RE: The Australian - Questions over claim that coal emissions cause low-birthweight babies in Latrobe Valley
First published 26 February 2018
Doctors for the Environment Australia recently wrote a submission to the Victorian EPA pointing out the link between air pollution exposure and the risk of low birth weight which has been called alarmist. We would call it alarmingly realistic.
Now read on.
The weight of a baby at birth is a good indicator of whether they have experienced optimal growth conditions during pregnancy, and is a strong predictor of health during childhood as well as predicting the risk of adult chronic diseases such as high blood pressure, heart, and kidney disease. Babies weighing less than 2500g are regarded as low birthweight. It has long been known that various factors will reduce birth weight, such as smoking, poor diet, teenage pregnancy, and high blood pressure during pregnancy known as pre-eclampsia.
Emerging evidence is now indicating that exposure to air pollution also has an effect on foetal growth. The evidence base for the claim of foetal harm is supported by multiple published studies and a systematic review1 although the systematic review shows some heterogeneity. One of the most convincing studies was of babies born in Beijing during the 6 weeks of clean air for the 2008 Olympic Games2. The birth weight of babies born during the games was statistically significantly higher than the babies born in the same month of 2007 and 2009. The impact was greatest during the last month of pregnancy when growth is fastest, and not apparent during the early months of organ formation. While some studies have examined particles (particulate matter), others nitrogen dioxide, and others sulphur dioxide, the distinction is artificial, as air pollution is nearly always a complex mix of all these pollutants. The mechanism by which air pollution reduces growth is thought to be by increasing placental resistance, and this has been measured by Doppler ultrasound and compared to ozone exposure in a group of women in Brazil3.
Other evidence comes from London4, Canada5 and New Jersey in North America6. The New Jersey study is especially relevant as it examined the birth weights before and after shutdown of a highly polluting coal fired power station that was the only regional source of sulphur dioxide. It showed a 15% reduction in the incidence of low birth weight babies in the down wind counties compared to those counties not down wind. This was apparent even though these areas were relatively advantaged in socio economic terms, so the women had good access to health care.
In the DEA submission we applied the observed change in risk from New Jersey to the number of babies born in the Latrobe and Wellington Local Government Areas to arrive at a putative number of low birth weight babies that may be due to pollution exposure. The actual risk may be higher or lower. On the one hand the measured levels of SO2 in the Latrobe valley are lower than the reported (modelled) levels in New Jersey, but on the other hand the three Latrobe generators annually emit three times as much SO2 as the one which had been polluting New Jersey.
There is some uncertainty about the estimate (as it is an estimate), but that should not be a reason to sit back and accept that the risk to health should be ignored and allowed to continue year after year. This is a preventable risk for electricity generation can be cleaned up by the use of modern pollution control technology such as fabric filters (as used in all NSW coal fired power stations) and post combustion desulphurisation (as required in European and most North American coal fired power stations).
The responses in The Australian from the Latrobe Valley are disappointing yet understandable in the context of worry around local employment resulting from the lack of action by successive governments to plan an inevitable and just transition. Nevertheless surely media should be attempting to raise awareness of evidence which can help protect community health?