Metal accumulation in relation to size and body condition in an all-alien species community

Abstract

Metal pollution is one of the main environmental threats in freshwater ecosystems. Aquatic animals can accumulate these substances and transfer them across the food web, posing risks for both predators and humans. Accumulation patterns strongly vary depending on the location, species, and size (which in fish and crayfish is related to age) of individuals. Moreover, high metal concentrations can negatively affect animals’ health. To assess the intraspecific relationship between metal accumulation and size and health (proxied by the body condition) of individuals, the concentration of 14 metals (Al, As, Cd, Co, Cr, Cu, Fe, Hg, Mg, Mn, Ni, Pb, Se, Zn) was analyzed in six alien species from the highly anthropogenically altered Arno River (Central Italy): five fish (Alburnus alburnus, Pseudorasbora parva, Lepomis gibbosus, Ictalurus punctatus, and Silurus glanis) and one crayfish (Procambarus clarkii). We found that in P. clarkii, Cu was negatively related to size, as well as Al in L. gibbosus and Mg for adult I. punctatus. Positive size-dependent relationships were found for Hg in L. gibbosus, Fe in S. glanis, and Cr in juvenile I. punctatus. Only Co and Mg in S. glanis were found to negatively correlate with individual health. Since metal concentrations in animal tissue depend on trade-offs between uptake and excretion, the few significant results suggest different types of trade-offs across different species and age classes. However, only predatory fish species (L. gibbosus, I. punctatus, and S. glanis) presented significant relationships, suggesting that feeding habits are one of the primary drivers of metal accumulation.

Health risk assessment and metal contamination in fish, water and soil sediments in the East Kolkata Wetlands, India, Ramsar site

“…It is well-known fact that cobalt has low accumulation rate in fish tissues 63 , 64 . Similar results were also obtained in the present investigation as the lowest bioaccumulation in fish tissues.…”

Factors influencing accumulation of the selected metals in the tissues of spiny-cheek crayfish (Orconectes limosus Raf.)

“…The lack of signi cant relationships between the length of the body and the concentration of metals (negative correlations) in the meat may result from the dilution of the concentration of metals as the animal's body grows, moreover, it may indicate faster metabolism in younger animals compared to older ones (Balzani et al 2021), and it may also results from the growth-hindering effect of metals. Conversely, positive correlations indicate a trend of metal accumulation as the animal grows (Ergen et al 2015).…”

“…According to the authors of these studies, the abdomen and chelae meat can be a source of minerals, too. As con rmed by numerous studies, crab, shrimp, cray sh and lobsters are a valuable source of macroelements and microelements essential for humans, but also of toxic metals in the event of water pollution (Balzani et al 2021, Barrento et al 2009, Heidarieh et al 2013, Nędzarek et al 2020, Raissy et al 2011. But what about the exoskeleton?…”

Potential health risk assessment of metals in the muscle of seven wild fish species from the Wujiangdu reservoir, China

“…The average length and weight of P. fulvidraco and S. meriaionali were relatively lower than those of C. idellus and P. pekinensis (Table 1), while the metal concentrations of the former were relatively higher than those of the latter in the present study (Table 4). It could be caused by higher potential intake of metals in smaller than larger fish (Balzani et al, 2022;Merciai et al, 2014). Actually, there were no consistent differences between the different fish species.…”