Sex and seasonal differences in metal accumulation of selected tissues in red swamp crayfish from Lake Trasimeno (Umbria, Italy)

Fish as environmental sentinels for metal contaminants of human health concern in the Lower Mississippi River Basin

Industrial expansion and population growth have lowered water quality, polluting aquatic ecosystems world-wide. Metal pollution in the rivers across the United States are a major health concern. The level of metal contamination in fish from the Lower Mississippi River Basin and their threat to public health were last evaluated 20 years ago. The goals of this study were to measure metal contamination in various fish species from the Lower Mississippi River Basin, evaluate the human consumption risk, and estimate bioindicator potential of these species for monitoring toxic metals on a larger scale. Various fish species (n = 203) were analyzed for 15 metal contaminants (Al, As, Ba, Cd, Co, Cr, Cu, Fe, Hg, Mg, Mn, Ni, Pb, Se, and Zn). Species included: blue catfish (Ictalurus furcatus), channel catfish (Ictalurus punctatus), flathead catfish (Pylodictis olivaris), bigmouth buffalo (Ictiobus cyprinellus), smallmouth buffalo (Ictiobus bubalus), alligator gar (Atractosteus spatula), spotted gar (Lepisosteus oculatus), American gizzard shad (Dorosoma cepedianum), freshwater drum, (Aplodinotus grunniens), and white crappie (Pomoxis annularis). Fish consumption safety revealed toxic metals (As, Cd, Cr, Hg, and Pb) are a major human health concern in the Lower Mississippi River. Non-cancerous health hazard assessments indicated blue catfish, flathead catfish, gar species, and freshwater drum as species of concern. Consumption of all species posed human cancer risks. Computational modeling, with an accuracy of 98.5 %, identified Hg, Pb, Zn, Cr, Co, As, and Cd as major drivers of fish consumption safety. Using bioaccumulation factor analysis, we estimated the bioindicator potential of toxic metals for each fish species, finding Hg and Cd to be greatly bioaccumulative in predatory gar species. Overall, our data indicated that gar can serve as select environmental sentinels useful for monitoring toxic metal pollutants of public health concerns providing valuable insight to research scientist and monitoring agencies throughout the Lower Mississippi River Basin.

Investigating heavy metals and other elements in Procambarus clarkii and environmental matrices from three wetlands of Sicily (Italy)

A qualitative and quantitative analysis of 18 elements was conducted on Procambarus clarkii and its environmental samples to evaluate its potential as a bioindicator species. Analysis of biological samples was carried out to both assess the safety of the use of raw materials and, together with environmental samples, to assess the contamination status of the sampled sites. Significant differences highlighted by the PERMANOVA, HCA and PCA analyses confirmed the valid use of P. clarkii as a bioindicator of the health status of the studied ecosystem. The bioaccumulation factor (BAF) and the biotic sediment accumulation factor (BSAF), except in a few cases, reported values below the bioaccumulative criterion and showed the highest BAF values for manganese, iron and barium in the exoskeleton while the highest BSAF values concerned mercury, copper and zinc in the muscle and barium in the exoskeleton. These findings indicate that, for most of the trace elements (TEs), the extent of pollution at these sites is such that it does not result in significant bioaccumulation in the muscle and exoskeleton of P. clarkii. The TE concentration levels signalled mild contamination of the sampling sites, proving a good health status of the studied aquatic ecosystem. Finally, the results obtained in P. clarkii muscle were below the threshold limits of EU Regulation 2023/915 suggesting that these edible parts are safe for human consumption.

Sex-Dependent Differences in the Elemental Composition of Internal Organs Determined via Total Reflection X-Ray Fluorescence and Inductively Coupled Plasma Optical Emission Spectroscopy

BACKGROUND

Research on elemental changes in tissues and organs provides valuable information enabling better understanding of the physiological processes occurring in a living organism, as well as the pathogenesis and course of various diseases. They may also contribute to the development of new, more effective, and safer therapeutic strategies. So far, they have been carried out mainly on male individuals because of the easier planning and conducting of experiments as well as the lower variability of the results in comparison with studies involving females.

METHODS

The significance of incorporating both sexes in research concerning elemental alterations of tissues may be unveiled by data concerning the influence of sex on the physiological levels of selected elements in various rat organs. Therefore, here we determined and compared the levels of P, S, K, Ca, Fe, Cu, Zn, and Se in brains, hearts, kidneys, livers, and spleens taken from male and female rats. To measure the concentrations of the elements in digested tissue samples, ICP-OES and TXRF methods were utilized.

RESULTS

Significant differences between male and female rats were found for all the organs examined, and the concentrations of most of the tested elements were higher in males than females. The exception was Fe, the level of which in the kidneys and liver was higher in female rats. Sex influenced the elemental composition of spleen the most. For the brain, heart, kidneys, and liver, differences were sparse and were found mainly for the heavier elements.

Contamination Profiles of Selected Pollutants in Procambarus clarkii Non-Edible Portions Highlight Their Potential Exploitation Applications

Properly managing aquatic organisms is crucial, including protecting endemic species and controlling invasive species. From a circular economy perspective, the sustainable use of aquatic species as a source of bioactive molecules is an area that is increasingly being explored. This includes the use of non-edible portions of seafood, which could pose considerable risks to the environment due to current methods of disposal. Therefore, it is of paramount importance to ensure that the exploitation of these resources does not result in the transfer of pollutants to the final product. This study analyzed two types of non-edible parts from the crayfish Procambarus clarkii: the abdominal portion of the exoskeleton (AbE) and the whole exoskeleton (WE), including the cephalothorax. These portions could potentially be utilized in the context of eradication activities regulated by local authorities. A screening analysis of four classes of pollutants, including pesticides, per- and polyfluoroalkyl substances (PFAS), phthalic acid esters (PAEs), and trace elements (TEs), was performed. The only analytes detected were TEs, and significant differences in the contamination profile were found between AbE and WE. Nevertheless, the levels recorded were comparable to or lower than those reported in the literature and below the maximum levels allowed in the current European legislation for food, suggesting that their potential use is legally permitted. In terms of scalability, the utilization of the entire non-edible P. clarkii portion would represent a sustainable solution for the reuse of waste products.

Phylogenetic Diversity of the Red Swamp Crayfish Procambarus clarkii and Its Dispersal Pattern in Northern and Central Italy

The red swamp crayfish Procambarus clarkii is one of the most threatening freshwater species in the world. The aim of this study is to provide a better understanding of the phylogeography and the invasion routes of P. clarkii populations in the Italian Peninsula through the analysis of mitochondrial phylogeny. Mitochondrial control region and cytochrome c oxidase subunit I (COI) sequences of 153 samples collected from six Italian basins were analyzed and compared to worldwide data. Except for the lakes Bolsena and Posta Fibreno, a high genetic variability was found in the other basins. The mitochondrial DNA pattern of P. clarkii from the lakes Candia and Massaciuccoli confirmed the hypothesis of double introduction events. Another entry point could be represented by Lake Trasimeno, which shows haplotypes originating from Louisiana and not shared with other Italian basins. Moreover, unique lineages were also found in the Stella River, thus enhancing the hypothesis that multiple introductions of P. clarkii occurred in northern and Central Italy and strengthening the idea that knowledge about the dispersion routes of this alien species can be useful to predict its invasiveness and elaborate control strategies to preserve biodiversity.