prior to its start-up involving the characterisation of drinking water, soil, vegetable and air samples across the Island. The purpose of the studies was to determine the presence of inorganic cations and anions, heavy metals and the organic constituents dioxin, furan and polycyclic aromatic hydrocarbons, noted Dr. Kent Simmons in the Bermuda Biological Station's 1994 annual report. More than 4500 analyses were performed on 225 samples which were collected from a variety of locations on the Island with special emphasis on the one kilometre zone of deposition around the Tynes Bay area, he said. Added environmental engineer Dr. Tom Sleeter: "The baseline studies measured a lot of chemicals around Bermuda targeting those we knew would be coming out of the incinerator's emissions, especially those which are harmful. "We ended up with an excellent data base of what chemicals were found in various materials against which future changes can be measured. And we'll carry out a similar study in three to five years to look for any changes,'' he said. Monitoring the incinerator now involves the determination of pollutant gases, particulates and precipitation at the Prospect sampling station. "Prospect station was deliberately set up one kilometre away from the Tynes Bay incinerator stack because that's where we'd expect to see the most impact,'' noted Dr. Sleeter. "And so far, we haven't seen any impact from Tynes Bay on the air quality. The only changes we've seen occur when combustion sources from Hamilton blow toward Prospect,'' he said, adding that Prospect's ambient instrumentation has just been updated. Monitoring the incinerator also involves chemical testing of ash for the presence and potential release of toxic compounds, noted Dr. Simmons. The ash-concrete blocks, which are being deposited in Castle Harbour, are being completely analysed, said Dr. Sleeter.

"Before the incinerator was built, we brought ash in from the US and mixed it with concrete to see the leaching rates of chemicals in the water. Now we're looking at our ash to see if the chemical composition is any different. "We have to characterise the toxins in the ash produced by Tynes Bay to see if it is any weaker or stronger than the ash we brought in from the US,'' he said, adding that results are not yet available. The Biological Station is also monitoring the local ecology of the blocks in Castle Harbour. Said Dr.

Sleeter: "Dr. Robbie Smith is looking at the biological impact that the ash-concrete blocks may have on the water. He is looking to see whether or not toxins are transferred to organisms and he is checking the sediments around the blocks for metals, etc. "So far, the results show little difference between the ash-concrete blocks and the control blocks, which are just made out of concrete.'' Dr. Smith is also monitoring the north shore ecosystem outside of Tynes Bay to see the effect of the heated effluent, which is the incinerator's cooling water discharge. "He's testing sea grasses, coral reefs and animals found in the sediment,'' said Dr. Sleeter. "And he has not yet seen any effect from Tynes Bay, just seasonal variations.'' Dr. Sleeter noted that an ambient air quality study inclusive of the entire Island has been going on since 1987. Funded by the Environment Ministry and carried out by the Biological Station, the study shows Bermuda's air to be very good, he said.

"Bermuda's air basically reflects ocean air except in certain pockets of the city. Also in some areas, when the wind is blowing in a certain direction or when you test the air behind cruise ships, trucks or buses, the air quality changes,'' he said. In addition to the Prospect monitoring station, there are two other stations in St. David's and Southampton, which are available for air quality testing, said Dr. Sleeter. As well, the Air Quality programme now operates a mobile air quality testing unit which contains some of the latest ambient air testing instrumentation. The mobile vehicle is designed to travel to problem areas and address air quality complaints, noted Dr. Simmons.

Measurements of wind speed and direction along with the airborne pollutants outlined in the 1993 Clean Air Act can be made, he said. "The mobile van is a very useful instrument for air quality studies,'' added Dr. Sleeter. PHOTO SEAWORTHY BLOCKS -- Incinerator ash is mixed with concrete to form blocks, which are then deposited into Castle Harbour. LAND RECLAMATION -- The ash-concrete blocks in Castle Harbour are constantly being monitored by the Biological Station's Dr. Robbie Smith. MINI SUPPLEMENT SUP