Soft Tissues Of Mussels Research Articles

Radioactivity from oil and gas produced water accumulated in freshwater mussels

Legacy disposal of oil and gas produced water (OGPW) to surface water has led to radium contamination in streambed sediment creating a long-term radium source. Increased radium activities pose a potential health hazard to benthic organisms, such as freshwater mussels, as radium is capable of bioaccumulation. This project quantifies the impact of OGPW disposal on adult freshwater mussels, Eurynia dilatata, which were examined along the Allegheny River adjacent to a centralized waste treatment facility (CWT) that historically treated and then discharged OGPW. Radium isotopes (226Ra and 228Ra) were measured in streambed sediment, mussel soft tissue, and mussel hard shell collected upstream, at the outfall, 0.5 km downstream, and 5 km downstream of the CWT. Total radium activity was significantly higher (p < 0.05) in mussel tissue (mean = 3.44 ± 0.95 pCi/g), sediment (mean = 1.45 ± 0.19 pCi/g), and hard shell (mean = 0.34 ± 0.11 pCi/g) samples 0.5 km downstream than background samples collected upstream (mean = 1.27 ± 0.24; 0.91 ± 0.09; 0.10 ± 0.02 pCi/g respectively). Mussel shells displayed increased 226Ra activities up to 5 km downstream of the original discharge. Downstream soft tissue and hard shell 87Sr/86Sr ratios, as well as hard shell metal/calcium (e.g., Na/Ca; K/Ca; Mg/Ca) and 228Ra/226Ra ratios demonstrated trends towards values characteristic of Marcellus OGPW. Combined, this study demonstrates multiple lines of evidence for radium retention and bioaccumulation in freshwater mussels resulting from exposure to Marcellus OGPW.

Coastal Mussel (Mytilus spp.) Soft Tissues as Bioindicators of Methylmercury: Exploring the Relationship Between Condition Index and Methylmercury Concentrations.

We investigated total mercury (THg) and methylmercury (MeHg) concentrations in coastal mussels (Mytilus spp.) sampled from the Minas Basin, Bay of Fundy and evaluated the relationship with condition index (CI). THg concentrations were low in sediment (mean THg = 5.15 ± 2.11 ng/g dw; n = 6) and soft tissues (mean THg = 62.3 ± 13.7 ng/g; mean MeHg = 13.2 ± 6.3 ng/g; n = 57). The THg in tissues had no significant relationship with CI (Rs= -0.205, p = 0.126). MeHg in tissues were significantly and negatively correlated with condition index (Rs = -0.361, p = 0.006) indicating that healthier mussels (higher CI) have lower mercury content possibly due to elimination strategies or growth dilution.

Behavioral and Biochemical Variations in Unio tigridis After Exposure to Lead Nitrate

This study was carried out with the freshwater mussel Unio tigridis exposed to lead nitrate. The samples of water and mussels were collected from Qandil water resources situated in Qandil village at 36° 37' 39.55" north latitude and 44° 10' 51.80" east longitude, and it is 322 meters above sea level. In January 2022, rivers and aquariums water were tested for temperature, pH, EC, TDS, DO, total alkalinity, total hardness, and calcium and magnesium ions. Studied organisms were exposed to variable concentrations of lead nitrate ranging from 0 to 900 ppm. The 96-h median lethal concentration (LC50) was measured and a comparison was made between the behavioural responses of the control and treatment groups. Also, the concentrations of lead in the experimental media, shell, and soft tissue of mussels were measured. A sample of mussels collected from aquarium was tested for biochemical markers, including acetylcholinesterase (AChE), Glutathione S-Transferase (GST), Catalase (CAT) and malondialdehyde (MDA). After 96 hours, the LC50 was estimated to be 782.7 ppm. The findings on behaviours revealed that lead slows down species' activities. Lead concentratiom increased within the mussel body as the water lead level decreased. The value of AChE was inversely related to lead concentration. However, GST, CAT and MDA increased with lead exposure.

Seasonal and multi-decadal zinc isotope variations in blue mussels from two sites with contrasting zinc contamination levels

Zinc (Zn) isotope compositions in soft mussel tissues help identify internal biological processes and track coastal Zn sources in coastal environments, thus aiding in managing marine metal pollution. This study investigated the seasonal and multi-decadal Zn isotope compositions of blue mussels (genus Mytilus) from two French coastal sites with contrasting Zn environmental contamination. Concurrently, we characterized the isotope ratios of sediments and plankton samples at each site to understand the associations between organisms and abiotic compartments. Our primary objective was to determine whether these isotope compositions trace long-term anthropogenic emission patterns or if they reflect short-term biological processes. The multi-decadal isotope profiles of mussels in the Loire Estuary and Toulon Bay showed no isotope variations, implying the enduring stability of the relative contributions of natural and anthropogenic Zn sources over time. At seasonal scales, Zn isotope ratios were also constant; hence, isotope effects related to spawning and body growth were not discernible. The multi-compartmental analysis between the sites revealed that Toulon Bay exhibits a remarkably lower Zn isotope ratio across all studied matrices, suggesting the upward transfer of anthropogenic Zn in the food web. In contrast, the Zn isotope variability observed for sediments and organisms from the Loire Estuary fell within the natural baseline of this element. In both sites, adsorptive geogenic material carrying significant amounts of Zn masks the biological isotope signature of plankton, making it difficult to determine whether the Zn isotope ratio in mussels solely reflects the planktonic diet or if it is further modified by biological homeostasis. In summary, Zn isotope ratios in mussels offer promising avenues for delineating source-specific isotope signatures, contingent upon a comprehensive understanding of the isotope fractionation processes associated with the trophic transfer of this element through the plankton.

Lysosomal Membrane Stability of Mussel (Mytilus galloprovincialis Lamarck, 1819) as a Biomarker of Cellular Stress for Environmental Contamination.

The lysosomal membrane stability (LMS) of hemocytes in wild mussels (Mytilus galloprovincialis) as a biomarker of cellular stress for chemical pollution was tested by neutral red retention time (NRRT) assays. To assess the environmental contamination in the study area, seawater quality and pollutant bioaccumulation throughout the soft tissue of mussels were investigated. The samples were collected in July 2022 at four sites on the Romanian Black Sea coast considered to be differently affected by contamination. To support the suitability of LMS as a biomarker of contaminant-induced stress, the contaminant body burdens of the mussels were compared with the NRRT values. The results showed a significantly reduced NRRT in all investigated locations, particularly in port areas (mean retention time between 11 and 14 min). The elevated bioaccumulation of organochlorinated pesticides (OCPs) and polychlorinated biphenyls (PCBs) and low NRRTs were observed at the most contaminated sites (i.e., ports). The low lysosomal stability reflected stress and damage in the hemocytes of mussels and could be related to the body burdens of contaminants. LMS is an effective indicator of health status in mussels and could be considered a sensitive biomarker of cellular stress induced by contaminant exposure.

Bioaccumulation of pharmaceuticals and personal care products (PPCPs) in freshwater pearl mussels Hyriopsis cumingii in Poyang Lake

Thirty-five PPCPs were measured in representative freshwater pearl mussels (Hyriopsis cumingii) in Poyang Lake, the largest lake of China, as well as their responses to sedimentary PPCPs. We observed 32 PPCPs in soft tissues of mussels at a total concentration of 2721.5 ± 929.3 ng·g−1 dry weight (dw), much higher than those in sediments (21 PPCPs, 273.2 ± 89.4 ng·g−1 dw). Anti-inflammatories were the primary contaminants detected in both sediments and mussels. PPCP concentrations in mussels exhibited significant organ-specific characteristics, and gonads were identified as a hotspot for these contaminants. Correlation analysis showed that gonads were more likely to assimilate triclosan from sediments. Biochemical analysis revealed a higher physiological sensitivity of glutathione synthesis in gonads to sedimentary PPCPs, suggesting the long-term oxidative damage. Our findings highlight the concern on the potential effects of sedimentary PPCPs to propagation of mussels, and emphasize the necessity to formulate strategies for sedimentary PPCPs control targeting a healthy lake.

Shell Organic Matrix (Conchix) of the Mediterranean Mussel Mytilus galloprovincialis L. as the Medium for Assessment of Trace Metals in the Boka Kotorska Bay

The content of trace metals, namely Zn, Cu, Fe, Mn, Pb, Cd, and Hg, in four types of media, i.e., soft tissues, shells, and the products of shell demineralization (organic matrix—conchix and extract) of the Mediterranean mussel Mytilus galloprovicialis L., at three sites in the Boka Kotorska Bay of the Adriatic Sea were determined. The main aim was to investigate the accumulation patterns of trace metals in conchix and their possible relationship with other tested media. Conchix weight within a group of mussels from Sv. Nedjelja was significantly higher in comparison with the IMB, while conchix % in the shell showed a negative correlation with dry shell weight. The highest metal pollution index (MPI) values found in the soft tissues of mussels from Sv. Nedjelja, Cogi, and the IMB were 2.319, 2.711, and 2.929 µg g−1, respectively. PCA analysis showed similarities in trace metal accumulation in all media except conchix. According to CCA analysis, conchixes were grouped around Cu, Fe, and Hg, while Cd and Zn were in correlation with the soft tissues. Moreover, the shells were in correlation with Mn. Simple isolation with high yield, close contact to the environment in comparison with calcified shell layers, and susceptibility to possible pollution sources due to the accumulation of specific metals are the main reasons to consider conchix of M. galloprovincialis as a medium with potential in trace metal assessments of marine ecosystems.

Bioconcentration of Chromium (Cr) on The Soft Tissue of Mussels (Perna viridis, Linnaeus 1758) in Tambak Lorok Waters, Semarang

Industrial development provides economic benefits, but also increases the concentration of waste pollution which affects the aquatic environment of Tambak Lorok on the North Coast of Central Java. The existence of this waste will affect the life of the biota in it, such as mussels (Perna viridis). The heavy metal Chromium is the focus of research, considering that its presence in large quantities which accumulates in the human body causes health problems. The aims of the research were to determine the content of heavy metal Cr in the waters, sediments, and soft tissue of mussels, to determine the bioconcentration of heavy metal Cr in mussels, and to determine the tolerable intake of weekly consumption of the mussels cultivated in Tambak Lorok waters. The content of Cr in water samples, sediment, and mussel soft tissue was measured the APHA 3111B-2012 method, US EPA SW-846/3050 B-1996 SM 3111B-2012 method, and SSA method. The calculation of bioconcentration mussels, using the bioconcentration factor and Maximum Tolerable Intake. The heavy metal content of Cr in the water column was 0.015 – 0.025 mg.L-1 (upper the quality standard), in sediment was 25.12 – 28.72 mg.kg-1(lower the quality standard), and in the soft tissue of mussels was 0.155 – 0.265 mg/kg (upper the quality standard). The bioconcentration factor of metal Cr in mussels is classified as low, which is around 10.35 – 14. The maximum tolerable intake for mussels was 6,078 kg/week, it is considered safe for consumption.

Feeding intensity and daily mussel consumption of Rapa whelk (Rapana venosa) in the north-western Black Sea

Based on an experiment carried out in the north-western Black Sea (Snake Island), the feeding behavior of the Rapa whelk (Rapana venosa Valenciennes, 1846) was analyzed in relation to its size (N = 58; shell height: 30–90 mm). Mediterranean mussels (Mytilus galloprovincialis Lamarck, 1819) were placed in experimental cages with R. venosa to be used as food. It was found that the size of the prey was determined by the size of the predator. The mussels with a shell length of 20−40 mm were most affected by R. venosa. It was determined that the predator’s contribution to the deposition of mussel shells in the bottom sediments is also associated with its size. Feeding intensity varies from 41 mg to 99 mg of the total mass of mussels per 1 g of the total mass of R. venosa per day, depending on the size of the predator. The daily consumption of mussel soft tissue varied from 0.189 g ind.−1 per day−1 in small R. venosa specimens to 0.917 g ind.−1 per day−1 in large predators. Regression equations were obtained between the length and mass of the mussels consumed (total mass, soft tissue mass and shell mass) and the shell height of the predator.

Multi-characteristic toxicity of enantioselective chiral fungicide tebuconazole to a model organism Mediterranean mussel Mytilus galloprovincialis Lamarck, 1819 (Bivalve: Mytilidae)

The survey of available scientific literature shows a lack of data on the chronic effects of tebuconazole (TEB) on non-target aquatic organisms. Therefore, this study evaluates toxicity (10 and 20 days) of two considered concentrations 2 ng/L (E1) and 2 μg/L (E2) of TEB to bioindicator species Mytilus galloprovincialis. To this end, the TEB concentrations measured in soft mussel tissues showed a time-dependent increasing trend. The viability of haemocyte and digestive gland (DG) cells was higher than 95 % during the experiment. However, DG cells lost the ability to regulate their volume in both groups after 20-d. The E1 treatment increased Cl− and Na+ levels, and E2 decreased Na+ levels in the haemolymph. In addition, levels of superoxide dismutase (SOD) activity and oxidatively modified protein (OMP) increased after 10- and 20-d in both treatments. Histopathological findings showed abnormalities in the E2, e.g., haemocyte infiltration, hypertrophy, and hyperplasia in gills and DG. This study reveals the potential risks of TEB usage in the model organism M. galloprovincialis, primarily via bioaccumulation of TEB in food web links, and improves knowledge about its comprehensive toxicity.

Preliminary study on Microplastics in Bivalves Perna viridis, Crassostrea iredalei, and Venerupis philippinarum Harvested from Bacoor Bay, City of Bacoor, Cavite

An increasing number of studies have reported the presence of microplastics in marine organisms such as bivalves. Ingestion of microplastics can affect organisms and transport pollutants such as organic chemicals and heavy metals. In this study, the presence, quantity, and size of microplastics ingested by the three commercially important bivalve species Perna viridis, Crassostrea iredalei, and Venerupis philippinarum harvested from Bacoor Bay, Philippines, were investigated. The microplastics were extracted from the soft tissues of the bivalves using base digestion, recovered by filtration using 150 µm wire mesh, and analyzed microscopically. The results demonstrated that the quantity of recovered microplastics from the soft tissues of mussels, oysters, and clams are 0.93±0.12 items/g, 0.42±0.07 items/g, and 1.71±0.34 items/g, respectively. One-way analysis of variance (ANOVA) shows that the quantity of microplastics ingested by the three bivalve species was significantly different (α = 0.05, p =0.0031). The average size of microplastics ingested by mussels, oysters, and clams was 1.72±0.13 mm, 1.26±0.18 mm, and 1.21±0.1 mm, respectively. A slightly significant difference between the sizes of microplastics ingested by the three bivalve species (α = 0.05, p =0.049) was observed. This study presents preliminary data on the quantity and size of microplastics ingested by bivalves in Bacoor Bay. The results of this study further proved the necessity of determining programs and projects to reduce the potential risks of microplastics on the environment, economy, and, more importantly, on the safety of human food consumption. Further studies are needed to identify the specific polymers of plastics ingested by the three bivalve species harvested in Bacoor Bay.

Macro- and Microelements and Radionuclides in the Mussel Mytilus galloprovincialis from Recreational and Harbor Sites of the Crimean Peninsula (The Black Sea)

The concentrations of 29 elements in the soft tissues and of 24 elements in the shells of mussels (Mytilus galloprovincialis) collected in one selected recreational and two relatively polluted zones were determined and are presented. The high levels of elements in the mussels from a relatively polluted zone of the harbor (Kamyshovaya Bay) could be associated with phytoplankton, terrigenous matter and anthropogenic sources, but did not harm the mussel population, according to the calculated average condition factors. The low levels of the studied elements and condition factors in the mussels from another harbor (Sevastopol Bay) can be explained by the high circulation and influence of submarine desalinated waters in this zone. The mussels from a recreational site in the South coast of Crimea (Foros) showed high levels of the examined elements, commonly due to the coastal weathering of typical local rocks. The found levels of the radionuclides 40K, 137Cs, 232Th, 226Ra and 235U in mussel soft tissues were below the minimum detectable concentrations. The calculated enrichment factors and soft tissue/shells ratios demonstrated differences between groups of elements among the studied sites.

The Contents of Some Trace Elements (As, Br, Cu, Hg, Se, and Zn) in Mytilus galloprovincialis Mussels From Agigea Port, Romania

This study aimed at assessing the accumulation of some trace elements (arsenic, bromine, copper, mercury, selenium, and zinc) in the soft tissue of Mediterranean mussels (Mytilus galloprovincialis) from the Black Sea, near Agigea Port. The mussel samples were collected on a monthly basis between February and June 2019 from two stations located in front of the Danube–Black Sea Canal lock, along the two artificial dikes. The mussels (260 samples) were divided into three classes according to their length: A (3−5.9 cm), B (6−8.9 cm), and C (9−12 cm). The concentrations (dry basis) of As (12.5 ± 3.0 mg/kg), Br (173.6 ± 53.9 mg/kg), Cu (11.2 ± 2.5 mg/kg), Hg (0.02 ± 0.02 mg/kg), Se (2.9 ± 1.1 mg/kg), and Zn (179.5 ± 2.5 mg/kg) were determined using spectrometric techniques. The mean daily values of the physicochemical parameters of seawater (temperature, salinity, pH, chlorophyll a content, and dissolved oxygen content) within the study area were reported. Higher element concentrations were generally found for mussels from size classes A and B compared with those of the larger and older mussels from class C. Principal component analysis (PCA) suggested that the phytoplankton represented an important source of As and Br for the smaller mussels collected in February (when the levels of seawater temperature were lower and those of pH and salinity higher) compared to the larger mussels collected in June. Moreover, the multivariate analysis suggested that Cu, Se, Zn, and Br originated from similar anthropogenic sources and their higher concentrations reported in February and June were obtained at lower levels of seawater salinity. The contents of Cu, Zn, Se, As, and Hg in the mussel soft tissue were lower than the maximum permissible levels.

Chemical composition and morphology of the Mediterranean mussel, Black Sea coast of Russia

Mussels, whose soft tissues are used in food and are rich in high-quality protein, are essential in marine fisheries. Mediterranean mussels (Mytilus galloprovincialis Lam) used to assesses the pollution level of a coastal marine zone due to exposure to local technological processes populate the metal piles of a pier built for the 2014 Olympics in Sochi Olympic Park. The chemical composition of mussel soft tissues (61 elements analyzed by the ICP method) indicates anthropogenic pollution of the coastal zone ecosystem, most pronounced in the 50-m zone along the coast due to run off from the terrestrial ecosystem affected by the Olympic construction. Line measurements of annual rings of 6-year-old individuals of mussels showed stabilization of the ecological situation in the coastal-marine zone by 2019. This study can be used for comprehensive ecological monitoring of coastal-marine zones with similar conditions and anthropogenic load.

Trace elements in the detoxifying and accumulating body parts of Mytilus galloprovincialis Lamark, 1819 (Crimea, Black Sea): human health risks and effect of the sampling site location.

The mussel M. galloprovincialis is one of the most popular species in world's mariculture and environment pollution bioindicators. Although this mollusk was in a focus of numerous publications, the detoxifying and accumulating role of some of its body parts was insufficiently studied. The goals of the present work were as follows: (a) to study the distribution of potentially toxic elements (Cr, Co, Ni, Cu, Zn, As, Cd, Hg, Pb) in soft tissues, byssus, and shell liquor of this bivalve as a function of sampling location in the Black Sea near the southwestern coast of Crimea and (b) to assess human health risks from consuming soft tissues of mussels cultivated on a mollusk farm. Multivariate analysis showed significant differences in the overall distribution of the elements among the body parts and sampling sites under consideration. The trace element contents in soft tissues of M. galloprovincialis decreased in the following order: Zn > Cu > As > Ni > Pb > Cd > Cr > Co > Hg. The noncarcinogenic hazard index from the cultivated mussel consumption was found to be well below one and the carcinogenic risk index was found within the tolerable limits, which indicate the safety of consuming these mussels for humans. Byssus of M. galloprovincialis was characterized as a perfect indicator of marine environment pollution with Ni, Cu, Pb, Сo, and Cr. For the first time, the concentrations of trace elements were determined in the shell liquor and the function of byssus and shell liquor as the systems of trace element excretion from soft tissues was demonstrated.

Immunohistochemical Detection of Various Proteoglycans in the Extracellular Matrix of Zebra Mussels

Mussels have been used as animal models for studying ecotoxicology, biomineralization, and bio-adhesion for many years. Despite a wealth of studies on their shell matrix and byssus proteins, few studies have focused on the extracellular matrix molecules in mussel soft tissues. Extracellular matrix molecules may play important roles in biomineralization, immune reaction, and tissue homeostasis. In the present study, extracellular matrix and mineralization-related molecules in zebra mussel soft tissue were immunolocalized using well-characterized monoclonal antibodies. Our results demonstrate specific immunolocalization for collagen IV, fibronectin, and keratan sulfate in hemocytes; collagen IV in peripheral nerves; and aggrecan, link protein, and collagen XVIII in foot tissue. Laminin, decorin, and osteonectin were also broadly immunolocalized in mussel soft tissues. The distributions of these extracellular matrix molecules in mussel tissues are in line with the cell-mediated shell mineralization hypothesis, providing evidence for the molecules involved in the peripheral nervous system and byssus formation, and explaining the conservation of extracellular matrix molecules during evolution. These results further contribute to establishing zebra mussels as an attractive animal model in biomedical research.

The relative importance of suspended versus benthic food resources to freshwater mussels in central Texas, U.S.A.

Abstract As unionid mussels continue to decline in North America much remains unknown regarding their primary food resources and feeding relationships. Our objective was to investigate spatial, temporal, intra‐ and interspecific variation in food resource use. In this study, we quantified stable C (δ13C) and stable N (δ15N) isotopic signatures for five mussel species and their potential food resources across four catchments and three seasons in central Texas, U.S.A. Across all species and sites, Bayesian mixing models suggest C derived from coarse particulate organic matter (CPOM; bulk detrital leaf packs) contributed on average 51% to the mussel diet and C derived from suspended particulate organic matter contributed 41% on average to the mussel diet. Mussel stable isotope signatures exhibited minimal variation across species within a site, but significant differences across sites and seasons. Although significant differences in food source contributions were observed between sites and species, differences were relatively small and either CPOM or suspended particulate organic matter were consistently the primary food resource. Mussels were potentially consuming microbial biofilms associated with CPOM pools, but preferential assimilation of detrital biofilms remains to be quantified. Carbon:nitrogen ratios of mussel soft tissue varied seasonally with summer ratios approximately 3 times higher on average than spring and autumn ratios, which is suggestive of poor food quality and thermal stress during the summer. Some species had significant positive relationships between isotopic ratios and shell length, which indicates changes in food resource incorporation with increasing mussel size. Together these data suggest the C in mussel tissues was of benthic and suspended origin. These findings provide further evidence that mussels effectively exploit benthic in addition to planktonic food resources which emphasises the need to maintain riparian habitats and allochthonous inputs.

Efficiency assessment of microplastic extraction from green mussel \(\textit{Perna viridis}\) Linnaeus

Microplastics with particle size less than 5 mm are becoming a raising global environmental crisis. These pollutants were found from the poles to the equator, in continental shelves, coasts and in the oceans, moreover, they have also been identified in the water columns, sediments and even in a variety of organisms. The majority of microplastics that ended up in the oceans originate from the land. Due to their small size, they are easily accumulated in the food chain, causing harmful effects on organisms and human health. The bivalves especially caught the interest of scientific researchers because of their direct contact with microplastics through the filter-feeding habit. Therefore, it is essential to develop methods to determine the presence of microplastics in these organisms and identify their source. This study evaluated the efficiency of extracting microplastics from the tissues of green mussels (Perna viridis) using KOH 10% solution to digest and KI 50% as the separating solution. Mussel soft tissue samples were spiked five different types of microplastics: polystyrene (PS), polyvinyl chloride (PVC), polyethylene terephthalate (PET), polypropylene (PP), high-density polyethylene (HDPE) and treated with KOH 10% solution and KI 50% solution. The presence of microplastics in some green mussel species was also investigated in some mussel farming areas in Giao Thuy, Nam Dinh province, Thi Nai, Quy Nhon, Binh Dinh province and Hue city, Thua Thien Hue province. The research results showed high efficiency of microplastic extraction and recovery with the range from 76% to 97%. Microplastic concentration obtained in all mussel samples variates from 1.0 ± 0.1 particles/g to 1.7 ± 0.6 particles/g, in which fiber microplastics predominated. Microplastics in mussel samples have small sizes of &lt; 1,000 µm and 1,000–2,000 µm, make up 74.15–82.32% and 9.76–14.71%, respectively. Purple was dominant among all mussel samples. This study proved that using KOH 10% solution and KI 50% solution to isolate microplastics is a suitable approach and can be used in monitoring studies of microplastic pollution in bivalves.

Levels of Elements in Typical Mussels from the Southern Coast of Africa (Namibia, South Africa, Mozambique): Safety Aspect

The soft tissues of mussels are often used as the main food source, especially in coastal areas. Neutron Activation Analysis was used to measure the content of 24 macro- and microelements in the soft tissues and 18 elements in the shells of selected sets of mussels of the species Mytilus galloprovincialis. The mussels were collected in 8 polluted and 4 pristine zones, which included Namibia, the west and east coasts of South Africa, and Mozambique. According to factor analysis Co, Ni, Zn, As, Se, Br, I, Sb could have anthropogenic origin. The concentrations of elements such as Cr, As, Se and partly Zn at polluted stations were above the maximum permissible levels for seafood. The concentrations of Sc, V, Cr, Mn, Co, Ni, Sb, Cs, Th, U in shells and soft tissues of the same mussels were at the close levels. Elements such as Al, Cr, Co, As (partly Zn, Se, and I) are considered to be harmful to human health at the levels of mussels consumption of 200 g/week per person and lower in such zones as Swakopmund, East London, Port Shepstone, Richards Bay, Xai-Xai according to calculated risk quotients and target hazard indices.

Effect of the Elemental Content of Shells of the Bivalve Mollusks (Mytilus galloprovincialis) from Saldanha Bay (South Africa) on Their Crystallographic Texture.

Simple SummaryThe aim was to study the question of whether the texture of mollusk shells changes with alteration in their elemental composition. Even though significant differences between concentrations of elements among the stations were found, the crystallographic textures of mussel shells from the studied bays showed insignificant dissimilarities. The observed differences in the maximum values in the pole figures fell within the range of variability identified for the genus Mytilus. Nevertheless, they appeared to correlate with the concentrations of Br, Mg, and Sr, which merits further investigation using larger sample sizes and higher variabilities of the ecological state of mussels.A both wild and farmed mussels in natural conditions, anthropogenic inputs are usually reflected in the increase of the content of specific elements. To determine the possible effect of the elemental patterns of farmed and wild mussels (Mytilus galloprovincialis) collected in the Saldanha Bay area (South Africa) on the crystallographic texture of the shells, the content of 20 elements in shells and 24 in the soft tissue of mussels was determined by neutron activation analysis. The crystallographic texture of mussel shells was analyzed using time-of-flight neutron diffraction. The wild mussels from open ocean site live in stressful natural conditions and contain higher amounts of the majority of determined elements in comparison with mussels farmed in closed water areas with anthropogenic loadings. The changes between the maximums of the same pole figures of the three samples are in the range of variability identified for the genus Mytilus. The content of Cl, Sr, and I was the highest in mussels from the open ocean site, which is reflected by the lowest mass/length ratio. The determined crystallographic textures of mussels are relatively stable as shown in the analyzed pole figures despite the concentrations of Na, Mg, Cl, Br, Sr, and I in shells, which significantly differ for wild and farmed mussels. The stability of the crystallographic texture that we observed suggests that it can be used as a reference model, where if a very different texture is determined, increased attention to the ecological situation should be paid.