Microplastics dispersed in the environment cause genetic damage (genotoxicity) to freshwater shrimp.
The new evidence emerges from an Italian study published in Water and adds to an abundant literature on the effects caused by the dispersal of small plastic particles to the aquatic ecosystem, the first piece of a food chain that ends up on our plates. (1)
Microplastics, the study on crustaceans and water lentils
Italian researchers (from ENEA and CNR) measured the ecotoxicological and genotoxic effects of exposure to polyethylene microparticles on two freshwater organisms, water lentils and freshwater shrimps. Environments increasingly polluted by plastic fragments, as we have seen. (2)
Both organisms are commonly used as bioindicators of water quality and in toxicity testing of various inorganic and organic chemicals, as well as microplastics (carriers of heavy metals and other contaminants).
Two bodies that are widespread in Italy
Water lentils(Spirodela polyrhiza (L.) Schleid.) are tiny species of floating aquatic plants characterized by
– High multiplication rates,
– susceptibility to pollutants and
– importance in the aquatic food web as primary producers. (3)
The freshwater shrimp – Echinogammarus veneris (Heller, 1865) – used in the research are gammarids widely found in Italian freshwaters, the main food of trout. In Lake Garda, moreover, they are threatened with extinction by a killer shrimp from the Danube. (4)
The result of the experimentation
Aquatic lentil plants were submerged in water contaminated with microplastics smaller than the diameter of a hair (<50 μm) of polyethylene (PE, the most common plastic), colored red. After 24 hours, they were transferred to the shrimp tank, which feed on the roots of these plants.
A slight reduction in chlorophyll is the only measured effect on plants. But the microplastics accumulated in the roots were ingested by the shrimp. On average, the intestinal content of each of the 50 organisms tested was measured to be 7.6 particles of polyethylene fragments. No trace of microplastics was found in the 15 control amphipods.
Genotoxicity of microplastics in shrimps
The outcome of the shrimp test is worrisome. A first aspect concerns the domino effect of environmental contamination.
Microplastics ingested by crustaceans (through plant contamination) are in fact digested and excreted as excrement in an even more insidious form of water contamination. These shrimp are also ingested by fish, which in turn accumulate microplastics, which are inevitably transferred to humans who eat them.
Finally, analysis of the effects on crustacean DNA demonstrated the genotoxicity of microplastics. After just 24 hours, the shrimp that ingested the polyethylene fragments manifested three times more DNA fragmentation when compared with the control group.
Marta Strinati
Notes
(1) Iannilli, V.; Passatore, L.; Carloni, S.; Lecce, F.; Sciacca, G.; Zacchini, M.; Pietrini, F. Microplastic Toxicity and Trophic Transfer in Freshwater Organisms: Ecotoxicological and Genotoxic Assessment in Spirodela polyrhiza (L.) Schleid. and Echinogammarus veneris (Heller, 1865) Treated with Polyethylene Microparticles. Water 2023, 15, 921. https://doi.org/10.3390/w15050921
(2) Dario Dongo, Sabrtina Bergamini. Microplastics in the water of Italian lakes, the silent emergency. GIFT (Great Italian Food Trade). 5.7.20
(3) On water lentils see also.
Marta Strinati. Water lentil, a superfood to be discovered. GIFT (Great Italian Food Trade). 3.11.19
Dario Dongo, Andrea Adelmo Della Penna. Novel food, EFSA approves turmeric extracts and rejects Tongkat Ali. Water lentil in the center. GIFT (Great Italian Food Trade). 30.12.21
(4) The killer shrimp. City of Verona. https://admin. comune.verona.it/nqcontent.cfm?a_id=44672&tt=museo
Professional journalist since January 1995, he has worked for newspapers (Il Messaggero, Paese Sera, La Stampa) and periodicals (NumeroUno, Il Salvagente). She is the author of journalistic surveys on food, she has published the book "Reading labels to know what we eat".
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