"We think this tool could be used to help farmers more accurately apply fertiliser by measuring nutrients in the soil around plant roots," he says.

Scientists at Xi'an Jiaotong-Liverpool University have invented a unique soil solution sampling tool that could help ensure the safety of food grown on land once polluted by harmful heavy metals.

Dr Zheng Chen from XJTLU's Department of Health and Environmental Sciences says the new tool could monitor soil contamination risks in the agriculture industry.

"A large amount of agricultural land worldwide is contaminated by heavy metals that can be harmful to people's health, so engineers are trying to design methods to grow crops on these lands safely," he says.

"If they were able to predict how a concentration of heavy metals in soil is linked to a concentration of heavy metals in the edible part of a plant, they could devise better ways to manage the soil. We hope our device can help them make that prediction."

In addition to promoting food safety, he and his team believe the tool could aid farmers in growing crops more efficiently.

"We think this tool could be used to help farmers more accurately apply fertiliser by measuring nutrients in the soil around plant roots," he says.

"We are in the process of testing this tool for these uses in agriculture and hope to have it available for engineers and farmers in about one year."

The tool features a tube made of special plastic that is inserted into the soil. The tube's surface is porous, with holes so small that large molecules or soil particles cannot pass through. However, the holes are large enough that heavy metal ions and small molecules can enter.

"When we bury the tube in soil and fill it with oxygen-free pure water, the heavy metals diffuse into the tube," Dr Chen says.

"The solution inside the tube with the target chemicals can then be taken out and analysed. This process can be repeated."

"We are able to collect samples close to each other but at different depths by assembling samplers together."

Interdepartmental collaboration at XJTLU helped make the tool a reality, Dr Chen notes.

"Yang Zou, an undergraduate student from the Department of Industrial Design, used a 3D printer to build the model."

XJTLU is the largest international collaborative university in China, a partnership between Xi'an Jiaotong University and the University of Liverpool.