Mikroplast RAS-süsteemis kasvatatud siberi tuura (Acipenser baerii) ja euroopa säga (Silurus glanis L.) näitel
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Kuupäev
2024
Kättesaadavus
07.09.2024
Autorid
Ajakirja pealkiri
Ajakirja ISSN
Köite pealkiri
Kirjastaja
Eesti Maaülikool
Abstrakt
Publitseeritud teadustöödest lähtudes on kõigil veeorganismide rühmadel suur oht mikroplastiga kokkupuuteks. Toiduahela kaudu veeorganismidesse sisenev mikroplast jõuab lõpuks ka inimeste toidulauale, ohustades otseselt inimeste tervist.
Kuigi plastisaaste kontsentratsioone keskkonnas on mõõdetud mitmesugustes maatriksites, on teavet mikro- ja nanoplastide esinemise kohta vee korduvkasutusega vesiviljelussüsteemides (RAS) vähe. Mikro- ja nanomõõdus plastisaaste on samas suurusjärgus paljude veeorganismidega ning sellest tulenevalt saavad toiduobjektiks filtreerijatele, detrivooridele ja settetoidulistele organismidele, samuti vähilaadsetele ja kaladele.
Mikroplasti reostust looduslikes kalavetes on praeguseks põhjalikult uuritud kuid, millisel määral ja ulatuses ning milliste tegurite koosmõjul antud probleem ilmneb RAS-i intensiivse tootmise käigus on suures osas ebaselge. Erinevas mikromõõdus plastisaaste vesiviljelusüksustesse sattumise teed võivad hõlmata nii heit- kui ka torude kaudu voolavat vett, lagunevaid vesiviljelusseadmeid, kalasööta kui kalapüügivahendeid. Keskkonnaohutuse, majandusliku tõhususe ja toiduohutuse kaalutlustel on vajalik igakülgne arusaam vesiviljeluse mikroplastireostusest intensiivse tootmise käigus. Käesoleva uurimistöö eesmärk oli uurida mikroplastide esinemist RAS-majandite süsteemi vees ja kalade elundites, määrata polümeerid ning kvantifitseerida nende kontsentratsioon.
Uurimistöös analüüsiti kolmest, suletud vee korduvkasutusega kalamajandist pärit magevee, siirde- ja poolsiirde kalade, euroopa säga (Silurus glanis L.) ja siberi tuur (Acipenser baerii B.) seedetrakti ja hingamiselundeid, kalabasseinidest pärit veeproove ning tuvastati mikroplasti keemiline kompositsioon. Tuvastatud mikroplasti domineeriv kuju oli kild, värvidest must, lilla ja sinine. FTIR-spektroskoopia abil määratud polümeeri tüüpide hulgas olid polüamiid (PA) ja polüvinülideenkloriid (PVDC) levinuimad.
Laboris läbi viidud katsete eesmärk oli selgitada välja:
1) kas ja millises ulatuses võib Eesti kolmes RAS majandis kasvatatavatel kaladel tuvastada mikromõõdus plastisaastet;
2) millised on potentsiaalsed mikroplasti vesiviljelusüksustesse sattumise teed uuritavates kalamajandites.
Tõestatud said hüpoteesid:
- RAS-süsteem saastub süsteemi komponentidest tuleneva plastireostusega;
- RAS-süsteemis leidub plastireostust mikroplasti suuruse tasemel;
- RAS majandi kala seedetrakt ning hingamiselundid reostuvad mikroplastiga.
Uuringu tulemused võivad anda võrdlusaluse mikroplastide edasiseks jälgimiseks ning eemaldamiseks erinevatest kalakasvatussüsteemidest.
Microplastic pollution has become a major global environmental issue. Since fish is an important source of animal protein for human beings, the occurrence and potential impacts of microplastics in fishes deserve very special attention. For environmental safety, economic efficiency and food safety considerations, a comprehensive understanding of microplastic pollution in aquaculture is necessary. External environmental inputs and aquaculture processes are sources of microplastics in aquaculture. The aim of this research was to investigate the presence of microplastics in RAS farms, to identify the polymers present in the water of the system as well as in the organs of the fish, and to quantify their concentration. The research analyzed the digestive and respiratory organs of Wels catfish (Silurus glanis L.) and Siberian sturgeon (Acipenser baerii B.), water samples from fish ponds, and identified the chemical composition of microplastics. The dominant shape of microplastics detected was fragment, with colors of black, purple and blue. Among the types of plastic polymers determined by FTIR spectroscopy, polyamide (PA) was the most common type of polymer. The experiments carried out in the laboratory were designed to find out: 1) whether and to what extent microscale plastic contamination can be detected in fish farmed in three RAS farms in Estonia; 2) the potential pathways for microplastics to enter the aquaculture units in the fish farms under study. The hypotheses were proved: - The RAS system is contaminated by plastic pollution from system components; - Plastic pollution is present in the RAS system at the microplastics size level; - The digestive tract and respiratory tract of fish in RAS farms are contaminated with microplastics. The results of the study may provide a benchmark for further monitoring and removal of microplastics from different fish farming systems.
Microplastic pollution has become a major global environmental issue. Since fish is an important source of animal protein for human beings, the occurrence and potential impacts of microplastics in fishes deserve very special attention. For environmental safety, economic efficiency and food safety considerations, a comprehensive understanding of microplastic pollution in aquaculture is necessary. External environmental inputs and aquaculture processes are sources of microplastics in aquaculture. The aim of this research was to investigate the presence of microplastics in RAS farms, to identify the polymers present in the water of the system as well as in the organs of the fish, and to quantify their concentration. The research analyzed the digestive and respiratory organs of Wels catfish (Silurus glanis L.) and Siberian sturgeon (Acipenser baerii B.), water samples from fish ponds, and identified the chemical composition of microplastics. The dominant shape of microplastics detected was fragment, with colors of black, purple and blue. Among the types of plastic polymers determined by FTIR spectroscopy, polyamide (PA) was the most common type of polymer. The experiments carried out in the laboratory were designed to find out: 1) whether and to what extent microscale plastic contamination can be detected in fish farmed in three RAS farms in Estonia; 2) the potential pathways for microplastics to enter the aquaculture units in the fish farms under study. The hypotheses were proved: - The RAS system is contaminated by plastic pollution from system components; - Plastic pollution is present in the RAS system at the microplastics size level; - The digestive tract and respiratory tract of fish in RAS farms are contaminated with microplastics. The results of the study may provide a benchmark for further monitoring and removal of microplastics from different fish farming systems.
Kirjeldus
Magistritöö
Kalanduse ja rakendusökoloogia õppekaval
Märksõnad
magistritööd, RAS, mikroplast, säga, siberi tuur