The federal environmental protection agency says toxic algae was responsible for the deaths of 48 manatees in Tabasco earlier this year.
Profepa said there was no evidence that oil pollution from Pemex facilities was responsible.
Most of the manatee deaths occurred in the municipalities of Macuspana, Centla and Jonuta in an area known as the Bitzales region.
Agency chief Guillermo Haro Bélchez said experts analyzed the causes of the deaths during 13 meetings between May and October, concluding that a prolonged drought, high temperatures and the presence of fecal matter and urban solid waste in the water led to the algae growth.
“The cause of death was food poisoning from the chronic accumulation of toxic algae, in lethal concentrations, leading to the death of the 48 manatees,” he stated.
Haro observed that of 35 studies conducted on the waters of the Bitzales region, only one revealed elevated concentrations of heavy metals.
But he said that study was conducted by an unaccredited laboratory that did not follow chain of custody procedures with the water samples.
The other studies found that heavy metal levels were well below the maximum concentration allowed.
Haro said no manatee deaths have been reported since October 26 in the region, which has an estimated population of 500 to 1,000 animals.
Profepa recommended monitoring the water to permit the early detection of toxic algae blooms, controlling the spread of invasive species and reforestation programs on river banks among other measures.
Haro said recent studies show that toxic algae levels have returned to normal.
Source: Milenio (sp)