Kenya's flamingos weighed down by heavy metals

Posted: 2 August 2001

Veterinary pathologists in Kenya have identified heavy metals as the leading cause of massive deaths of flamingos in two Rift Valley Lakes of Kenya, and warned that these majestic pink birds of Lakes Nakuru and Bogoria remain threatened unless the lakes are cleared of pollutants.

"The presence of heavy metals in the birds tissue is alarming," cautioned Dr Gideon Motelin, a leading Kenyan researcher on flamingos and veterinary pathologist at Egerton University, who conducted a three-day fact-finding mission in the two lakes in May (2001).

Flamingoes grace the waters of Lake Nakuru© M & C Denis-Huot/Kenya Bios Still PicturesBut the Kenya Wildlife Service (KWS) refutes that pollution is the cause of death. "If it's a question of pollution, why is it affecting both Lakes. We could understand if it was only in Nakuru but Bogoria is far away from industries," said Daniel Njaga, a communications officer at KWS. He also points out that other species of birds and wildlife that use the lakes have not been affected in the same way. The KWS have given no data on the number of dead birds but journalists have counted hundreds of birds' carcasses littering the shores of both lakes.

A preliminary report released by Dr Motelin and Dr Ramesh Thampy, a World Wide Fund for Nature (WWF) Rift Valley lakes specialist, says, "Detectable levels of lead, zinc, mercury, copper, and arsenic have been found in the birds' tissues and this threatens the very existence of the flamingos."

Experts warn that the level of pollution in Kenyan lakes is growing due to collapse of the sewage works in many urban centres and growth of industries whose effluent flows into the lakes. The rise of horticultural farms along most of the Rift Valley lakes has also caused fertilizers to run off into the lakes.

Dr. Motelin said cadmium, a metal found in the birds' tissues, is "dangerous as it replaces calcium in the bones making them brittle."

"This may be one of the reasons why birds are finding it difficult to co-ordinate in the water. The birds have become weak and cannot manage to migrate from different lakes without succumbing," said Dr. Thampy.

Flamingos can fly up to 300 kilometres in a day, and researchers also think the deaths could be as a result of "flying stress". According to Dr Thampy, the clinical signs of the current birds resemble episodes in 1993, 1995 and 2000 when similar deaths occurred. Current deaths began mid-May (2001), but are not as high as in previous years.

The preliminary report indicates that migration and breeding, plus organochlorines are other cause of deaths. Organochlorines find their way into Lake Nakuru through water systems from nearby farms, which use large quantities of fertilizers, pesticides and agrochemicals. Organochlorines discovered in flamingo body tissues can enter Lake Bogoria through River Sandai, which passes through farmlands in Laikipia district. The toxic chemical DDT, which is banned in Kenya, is reportedly used in Ethiopia.

"It is true that flamingos have a vast home range. Some of their feeding sites in Ethiopia are close to factories, which could be discharging harmful effluent," said Motelin.

The KWS says the situation is environmental, associated with ecology rather than pollution. "I would attribute the cause of the deaths to regular changes in the water volume," said Njaga. Since El Niño there have been adjustments of water volume that affect water chemistry, its salinity, productivity, bio-chemical oxygen demand and even nutrients. When the water volume drops, the level of salinity rises which may render flamingos' food toxic."

Still, this does not ease WWF's concern that if the majestic birds continue to decline by 20 per cent every two decades, "The entire flamingo population may be wiped out in a 100 years," the group warns.

Related link:

Uphill fight for Lake Nakuru

Source: Environmental News Service, June 2001.