Lead poisoning plummets thanks to cleaner petrol

Lead poisoning in expectant mothers has fallen dramatically since lead was finally phased out of petrol in 2006.

Pre-birth exposure to lead in South African coastal populations is around a fifth of its 1996 levels‚ and lower than in New York in the US and Montreal in Canada.

Researchers from the universities of Pretoria and Johannesburg‚ who reported their findings on Monday‚ also examined possible socio-economic‚ behavioural and lifestyle factors linked to lead exposure. They found higher lead levels in:

- Black mothers and those with lower educational levels;

- Mothers who sourced drinking water from communal taps‚ boreholes or rivers;

- Mothers who cooked using wood or gas; and

- Those who used pesticides in their homes.

South Africa began phasing out lead in petrol in 1986 after evidence emerged that it reduces IQ and causes hyperactivity‚ poor school performance and violent behaviour.

“There are no safe levels of lead exposure in humans‚ particularly in susceptible populations such as pregnant women and their developing foetuses‚” said lead researcher Halina Röllin‚ from the University of Pretoria and the Medical Research Council.

“Elevated lead levels in pregnant women have been shown to affect birth outcomes by reducing foetal growth‚ increasing rates of congenital abnormalities and promoting premature labour.”

Writing in the journal PLOS ONE‚ Röllin said her team measured lead in the blood‚ urine and umbilical cord blood of a total of 640 women in KwaZulu-Natal (in 2008) and the Western Cape (in 2012 and 2013).

About one in eight women measured in 1996 had lead above the international “concentration of concern” but the new measurements showed a dramatic fall‚ particularly in the Western Cape.

Maternal lead concentrations were “far lower” than those reported in an industrial area in Italy‚ the general population in Thailand and Japan‚ and children in Kinshasa‚ capital of the Democratic Republic of the Congo. They were dramatically lower than Shanghai (China)‚ Mumbai (India) and Mexico City.

“The final removal of lead from South African fuels in 2006 and the introduction of lead-free paint in 2009 mat well be the main explanatory factors‚” said Röllin.