The effects of microplastic fibers (MPF) on the survival, molting and oxygen consumption rates of larval (I-III) and post-larval (IV) stages of the American lobster, Homarus americanus, were quantified as a function of MPF concentration and food availability. Only the highest MPF concentration decreased early larval survival. MPF did not affect the timing or rate of molting across MPF treatments. While all larval and post-larval stages accumulated MPF under the cephalothorax carapace, stage II larvae and stage IV post-larvae showed the highest and lowest accumulation, respectively. MPF ingestion increased with larval stage and with MPF concentration; under starvation conditions, stage I larvae only ingested them at low MPF concentrations. Oxygen consumption rates were lower only in later larval stages when exposed to high MPF concentrations. Combined, our results indicate that MPF interactions and effects on American lobster larvae are dependent on larval stage, MPF concentration, and presence of food.

The giant freshwater prawn, Macrobrachium rosenbergii, is an important species for Bangladesh’s national economy, aquatic biodiversity, and employment opportunities; furthermore, human health risk associated to consumption of this species has become a crucial issue. Eight trace metals (Pb, Cr, Ni, Cd, Fe, Cu, Zn, and Mn) in different body parts of M. rosenbergii (U/10 as large and U/12 and U/15 as medium size), and water collected from farm and wild sources along with the human health risks were assessed in this study. Except Cd, all trace metals exceeded the maximum permissible limits proposed by different authorities. Elevated levels of Pb, Cr, Fe, Cu, Zn, and Mn were found in the wild-caught prawn, whereas Ni and Cd were higher in farmed prawn. A higher trace metal contamination was recorded from the cephalothorax part than the abdomen of both sized prawns. However, trace metal concentrations between two sizes of prawns were not statistically significant (p > 0.05). The estimated daily intakes (EDI) values were higher than the recommended and/or tolerable daily intake for Pb and Cr. Moreover, the target hazard quotient (THQ) values were > 1 for Pb, Cd, Cu, and Zn, elucidating non-carcinogenic risks to the consumers. In addition, the target cancer risk (TR) values of Pb and Ni were high and exceeded the acceptable guideline of 10⁻⁶, explicating the possibility of carcinogenic risks. Therefore, the study concludes that the consumption of the studied prawn species contaminated with elevated levels of toxic metals is associated with higher degree of potential health risks.

Freshwater crayfish are bioindicators of environmental pollution, often used for the assessment of heavy metal (HM) presence in the tissues, a time-consuming and expensive task. In this study, we propose the use of the vibrational spectroscopy to detect in a fast, non-destructive and sensitive way the presence of HM in the cephalothorax exoskeleton of the freshwater crayfish. Incorporation of HM into the cephalothorax exoskeleton was investigated under controlled laboratory conditions. In particular, the cephalothorax exoskeleton of five crayfish species (Astacus leptodactylus, Procambarus clarkii, Austropotamobius pallipes, Faxonius limosus, and Pacifastacus leniusculus) was analyzed by attenuated total reflection–Fourier transformed infrared (ATR–FTIR) spectroscopy in the presence or absence of cadmium (Cd), chromium (Cr), lead (Pb), nickel (Ni), and zinc (Zn) up to 4 weeks at various concentrations (0.01, 0.1, 1, 10, ppm). The ATR–FTIR profile of the crayfish cephalothorax exoskeleton was compatible with the presence of amorphous calcium carbonate, chitin, and proteins. The incubation with the HM revealed two main modifications: the shift of the peak from 859 to 872 cm⁻¹ and the appearance of a peak at 712 cm⁻¹. Both are ascribable to the HM interaction with calcium carbonate. The absorbance of both peaks increased along with the time of incubation, and the HM concentration. We conclude that ATR–FTIR analysis can be a useful, quick, and cost-sensitive tool to detect HM presence in the crayfish cephalothorax exoskeleton. However, it has to be regarded as a non-specific analytical technique for assessing HM contamination, since it is unable to discriminate between different HM.