Yury Azhichakov set out early by bike for Senogda
Bay, his favorite beach, on the northwestern shore of Lake
Baikal in Siberia. The world’s oldest, deepest and most
voluminous lake, Baikal holds 20 percent of the planet’s
unfrozen freshwater. It is often described as the world’s cleanest
lake.
As Mr. Azhichakov discovered, that is no longer the
case. Senogda’s once pristine sands were buried under thick
mats of reeking greenish-black goo.
“This stuff stretched far into the distance, for several
kilometers,” said Mr. Azhichakov, 61, a retired ecological
engineer. “The beach was in terrible condition.”
The muck, scientists have discovered, follows mass
algal blooms at dozens of sites around Lake Baikal’s 1,240-mile
perimeter. Confined to shallow water and shores near towns and
villages, the problem seems to stem from an influx of untreated
sewage – the result of inadequate wastewater treatment.
Algal blooms threaten iconic freshwater bodies around
the world, including the Great Lakes, Lake Geneva, and Lake
Biwa in Japan. But Lake Baikal is especially precious: a World
Heritage site home to more than 3,700 species, more than half
found nowhere else.
“People are dumping sewage, waste and rubbish
around the lake, creating pretty appalling conditions in some
places,” said Anson MacKay, an environmental scientist at
University College London.
Disponível em: www.nytimes.com. Acesso em: 15 nov. 2018 (adaptado).
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