You may have heard of the Great Pacific Garbage Patch, that vast swath of the Pacific Ocean which has accumulated a massive volume of discarded plastics, swept there by the ocean’s currents. A great deal of the plastics in this area of ocean are what are known as microplastics, plastic debris less than five millimeters in length. However, microplastics aren’t just in this patch of the pacific, they’re scattered throughout the worlds oceans. For fish and other sea creatures, this means that consuming these tiny particles is unavoidable. This in turn leads to the transfer of microplastics into the food web.
As seen in this study on organic composting and microplastics, published on Wednesday, these microplastics inevitably end up in the compost created from that food. Composting has often been seen as the best option for replacing artificial fertilizers, which lowers soil quality and can release large quantities of various chemicals which have a very negative effect on the enviroment, as can be seen from this study, a great hope for the 815 million people who suffer from food scarcity.
As seen in the study, regardless of the method of composting used the complete removal of microplastics is, at the very least, extremely difficult if not completely impossible. This is especially evident from the study’s limiting to particles larger than 1 mm, citing difficulties in the removal of large organic loads and associated difficulties in reliable analysis.
Given the rather substantial food demands inherent to the eight billion people currently living on Earth, a number projected to rise to some ten billion by 2050, food producers use large quantities of artificial fertilizers. These fertilizers release dangerous levels of nitrogen and phosphorous, leading to environmental issues such as sea dead zones and the like. As such the use of compost is seen as an attractive alternative to such fertilizers. Given the presence of potentially toxic microplastics it seems like a far less attractive option. As noted by Chelsea Rochman in this literature review, there is little chance of microplastics entering food and crops grown in soil contaminated with microplastics, however it is noted that the presence of microplastics hurts the microbes in the soil, thereby damaging the productivity of the crops grown there.
While little is known about the effect of microplastic on terrestrial and fresh water ecosystems, as noted by Chelsea Rochman, and that there may be no toxic effect on human being directly, it has been proven that microplastic contamination has a distinct negative effect on the delicate ecosystem that we humans rely on to produce our food.
Written by Brian McGloughlin