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Dakhla Bay is a paralic environment distinguished by various potentialities, including fishing, aquaculture, and tourism. However, the development of these human activities can lead to negative impacts on this environment, posing a threat to human health. This situation requires special attention to the environment and the implementation of a program for the protection and preservation of this ecosystem. This study aims to identify solutions to protect the marine environment from cadmium contamination by the macroalgae Gracilaria gracilis. The results of cadmium analyses in different compartments of Dakhla Bay, including bivalve molluscs, seawater, sediment, and macroalgae, indicate a difference in cadmium accumulation across the various studied compartments. The highest levels of cadmium are noted in macroalgae, with concentrations ranging from a minimum of 0.9 mg/kg fresh weight in the summer of 2019 to a maximum of approximately 2.55 mg/kg fresh weight recorded during the summer of 2022 at the Lassargua station. In comparison, bivalve molluscs such as Perna perna showed Cd levels ranging from 0.2 mg/kg to 1.4 mg/kg fresh weight at the same station. The sediment samples revealed average Cd levels ranging from 0.02 to 1.39 mg/kg dry weight in samples collected from Lassargua, while seawater concentrations were recorded at approximately 0.65 µg/L. The decontamination of cadmium by the macroalgae Gracilaria gracilis without impacting the quality of the algae has been well confirmed. Indeed, cadmium levels noted in macroalgae remain below the thresholds set by the regulations in force. In conclusion, the results of this study encourage the use of algocultures in Dakhla Bay to protect its ecosystem from various types of pollution. [ABSTRACT FROM AUTHOR]

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Dakhla Bay is a paralic environment distinguished by various potentialities, including fishing, aquaculture, and tourism. However, the development of these human activities can lead to negative impacts on this environment, posing a threat to human health. This situation requires special attention to the environment and the implementation of a program for the protection and preservation of this ecosystem. This study aims to identify solutions to protect the marine environment from cadmium contamination by the macroalgae Gracilaria gracilis. The results of cadmium analyses in different compartments of Dakhla Bay, including bivalve molluscs, seawater, sediment, and macroalgae, indicate a difference in cadmium accumulation across the various studied compartments. The highest levels of cadmium are noted in macroalgae, with concentrations ranging from a minimum of 0.9 mg/kg fresh weight in the summer of 2019 to a maximum of approximately 2.55 mg/kg fresh weight recorded during the summer of 2022 at the Lassargua station. In comparison, bivalve molluscs such as Perna perna showed Cd levels ranging from 0.2 mg/kg to 1.4 mg/kg fresh weight at the same station. The sediment samples revealed average Cd levels ranging from 0.02 to 1.39 mg/kg dry weight in samples collected from Lassargua, while seawater concentrations were recorded at approximately 0.65 μg/L. The decontamination of cadmium by the macroalgae Gracilaria gracilis without impacting the quality of the algae has been well confirmed. Indeed, cadmium levels noted in macroalgae remain below the thresholds set by the regulations in force. In conclusion, the results of this study encourage the use of algocultures in Dakhla Bay to protect its ecosystem from various types of pollution.

A procedure based on dispersive liquid-liquid microextraction (DLLME) for cobalt (Co) quantification in an Iraqi environmental matrix by flame atomic absorption spectroscopy (FAAS) was applied in this work. A case-study approach was chosen to obtain further in-depth information on the Co levels and to evaluate the effectiveness of N-salicylideneaniline (SAN) as a complexing agent for pre-concentration and extraction of Co. An univariate strategy was utilized to achieve the optimum extraction conditions. The estimated limits of detection (LOD) and quantification (LOQ) under optimum conditions were 1.04 and 3.47 µg L−1, respectively. The results achieved by the proposed system were compared with those using the microwave digestion/graphite furnace atomic absorption spectrometer (MWD/GF-AAS) for digest samples and also for some water samples (Direct GF-AAS). The proposed procedure was applied for analyzing eleven environmental samples. The detectable Co levels for water samples ranged from 0.72 to 4.30 µg L−1 with a relative standard deviation of 3.7–8.8%, while the concentration for solid samples ranged from 0.17–4.51 µg g−1 (2.4–11.8 RSD %). DLLME/FAAS proposed procedure is effective, simple, and has the benefit of minimizing the organic solvent consumption by a few microliters, which results in little waste.

In this work, a procedure based on dispersive liquid-liquid micro-extraction for lead (Pb) pre-concentration and quantification in an environmental matrix by flame atomic absorption spectroscopy (FAAS) was applied. A case-study approach was chosen to obtain further in-depth information on the Pb levels. The green chemistry principles have been applied for the pretreatment and preparation of real samples by focusing on some features such as the volume of reagents/sample, employ of energy efficient equipment, and production of waste. A univariate strategy was utilized to achieve the optimum extraction conditions. 1750 mL of acetonitrile containing 100 mL of carbon tetrachloride, were rapid injection into: 12.0 mL of a sample solution adjusted the pH at 9.0 and 0.07% (m v-1) Dithizone. The estimated limits of detection (LOD) and quantification (LOQ) under optimum conditions were 2.85 and 9.5 mg L-1, respectively. The enrichment factors EFs were found to be 60.6 (aqueous standards/DLLME-FAAS) and 30.8 (matrix matched/DLLME-FAAS). It was applied for the analyzing eleven environmental samples. The detectable Pb levels for water samples were ranged from 1.87 to 8.11 mg L-1, while in solid samples were ranged 0.39e4.66 mg g-1. The relative standard deviation for three concentrations (low, medium, and high) were found to be 10.64, 6.87, and 2.7, respectively. The presented system was validated by analyzing eleven environmental samples (water, bivalve molluscs, lettuce, and medicinal plants). The results indicated that high recoveries were obtained in the range of 92e104 %. The lead concentration was found in these samples always lower than permissible maximum levels stipulated by Iraqi Standards Specifications 2009 (number 417) for neutral water. The DLLME/FAAS procedure has proven to be a fast, simple, low-cost, and efficient analytical protocol, therefore allowing for employing this protocol in routine analysis of trace metals in such matrixes. [ABSTRACT FROM AUTHOR]

Simple Summary: Microplastics (MPs) are anthropogenic microscopic pieces of plastic in marine sediments and the water column that can originate from two different sources. Primary MPs are industrially produced microbeads, while secondary MPs result from the fragmentation of larger plastic debris by physical, chemical, and biological processes. Although not yet considered a food contaminant, they are readily ingested by marine organisms at several trophic levels, thus entering the food chain and representing a risk to consumers of fishery products. In this study, Donax trunculus (Truncate donax) specimens collected from Class A production areas in the Tyrrhenian Sea (Mediterranean Sea), and therefore destined directly for the final consumer, were analyzed for the presence of MPs. First, all items were morphologically classified and measured, and some of these were chemically identified. Then, the MPs' mean abundance (MA) was calculated, and a risk assessment of human exposure to MPs was carried out. Both the MA of MPs and human exposure to MPs were found to be low. However, given the magnitude of the problem, the collection of further data using standardized methods is essential for a better risk assessment. Microplastics (MPs) (0.1 µm–5 mm particles) have been documented in oceans and seas. Bivalve molluscs (BMs) can accumulate MPs and transfer to humans through the food chain. BMs (especially mussels) are used to assess MPs' contamination, but the genus Donax has not been thoroughly investigated. The aim of this study was to detect and characterize MPs in D. trunculus specimens collected along the Tuscan coast (Italy), and to assess the potential risk for consumers. The samples (~10 g of tissue and intervalval liquid from 35 specimens) were digested using a solution of 10% KOH, subjected to NaCl density separation, and filtered through 5 μm pore-size filters. All items were morphologically classified and measured, and their mean abundance (MA) was calculated. Furthermore, 20% of them were analyzed by Raman spectroscopy and, based on the obtained results, the MA was recalculated (corrected MA) and the annual human exposure was estimated. In the 39 samples analyzed, 85 items fibers (n = 45; 52.94%) and fragments (n = 40; 47.06%) were found. The MA was 0.23 ± 0.17 items/grww. Additionally, 83.33% of the items were confirmed as MPs (polyethylene and polyethylene terephthalate). Based on the correct MA (0.18 MPs/grww), D. trunculus consumers could be exposed to 19.2 MPs/per capita/year. The health risk level of MPs was classified as level III (moderate). [ABSTRACT FROM AUTHOR]

Microplastics (MPs) (0.1 µm–5 mm particles) have been documented in oceans and seas. Bivalve molluscs (BMs) can accumulate MPs and transfer to humans through the food chain. BMs (especially mussels) are used to assess MPs’ contamination, but the genus Donax has not been thoroughly investigated. The aim of this study was to detect and characterize MPs in D. trunculus specimens collected along the Tuscan coast (Italy), and to assess the potential risk for consumers. The samples (~10 g of tissue and intervalval liquid from 35 specimens) were digested using a solution of 10% KOH, subjected to NaCl density separation, and filtered through 5 μm pore-size filters. All items were morphologically classified and measured, and their mean abundance (MA) was calculated. Furthermore, 20% of them were analyzed by Raman spectroscopy and, based on the obtained results, the MA was recalculated (corrected MA) and the annual human exposure was estimated. In the 39 samples analyzed, 85 items fibers (n = 45; 52.94%) and fragments (n = 40; 47.06%) were found. The MA was 0.23 ± 0.17 items/grww. Additionally, 83.33% of the items were confirmed as MPs (polyethylene and polyethylene terephthalate). Based on the correct MA (0.18 MPs/grww), D. trunculus consumers could be exposed to 19.2 MPs/per capita/year. The health risk level of MPs was classified as level III (moderate).

Heavy metals in the marine environment are significant contaminants that readily bioaccumulate in the tissues of aquatic organisms, particularly in filter-feeding animals such as bivalve molluscs. Human exposure to elevated concentrations of heavy metals, including essential elements such as Fe, Cu, and Zn, through the consumption of seafood can lead to various pathological effects. Research has demonstrated that among bivalve molluscs, mussels are the most effective indicators for monitoring marine pollution. Consequently, this study focused on the species Mytilus galloprovincialis to evaluate the levels of Al, As, Cd, Cr, Cu, Fe, Mg, Ni, Pb, and Zn in the two primary harvesting areas of Albania and to assess the associated human health risks from mussel consumption. The results revealed a concerning situation, particularly for Pb and Cd, with average concentrations of 2.15 μg/g and 4.14 μg/g, respectively, significantly exceeding the limits established by Regulation (EC) No. 915/2023. The levels of the other investigated elements also raised concerns, as only half of them were within the dietary intake values recommended by scientific authorities for weekly consumption of 250 g of mussels., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier Ltd.. All rights reserved.)

This work describes a method for the determination of paralytic shellfish toxins in mussels (M. galloprovincialis) , oysters (Crassostrea gigas), and clams (Ruditapes decussatus) samples. The acetic acid extraction method is used for simultaneous analysis of Paralytic Shellfish Poisoning (PSP) and the separation of these compounds was achieved on ethylene bridged hybrid (BEH) Amide column with gradient mobile phase composed of acetonitrile (MeCN) and water (as eluent A and eluent B) both containing 2 mM ammonium formate and 50 mM formic acid. The method specificity, linearity, sensitivity, precision, and accuracy were successfully evaluated towards the detection of 13 hydrophilic marine biotoxins analyzed together (single run) in different sample matrixes such as mussels. oysters. and clams. Calibration curves were found to be linear (R2 ≥ 0.98). average Recovery% of 98.5–99.9%. limits of detection (LODs): 0.16–1.92 µg·kg−1; limits of quantitation (LOQs): 0.54–6.41 µg·kg−1) and the relative standard deviation (RSD%) of the precision was ≤ 2.8%. The method was applied for the determination of PSP in shellfish collected from several Tunisian locations. All LC-MS/MS results of analyzed molluscs collected from different Tunisia locations, reveal no PSP toxin group contamination and that the amount found does not exceeding the threshold of 800 µg STXequ·kg−1. [Display omitted] • A proposed official alternative method of analysis for regulatory control and food safety. • Simultaneous determination of paralytic shellfish toxins using LC-MSMS. • A highly sensitive detection of shellfish biotoxins. • Validation of the method for paralytic shellfish toxins determination. • Effectiveness of proficiency testing within 34 different laboratories. [ABSTRACT FROM AUTHOR]

We examined the occurrence and levels of 19 legacy and emerging per- and polyfluoroalkyl substances (PFASs) in 7 species of marine bivalve molluscs collected from four coastal cities of Shandong Province, China. Perfluorooctanoic acid (PFOA) was the most prevalent component, accounting for 68.1 % of total PFASs. The total PFASs in bivalve molluscs ranged from 0.86 to 6.55 ng/g wet weight, with the highest concentration found in Meretrix meretrix L. The concentration of total PFASs in bivalve molluscs showed the following trend: clams > scallops > oysters > mussels. Estimation on the human intake of PFASs from consumption of bivalve molluscs resulted in hazard ratios (HR) ranging from 0.12 to 6.40. Five of the seven species had HR >1, indicating high exposure risks associated with PFASs. Therefore, the occurrence of PFASs in marine biota is particularly concerning and further investigations on the sources of PFASs in Shandong are warranted. • First time detection of 19 PFASs in bivalve molluscs in Shandong Province • PFASs levels in bivalve molluscs varied from 0.86 to 6.55 ng/g wet weight. • PFOA, PFBA, PFNA and PFOS were the compounds most frequently detected. • Frequent consumption of bivalve molluscs may pose health risk. [ABSTRACT FROM AUTHOR]