• Lake Victoria, Turkana, Baringo, Nakuru, and Bogoria had good water, but water from Lake Elementaita and Magadi is of poor quality.
• Prof Gituru and his colleagues assessed water quality, concentrations and health risks of heavy metals in lakes Naivasha, Elementaita, Nakuru, Baringo, Bogoria, Turkana, Victoria and Magadi.
Image: FILE
Nearly all fresh-water lakes in Kenya have water that is not fit for human consumption.
Only Lake Naivasha has potable water, but it remains under increased threat from heavy farming activities around it.
Those are the findings of new tests conducted by scientists from the Sino-African Joint Research Centre based at the Jomo Kenyatta University of Agriculture and Technology.
“Based on water quality index, Lake Naivasha water was excellent for drinking. Lake Victoria, Turkana, Baringo, Nakuru, and Bogoria had good water, but water from Lake Elementaita and Magadi was of poor quality,” the researchers said.
The tests also show Lake Magadi – a soda lake – has the most toxic water in Kenya, laced with heavy metal from ground sources.
The study was led by Sajorec director Prof Robert Gituru and Prof Xue Yan of the centre’s branch at the Chinese Academy of Sciences in Wuhan.
Prof Gituru and his colleagues assessed water quality, concentrations and health risks of heavy metals in lakes Naivasha, Elementaita, Nakuru, Baringo, Bogoria, Turkana, Victoria and Magadi.
They tested the waters for aluminium, molybdenum, manganese, nickel, arsenic, zinc, selenium, lead, chromium, mercury, cobalt and cadmium.
“Aluminium, manganese, arsenic and molybdenum were relatively high in all the Rift Valley lakes and exceeded the maximum permissible levels for drinking water,” they said.
At high concentrations, all these elements are linked to chronic problems that include neurological disorders and cancer.
Notably, high heavy metal concentrations were recorded at the entry points of rivers and areas with high human activities.
“These results are important for formulating the necessary remediation policies to improve water quality in the eight lakes,” the researchers said.
The findings will be published in November in the Journal of Environmental Management.
Other researchers were Kelvin Githaiga and Samwel Njuguna.
Prof Gituru told the Star the study was funded by Sajorec, a JKUAT-based centre that bridges scientific cooperation between the Chinese and the African scientists.
Lake Naivasha remains under threat from the rapidly growing horticultural activities around it.
In February 2010, hundreds of fish at the southern end of the lake were found dead due to pollution. The same happened in April 2017.
Separately, according to the Kenya Marine and Fisheries Research Institute, the pollution at Lake Nakuru is so bad that even fish from that lake is not fit for human consumption.
The pollution is blamed on untreated industrial effluent from Nakuru town.
Lake Victoria also remains under pressure from pollution from urban areas in Kenya, Uganda and Tanzania.
A 2015 study of Lake Victoria, examining the fish guts of Nile perch and Tilapia, revealed that microplastics could be found in at least 20 per cent of the fish, which are important sources of food and income across the region.
Edited by P.O