17 August
2006 - Instead of pristine and inviting bathing
waters, tourists are being met by toxic algal
blooms. The recent hot and calm weather in Europe
has provided perfect conditions for algae. While
surface waters have remained still and undisturbed,
algae blooms have flourished uninterrupted. However,
the blooms are also helped by nutrient inputs
caused by human activities.
Nitrogen and phosphorus are
critical nutrients for algae growth. Some algae,
especially the blue/green algae found in Scandinavia,
can absorb atmospheric nitrogen. Consequently,
they can bloom in waters where only phosphorus
is present. Nitrogen and Phospherus enter coastal
waters as a result of human activities, such as
run-off from agricultural land, fish farming and
inadequately treated waste water. Phosphorus is
found in everyday household products such as detergents,
soap and shampoos.
It is not unnatural for the
population of algae to increase in summertime.
And algae are an important part of the food chain,
as they provide food for animal (zoo) planktons
which are in turn eaten by fish and other aquatic
wildlife. However, today's levels of algal blooms
appear excessive. Most importantly is that human
activities and favourable summer conditions combine
to increase the levels of algal blooms. With the
likelihood of climatic change bringing warmer
summers in the future, today's excessive algae
blooms may become more of a common sight in European
waters.
Health effects of algae:
Some algae contain toxins, and therefore represent
a health threat to humans and animals. These toxins
vary depending on the species of algae. Some types
of algae can cause skin and eye irritations, but
the main risk comes from swallowing contaminated
water. The symptoms of poisoning from toxic algae
include nausea, bowel or intestine problems and
fever.
Nevertheless, adults would have
to swallow a considerable amount of water before
any adverse health effects would occur. These
incidents are highly unlikely and very rare. However,
care should be taken with small children. Health
authorities recommended that children should refrain
from bathing in these waters. Similarly, pets
and farm animals could also be put at risk by
drinking contaminated water.
