Nanoplastics in human food chain

September 22, 2022

A new study published in the journal Nano Today revealed that nanoplastics travel up the human food web via plants, insects and fish.

Key facts

Nonplastics are plastic debris particles that are smaller than 1,000 nanometre, which is equal to one billionth of a metre.
Because of their miniscule size, nanoplastics are capable of passing through physiological barriers and enter different organisms through the food chain.
These particles were detected and measured in organisms by researchers from the University of Eastern Finland.
The researchers used a novel metallic fingerprint-based method to a model food chain that has three tropic levels.
Tropic level is the position an organism occupies in the food chain.
For this research, lettuce (primary producer), black soldier fly larvae (primary consumer) and an insectivorous fish (secondary consumer) were used.
Researchers exposed lettuce plants to nanoplastics from commonly found plastic wastes in the environment – polystyrene and polyvinyl chloride nanoplastics – through contaminated soil.
This lettuce was harvested and fed to black soldier fly larvae, which is used as a source of protein for children and cattle in many countries.
The black soldier fly was then fed to the roach (fish), which is commonly found in fresh and brackish waters and sometimes consumed or used as a bait.
From this experiment, researchers have found that nanoplastics from the contaminated soil have travelled from the lettuce plant to the fish.
The nanoplastics stayed in mouth and gut of black soldier fly despite allowing it to empty it guts for 24 hours.
This shows that nanoplastics pose significant health hazard to herbivores and humans by entering into their bodies and staying there.
Currently, agricultural soil is receiving microplastics from various sources like atmospheric deposition, irrigation using wastewater, usage of sewage sludge for agricultural purposes, and use of mulching film.