From the wheel to fire, from engine to microwaves; humanity has seen it all and accepted inventions with an open heart and mind. Well, maybe with too open a heart in some cases!

Even before we became inhabitants of a global village, science gifted us with the Green Revolution. It was hailed as the savior of agriculture and served a sigh of relief for the agri-based third world countries. Little did we know that it would soon turn to dust. The rising number of cancer cases being reported from Punjab province in India (one of the foremost locations adopting the revolutionary practices) and the alarming levels of pollutants in the groundwater are a cry for help. Intelligent use and application of the modern agricultural practices could have saved the masses from this chaos.

An exciting area of research and development is observing and manipulating the world at the nano scale. To understand the promise and risk it holds we need to first understand how small a nanometer (nm) is. It is basically one billionth of a meter and for comparisons’ sake, our average sheet of paper is 100,000 nanometers thick alone and our very own nail grows a nanometer each second! Even an individual human cell is bigger than a nanometer. The nanoscale has more to do with the properties of the material when it is stripped down as opposed to strict measurements. We have coarse nanoparticles (size range 2500nm to 10,000nm), fine nanoparticles (100nm to 2500nm) and, the infamous, ultrafine nanoparticles (1nm to 100nm). The nanoparticle counterpart of a bulk sized substance having same elemental composition acts very differently in terms of physical and chemical properties and hence we cannot put the two in the same basket. Gold slabs just sink in water but gold nanoparticles are able to form uniform suspensions in the same fluid. Similarly, creams using normal zinc oxide leave a white layer on skin whereas the nano form of same zinc oxide behaves differently and is not visible on the skin.

If we scout the web for applications of nanotechnology, we come across a plethora of information. According to the consumer product inventory published by The Project on Emerging Nanotechnologies, numbers of products containing different nanomaterials are touching 2000 mark and this number is just the tip of the iceberg. Cosmetics to food colors, plastic wraps to adhesive coatings on food containers, non-stick coating on utensils to multivitamins; products are laced with nanoparticles. Many more products likely contain nanoparticles but due to lack of labeling restrictions, fail to mention it on the label.

A study by researchers at University of Bath has shown that nanoparticles do not penetrate the skin, flouting their safety but on the other hand, nanoparticles have been shown to adversely affect the microbial and plant growth. Nanoparticles have also been shown to translocate from the soil up into plant cells; a discovery raising alarms for food safety. Such translocation has also been observed in our lab during Nanotoxicity studies in National University of Sciences and Technology, Pakistan. Plants have pores which easily allow entry of materials of the order of 5nm to 20nm and nanoparticles have shown to cause larger pore formation to enter the cellular environment as well.

Groundbreaking studies have shown uptake of multitude of nanoparticles by crops of importance. For instance, titanium dioxide nanoparticles are taken up by wheat plant and their translocation to wheat leaves has been reported. Cerium oxide nanoparticles have been seen ending up in the tomato fruit from the soil and water environment and cerium oxide as well as zinc oxide nanoparticles made their way into the edible portion of soybean plant from the soil. Pakistan’s wheat consumption is amongst the highest in the world and tomato fruit is a staple in our cuisine hence any disturbance in the environment which might upset the production of these crops is bound to have an impact on the economy. Besides translocation and directly affecting plants, nanoparticles alter the soil chemistry and can have serious repercussions for the crops.

Furthermore, it is known for a fact that silver nanoparticles are toxic for bacteria, whereas other classes have been implicated in damaging living cells as well. There is no guarantee that these commercial particles when meet the abiotic components will leave the system silently without affecting the agricultural areas. A recent evidence suggested that the engineered copper oxide nanoparticles damage the DNA of radish plants. However, very little experimental evidence is available so far that could explain the role of nanoparticles in edible plants. Yet the existing knowledge impels us to speculate on their potential deleterious effects on human health if we consume any of the food contaminated with them. It is beyond doubt that every product contains nanomaterials up to a permissible limit but on a greater scale, piling up of such individual products as waste has potentially disastrous consequences. Especially, countries like Pakistan importing used electronic and other products are at higher risk.

We have been given another chance; to mend bridges by welcoming the up-and-coming nanotechnology applications with a skeptic vision. Before we slather on sunscreens packed with titania or gorge on food laced with preservatives containing nanoparticles, we need to stop and think if the taste is really worth it. What happens to these miniscule particles in the plants? Are plants able to get rid of them or do the particles persist in foods we eat? Do these particles have the ability to enter our body via stomach when ingested with food? Or is our digestive system equipped with processes able to get rid of the nanoparticles? These are some of the many unanswered questions we need to ponder over and enact laws to keep the nanopollution at bay, and that too before it becomes another Green Revolution for the future generations.