‘The scale of the problem seems bigger than earlier anticipated and one should probably apply regulations on the use, probably on a regional or local scale.’
US researchers have concluded that sulphur from agricultural activity, and not coal-fired power stations, is now the most important source of the element in the environment.
Burning fossil fuels caused the emission of sulphur dioxide which led to acid rain, a topic hotly debated during the 1960s and 1970s. This led to the development of legislation and technologies to mitigate the impact of sulphur dioxide, which has been successful in taking atmospheric sulphur deposition back near pre-industrial levels in the US.
However, elemental sulphur is popular and effective as a fungicide, and once oxidised it becomes available to plants as well as producing acidity which can be detrimental to soils over time.
Researchers argue that the long-term addition of sulphur to crops is probably impacting soil health and aquatic ecosystems in the same way acid rain would, yet the effect is largely being ignored. ‘It is imperative we understand the environmental and human health consequences of these very high rates of sulphur that we are using in agriculture,’ the researchers said.
The presence of sulphur causes sulphate-reducing bacteria to release enzymes that help generate methylated mercury, converting the heavy metal into a form that can enter aquatic food chains. There can also be health impacts such as asthma when sulphur is sprayed on farmland.
Sulphur in agriculture is said to account for more than 50% of the element produced each year. The researchers said that while sulphur is a natural component of ecosystems it was the dose that had a bearing on the environment. ‘The scale of the problem seems bigger than earlier anticipated and one should probably apply regulations on the use, probably on a regional or local scale,’ the researchers said.
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