A new study found farmers who use sheep dips have impaired brain function. Alan Harman reports.
Farmers exposed to low levels of organophosphates (Ops) in sheep dip may have impaired brain function, a medical study at University College London has found. Many farmworkers believe they suffer physical and mental illnesses – both short- and long-term – as a result of this exposure.
University College London consultant clinical neuropsychologist Sarah Mackenzie Ross studied 132 sheep farmers with a history of low-level exposure to Ops.
A series of brain-function tests found they suffered a range of emotional, physical and cognitive problems including verbal and visual memory problems, mental flexibility and fine motor control. “Exposed farmers show deficits in working and general memory, response speed and mental flexibility, but continued verbal, visuo-spatial, reasoning and general intellectual functioning,” the report says. “Significant correlation was observed between duration of exposure and poor performance.”
The study suggests there may be a relationship between long-term, low-level exposure to organophosphates and the development of neurobehavioural problems.
“This has implications for working practice and policies,” said the report. “Guidelines about the use of organophosphate chemicals on the farm should be reviewed.”
Mackenzie Ross recommends follow-up studies to determine whether symptoms persist over time, improve or worsen. |fw
Is biofuel’s potential inflated?
With oil prices rising over the past decade, the search is on for alternative, renewable energy sources. The two basic products have been bioethanol – from sugar, starchy grain crops, and hemicellulose from plant biomass – and biodiesel from plant oils.
The governments of developed countries have supported it, but only recently has biofuel expanded into developing countries, where crop production is different. Biofuel also reduces global grain stocks, helping raise grain and food prices.
A team of US scientists reassessed global expectations by collating data from 238 countries, territories and protectorates on yields of 10 bioethanol crops and 10 biodiesel crops, as well as biofuel yields per hectare for each. They found reported crop yields varied substantially due to climate, soil and management. Biodiesel yields factored in oil content and percentages of oil extracted and converted to biodiesel. Bioethanol refining is more crop-specific.
The study found historical extrapolations were often based on data from industrial countries’ high-potential farming and experimental stations. Revised global expectations may be about half of what had been projected for most crops, and even less for wheat and groundnuts. Both bioethanol and biodiesel yields per hectare for industrial countries were higher than global estimates. For developing countries, they were lower. The study concluded that reliable, region-specific analyses were needed for drafting biofuel policies. – Wynand van der Walt ([email protected]).
Source: Johnston et al in Environ. Res. Lett., January 2009. |fw
