18-11-02 Offshore drilling platforms, such as Glomar on the Grand Banks of Newfoundland, generate thousands of litres of waste containing heavy metals and man-made contaminants.

On the continental shelf off Atlantic Canada, the steel towers of five massive platforms rise above the ocean, two off the coast of Newfoundland and three off Nova Scotia.
Where cod and crab and other ocean creatures were once the only resource sought from the sea, oil and gas are now prized as economic targets too. Yet Newfoundland's two producing oil projects, and the three natural gas platforms off Nova Scotia, pump far more than just petroleum from under the ocean floor.
Like other wells throughout the world, they also generate "produced water" -- a catch phrase for the thousands of litres of briny, liquid waste naturally present in underground petroleum reservoirs -- which gets extracted along with the oil and gas.

There are new scientific concerns that the huge amounts of produced water dumped at sea each year byoffshore platforms may be causing long-term harm to fish populations, and other organisms, in some areas where oil rigs operate. On Canada's East Coast, where a fledgling industry mines for wealth on some of the most important fishing grounds in the world, such concerns have caught the attention of the Department of Fisheries and Oceans (DFO), which now has a team of scientists probing the mysteries of oil rig effluent.
"Produced water is a concern, because we're looking at something, at least in this part of the world, that we don't know much about," says Dr Kenneth Lee, a biologist with the Bedford Institute of Oceanography in Halifax, a DFO agency.

Dr Lee leads a team of federal scientists trying to find out what happens to produced water when it is discharged into the sea -- where it goes and what its chemical make-up is. His team must also investigate a new issue, raised this year by Norwegian scientists, that produced water may be having a feminising effect on cod and other fish species, reducingtheir fertility.
Dave Burley, environmental manager for the federal-provincial agency that regulates the oil industry off Newfoundland, says the Norwegian research poses "an entirely new wrinkle we have to take into account."

Produced water is a natural part of an underground oil formation. The amount of water sucked up by offshore rigs tends to increase with the age of an oil well: As the oil is pumped out and oil levels fall inside the reservoir, more and more water comes out. In the North Sea, where hundreds of oil and gas wells are nearing the end of their life, almost 98 % of what is being generated by some sites is now simply waste water.
Many oilfields actually generate twice as much water over their lifetime as oil. In offshore operations, this effluent is separated from the oil during a treatment process, after which it is pumped into the sea. The discharged water is a complex soup of substances -- including heavy metals such as arsenic and mercury, radioactive materials, and droplets of oil and grease that could not be removed by treatment.

Produced water often also contains man-made chemicals, such as defoaming and anti-corrosion agents, used by oil rigs in the drilling and pumping process. The general view of the oil industry has been that produced water is harmless to the environment because the ocean is a big place, and the effluent becomes heavily diluted once it is released into the sea.
A report on the subject, published last year by the Canadian Association of Petroleum Producers, calls it high volume, low-toxicity waste. "Produced water is totally miscible in seawater, the pollutant load is comparatively low, and dispersion and dilution is very rapid," the report says.

That conclusion is supported by studies that have found only minor impacts on marine life in the waters immediately surrounding oil rigs in the Gulf of Mexico and the North Sea. Less well known, however, are the long-term impacts of produced water on the ecosystem. A few years ago, as volumes of produced water started to climb in the North Sea, scientists at Norway's Institute of Marine Research decided to try to find out.
The results of their first such study were released this spring. The Norwegian focus was alkylphenols, a natural component of crude oil and a common substance in produced water. Alkylphenols have long been known to have estrogenic, or feminising effects, on human beings and other mammals. When the Norwegians fed both large and small doses of alkylphenols to codfish in laboratory tanks, they discovered that the cod's reproductive abilities were similarly affected.

Dr Ole Arve Misund, the biologist who led the research, says the alkylphenols caused delays in the maturation of the fish, meaning that some cod spawned too late for other individuals to fertilize their eggs -- thereby damaging the animal's ability to reproduce.
It is not yet clear is how alkylphenols might affect entire populations of cod in the open ocean. Yet Dr Misund says his research does demonstrate that even small, diluted amounts of produced water could be harming cod stocks, and possibly other marine species.
"The discharge of produced water in the North Sea is now more than 300-mm tpy," he says. "It's really a very substantial amount. And the amount of alkylphenols is something like 20 tons in total." Even after produced water is dispersed at sea, says Dr Misund, such large, total volumes "might be enough to potentially have a harmful effect."

Dr Misund knows depleted cod stocks in both the North Sea and the East Coast of Canada are more the result of overfishing than oil rig effluent. But he says produced water could hamper efforts by fisheries to rehabilitate their stocks.
Canada's offshore oil and gas wells are much younger, and fewer, than those in the North Sea. As a result, says Dr Misund, there is probably little immediate danger to Canadian fish from the small volumes of produced water being discharged off Newfoundland and Nova Scotia.
The Hibernia platform, Canada's largest offshore project, pumps an average of 3,000 cm of produced water into the ocean each day -- about 1000th the total daily discharge into the North Sea. Still, says Dr Misund, "our conclusions should be borne in mind if activity in eastern Canada develops into more than just a handful of projects."

The Canadian oil industry's 2001 report says the produced water generated off Atlantic Canada is similar in "almost all respects" to that in the North Sea. Yet the report predicts "there is little potential for discharges from Canadian East Coast operations to cause significant adverse effects in the water column."
Dr Kenneth Lee is less certain. He says the industry report was published before the Norwegian study was released this year. He also says produced water may pose risks that are not yet understood.
For example, despite the "dilution solution" commonly cited for produced water, Dr Lee says certain particles in the effluent undergo chemical reactions in oxygen-rich seawater, that may make dilution difficult. Instead of dispersing into the ocean, the particles -- which may include metal contaminants -- sink in the water column around the oil platform. "Things may not be diluting and spreading out," he says, "but concentrating in the water close to the rig."

Dr Lee and his team of researchers have gathered samples in the vicinity of Canada's offshore platforms and have so far detected little damage to the marine environment. His concern lies in the future, when the existing oil and gas wells are older, and new ones may be operating beside them.
"Down the line, if we ever have a lot of oil rigs out there, produced water could potentially pose a significant danger."