The tiniest specks of plastic can enter the human food chain, finds a study
- September 23, 2022
- Posted by: OptimizeIAS Team
- Category: DPN Topics
The tiniest specks of plastic can enter the human food chain, finds a study
Subject: Environment
Context: Plastic in foiod chain
Introduction–
- There is growing concern about the environmental and health impact of plastic pollution, especially since it breaks down into smaller pieces that begin to accumulate in the environment.
- Now, researchers from the University of Eastern Finland have found that small pieces of plastic called nanoplastics can travel up the human food web, through plants, insects and even fish.
- Nanoplastics are tiny plastic debris particles smaller than 1,000 nanometres (1 nm is equal to one billionth of a metre).
How the study was conducted-
- Researchers have developed a new, metallic fingerprint-based method to detect and measurethe amount of nanoplastics in organisms.
- For their study, they applied the technique to a model food chain that contains three trophic levels (trophic level is the position an organism occupies in the food chain) — lettuce, which was the primary producer, black soldier fly larvae, the primary consumer, and insectivorous fish (roach) as the secondary consumer.
- For the study, the researchers exposed lettuce plants to nanoplastics from commonly found plastic waste in the environment — polystyrene (PS) and polyvinyl chloride (PVC) nanoplastics — through contaminated soil for 14 days.
- They were then harvested and fed to black soldier fly larvae, insects that are used as a source of protein in many countries, and are also used as feed for chickens and cattle.
- After five days of feeding them the lettuce, the insects were then fed to the fish (roach) for five days. The roach, (Rutilus rutilus) is widely found in fresh and brackish water and is sometimes eaten and used as bait.
Travelling up the food chain
- By using scanning microscopy, the researchers examined the dissected plants, insect larvae and fish.
- Images showed that the nanoplastics from the soil were taken up from the roots of the plants and accumulated in the leaves.
- Subsequently, the contaminated lettuce transferred the nanoplastics to the insects.
- Imaging of the black soldier fly’s digestive system showed that both PS and PVC nanoplastics were found in the mouth and gut, despite allowing them to empty their guts for 24 hours.
- Both the lettuce and insects, however, contained a lower amount of PS particles, as compared to the PVC nanoplastics.
- In the fish that had fed on the contaminated insects, particles were detected in the gills, liver and intestine tissues.
- The liver contained the highest concentration of nano plastic, indicating that it is the primary target tissue for nanoplastics entering vertebrates.
No barriers against nanoplastics?
- Due to their small size, nanoplastics can likely pass through physiological barriers and enter organisms.
- The researchers note that the measurement of the absorption of nanoplastics from the soil by vegetables and fruits will help tell us whether and to what extent nanoplastics can enter our food chain and then our own bodies.
- The results show that lettuce can take up nanoplastics from the soil and transfer them into the food chain.
- This indicates that the presence of tiny plastic particles in soil could be associated with a potential health risk to herbivores and humans if these findings are found to be generalizable to other plants and crops and to field settings.
- However, further research into the topic is still urgently needed.
Bioaccumulation It is typically associated with the build-up of damaging or harmful chemicals in a living thing. These chemicals will not break down in the body or are not able to be excreted. This will cause the chemical to accumulate over time Biomagnification Plants that are exposed to and absorb chemicals in the water or soil will accumulate them when they can’t break them down. When an animal starts to eat these plants they are also consuming the chemicals. The more plants they eat the more chemical they consume. This is called biomagnifications Biomagnification occurs as the chemical moves further up in the food chain. The amount of chemical magnifies or the amount increases at each level. |