Feature

Inviting Pollution Within

Some might call it poetic justice -- human-produced toxins have the potential to strike back through our prey.

by Deborah McCutchen

Are nations who insist on the continued consumption of whale and dolphin products poisoning their own populations? As with the wooden horse before the walls of Troy, humans often choose to ignore clear signs of danger, sometimes literally welcoming it inside, until the evidence becomes incontrovertible and deadly.

There are many indications that it is not a good idea to eat species from the top of the food chain. Toxic substances can build up within organisms, in the processes of bioaccumulation and biomagnification, and reach levels higher than those found in the environment. Concentrations of these substances tend to increase towards the top of the food chain. Marine mammals are the top predators in the oceans, as humans are on land.

Organochlorines are among those substances whose persistence in the environment lend themselves to bioaccumulation. They are human-made, difficult to metabolise, and toxic.

Humans have synthesised and produced over 50,000 new chemicals during the last 100 years. Many of these chemicals can be broken down naturally. The first synthetic pesticides to be manufactured, however, were the persistent organochlorines. They are known to the world under a variety of names including Chlordane, Heptachlor and DDT.

Most people have heard the story of DDT or dichlorodiphenyl trichloroethane, the wonder insecticide, and how it went from global popularity to global tragedy by virtue of human ignorance regarding its persistence. Today some of New Zealand's prime pasture is unfit for use because of the practice of mixing DDT with fertiliser 20 years ago. The residues still show up in dairy milk, human milk, terrestrial and marine ecosystems.

There are 11,000 different organochlorines and many of these are currently being manufactured, although few have been studied in depth. The few which have been examined are often banned from further production as their effects on the environment become known. Unfortunately, due to their nature, this does not mean they cease to exist.

PCBs

Like DDT, PCBs (polychlorinated biphenyls) are made up of chlorine and carbon. PCB is a generic name for a number of compounds with varying percentages of chlorine. Since the 1930s PCBs have been produced in the making of adhesives, paints and capacitors. They are used in hydraulic fluids, lubricants, plasticisers and pesticide extenders.

The stability of the PCB chemical group at high temperatures, along with their conducting abilities, make them ideal coolants for closed circuit electrical heat-transfer systems. Their use has been restricted for this last purpose in North America since 1972, with the plan that they be phased out by 1993 in answer to public pressure.

The problem is that PCBs are still leaching into the environment, and the marine ecosystem is particularly susceptible. The products and transformers which used PCBs are either in use, rotting in landfills, or dumped in the ocean. Whatever isn't dumped directly generally finds its way to the ocean eventually.

PCBs have a high dispersal rate across the entire globe through atmospheric transfer. They evaporate into the air, are transported by wind, and precipitate out where air and water meet. Thus areas which never manufactured the chemical still pay a price for its presence. Long lived organisms such as cetaceans  whales and dolphins  will continue building up their pollution burden long after the toxic substances are no longer being manufactured. Toxin loads found in marine mammals are higher than terrestrial mammals.

In 1988, an estimated 1.2 million tons of PCBs were reported to have been created. Sixty-five percent of that was in use or in landfills, 20% had found its way into the ocean, 11% was in soils and only 4% had degraded or been incinerated.

With a relatively small percentage of the existing total of organochlorines in the ocean -- so far -- effects have been recorded at every level in the ecosystem, from suppression of photosynthesis in phytoplankton to reduced fertility in fish. Whales and dolphins are particularly susceptible because of their place at the top of the food chain, where all the concentrations of toxins in their food are further concentrated in themselves.

Organochlorines, particularly PCBs, are fat soluble. Cetaceans tend to accumulate the toxins in their stored blubber. Toxins are passed on to offspring while in utero or when feeding on their mother's milk. If the animal is ill or under stress and begins burning the stored fats, the toxins can be released very quickly into its system.

Measurements can be taken of the amounts of PCBs, DDT and other toxins in samples taken from marine mammals. Seals have shown reproductive failure when exposed to even moderate levels of these toxins. In areas of high contamination, such as the Baltic and North Seas and in the North Pacific, uterine deformities, unusually high abortion rates, hormonal imbalance and depressed immune systems have been correlated with high levels of DDT and PCBs.

Cetaceans have a lower metabolic capacity than other animals. Their liver and kidneys have not evolved to detoxify artificially-made organochlorines quickly. Pelagic, or deep water, whales, such as the minke -- currently hunted for scientific purposes and used for meat in Japan and Norway -- have the lowest metabolic capacity of all marine mammals.

Minkes lack or have low levels of the enzymes needed to metabolise the more toxic organochlorines. Very little has been studied about the pollution burden of minke whales despite the fact that they are themselves a source of food for some humans. No correlations have been made between eating whale meat and human health.

PCBs can be incinerated at high temperatures, although Japanese researchers have estimated that it would take a century for toxin loads in marine mammals to be reduced if even half of the PCBs existing were destroyed in the next ten years.

Since this particular toxin affects the fertility of these slow-breeding mammals, it seems reasonable to attempt the reduction of other impacts, such as whaling, until such time as toxins can be controlled and more is known of marine mammals' survival capabilities.

The Politics of Pollution

PCBs were brought into New Zealand in 1970 by the electricity authorities. By the early 1980s they were already perceived as an environmental hazard. In 1987 an electrical capacitor containing 16 litres of PCBs exploded and contaminated surrounding farmland. Cleanup cost was estimated at $500,000 and involved the export of seven tonnes of contaminated material.

ECNZ has attempted to fulfill a government decree that by 1994 all PCBs would be located and destroyed. The corporation acts as the collection agent for PCBs in New Zealand, and a 1985 code of practice governs disposal procedures.

By 1992 over 200 tonnes of PCB-containing material had been shipped to an incinerator in Wales, to the distress of British environmental groups. Some blamed the plant in Wales for causing rare eye deformities in children and illness in livestock, though pollution levels in the area were never proven to be related to the plant. If Britain refuses to take more material it could cost New Zealand $50 million to build an incinerator of its own.

At present New Zealand's Marine Pollution Act of 1974 is administered by the Ministry of Transport and generally prohibits radioactive waste and the discharge of oil from ships. Fines of up to $100,000 can be levied on offenders, with possibly a $200,000 fine if the Resource Management Act is invoked.

This money generally goes to the Government consolidated funds. A treaty under the Act, called the London Dumping Convention, establishes liability for oil and other pollutants dumped from ships. Since only oil has been specified it is the only pollutant covered by the Act.

New Zealand is finally responding politically to the pollution within its boundaries. This year the Government announced a bill proposing the Hazardous Substances and New Organisms Act, intended to set up a framework for an Environmental Risk Management Authority (ERMA).

According to Ian Lineham from the Ministry of the Environment, the new Authority will be a non-government agency, whose purpose is to track toxic chemicals from cradle to grave and license new chemicals before testing, as well as during and after their release into the environment.

The Ministry expects ERMA to begin operating by late 1994. A June progress report seems to be the answer to suggestions made in 1992 by Forest and Bird, that New Zealanders should demand total use reporting of all pesticides and dangerous chemicals by manufacturers, inclusion of public participation in decision making, and monitoring of chemicals. An environmental user charge has also been suggested to recycle proceeds back into problem areas, rather than into consolidated funds.

The Ministry of the Environment's report states that "the Government has confirmed that the cost of administering and monitoring of hazardous substances and new organisms be recovered where private benefits accrue or where the actions of users are the reasons for incurring the costs".

This could be interpreted to mean that the individual user of the chemicals is liable -- or the commercial distributor. While this Act is still in the making, there is time for the public to demand specific accountability in its wording.

The need to have makers take responsibility for the environmental effects of the chemicals they create is an obvious deterrent to creating problems in the first place, says marine zoologist Steve Dawson. Fines for contamination should be concurrent with, and used for, cost of cleanup and reparation of the environment which was damaged. In general the mandate for all manufacturers should be that nothing is created which cannot be disposed of without causing harm. With the creator should ride the burden of proof.

Given the current knowledge of the detrimental effects of organochlorines it is crucial that restrictions be put on the disposal of those toxins already in existence, something the progress report on the new Act does not actively address. Extreme caution should be exercised in the release of new compounds, Dawson states.

Before taking in the unknown, perhaps human beings should give themselves and other species time to adjust to impacts we can still control -- to whatever small degree -- rather than opening the door to our own folly.

Deborah McCutchen is undertaking a Diploma of Wildlife Management at Otago University.