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SEA creatures across the globe are being poisoned by tiny plastic pellets
floating in the ocean. Japanese researchers have found that these pellets adsorb
toxic chemicals from the seawater. The poisons enter the food chain when marine
animals eat them.

鈥淚t鈥檚 a frightening prospect,鈥� says David Laist, a policy analyst at the US
Marine Mammal Commission in Washington DC. 鈥淭his opens a whole new window of
肠辞苍肠别谤苍.鈥�

Chemicals companies often produce polymers in the form of pellets just a few
millimetres in diameter, which are shipped to manufacturers to be melted and
moulded into plastic products. But thousands of tonnes enter the oceans in
effluent and storm-water discharges from factories and cities, and from ships
that lose or dump their cargo at sea. In 1992, a US Environmental Protection
Agency report concluded that plastic pellets account for nearly 94 per cent of
all human-made debris in harbours along American coasts.

Now researchers in Japan have established that the pellets are toxic.
Hideshige Takada of the Tokyo University of Agriculture and Technology and his
colleagues collected and analysed polypropylene pellets from sites on the
Japanese coast. They found that the pellets had accumulated two types of
chemical鈥攑olychlorinated biphenyls (PCBs) and DDE, which is similar to
DDT鈥攊n concentrations up to a million times greater than in the
surrounding seawater. These chemicals are known to damage immunity and fertility
in animals.

The pellets also contained a chemical called nonylphenol, which interferes
with animals鈥� hormonal systems, at around 100 times the concentration at which
it occurs in sediment in Tokyo Bay.

To confirm that the pellets were concentrating the chemicals, the researchers
submerged cages filled with uncontaminated pellets into the ocean for six days.
They found that the pellets adsorbed PCBs and DDE from the seawater, and that
the concentrations increased day by day.

The impact of contaminated pellets on wildlife could be enormous. To
seabirds, fish and turtles, the pellets strongly resemble the fish eggs and
other food they normally eat. 鈥淚n the samples that we looked at from the
Northeast Pacific, just about every bird had plastic in them,鈥� says biologist
Alan Burger of the University of Victoria in British Columbia.

In another study of seabirds in the South Atlantic, other researchers linked
toxic chemicals found in great shearwaters to polymer pellets they had
eaten.

In the US, manufacturers have started cleaning up after pellet spills and
filtering them out of their drainage systems. But 鈥渋t鈥檚 still a risk鈥�, says
Laist. Takada believes that the problem could be even more widespread. 鈥淲hile
the study focused on resin pellets, it suggests that other plastic trash can
also adsorb PCBs and DDE and pose a great threat to marine organisms.鈥�