A Canada-wide survey has found high levels of a liver toxin floating in many of our country's lakes.
The toxin is contained in blue-green algae that is fed by agricultural runoff.
It could pose health risks to people near the affected lakes.
Over 250 lakes were surveyed.
Ten per cent of those had levels of the toxin - microcystin (MICRO-sist-in) - that exceed Canadian guidelines.
Shallow lakes in Manitoba and Alberta showed the highest levels of the blue-green algae.