a testing programme for cholera in 1992 of all vessels from South America and other ports known for Cholera outbreaks. This programme is continuing. A number of presumptive positive test for cholera were documented. Six vessels that had been taken ballast on board in ports of the Persian Gulf, Singapore and Indochina provided presumptive readings, indicating possible Cholera. On serological testings all were subsequently proven to be negative. Since that time studies are being carried out in order to evaluate the risk of Cholera introductions to Australia via ballast water.

The introduction in coastal waters of Latin America caused a serious threat to thousands of peoples health after consumption of seafood as bivalves (oysters), crustacean and finfish caught in affected areas (Murphree & Tamplin 1992).

3 Treatment options

It has so far been concluded that no single or simple solution exists for shipboard treatment of ballast water. However, a combination of techniques might at least be partially effective and feasible in terms of economic and shipboard constraints. These would most likely comprise of some form of mechanical removal of organisms followed by a physical or chemical treatment method.

Ballast water management procedures have been investigated to a certain extent but insufficient research has been carried out to assess the effectiveness of applicable ballast water treatment techniques.

Shipboard treatment of ballast water is considered preferable to land based reception / treatment facilities. Particular emphasis has therefore been placed on potential options for shipboard treatment.

A quarantine system does not provide an absolute barrier to prevent the introduction of unwanted non-indigenous species (Carlton et al 1995). It is also assumed that no single treatment process was likely to achieve the required inactivation or removal of unwanted organisms. A two stage approach seems to be most likely. After an initial mechanical treatment process followed by disinfection, a physical treatment process or a technique involving manipulation of the environmental conditions within the ballast tank could provide a solution. Thus when considering the options reviewed, it should be assumed that the mechanical options are largely viewed as preliminary treatment method.

At this stage various methods of treatment that have been put forward and are described as a "tool box" from which the most practical (easy and safe to apply, not damaging existing ship installations as ballast tank coating, isolators and sealing rings), cost effective safe and environmentally sound combination should be selected. To date, international guidelines have been adopted as the IMO Assembly Resolution A.868(20).

Several of the listed options are straightforward statements of good practice but in many circumstances the choices available to an operator will be very restricted. There are indeed two different possibilities of using the ballast water treatment options listed below. First of all, the ballast water is treated en-route. Secondly, a treatment of ballast water may take place at the port of destination. In this way only the countries concerned need to invest, ports can maintain the treatment equipment and the operation would meet port quarantine and local environmental protection laws. But, the IMO does not promote regional (different) systems,

emphasising that the ballast water problem is a global issue. Using different provisions and options could result in unwanted regional restrictive practices, restraints of trade and competitive advantages.

The following list gives an overview on the amount of ballast water introduced into the waters of several countries. Estimated by scientists and technicians the amount of annually transported ballast water has been summarises world-wide to 10 billion tonnes (Gerlach 1992, Bettelhäuser & Ullrich 1993, Rigby & Taylor 1995).

No country seems to keep records or statistical data on the release of ballast water in their waters. The volume of the water of overseas origin released in territorial waters of a country would be only an indicator of the potential for further species introductions. The degree of risk depends also on the characteristics of the port of origin and port of arrival. In addition, several shipping studies showed, that one single vessel is able to introduce an unwanted species by discharging its ballast water.

The quantitative data on ballast water discharges have to be gathered from individual ports respectively through port authorities or the shipping industry. Therefore the mentioned data are estimated amounts of ballast water discharged. The reason for mentioning these data here is to demonstrate which amounts of ballast water could have to be treated in order to minimize the risk of introduced species.

Europe

Ballast water discharges per year in English and Welsh ports amount to 16.8 million tonnes (Laing 1995) and in Scottish ports to 25.7 million tonnes (Macdonald 1994). About 10 - 15 % of the discharged ballast water originated from outside Europe. In Ireland less than 2 million were discharged, most of it from Europe (Minchin & Sheehan 1996). The estimations of the amount of ballast water in German ports and waterways varied from 8 to 38 million tonnes. The non-European origin was estimated to range from 1.4 to 7 million tonnes (Golchert, pers. comm., Gollasch 1996). Data from Norway are available from one port only: 8 - 10 million tonnes, 15 % of non-European origin (Swedish Environmental Protection Agency 1997)

North America

In all 226 US ports (including Great Lakes) in total 79 million tonnes of ballast water were dumped from vessels from abroad. (Carlton 1995, Carlton et al. 1995).

Gauthier and Steel (1995) estimated that 62 million tonnes of ballast water were discharged.

South Africa

Information on ballast water discharges were collected from several ports around the South African coastline. The estimation summarised relevant data to more than 12 million tonnes (based on data from 1991 / 1992). Data from some ports are missing until today. It is likely that one of these, e.g. Port Elisabeth, does receive about 20 million tonnes of ballast water each year. Roughly a third of these ballast waters are from Far East. Remarkable is that a relatively high percentage of the water was exchanged en route. It is assumed that this is the result of controls introduced in many ports of the world (Jackson in prep.).

Australia

Vessels calling for Australian ports are discharging approx. 121 million tonnes of ballast water each year (Jones 1991, Mills 1992, O´Reilly 1992, Paterson 1992, Kerr 1994, MEPC35/INF.19). In addition over 4,000 vessels per year move more than 34 million tonnes of ballast water between Australian ports.

New Zealand

The total amount of discharged ballast water, mostly of Asian origin, was estimated as 4.5 to 4.7 million tonnes each year (Hayden 1995).

IMO Recommendations

A set of recommended actions have been adopted by IMO in relation to the uptake of ballast water. The taking in of ballast water in shallow habitats, during prevailing turbidity of water, nearby sewage outfalls, when a tidal stream is known to be more turbid, in areas where tidal flushing is known to be poor, during phytoplankton blooms or relevant disease outbreaks and near dredging sites have to be avoided to minimize the risk of up taking species. In addition ballast water should be wherever possible not be taken in darkness (when bottom dwelling organisms may rise up in the water column) and in very shallow waters or when propellers may stir up sediments.

Ballast water uptakes in port areas characterised by slow tidal currents could result in the uptake of ballast water formerly used by another vessel and just released. This scenario could

enable some organisms discharged in the ballast water from one vessel to become transported again pumped in with the ballast water of another vessel.

It has been proposed that ballast water may be analysed in a laboratory on board and that the investigation may provide a certificate of cleanness of the ballast water documenting the absence of harmful aquatic organisms. However, this may not be an effective method of risk minimization due to e.g. taxonomically problems regarding the identification of the organism and pathogens.

Another option deals with the fact that populations of species decrease with their increasing stay in the ballast tanks. The absence of light provides an uncomfortable environment for some species. Water that has been located in a ballast tank longer than 100 days provides a small risk discharging unwanted species. Research showed that even after 116 days living macrobenthos organisms were found (Gollasch 1996). In addition, some species, as phytoplankton organisms may form cysts during unfavourable conditions surviving in the sediment of ballast tanks for a long period. Some zooplankton species may form resting stages as well. These cysts may remain active over longer periods of up to several years. In this way e.g. cysts of dinoflagellates may be transported over long distances. After sediment discharges the cysts may hatch in foreign waters. If these dinoflagellates are toxic they may cause harm to local aquaculture. It is assumed that many phytoplankton blooms may be initiated by these discharges (Hallegraeff et al. 1986, Bolch & Hallegraeff 1993, 1994).