Food safety risk assessment of metal pollution in crayfish from two historical mining areas: Accounting for bioavailability and cooking extractability

Construction of a triple-mode sensing platform for effective differentiation, speciation, and monitoring of mercury and methylmercury bioaccumulation in crayfish via cation exchange reaction

Developing rapid and sensitive methods for monitoring inorganic mercury (Hg2+) and methylmercury (CH3Hg+) in crayfish is crucial for understanding the environmental impact of these contaminants. In this work, a novel tri-mode strategy was developed for highly sensitive monitoring of Hg2+ and CH3Hg+ bioaccumulation in crayfish by inductively coupled plasma mass spectrometry (ICP-MS)/ fluorescence /smartphone colorimetric (RGB) analysis without chromatographic separation. Cation exchange reaction (CER) was performed between Hg2+ and luminescent CdTe quantum dots (QDs), while CH3Hg+ unrealizable CER. The CH3Hg+ can be transformed to Hg2+ by simple UV irradiation, speciation analysis can be realized by detecting the fluorescence of CdTe QDs after incubation by Hg2+ and total Hg2+. In addition, the filtration of reacted CdTe QDs was carried out, ICP-MS was performed to detect exchanged Cd2+ by Hg2+ and total Hg2+, as well the smartphone RGB analysis was performed for membrane colorimetry. The limits of detection (LODs) of Hg2+ and CH3Hg+ for ICP-MS, fluorescence, and colorimetric (RGB) modes were 0.03 ng mL-1, 18 ng mL-1, and 0.9 μg mL-1 respectively. Density Functional Theory (DFT) was employed to validate the mechanism of the CER reaction. CdTe QDs array analysis with five different ligands was performed to eliminate potential ion interferences of Ag+ and Cu2+ that could occur during the CER reaction. The well-designed system was successfully utilized for monitoring trace Hg2+ and CH3Hg+ in crayfish fed Hg2+ and CH3Hg+ contaminative food over a two-week "uptake" period and a three-week "depuration" period. The results indicated that the Hg2+ uptake in different tissues was significantly different from that of CH3Hg+ in all tissues. There was evidence of Hg uptake from water via leaching from food, although the principal source of uptake was from food.

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.

The identification, evolutionary analysis, and immune roles of Rab family members in red swamp crayfish, Procambarus clarkii

The Rab GTPase constitutes the largest family of small GTPases that regulate intracellular trafficking. Different eukaryotes possess varying numbers of Rab paralogs. However, limited knowledge exists regarding the evolutionary pattern of Rab family in most major eukaryotic supergroups. This study cloned 24 Rab genes from transcriptome data of Procambarus clarkii haemocytes. The multiple sequence alignment and phylogenetic tree analysis revealed a relatively high degree of conservation for PcRab. Furthermore, PcRab exhibited similarities in motif composition with all members showing presence of G, PM, RabF, and RabSF motifs. The tertiary structure indicated that PcRab proteins mainly consisted of α-helices and β-strands, and most PcRab proteins shared similar tertiary structures, and it was indicated that they have similar protein characteristics. Protein-protein interaction prediction identified a total of 20 interacting proteins involved in vesicle trafficking, phagocytosis, and signal transduction with 193 interactions. Expression analysis showed wide expression patterns for PcRab in P. clarkii organs. Upon infection by white spot syndrome virus and Aeromonas veronii, significant induction was observed for PcRab gene expression levels, indicating their involvement in pathogen response mechanisms. The present study represents the pioneering effort in comprehensively identifying and cloning the Rab family genes in crustacean, followed by a systematic investigation into their evolutionary patterns and immune response upon pathogen infection. The results provided valuable insights for further investigation into the molecular mechanism underlying the response of P. clarkii to pathogen infection.

Human exposure to elements through consumption of raw and cooked fish in an urban region of the central Brazilian Amazon biome: Health risks

Fish is an important source of animal protein for local communities in the Amazon basin, whose food safety must be assured. However, certain potential toxicants elements, can bioaccumulate in fish species, which inhabit anthropogenically polluted waters, ultimately posing a risk to human health. In the present study, the concentrations of nine elements (Al, As, Cd, Cr, Cu, Hg, Ni, Pb and Zn) were determined in raw and cooked samples of eight fish species consumed in Santarém (northern Brazil, Amazon biome). The potential for non- carcinogenic human health risks linked to the consumption of cooked fish were evaluated for adults and children in two different scenarios. Four carnivores, three omnivores and one detritivore, all of them regularly marketed and consumed by the Santarém population, were the target species. The safety reference values set by national and international guidelines for humans, in both raw and cooked preparations, were used. In most cases, the cooking process showed a trend to increase elements concentrations compared to raw samples, however the differences were not significant. Moreover, the risk assessment showed danger for children in relation to Hg from the consumption of fish, in both scenarios evaluated. For adults, in one of the scenarios, there was a health risk associated to Hg as a result of carnivorous fish consumption. In a context of combined exposure to all elements, children were at risk when consuming fish, especially carnivorous and omnivorous species. For adults, the mixture of elements posed a risk to health human only for carnivorous fish consumption. The results reveal an environmental scenario of Hg contamination, which requires monitoring actions to preserve the aquatic biodiversity and human health in the Brazilian Amazon biome.

The Accumulation of Toxic Elements (Pb, Hg, Cd, As, and Cu) in Red Swamp Crayfish (Procambarus clarkii) in Qianjiang and the Associated Risks to Human Health

Due to rapidly expanding crayfish consumption worldwide, the food safety of red swamp crayfish (Procambarus clarkii) is of great concern. China is the largest consumer and producer of crayfish globally. As of yet, it is unknown whether the main crayfish production cities in China are within safe levels of toxic heavy metals and metalloids. For 16 consecutive years, Qianjiang city ranked first in China in processing export volumes of red swamp crayfish. This study presents a comprehensive analysis of the enrichment levels and associated health risks of the species in Qianjiang. In our research, samples of four crayfish tissues, including the head, hepatopancreas, gills, and muscles, were collected from 38 sampling sites distributed in Qianjiang to evaluate the concentration levels of five heavy metals (Pb, Hg, Cd, As, and Cu). The concentration levels of all five metals in muscle did not surpass the national standard. Furthermore, eight significant correlations have been found. For further in-depth assess risk of crayfish in Qianjiang, estimated daily intake (EDI), target hazard quotient (THQ), carcinogenic risk (CR), and estimated maximum allowable consumption rates (CR_mm) were evaluated in the abdomen muscle and hepatopancreas. The THQ values for each metal were found to be less than 1, while the CR values were below 10^-6. Additionally, the CR_mm for adults was determined to be 17.2 meals per month. These findings, based on the analysis of five metallic elements included in this study, suggest that the consumption of crayfish abdomen muscle in Qianjiang does not pose any significant health risks. However, it is noteworthy that certain regions exhibit elevated levels of arsenic in the hepatopancreas, surpassing the national standard, thereby rendering them unsuitable for excessive consumption. In general, the findings can be used to provide guidance for safe dietary practices in China.

Evaluation of the Effect of Different Cooking Methods on the Heavy Metal Levels in Crayfish Muscle

The current study investigated the effects of various cooking styles (boiling, frying, and steaming) and seasoning methods (home cooking and ready-to-eat commodity) on levels of nine heavy metals in the crayfish (Procambarus clarkii) muscle. The estimated daily intake (EDI), target hazard quotients (THQ), and target cancer risk (TCR) were used to assess the health risk in the crayfish muscle. The results showed that cooking processes significantly increased the concentration of Cu, which raises a potential risk for children (the THQ values > 1). The levels of toxic heavy metals in the ready-to-eat crayfish muscle were significantly higher than those in household cooking. Especially for As, the THQ values rose to 7.1 and 13.2 for adults and children respectively. Therefore, home cooking is safer than ready-to-eat crayfish, and children should consume crayfish within a limited range. The recommended consumption of the cooked abdominal muscle of crayfish should be 257 and 58 g/day, for children (16 kg) and adults (70 kg), respectively.

Factors influencing lead, mercury and other trace element exposure in birds from metal mining areas

Non-ferrous metal mining is considered one of the largest sources of toxic metal released to the environment and may threaten ecosystems, notably biota. We explored how birds that inhabit non-ferrous metal mining sites are exposed to mercury, lead, and other trace elements by analyzing their feathers and verifying which factors may influence element concentrations in feathers. We sampled a total of 168 birds, representing 26 species, with different feeding habits and migration patterns in a non-polluted reference site and two historical metal mining areas: Almadén, which is considered one of the most heavily mercury-contaminated sites worldwide, and the Sierra Madrona mountains where lead has been mined since ancient times. The quantification of aluminum (Al), arsenic (As), barium (Ba), beryllium (Be), cadmium (Cd), cobalt (Co), chromium (Cr), copper (Cu), iron (Fe), mercury (Hg), magnesium (Mg), manganese (Mn), molybdenum (Mo), nickel (Ni), lead (Pb), selenium (Se), thorium (Th), thallium (Tl), uranium (U), vanadium (V) and zinc (Zn) was performed by inductively coupled plasma mass spectrometry (ICP-MS). Feather analysis revealed contamination by Hg and Pb, in Almadén and Sierra Madrona, respectively. We found that granivorous birds had the lowest feather Hg levels compared to those found in omnivorous, insectivorous, and piscivorous species, whereas feather Pb was about twice as high in granivores and omnivores, than in insectivorous and piscivorous birds. We also found differences among study sites in 13 elements and confirmed the influence of feather age, migratory patterns of the birds, and external deposition of elements, on metal concentrations in the feathers. Our results highlight that despite the cessation of metal mining in the study areas, local avifauna are being exposed to Hg and Pb from abandoned mines and old tailings sites, indicating that appropriate measures are needed to protect biota from overexposure to these toxic metals.

Investigation of Bioaccumulation and Human Health Risk Assessment of Heavy Metals in Crayfish (Procambarus clarkii) Farming with a Rice-Crayfish-Based Coculture Breeding Modes

Due to the rapid development of the crayfish (Procambarus clarkii) industry in Chinese catering, people are paying more attention to the bioaccumulation of heavy metals in crayfish. To evaluate the health risks associated with the consumption of crayfish, nine types of heavy metals in both crayfish and abdominal muscles of crayfish were investigated. Crayfish samples were collected from rice-crayfish-based coculture breeding modes from different areas located in the middle and lower reaches of the Yangtze River. The average concentrations of heavy metals in the whole crayfish were much higher than the abdominal muscle of crayfish. The estimated daily intake (EDI) of heavy metals in the abdomen of crayfish was calculated to assess the noncarcinogenic risk and the overall noncarcinogenic risk including the target hazard quotient (THQ), the hazard index (HI) and carcinogenic risk (CR). The results of the present study showed that the consumption of crayfish may not present an obvious health risk to human associated with heavy metals. However, the THQ values of As in the abdominal muscles of crayfish for adults in EnShi (ES) and children in JiaYu (JY) should be of concern due to the higher contribution to the potential health risks of crayfish compared to other metals. Through X-ray photoelectron spectroscopy (XPS) detection of heavy metal As, it is found that As in crayfish culture environment mainly exists in the form of As3+.Therefore, the quality and quantity of crayfish consumption should be moderated to prevent the bioaccumulation of As. The results indicate that crayfish cultured in different areas may have similar pollution levels and/or emissions from the same pollution sources.

Heavy metal accumulation and health risk assessment of crayfish in the middle and lower reaches of Yangtze River during 2015-2017

This study performed statistical analysis and risk assessment of five heavy metals (As, Cd, Cr, Hg, Pb) in crayfish samples collected from six provinces in the middle and lower reaches of Yangtze River during 2015-2017. The Spearman correlation test and the results of hierarchical cluster analysis (HCA) indicated that As, Pb, and Cd in crayfish were significantly correlated, and the results of HCA showed that Jiangxi, Jiangsu, and Zhejiang were clustered into one group; Hubei, Hunan, and Anhui were clustered into another group; and provinces in the same group had spatial similarities in heavy metals. The pollution index (PI) values of five heavy metals in all provinces were below 1, implying that crayfish samples in this area were not highly contaminated. The target hazard quotient (THQ) values of five heavy metals were mainly below 1 except Hg in Anhui (2.9709), which was far beyond 1, indicating that the health risk posed by Hg exposure should not be ignored in Anhui.

Multivariate linear regression models for predicting metal content and sources in leafy vegetables and human health risk assessment in metal mining areas of Southern Jharkhand, India

The present study was intended to investigate the metal concentrations in the leafy vegetables, irrigation water, soil, and atmospheric dust deposition in the iron and copper mining areas of Southern Jharkhand, India. The study aimed to develop a multivariate linear regression (MVLR) model to predict the concentration of metals in leafy vegetables from the metals in associated environmental factors and assessment of the risk to the local population through the consumption of leafy vegetables and other allied pathways. The developed species-specific MVLR models were well fitted to predict the concentration of metals in the leafy vegetables. The coefficient of determination values (R²) was greater than 0.8 for all the species-specific models. Risk assessment was carried out considering multiple pathways of ingestion, inhalation, and dermal contact of vegetables, soil, water, and free-fall dust. Consumption of leafy vegetables was the major route of metal exposure to the local population in both the metal mining areas. The average hazard index (HI) value considering all the metals and pathways was calculated to be 5.13 and 12.1, respectively for iron and copper mining areas suggesting considerable risk to the local residents. Fe, As, and Cu were the major contributors to non-carcinogenic risk in the Iron mining areas while in the case of copper mining areas, the main contributors were Co, As, and Cu.

Exposure of street sweepers to cadmium, lead, and arsenic in dust based on variable exposure duration in zinc smelting district, Northeast China

Street dust is an important contributor to heavy metal exposure in street sweepers. In this work, the levels of cadmium (Cd), lead (Pb), and arsenic (As) in street dust were evaluated, and the corresponding health implications for street sweepers in the smelting district of Huludao city northeast China were assessed. The contributions of dietary sources and dust to total metal exposure in street sweepers were compared. Because street sweepers are exposed to street dust both during work and nonwork hours, the health risks faced by street sweepers are uncertain. Therefore, variable exposure duration was considered using a deterministic model. A probabilistic risk assessment model was developed to explore the health effects of street dust on street sweepers via Monte Carlo simulation. The various exposure parameters that affect risk were analyzed using sensitivity analysis. The average Cd, Pb, and As levels in the hair of street sweepers were 2.04, 20.12, and 0.52 mg·kg^-1, respectively. These values were higher than those for residents (i.e., not street sweepers) of Huludao. Strong correlations were found between the logarithms (base 10) of the Cd, Pb, and As contents in dust and hair (r_Cd = 0.581, p < 0.01; r_Pb = 0.428, p < 0.01; r_As = 0.378, p < 0.01; n = 62). Based on analysis using deterministic models, the maximum exposures to Cd and Pb via dust through the alimentary canal were nearly three and six times higher than the dietary exposures, respectively. Sensitivity analysis indicated that exposure duration is an important parameter.

Value-conflicts in the conservation of a native species: a case study based on the endangered white-clawed crayfish in Europe

The future of the native European crayfish Austropotamobius pallipes depends on accurate conservation management. The goal of this paper is to attempt an investigation of the major ethical conflicts that can emerge in the conservation of this endangered crayfish threatened by invasive competitors, introduced diseases, and landscape alteration. To assess this issue, we will employ the Ethical Matrix, in a version explicitly tailored for its use in conservation. The filled Ethical Matrix will highlight several potential conflicts between values such as environmental protection, social and economic interests, animal welfare, cultural and aesthetic value, etc. We will discuss these conflicts, alongside some potential mitigating strategies present in the literature. We will stress in particular the need to take into account the ethical principle of fairness when assessing the economic and recreational value of invasive species, especially concerning the unfair distribution of costs. Moreover, we will assert the importance of conservation of A. pallipes both for its existence value and for its role as an umbrella and keystone species. Beyond its focus on A. pallipes, the Ethical Matrix here discussed might also provide insights on the value conflicts relative to analogous in situ conservation efforts involving a native species threatened by invasive alien competitors.

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Metals and metalloids in freshwater fish from the floodplain of Tablas de Daimiel National Park, Spain

The Tablas de Daimiel National Park (TDNP) is a floodplain ecosystem in central Spain with a potential risk of heavy metal and metalloid pollution. The objective of this study was to know the accumulation of arsenic (As), cadmium (Cd), mercury (Hg), lead (Pb), and selenium (Se) in muscle of six species of freshwater fish from the floodplain of TDNP. We obtained muscle samples of Cyprinus carpio (n = 89); Squalius pyrenaicus (n = 16); Ameiurus melas (n = 9); Lepomis gibbosus (n = 8); Micropterus salmoides (n = 6) and Carassius auratus (n = 5). A. melas, which is a predatory species, had significantly higher Hg concentrations than omnivorous or herbivorous species (i.e. C. carpio). On the contrary, A. melas showed lower concentrations of As, Pb and Se than omnivorous species (i.e. S. pyrenaicus and L. gibbosus ). The concentration of Hg was positively associated with fish size in C. carpio and A. melas. Some individuals of C. carpio (5.7%) and S. pyrenaicus (12.5%) showed Pb muscle concentrations above the maximum residue levels established by the European legislation for human consumers. The observed muscle Se concentrations can be associated with adverse effects on fish such as blood changes, reduced growth, mortality of juveniles and reproductive failure. The accumulation of Se in this floodplain located in a seleniferous area and the contamination produced by spent Pb shot pellets used for hunting in the past are discussed as potential sources of the elevated levels of these two elements in fish from this floodplain wetland.

Risk Assessment of Veterinary Drug Residues in Meat Products

With the improvement of the global food safety regulatory system, there is an increasing importance for food safety risk assessment. Veterinary drugs are widely used in poultry and livestock products. The abuse of veterinary drugs seriously threatens human health. This article explains the necessity of risk assessment for veterinary drug residues in meat products, describes the principles and functions of risk assessment, then summarizes the risk assessment process of veterinary drug residues, and then outlines the qualitative and quantitative risk assessment methods used in this field. We propose the establishment of a new meat product safety supervision model with a view to improve the current meat product safety supervision system.

Total mercury levels in the muscle and liver of livestock and game animals in Poland, 2009-2018

The bioaccumulation of mercury (Hg) in the food chain may pose a threat to human health. The risk of dietary Hg intake is mostly caused by the consumption of fish and seafood, therefore the knowledge on the exposure from land animal products is limited. In our article, we summarized the results of analyses of Hg in muscle tissue and liver of different livestock and game animals obtained during ten years of official monitoring that was carried out in Poland from 2009 to 2018. The majority of the results in muscle tissue were below the limits of quantification (LOQs). The mean Hg concentrations in muscle tissue ranged from 0.6 to 5.6 μg kg^-1 of wet weight and the mean liver Hg concentrations were within the range of 0.8-16.4 μg kg^-1 of wet weight, with lowest levels in chickens and highest in wild boars. The results revealed decreasing trends in liver Hg in cattle and cervids over the years, which was congruous with decreasing emission of Hg in Europe. Our results showed that the consumption of meat and liver of livestock and game animals in Poland may be considered to be safe for human health, which was confirmed by the low number of noncompliant samples relative to the applicable legal limits, as well as by estimated dietary exposure.

Metals, autoimmunity, and neuroendocrinology: Is there a connection?

It has been demonstrated that metals can induce autoimmunity. However, few studies have attempted to assess and elucidate the underlying mechanisms of action. Recent research has tried to evaluate the possible interactions of the immune system with metal ions, particularly with heavy metals. Research indicates that metals have the potential to induce or promote the development of autoimmunity in humans. Metal-induced inflammation may dysregulate the hypothalamic-pituitary-adrenal (HPA) axis and thus contribute to fatigue and other non-specific symptoms characterizing disorders related to autoimmune diseases. The toxic effects of several metals are also mediated through free radical formation, cell membrane disturbance, or enzyme inhibition. There are worldwide increases in environmental metal pollution. It is therefore critical that studies on the role of metals in autoimmunity, and neuroendocrine disorders, including effects on the developing immune system and brain and the genetic susceptibility are performed. These studies can lead to efficient preventive strategies and improved therapeutic approaches. In this review, we have retrieved and commented on studies that evaluated the effects of metal toxicity on immune and endocrine-related pathways. This review aims to increase awareness of metals as factors in the onset and progression of autoimmune and neuroendocrine disorders.

Assessment of ecotoxicological risks to river otters from ingestion of invasive red swamp crayfish in metal contaminated areas: Use of feces to estimate dietary exposure

The invasive red swamp crayfish (Procambarus clarkii) has become a major food resource for Eurasian otters (Lutra lutra) in the Iberian Peninsula. Crayfish accumulate large amounts of metals, and hence otters could be at risk of exposure and intoxication through crayfish consumption. We conducted a food safety risk assessment for otters inhabiting two historical mining areas in central Spain affected by lead (Pb) and mercury (Hg) pollution. Estimated daily intakes (EDI) of Pb and Hg were non-invasively calculated from the proportion of crayfish remains and metal levels in otter feces. We considered that the abdominal muscle and the carcass of crayfish differ significantly in relative weight, total metal content and bioavailability of metals to reduce the uncertainty of risk characterization. Fecal concentrations of Hg and Pb in the polluted areas were 1.878 and 6.554 μg/g d. w., respectively (13-fold and 7-fold higher compared to a non-polluted area). EDI of Hg and Pb in the polluted areas were 66.02 and 78.26 μg/kg-day, respectively (14- and 8-fold higher than in the reference area). EDI from the Hg area were above minimum levels susceptible to cause neurotoxicity in mustelids, and 6.3% were above levels susceptible to cause histopathological lessions. In the Pb area, 16.7% of EDI were consistent with levels causing reproductive effects. Metal exposure through crayfish consumption might prevent or slow the recovey of otters in these polluted environments, thus this factor should be considered in management strategies aimed to protect otter populations.