engleski

Infection dynamics and metal accumulation efficiency of endemic acanthocephalan Dentitruncus truttae in the Krka River, Croatia

Introduction: Dentitruncus truttae is an acanthocephalan species endemic to limited areas in Croatia, Italy, and Bosnia and Herzegovina. Since these parasites are characterised as effective metal accumulators, we estimated for the first time application of D. truttae as bioindicator of metal exposure. Therefore, metal distribution, seasonal variation and accumulation were compared in D. truttae and its host Salmo trutta from the Krka River in order to evaluate their sensitivity and indications of metal exposure in the moderately contaminated watercourse. Methods: Sampling was conducted in autumn 2015, spring 2016 and autumn and spring 2021 at Krka River source (KRS) as reference site, and location near the Town of Knin (KRK) impacted by industrial and municipal wastewaters. Molecular analysis confirmed species D. truttae and its taxonomic classification in the family Illiosentidae. Metals were measured by HR ICP-MS in aciddigested acanthocephalans and fish intestine, and their ratio was used to calculate bioconcentration factors (BCFs = C[parasite]/C[host intestine]), as possible indication of exposure duration. Results: Parasite prevalence ranged 92-100% at KRS and 80-97% at KRK. Fish and acanthocephalans showed higher levels of most elements at KRK compared to KRS, while metal accumulation was more efficient in acanthocephalans than fish. That is especially valid for Cd, Cu, Mn, Pb or Sr, resulting in higher BCFs and therefore, reflecting their higher input into Krka River watercourse in recent times. Conclusions: D. truttae showed more effective metal accumulation than fish and even significant differences in metal accumulation between two sites, confirming this parasite as a promising bioindicator species sensitive even to low environmental metal concentrations

intestinal parasites ; brown trout ; trace elements ; bioconcentration factors

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