Thursday, September 6, 2012


Nano technology has emerged as a major breakthrough for many industries because of its ability to deliver designer materials to well defined targets, overcoming normal physical barriers. Though no where in the world its safety has been established conclusively, in absence of any regulatory mechanism, there is an unwritten understanding that the technology can be used without any consumer knowing about it! Food industry is eagerly looking forward to use Nano technology in processing as and when regulatory approvals are forthcoming. There are a few alarming reports about the potential harm nano particles can cause to human beings because of the ability of nano particle chemicals to pass through the cell membrane and the unpredictable consequences of such a scenario on human health. A problem of a different dimension has recently been highlighted by health experts regarding the impact of unanticipated nano size contaminants in soil like Zinc Oxide and Cerium Oxide coming from industrial effluents on the soil productivity and food safety. Here is a critique on this emerging issue.  

STAR researchers at the University of California Center for Environmental Implications of Nanotechnology, have published an article in Proceedings of the National Academy of Sciences showing that manufactured nanoparticles in agricultural soil can accumulate in plants and can  affect plant growth and food quality.  This was the first major study of soybeans grown in manufactured nanomaterials-tainted soil. The researchers looked at the effects of zinc and cerium oxides. Nano materials, used in everything from lotions and makeup to fuel additives can be transported into air, water and soil and can impact plant growth and food quality.  Soil contamination may come from the final stage of waste water treatment which creates biosolids, which are applied to soils in many parts of the U.S. This solid material fertilizes the soil, returning nitrogen and phosphorus that are captured during waste water treatment but is also a point at which zinc oxide and cerium oxide can enter the soil. Cerium oxide may also contaminate soils from air deposition as a combustion biproduct. The researchers found that zinc oxide accumulated in the plants grown in the tainted soil and affected food quality although it may not be harmful to humans if the zinc is in salt or ion form in the plant. The cerium oxide however stunted plant growth, affecting the root nodules where bacteria symbiotically convert nitrogen in the air to a form plants can use. The researchers conclude there is a high probability of nanoparticles in crop soil but more research is necessary to determine impact on crops and consumers.  This research was co-funded by EPA and NSF.
It is true with any technology that both good and bad aspects will have to be considered before mass application. Genetic Engineering, food irradiation, use of chemical preservatives and antibiotics etc are all beautiful technologies of immense benefit to the consumers but safety of their applications under all conditions must be established before wide scale use. Same holds good for Nano technology also with opinions differing widely among the scientists. Unofficial use of Nano technology in non-food applications was ignored so far because the nano sized particles used by the non-food industry does not cause any direct dangers to humans. But the new revelation that these dangerous particles can end up in food crops through cultivated soil raises the bar vis-a-vis unrestricted use of Nano technology in any field without properly assessing the consequences.  


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