Unraveling the depuration mechanisms of metals in the burrowing crab (Neohelice granulata Dana, 1852): Biochemical biomarkers, metal-rich granules and bioaccumulation patterns

Impact of mangrove restoration on microplastic bioaccumulation in fiddler crabs across degraded, restored, and natural ecosystems

Understanding the role of mangroves in microplastic (MPs) bioaccumulation is crucial to addressing the pollution in these ecosystems, particularly in restored areas. Here, we 1) evaluate the MPs plastic-biota-sediment accumulation factor (pBSAf) in the fiddler crab Minuca rapax and 2) describe MPs type, colour, and polymeric characteristics in areas with varying restoration and degradation levels in the Southern Gulf of Mexico. We used regression models to evaluate the role of mangrove tree height, basal area, and crab individuals' density in explaining pBSAf. The highest pBSAf values were observed in natural and restored mangrove areas, particularly those with higher crab densities and taller trees. MPs were more diverse in composition in both crabs and sediments from natural areas. Mangrove biota tissue's bioaccumulation may provide insights into ecosystem health and food web impacts and indicate restoration progress.

Assessing Metal Toxicity on Crustaceans in Aquatic Ecosystems: A Comprehensive Review

Residual concentrations of some trace elements and lightweight metals, including cadmium, copper, lead, mercury, silver, zinc, nickel, chromium, arsenic, gallium, indium, gold, cobalt, polonium, and thallium, are widely detected in aquatic ecosystems globally. Although their origin may be natural, human activities significantly elevate their environmental concentrations. Metals, renowned pollutants, threaten various organisms, particularly crustaceans. Due to their feeding habits and habitat, crustaceans are highly exposed to contaminants and are considered a crucial link in xenobiotic transfer through the food chain. Moreover, crustaceans absorb metals via their gills, crucial pathways for metal uptake in water. This review summarises the adverse effects of well-studied metals (Cd, Cu, Pb, Hg, Zn, Ni, Cr, As, Co) and synthesizes knowledge on the toxicity of less-studied metals (Ag, Ga, In, Au, Pl, Tl), their presence in waters, and impact on crustaceans. Bibliometric analysis underscores the significance of this topic. In general, the toxic effects of the examined metals can decrease survival rates by inducing oxidative stress, disrupting biochemical balance, causing histological damage, interfering with endocrine gland function, and inducing cytotoxicity. Metal exposure can also result in genotoxicity, reduced reproduction, and mortality. Despite current toxicity knowledge, there remains a research gap in this field, particularly concerning the toxicity of rare earth metals, presenting a potential future challenge.