When thousands of tourists quit the beach in Ostend at the end of a nice summer day, they leave behind heaps of trash. Plastic bags, cigarette butts, dirty diapers and a host of tins and bottles. After a busy weekend, the Ostend municipal beach-cleaning services collect up to ten tonnes of refuse – a process that has a catastrophic impact on the flora and fauna there. The juggernaut they use to sweep the beach along the tide line turns over the sand up to ten centimetres deep, raising a great quantity of organic matter to the surface and damaging the microbiotic organisms in the sand. What is more, a lot of the plastic disappears under the sand. “You don’t see it, but our beach is largely composed of plastic at present,” says Pavel Klinckhamers of Greenpeace Netherlands.

But not all the plastic comes from tourists. On the contrary, by far the bulk of it is from refuse thrown overboard by the boats, whether on purpose or by accident. It is estimated that year in, year out, between two and ten thousand containers go by the board. Sea fowl take them for food and eat them. A 2003 Dutch study showed that 95% of the northern fulmars washed ashore have plastic in their stomachs, as do many beached seals.

The number of oil-covered marine birds that drift ashore has gone down, on the other hand, which goes to show that the international efforts to combat illegal oil dumping in the North Sea are not in vain. Back in the 1980s, all the beached fowl were covered in oil; nowadays, only one quarter of them are. But that is still a quarter too many. Sailors are stubborn.

A time bomb

Very few people are aware that the sea bed along the shores of Heist holds a huge ammunition dump from the two world wars. The contents thereof are put at between 35,000 and 200,000 tonnes, a third of which is said to contain toxic gas. Attempting a cleanup could cause an ecological disaster. But leaving the bombs where they are is also dangerous, seeing as sooner or later they will end up rusting and releasing their toxic load. The MUMM (Management Unit of the North Sea Mathematical Models and the Scheldt Estuary) is closely monitoring the situation.

Chemicals and hormonal interference

Adolescents who go swimming in the North Sea don’t have to worry about suddenly sprouting a beard: the concentration of the chemical pollutants in the water is far too low. But these chemicals do cause hormonal interference in marine life. In the space of only two years, Francis Kerckhof, a biologist at the MUMM, has seen the entire North Sea population of murex die out. The chemicals caused the female snails to grow a penis, which prevented them from reproducing and resulted in the extinction of the entire species. “We are now seeing malformations and reduced fertility in oysters and cockles, but also in fish,” observes Kerckhof.

The scientists are most worried by three types of chemicals. Although highly toxic PCBs – recall the dioxin crisis – have been banned for some time now, they will remain in the seawater for a thousand years. PAHs (polycyclic aromatic hydrocarbons) are tarry substances released by the funnels on boats that use very heavy and polluting fuels. And TBT (Tributyltin) is a tin substance found in the paint used on boat hulls.

Overfishing

It is hard to gauge the impact of pollution on fish stocks with any accuracy, because the fish in the North Sea have already been decimated by overfishing. “The tuna, cod over one metre long, big weevers, sharks, common oysters, big whelks, they’ve all vanished from our shores,” reports Francis Kerckhof. After a ban on fishing, the endangered species return very slowly. “Probably because they’ve been too hard hit by the pollution to recuperate. And because their fertility has declined too far,” explains Ann-Katrien Lescrauwaet of Vliz, the Flemish Marine Institute.

Every morning the beach is thoroughly scoured, the coastal waters look clean and the fish market is teeming with fresh sole. But according to Patrick Roose and Kerckhof, the North Sea is in bad shape. For the time being, there is no sign of any truly dramatic consequences because the North Sea benefits from a strong current that completely renews the water every two years. “But marine life is approaching the point of no return,” warns Kerckhof.