Shellfish and residual chemical contaminants: hazards, monitoring, and health risk assessment along French coasts

Combined Effects of Cadmium and Lead on Growth Performance and Kidney Function in Broiler Chicken

Cadmium (Cd) and lead (Pb) are heavy metals prevalent in the environment and feed, and they reduce production performance of domestic animals, as well as they result in residue in animal tissues. The kidney is the target tissue for Cd and Pb. And the kidney is crucial for the reabsorption of calcium (Ca), which consequently influences bone strength. However, there are relatively few studies related to the effects of Cd and Pb exposure on performance, bone strength and kidney damage in livestock. The purpose of this experiment was to explore the combined effect of Cd and Pb on growth performance and renal impairment and the possible underlying mechanism. For this, 168 1-day-old Ross 308 broilers were randomly divided into four groups of six birds each, with seven replicates in each group: control group, 50 mg Cd/kg body weight group, 200 mg Pb/kg body weight group and 50 mg Cd/kg body weight + 200 mg Pb/kg body weight group. Feed intake was recorded daily and body weight was recorded weekly. The results show that at the end of the 3rd and 6th week, one broiler from each replicate was randomly selected for sampling. Boilers co-exposed to Cd and Pb for 3 weeks and 6 weeks had significantly decreased average daily feed intake (ADFI) and average daily body weight gain (ADG) than the control group, and the ratio of feed-to-weight gain (F/G) significantly increased after 6 weeks of co-exposure to Cd and Pb. Microscopic picture and ultrastructure analyses of the kidneys showed that Cd and Pb caused kidney damage to broiler chickens, and the damage was more serious in the Cd + Pb group, which was manifested by increased renal tubular epithelial degeneration and increased interstitial stasis points. Dietary exposure to Cd and Pb impaired production performance and induced renal oxidative damage in broilers. The combined effects of Cd and Pb on the kidneys are greater than their effects alone. The PERK-ATF4 pathway mediated endoplasmic reticulum stress participates the renal oxidative damage during chronic Cd and Pb exposure.

The dynamic face of cadmium-induced Carcinogenesis: Mechanisms, emerging trends, and future directions

Cadmium (Cd) is a malleable element with odorless, tasteless characteristics that occurs naturally in the earth's crust, underground water, and soil. The most common reasons for the anthropological release of Cd to the environment include industrial metal mining, smelting, battery manufacturing, fertilizer production, and cigarette smoking. Cadmium-containing products may enter the environment as soluble salts, vapor, or particle forms that accumulate in food, soil, water, and air. Several epidemiological studies have highlighted the association between Cd exposure and adverse health outcomes, especially renal toxicity, and the impact of Cd exposure on the development and progression of carcinogenesis. Also highlighted is the evidence for early-life and even maternal exposure to Cd leading to devastating health outcomes, especially the risk of cancer development in adulthood. Several mechanisms have been proposed to explain how Cd mediates carcinogenic transformation, including epigenetic alteration, DNA methylation, histone posttranslational modification, dysregulated non-coding RNA, DNA damage in the form of DNA mutation, strand breaks, and chromosomal abnormalities with double-strand break representing the most common DNA form of damage. Cd induces an indirect genotoxic effect by reducing p53's DNA binding activity, eventually impairing DNA repair, inducing downregulation in the expression of DNA repair genes, which might result in carcinogenic transformation, enhancing lipid peroxidation or evasion of antioxidant interference such as catalase, superoxide dismutase, and glutathione. Moreover, Cd mediates apoptosis evasion, autophagy activation, and survival mechanisms. In this review, we decipher the role of Cd mediating carcinogenic transformation in different models and highlight the interaction between various mechanisms. We also discuss diagnostic markers, therapeutic interventions, and future perspectives.

Pollutants in Breast Milk: A Scoping Review of the Most Recent Data in 2024

Perinatal exposure to pollutants, including persistent organic pollutants (POPs) and heavy metals, poses significant risks to both mothers and children, marking this period as highly vulnerable. Despite the well-acknowledged benefits of breastfeeding, there exists a gap in comprehensive understanding regarding the impact of environmental pollutants on breast milk, underscoring the critical need for this study. Our research addresses this gap by exploring the intersection of environmental health and lactation, situated within the broader 'One Health' concept, thus contributing a novel perspective to the existing body of knowledge. This scoping review aims to examine recent research on the persistent presence of organic pollutants (POPs) and heavy metals in breast milk, thereby elucidating the environmental setting's impact on milk quality. We seek to highlight the innovative angle of our study by emphasizing the 'One Health' concept, which has not been thoroughly explored in the context of lactation and environmental pollutants. We performed a scoping review, consulting two online databases to identify articles published from 1995 to 2023 that reported on pollutants in breast milk, using the PRISMA checklist. This methodological approach underlines the comprehensive and up-to-date nature of our literature review, ensuring the relevance and timeliness of our findings. From a total of 54 relevant articles, findings indicate that POPs are present in higher concentrations in breast milk the longer the lactation period. These findings highlight the persistent and bioaccumulative nature of such contaminants, offering new insights into their long-term implications for maternal and infant health. This exposure does not appear time-sensitive, suggesting pollutants accumulated in maternal fat compartments can be excreted into human milk years after exposure, a novel finding that underscores the importance of considering long-term environmental exposures in lactation research. The presence of POPs and heavy metals in both infant formula and maternal milk underscores a critical need for further comparative studies to understand the health implications better. Our discussion extends the current dialogue on the safety of breastfeeding in polluted environments, providing a new framework for assessing risks and benefits. While breastfeeding remains the WHO-recommended nutrition for optimal infant growth, the findings emphasize the importance of continued risk reduction policies to protect mothers and infants from environmental contaminants in breast milk. Our conclusion calls for an integrated approach, combining public health, environmental science, and clinical practice to develop effective strategies for reducing exposure to environmental pollutants. This multidisciplinary perspective is a significant contribution to the field, paving the way for future research and policy development.

Studies of Endocrine Disruptors: Nonylphenol and Isomers in Biological Models

Certain emerging pollutants are among the most widely used chemicals globally, causing widespread concern in relation to their use in products devoted to cleaniness and asepsis. Nonylphenol ethoxylate (NPEOn) is one such contaminant, along with its degradation product, nonylphenol, an active ingredient presents in nonionic surfactants used as herbicides, cosmetics, paints, plastics, disinfectants, and detergents. These chemicals and their metabolites are commonly found in environmental matrices. Nonylphenol and NPEOn, used, are particularly concerning, given their role as endocrine disruptors chemical and possible neurotoxic effects recorded in several biological models, primarily aquatic organisms. Limiting and detecting these compounds remain of paramount importance. The objective of the present review was to evaluate the toxic effects of nonylphenol and NPEOn in different biological models. Environ Toxicol Chem 2023;00:1-12. © 2023 SETAC.

Elements in Mediterranean mussels from Istanbul and exposure assessment

In this study, concentrations of elements were determined in edible tissues of Mytilus galloprovincialis by means of inductively coupled plasma mass spectrometry (ICP-MS). The mean levels (mg kg^-1) of 0.67 for Cd, 6.9 for As, 0.79 for Pb, 2 for Ni, and 42.6 for Zn exceeded the maximum limits in the digestive glands. Also, the mean concentrations of Cd and As in muscle and of Cd and Ni in gills were above the maximum limits. The highest value was found for As in a digestive gland, with 65.4% of the Provisional Tolerable Weekly Intake. In addition, the lowest percentage belonged to Zn with 0.2% of PTWI in muscles and 0.3% of PTWI in gills of the mussels. Mercury concentrations were well below legal limits.

Heavy metals and PAHs in mussels on the Serbian market and consumer exposure

The goal of the study was to investigate the concentration of heavy metals and polycyclic aromatic hydrocarbons (PAHs) in 84 samples of mussels, collected from supermarkets and fish markets in Serbia. Lead, cadmium, mercury and arsenic concentrations were determined using an inductive coupled plasma mass spectrometry method. Sixteen PAHs were determined using a gas chromatography-mass spectrometry method. Heavy metals in the mussels were in the range (mg/kg) of 0.01-0.74 for lead, 0.01-0.38 for cadmium, 0.01-0.15 for mercury and 1.12-5.87 for arsenic. Metals and PAHs levels in all analysed samples were under the legal European and Serbian legislation limits. The provisional tolerable intake values were calculated on the base of the obtainable values of heavy metals. Mussels are considered to be safe for human consumption. However, one should take care of the amount and frequency of mussel consumption, primarily due to consumer's cadmium and mercury burden.

Cadmium and Lead Exposure, Nephrotoxicity, and Mortality

The present review aims to provide an update on health risks associated with the low-to-moderate levels of environmental cadmium (Cd) and lead (Pb) to which most populations are exposed. Epidemiological studies examining the adverse effects of coexposure to Cd and Pb have shown that Pb may enhance the nephrotoxicity of Cd and vice versa. Herein, the existing tolerable intake levels of Cd and Pb are discussed together with the conventional urinary Cd threshold limit of 5.24 μg/g creatinine. Dietary sources of Cd and Pb and the intake levels reported for average consumers in the U.S., Spain, Korea, Germany and China are summarized. The utility of urine, whole blood, plasma/serum, and erythrocytes to quantify exposure levels of Cd and Pb are discussed. Epidemiological studies that linked one of these measurements to risks of chronic kidney disease (CKD) and mortality from common ailments are reviewed. A Cd intake level of 23.2 μg/day, which is less than half the safe intake stated by the guidelines, may increase the risk of CKD by 73%, and urinary Cd levels one-tenth of the threshold limit, defined by excessive ß₂-microglobulin excretion, were associated with increased risk of CKD, mortality from heart disease, cancer of any site and Alzheimer's disease. These findings indicate that the current tolerable intake of Cd and the conventional urinary Cd threshold limit do not provide adequate health protection. Any excessive Cd excretion is probably indicative of tubular injury. In light of the evolving realization of the interaction between Cd and Pb, actions to minimize environmental exposure to these toxic metals are imperative.

Metal accumulation in the marine bivalve, Marcia optima collected from the coastal area of Phuket Bay, Thailand

Metal contamination in seafood has raised public health concerns, especially for local residents who live in coastal areas. In this study, the levels of cadmium (Cd), lead (Pb), mercury (Hg), and zinc (Zn) were determined in the marine bivalve, Marcia optima, as well as in water, and sediment samples collected from the coastal area of Phuket Bay, Thailand. The results showed that metal concentrations in sediments (4.05-7.14, 16.68-18.13, 164-213 mg kg^-1 for Cd, Pb, and Zn, respectively) and water samples (0.16-0.44, 0.15-0.26, and 0.32-0.48 mg L^-1 for Cd, Pb, and Zn, respectively) were below the threshold effects concentration of the sediment quality guidelines for adverse effects to occur and the marine water quality standards of Thailand. A human risk assessment was performed and the results showed that the risks associated with M. optima consumption at Saphan Hin and Paklok were negligible for most of the metals studied, with the maximum estimated daily intake value being observed for Zn (0.00663 mg kg^-1 per day) at Saphan Hin. In addition, Cd, Zn, Pb, and Hg would be unlikely to pose a risk to human health with a hazard quotient of less than 1, with only the bioaccumulation factor of Zn being detectable in both locations (0.034 and 0.026 at Saphan Hin and Paklok, respectively). However, continuous monitoring is encouraged to prevent the risks associated with the consumption of metal-contaminated seafood.

Assessing the Risk of Hg Exposure Associated with Rice Consumption in a Typical City (Suzhou) in Eastern China

Recent studies have revealed that not only fish but also rice consumption may significantly contribute to human exposure to mercury (Hg) in Asian countries. It is therefore essential to assess dietary exposure to Hg in rice and its associated health risk. However, risk assessments of Hg in rice in non-contaminated areas are generally lacking in Asian countries. In the present study, Hg concentrations were measured in rice samples collected from markets and supermarkets in Suzhou, a typical city in Eastern China. In addition, the rice ingestion rates (IR) were assessed via a questionnaire-based survey of Suzhou residents. The data were then used to assess the risk of Hg exposure associated with rice consumption, by calculating the hazard quotient (HQ). Hg contents in rice samples were well below the national standard (20 μg/kg), ranging from 1.46 to 8.48 ng/g. They were also significantly (p > 0.05) independent of the area of production and place of purchase (markets vs. supermarkets in the different districts). Our results indicate a low risk of Hg exposure from rice in Suzhou (HQ: 0.005–0.05), despite the generally high personal IR (0.05–0.4 kg/day). The risk of Hg associated with rice consumption for Suzhou residents was not significantly affected by the age or sex of the consumer (p > 0.05). Overall, our results provide a study of human exposure to Hg in rice in Chinese cities not known to be contaminated with Hg. Future studies should examine Hg exposure in different areas in China and in potentially vulnerable major food types.

Temperature increases, hypoxia, and changes in food availability affect immunological biomarkers in the marine mussel Mytilus galloprovincialis

Temperature increases, hypoxia, and changes in food availability are predicted to occur in the future. There is growing concern for the health status of wild and farmed organisms, since environmental stressors alter organism functions, and elicit coordinated physiological responses for homeostasis. Mussels are good bioindicators of environmental conditions. Their ability to maintain unaltered immunosurveillance under adverse environmental conditions may enhance their survival capability. Few studies are currently concerned with the relationships and feedback among multiple stressors. Here, food concentration, temperature, and oxygenation treatments were evaluated for their effects on immune enzymatic parameters of Mytilus galloprovincialis detected in the digestive gland and the lysosomal viability by neutral red uptake. Mussels were exposed to three temperatures (12, 20, and 28 °C) under normoxic (8 mg O₂l^-1) and anoxic conditions and specimens were fed with six food concentrations, ranging 0.2-5 g chlorophyll l^-1. Temperature increases affected esterase and alkaline phophatase enzyme functionality, and addition of food buffered detrimental effects generated by harsh conditions, such as those provided by low oxygen concentrations. Kinetics of the phenoloxidase was negatively correlated with increasing temperature. In this case, food had a buffering effect that counteracted the limiting temperature only under normoxic conditions. In addition, the stability of the lysosomal membrane was altered under conditions of thermal stress and food change, under normoxic and anoxic conditions. Overall, environmental stress factors affected immune biomarkers of Mediterranean mussels, and the level of food acted as a buffer, increasing the thermal resistance of the specimens.

Multi-matrix quantification and risk assessment of pesticides in the longest river of the Iberian peninsula

The distribution of pesticides in dissolved aqueous phase (DAP), suspended particulate matter (SPM) and Scrobicularia plana soft tissues from the Tagus River estuary was determined to evaluate the chemicals pollution status and their hazard potential in this area. Samples were collected in 6 campaigns (December 2012-October 2013), from 3 strategical sites, and analysed via different extraction procedures followed by gas chromatography tandem mass spectrometry (GC-MS/MS) determination. The contamination profile among matrices (DAP, SPM, and soft tissue from bivalves (STB)) was marked by average concentrations of 345ng/L, 0.51mg/kg, and 0.02mg/kg, respectively, with several samples above the 2013/39/EU Directive of environmental quality standards (EQS); no differences were observed between sex. A wider range of pesticides was present in STB (n=53) than in SPM (n=36) and DAP (n=19) matrices. Sediment-water partition coefficient, bioaccumulation factor in both DAP and SPM fraction were estimated ranging between 2.5 and 4.4 and 0.008-2799, respectively. The spatial distribution of most pesticides and physicochemical parameters were consistent, indicating a pollution pattern primarily near the Trancão River mouth. Due to the presence of the target compounds, calculated risk quotients pointed out potential hazards for aquatic organisms, mainly to invertebrates. The estimated average daily intake, theoretical maximum daily intake, and hazard quotient of the studied pesticides-via bivalve ingestion-indicated no risk for human health, although it is important to note possible biomagnification processes that may happen along the estuarine food-chain.

Estrogenic evaluation and organochlorine identification in blubber of North Sea harbour porpoise (Phocoena phocoena) stranded on the North Sea coast

Thirteen individual organochlorine compounds at 3 concentrations (80, 400, and 2000 ng/mL culture medium), as well as mixtures, were assayed for the estrogen receptor (ER) activation or inhibition, using a luciferase reporter gene assay (RGA). None of the PCB 138, 153, or 180 or their mixture induced a response in the RGA. o,p′-DDT was the most potent xenoestrogen from the DDT group, inducing a response already at 80 ng/mL. From the HCH and HCB group, only β-HCH (at 400 and 2000 ng/mL) and δ-HCH (at 2000 ng/mL) displayed estrogenic activities. These 13 organochlorines were determined by GC-MS in 12 samples of North Sea harbor porpoise blubber. The PCBs were the main contaminants. Within each group, PCB 153 (6.0 × 10²~4.2 × 10⁴  μg/kg), p,p′-DDE (5.1 × 10²~8.6 × 10³  μg/kg), and HCB (7.6 × 10¹~1.5 × 10³  μg/kg) were the compounds found in highest concentrations. The hormonal activity of the porpoise blubber samples was also assayed in RGA, where two samples showed estrogenic activity, seven samples showed antiestrogenic activity, and one sample showed both estrogenic and antiestrogenic activity. Our results suggest that the 13 POPs measured by GC-MS in the samples cannot explain alone the estrogenicity of the extracts.

Metallothioneins, unconventional proteins from unconventional animals: a long journey from nematodes to mammals

Metallothioneins (MTs) are ubiquitous low molecular weight cysteine-rich proteins characterized by high affinity for d10 electron configuration metals, including essential (Zn and Cu) and non-essential (Cd and Hg) trace elements. The biological role of these ancient and well-conserved multifunctional proteins has been debated since MTs were first discovered in 1957. Their main hypothesized functions are: (1) homeostasis of Zn and Cu; (2) detoxification of Cd, and Hg; and (3) free radical scavenging. This review will focus on MTs in unconventional animals, those not traditionally studied in veterinary medicine but of increasing interest in this field of research. Living in different environments, these animals represent an incredible source of physiological and biochemical adaptations still partly unexplored. The study of metal-MT interactions is of great interest for clinicians and researchers working in veterinary medicine, food quality and endangered species conservation.

Aquaglyceroporins: generalized metalloid channels

BACKGROUND

Aquaporins (AQPs), members of a superfamily of transmembrane channel proteins, are ubiquitous in all domains of life. They fall into a number of branches that can be functionally categorized into two major sub-groups: i) orthodox aquaporins, which are water-specific channels, and ii) aquaglyceroporins, which allow the transport of water, non-polar solutes, such as urea or glycerol, the reactive oxygen species hydrogen peroxide, and gases such as ammonia, carbon dioxide and nitric oxide and, as described in this review, metalloids.

SCOPE OF REVIEW

This review summarizes the key findings that AQP channels conduct bidirectional movement of metalloids into and out of cells.

MAJOR CONCLUSIONS

As(OH)3 and Sb(OH)3 behave as inorganic molecular mimics of glycerol, a property that allows their passage through AQP channels. Plant AQPs also allow the passage of boron and silicon as their hydroxyacids, boric acid (B(OH)3) and orthosilicic acid (Si(OH)4), respectively. Genetic analysis suggests that germanic acid (GeO2) is also a substrate. While As(III), Sb(III) and Ge(IV) are toxic metalloids, borate (B(III)) and silicate (Si(IV)) are essential elements in higher plants.

GENERAL SIGNIFICANCE

The uptake of environmental metalloids by aquaporins provides an understanding of (i) how toxic elements such as arsenic enter the food chain; (ii) the delivery of arsenic and antimony containing drugs in the treatment of certain forms of leukemia and chemotherapy of diseases caused by pathogenic protozoa; and (iii) the possibility that food plants such as rice could be made safer by genetically modifying them to exclude arsenic while still accumulating boron and silicon. This article is part of a Special Issue entitled Aquaporins.

Expressions of oxidative stress-related genes and antioxidant enzyme activities in Mytilus galloprovincialis (Bivalvia, Mollusca) exposed to hypoxia

Background

In this study, we investigated transcription and enzyme level responses of mussels Mytilus galloprovincialis exposed to hypoxic conditions. Genes for catalase (CAT), cytochrome P450, glutathione S-transferase (GST), metallothionein, superoxide dismutase (SOD), cytochrome c oxidase subunit 1 (COX-1), and NADH dehydrogenase subunit 2 were selected for study. Transcriptional changes were investigated in mussels exposed to hypoxia for 24 and 48 h and were compared to changes in control mussels maintained at normal oxygen levels. Activities of CAT, GST, and SOD enzymes, and lipid peroxidation (LPO) were also investigated in mussels following exposure to hypoxia for 24, 48, and 72 h.

Results

Relative to the control group, the CAT activity decreased in all hypoxia treatments, while the activity of GST significantly increased in mussels exposed to hypoxia for 24 and 48 h, but decreased in those exposed for 72 h. The LPO levels were significantly higher in mussels in the 24- and 48-h hypoxia treatments than those in the control mussels, but there was no significant change in the SOD activities among all hypoxia treatments. Messenger RNA levels for the CAT, cytochrome P450, GST, metallothionein, and SOD genes were not significantly affected by hypoxic conditions for 48 h, but the expressions of the COX-1 and NADH dehydrogenase subunit 2 genes were significantly repressed in mussels in both the 24- and 48-h exposure treatments.

Conclusions

These results demonstrate the transcriptional stability and changes among several genes related to oxidative stress under oxygen-depletion conditions in M. galloprovincialis and provide useful information about the modulation of antioxidant enzyme activities induced by hypoxia in a marine animal.

DNA damage and transcriptional changes in the gills of mytilus galloprovincialis exposed to nanomolar doses of combined metal salts (Cd, Cu, Hg)

Aiming at an integrated and mechanistic view of the early biological effects of selected metals in the marine sentinel organism Mytilus galloprovincialis, we exposed mussels for 48 hours to 50, 100 and 200 nM solutions of equimolar Cd, Cu and Hg salts and measured cytological and molecular biomarkers in parallel. Focusing on the mussel gills, first target of toxic water contaminants and actively proliferating tissue, we detected significant dose-related increases of cells with micronuclei and other nuclear abnormalities in the treated mussels, with differences in the bioconcentration of the three metals determined in the mussel flesh by atomic absorption spectrometry. Gene expression profiles, determined in the same individual gills in parallel, revealed some transcriptional changes at the 50 nM dose, and substantial increases of differentially expressed genes at the 100 and 200 nM doses, with roughly similar amounts of up- and down-regulated genes. The functional annotation of gill transcripts with consistent expression trends and significantly altered at least in one dose point disclosed the complexity of the induced cell response. The most evident transcriptional changes concerned protein synthesis and turnover, ion homeostasis, cell cycle regulation and apoptosis, and intracellular trafficking (transcript sequences denoting heat shock proteins, metal binding thioneins, sequestosome 1 and proteasome subunits, and GADD45 exemplify up-regulated genes while transcript sequences denoting actin, tubulins and the apoptosis inhibitor 1 exemplify down-regulated genes). Overall, nanomolar doses of co-occurring free metal ions have induced significant structural and functional changes in the mussel gills: the intensity of response to the stimulus measured in laboratory supports the additional validation of molecular markers of metal exposure to be used in Mussel Watch programs.