Mussel-based monitoring of trace metal and organic contaminants along the east coast of China using Perna viridis and Mytilus edulis

Analysis of Pollutant Accumulation in the Invasive Bivalve Perna viridis: Current Status in the Colombian Caribbean 2020-2023

The Colombian Caribbean faces environmental challenges due to urbanization, industrialization, and maritime activities, which introduce pollutants such as heavy metals, hydrocarbons, and microplastics into aquatic ecosystems. Perna viridis (Asian green mussel), an invasive species that has been established in Cartagena Bay since 2009, exhibits potential bioaccumulation capacity, making it a promising biomonitor. This study assessed the concentrations of mercury (Hg), cadmium (Cd), lead (Pb), and selenium (Se) in P. viridis across two key sites-a port area at the Cartagena Bay (CB) and Virgen marsh (VM) in Colombia-from 2020 to 2023. Seasonal variations driven by La Niña and El Niño phenomena significantly influenced metal concentrations, with transitional periods modulating pollutant accumulation. The levels of trace metals in soft tissue of P. viridis (dry weight) ranged from 0.0003 to 0.0039 µg/g (Cd), 0.04 to 0.21 µg/g (Hg), 0.05 to 1.18 µg/g (Pb), and 0.0029 to 0.0103 µg/g (Se). In suspended particulate matter (SPM), Cd ranged from 0.07 to 0.33 µg/g; Pb ranged from 4.94 to 25.66 µg/g; and Hg ranged from 0.18 to 1.20 µg/g. Results revealed differences in metal concentrations between sites and seasons, highlighting the role of environmental and anthropogenic factors in pollutant distribution. The findings confirm P. viridis as an effective biomonitor of complex pollution scenarios in Cartagena Bay. However, its invasive status highlights ecological risks to be addressed, such as interaction with native bivalves and benthic community structures. These results emphasize the need for ongoing monitoring efforts to mitigate pollution and preserve marine biodiversity in the Colombian Caribbean.

Toxicokinetics and Mussel Watch: Addressing Interspecies Differences for Coastal Cadmium Contamination Assessment

Bivalves are often employed for biomonitoring contaminants in marine environments; however, in these large-scale programs, unavoidably, using multiple species presents a significant challenge. Interspecies differences in contaminant bioaccumulation can complicate data interpretation, and direct comparisons among species may result in misleading conclusions. Here, we propose a robust framework based on toxicokinetic measurements that accounts for interspecies differences in bioaccumulation. Specifically, via a recently developed double stable isotope tracer technique, we determined the toxicokinetics of cadmium (Cd)─a metal known for its high concentrations in bivalves and significant interspecies bioaccumulation variability─in six widespread bivalve species including mussels (Perna viridis, Mytilus unguiculatus, Mytilus galloprovincialis) and oysters (Magallana gigas, Magallana hongkongensis, Magallana angulata). Results show that oysters generally have higher Cd uptake rate constants (ku: 1.18-3.09 L g-1 d-1) and lower elimination rate constants (ke: 0.008-0.017 d-1) than mussels (ku: 0.21-0.64 L g-1 d-1; ke: 0.018-0.037 d-1). The interspecies differences in tissue Cd concentrations are predominantly due to Cd uptake rather than elimination. Utilizing toxicokinetic parameters to back-calculate Cd concentrations in seawater, we found that the ranking of Cd contamination levels at the six sites markedly differs from those based on tissue Cd concentrations. We propose that this approach will be useful for interpreting data from past and future biomonitoring programs.

Metal bioaccumulation in marine invertebrates and risk assessment in sediments from South African coastal harbours and natural rocky shores

Industrial and urban activities are major contributors to metal contamination in coastal systems, often impacting the physiology, distribution and diversity of marine invertebrates. This study assessed metal contaminations in sediments, seawater, algae and invertebrates across four armoured systems (harbours) and two natural sites along the south coast of South Africa. Bioaccumulation factors such as Biosediment (BSAF), Biowater (BWAF), Bioaccumulation (BAF) and bioremediation of metals by invertebrate bioindicators were also determined. Spatial variation in metal concentrations were observed, however, bioaccumulation of metals was site and species-specific. Invertebrates bioaccumulated higher metal concentrations in armoured than natural sites, with filter feeders exhibiting higher concentrations than grazers. Among filter feeders, Octomeris angulosa and Crassostrea gigas bioaccumulated elevated aluminium (Al), arsenic (As), chromium (Cr), zinc (Zn) and copper (Cu), while, Perna perna accumulated elevated nickel (Ni), cadmium (Cd) and lead (Pb). Among grazers, Siphonaria serrata and Scutellastra longicosta bioaccumulated elevated Al, Cr, Cd, cobalt (Co), Cu, Ni and Zn. Bioaccumulation factors indicated that (As, Ni, Zn) were bioaccumulated by algae, and invertebrates from sediment (BSAF>1) and from seawater (BWAF>1). Additionally, invertebrates bioaccumulated metals from their prey item, algae as indicated by (BAF>1). Arsenic Cd and Pb in invertebrates were above the maximum limit set for human consumption by various regulatory bodies. Our findings underscore the significant role of coastal invertebrates in bioaccumulating and bioremediating metals, suggesting a natural mechanism for water quality enhancement, especially in urbanised coastal areas.

Oxidative response to accumulation of trace metals in tissue of two bivalves, the Asian green mussel Perna viridis and the blood cockle Tegillarca granosa, living in Pattani Bay, Thailand

OBJECTIVE

Using bivalves to indicate aquatic pollutants was favorable for discerning the negative effects of high levels of metal accumulation in tissue. We investigated the correlation between trace metal accumulation and the tissue oxidative response of two bivalves.

METHODS

The Asian green mussel Perna viridis and the blood cockle Tegillarca granosa were sampled along with seawater and sediments from three locations around Pattani Bay, Thailand. Accumulation of nine trace metals (cadmium, cobalt, copper, chromium, nickel, manganese, iron, zinc, and lead) in seawater, sediments, and tissue and the oxidative tissue response were evaluated. Metal bioaccumulation factor, biota-sediment accumulation factor, and histopathology were also indicated.

RESULT

The present study found that P. viridis and T. granosa were macroconcentrators and bioaccumulative of cadmium, and their tissue accumulation of cadmium was strongly related to lipid peroxidation activation. Perna viridis exhibited a higher oxidative response than T. granosa, as indicated by malondialdehyde, catalase, and reduced glutathione levels.

CONCLUSION

The present study indicated that P. viridis and T. granosa were macroconcentrators and bioaccumulative of cadmium, and their tissue accumulation of cadmium was strongly related to lipid peroxidation activation. Research has shown discernible negative effects of a high level of metal accumulation in tissue, and deformed and damaged tissues were present in the gills, digestive glands, intestines, and feet of P. viridis and T. granosa.

The Status of Marine Mussel Pollution Research in South Africa (2012-2022)

The growing human population requires more food each year, and seafood products can help meet this demand if clean water resources are available for their growth. Farmed and wild mussels are environmentally friendly seafood with many health benefits to human consumers, but they can also pose a health risk if they are harvested from areas where marine anthropogenic pollution is uncontrolled or unmonitored. While the coastline in South Africa has long been assumed to be pristine, a growing number of recent studies are raising contamination concerns. Baseline studies establish a wide range of anthropogenic pollutants to be present in the marine environment, specifically in urbanised or industrialised areas like major cities or harbours. This review summarises how mussels could pose health risks to human consumers and the current research that is being conducted by private researchers and institutions in South Africa. The review emphasises the need for more research in the field and for governmental pollution monitoring data to be released to the public.

Spatial distribution and source identification of phthalates and organochlorine compounds in Galician mussels (NW Spain)

The spatial distribution of five phthalate esters (PAEs) and 17 organochlorine compounds (OCs) in wild and raft mussels from Galician littoral collected in 2020, and its relationship with anthropogenic activities was studied in this work. The Rías de Foz and Muros-Noia were the most polluted by PAEs, while the Rías de Ferrol and Barqueiro by PCBs. The highest levels of all contaminants were present in wild mussel, except DEHP that were predominant in raft mussel. The levels of most PAEs were negatively correlated with levels of the lower chlorinated PCBs and OCPs. The spatial distribution of pollutants confirmed by PCA was affected by the proximity to anthropogenic sources, phthalates by urban wastewater and PCBs by industrial inputs, mainly. The study of human exposure assessment suggests that Risk Quotient values were < 1, so the consumption of Galician raft mussels did not pose a risk to human health.

Lower Health Risks of Potentially Toxic Metals after Transplantation of Aquacultural Farmed Mussels from a Polluted Site to Unpolluted Sites: A Biomonitoring Study in the Straits of Johore

The present field-based study aimed to determine the levels of six potentially toxic metals (PTM)s (Cd, Cu, Fe, Ni, Pb, and Zn determined using a flame atomic-absorption spectrophotometer) using transplanted green-lipped mussel Perna viridis from a polluted site at Kampung Pasir Puteh (KPP) to unpolluted sites at Kampung Sungai Melayu (KSM) and Sungai Belungkor (SB) in the Johore Straits (SOJ), and to estimate the human health risks of the PTMs after the depuration periods. Interestingly, after 10 weeks of depuration in the two unpolluted sites, there were 55.6-88.4% and 51.3-91.7% reductions of the six PTMs after transplantation from KPP to SB and KSM, respectively. Lower risks of health assessments were recorded and judged on the present findings of significantly (p < 0.05) lower levels of safety guidelines, significantly (p < 0.05) lower values of target hazard quotient, and significantly (p < 0.05) lower values of estimated weekly intake, of all the six PTMs after 10 weeks of depuration of the transplanted polluted mussels to the two unpolluted sites in the SOJ. Thus, further reducing the noncarcinogenic risks of the PTMs to the consumers. From an aquacultural point of view, this depuration technique can be recommended to reduce the health risks of PTMs to mussel consumers.

Occurrence of quinolones in cultured fish from Shandong Province, China and their health risk assessment

The residue levels of 6 quinolones in 160 cultured fish samples from Shandong Province, China were investigated using UPLC-MS/MS. The detection rate was 43.1% and enrofloxacin had the highest detection rate as well as the highest residue concentration. The violation rates were 2.50% for the sum of enrofloxacin and ciprofloxacin and 1.25% for ofloxacin. Among the 9 fish species, quinolone contamination problems should receive more attention in Carp, Grass carp, Crucian and Catfish. The health risk assessment showed that when calculated by the maximum concentration, the estimated daily intakes (EDIs) of Carp, Grass carp and Crucian for the high consumption group accounted for more than 10% of the acceptable daily intakes (ADIs), indicating that a large intake of these fish species might pose a potential health risk and health risk monitoring of quinolones in cultured fish should be continually performed.

Industrialization and food safety for the Tsleil-Waututh Nation: An analysis of chemical levels in shellfish in Burrard Inlet

While Indigenous food systems remain critical for community well-being, traditionally harvested foods are a potential source of toxic exposures. The Tsleil-Waututh Nation (TWN) is seeking to restore shellfish harvesting in Burrard Inlet (British Columbia [BC], Canada), where the cumulative effects of industrial activity have nearly eliminated safe harvesting. The Trans Mountain Expansion project would triple the capacity to transport oil through the inlet, threatening TWN's progress to restore shellfish harvesting. To inform ongoing efforts we assessed contamination by heavy metals (arsenic, cadmium, lead, and mercury) and 48 polycyclic aromatic hydrocarbons (PAHs) congeners in different shellfish species (Softshell clams, Varnish clams, and Dungeness crab) in three areas. We compared our results against local screening values (SVs) established by the TWN and BC Ministry of Environment and Climate Change Strategy, as well as provincial and national benchmarks. In total, we analyzed 18 composite samples of Softshell clams and Varnish clams (5 individuals per sample), as well as 17 individual crabs. We found chemical contamination in all species at all sites. PAHs were most frequently detected in Softshell clams, highest in the site closest to the pipeline terminus. Clams presented higher levels of contamination than crabs for PAHs, but not for heavy metals. For Softshell and Varnish clams, all heavy metals across study sites exceeded at least one of the population-specific SVs. Of the 14 PAHs detected, benzo(a)pyrene presented a median concentration in Softshell clams of 3.25 μ/kg, exceeding local SV for subsistence fisher. Our results call for further assessment of human health impacts related to food harvesting within Burrard Inlet and establishing a long-term coordinated program co-led by the TWN to monitor contamination and inform future harvesting programs. The study draws attention to the need to consider locally-relevant toxicity benchmarks, and include potential health impacts of food contamination in appraising development project proposals.

The High Risk of Bivalve Farming in Coastal Areas With Heavy Metal Pollution and Antibiotic-Resistant Bacteria: A Chilean Perspective

Anthropogenic pollution has a huge impact on the water quality of marine ecosystems. Heavy metals and antibiotics are anthropogenic stressors that have a major effect on the health of the marine organisms. Although heavy metals are also associate with volcanic eruptions, wind erosion or evaporation, most of them come from industrial and urban waste. Such contamination, coupled to the use and subsequent misuse of antimicrobials in aquatic environments, is an important stress factor capable of affecting the marine communities in the ecosystem. Bivalves are important ecological components of the oceanic environments and can bioaccumulate pollutants during their feeding through water filtration, acting as environmental sentinels. However, heavy metals and antibiotics pollution can affect several of their physiologic and immunological processes, including their microbiome. In fact, heavy metals and antibiotics have the potential to select resistance genes in bacteria, including those that are part of the microbiota of bivalves, such as Vibrio spp. Worryingly, antibiotic-resistant phenotypes have been shown to be more tolerant to heavy metals, and vice versa, which probably occurs through co- and cross-resistance pathways. In this regard, a crucial role of heavy metal resistance genes in the spread of mobile element-mediated antibiotic resistance has been suggested. Thus, it might be expected that antibiotic resistance of Vibrio spp. associated with bivalves would be higher in contaminated environments. In this review, we focused on co-occurrence of heavy metal and antibiotic resistance in Vibrio spp. In addition, we explore the Chilean situation with respect to the contaminants described above, focusing on the main bivalves-producing region for human consumption, considering bivalves as potential vehicles of antibiotic resistance genes to humans through the ingestion of contaminated seafood.

Evidence of complementarity between targeted and non-targeted analysis based on liquid and gas-phase chromatography coupled to mass spectrometry for screening halogenated persistent organic pollutants in environmental matrices

This study explored the complementarity between targeted (TS) and non-targeted screening (NTS) based on liquid and gas-phase chromatography coupled to (high-resolution) mass spectrometry (LC-/GC-(HR)MS) for the comprehensive characterization of organohalogen fingerprints within a set of Lake Ontario lake trout samples. The concentrations of 86 legacy, emerging and novel halogenated compounds (HCs), were determined through 4 TS approaches involving no less than 6 hyphenated systems. In parallel, an innovative NTS strategy, involving both LC and GC-Q-Orbitrap, was implemented to specifically highlight halogenated signals. Non-targeted HRMS data were processed under the HaloSeeker software based on Cl and Br isotopic ratio and mass defect to extend the screening to unsuspected and unknown HCs. A total of 195 halogenated mass spectral features were characterized in the Lake Ontario lake trout, including well known HCs (PCBs, PBDEs, PBBs, DDT and their degradation products), emerging HCs (novel brominated flame retardants, short-, medium- and long-chain chlorinated paraffins) or suggested molecular formula (mainly polychlorinated ones). Among the 122 HCs highlighted by TS, only 21 were identified by NTS. These results fueled a discussion on the potential and limitations of both approaches, and the current position of NTS within environmental and health monitoring programs.

Comparing the concentrations of heavy metals on two bivalve species in Santos Bay, Brazil: Subsidies to understanding the assimilation dynamic of bivalve contaminants

Contaminant substances consist of chemical elements that present the potential to adversely impact the ecology of the environment, thus representing a threat to local fauna and flora. In this context, heavy metals are critical agents that, depending on the nature and level, are potentially toxic to living organisms. In order to evaluate the bioaccumulation of heavy metals in the Santos estuary and to determine the potential influence of salinity gradient on the heavy metal bioconcentration, the present study measured the concentrations of As, Cd, Pb, Cu, Cr, Fe, Ni, and Zn in two bivalve species (Crassostrea rhizophorae and Perna Perna) sampled at different sites of Santos Bay, in the southeastern region of Brazil. Throughout the study, the "sentinel species" used were effective in bioaccumulating contaminants. In oysters, based on the Brazilian legislation, critical limits were exceeded for As, Zn, Cu, and Cr. In the case of mussels, on the other hand, only for As, Zn, and Cr, the critical limits were overcome. In the present study, obtained data suggested salinity as a determinant parameter in As incorporation processes of bivalve mollusks. PRACTITIONER POINTS: The present study presents important results for the development of environmental management policies in estuarine environments. The present study points out differences between different organisms as biomonitors, providing subsidies for the decision of an effective biomonitoring program. The present study discusses values of contaminants as a danger to public health in Santos Bay, which can be extrapolated to other similar environments around the world.

Chemical Content of Five Molluscan Bivalve Species Collected from South Korea: Multivariate Study and Safety Evaluation

Bivalves are a good source of nutrients but also a potential source of environmental contaminants, which could pose a risk for consumers. The aims of this study were: the determination of 16 elements by ICP-MS in 48 samples of five bivalve species purchased from market in Korea; the identification of elements useful for species classification using multivariate analyses; and the benefit-risk evaluation associated to the consumption of these bivalves. The highest difference among content of elements between species was found for Cd, Mn, Ni, Zn, and Fe. Partial last squares discriminant analysis revealed elements with a VIP score >1 which were considered as the most relevant for explaining certain species. As, Cd, Co, and Ni were found as taxonomical markers of V. philippinarum; Mn, Zn, Mg, and Na of A. irradians; and Cd, Ni, and Fe of M. yessoensis. These species could serve as good dietary sources of essential elements. Cd exposure by consumption of Manila clams is not representing a health risk for the Korean population; however, through consumption of Yesso scallops, 5.3% of the Korean population has a potential health risk. Removal of the digestive gland before eating will drastically reduce the amount of Cd ingested.

Temporal and spatial characteristics of PAHs in oysters from the Pearl River Estuary, China during 2015-2020

Estuary connects the inland freshwater and open seawater, which may become a sink for pollutants from land-derived outflows, especially for persistent organic pollutants (e.g., polycyclic aromatic hydrocarbons, PAHs). Due to complex fluctuation in estuary, it's difficult to achieve a comprehensive assessment of the pollution characteristics by grabbed environmental samples. Oysters serve as efficient biomonitors of pollution status in highly dynamic and anthropogenically impacted estuaries, like the Pearl River Estuary (PRE), South China. Here, we investigated the annual, seasonal, and spatial variations of PAHs in the soft tissues of oysters from the PRE over the last six years (2015-2020) and quantitatively analyzed the influence of environmental factors on PAH occurrence in the oysters. The concentrations of Σ₁₅PAH in oysters ranged from 74 to 1164 (337 ± 218) ng/g dry wt., with a peak occurrence in 2017. Highly seasonal and geographical variations in PAH pollution were documented in the PRE, with higher concentrations in oysters during the wet season than dry season, and in the eastern coast than western coast. Furthermore, geographical variation in PAH levels in the oysters was enhanced during the wet season, indicating a possible contribution of heavy rainfall flushing from the Pearl River. In addition to precipitation, water temperature and salinity also significantly influenced PAH levels in the oysters from the PRE by changing the bioavailability and biokinetics. Long-term biomonitoring using oysters in the current study reflected the pollution status and variation trends of PAHs in the highly dynamic PRE.

Human health risk assessment associated with the consumption of mussels (Perna perna) and oysters (Crassostrea rhizophorae) contaminated with metals and arsenic in the estuarine channel of Vitória Bay (ES), Southeast Brazil

The estuarine channel of Vitória Bay was evaluated regarding bioaccumulation of metals (Al, Ba, Mn, Fe, Zn, Cu, Cr, Pb, Ni, Cd, Hg) and As in mollusks. Mussels from an aquaculture farm and transplanted into the estuary, whereas oysters were collected in situ in the same area. Concentrations of Al, Mn, Fe, Cr and As were higher in P. perna, whereas C. rhizophorae bioaccumulated more Ba, Zn and Cu. Arsenic concentrations in P. perna exceeded the limit of the Brazilian legislation in the outer estuary. Salinity seemed to influence metal uptake differently for each bivalve, with P. perna absorbing more metal at higher salinities and C. rhizophorae in areas of lower salinity. Hazard index (HI) >1 revealed risk for both bivalves for high level consumers. Target Cancer Risk (TCR) for As revealed threat for human health associated with the consumption of mussels and oysters from the study area.

A Commentary on the Use of Bivalve Mollusks in Monitoring Metal Pollution Levels

The objective of this commentary is to promote the use of bivalves as biomonitors, which is a part of the continual efforts of the International Mussel Watch. This commentary is an additional discussion on "Bivalve mollusks in metal pollution studies: From bioaccumulation to biomonitoring" by Zuykov et al., published in Chemosphere 93, 201-208. The present discussion can serve as a platform for further insights to provide new thoughts and novel ideas on how to make better use of bivalves in biomonitoring studies. The certainty of better and more extensive applications of mollusks in environmental monitoring in the future is almost confirmed but more studies are urgently needed. With all the reported studies using bivalves as biomonitors of heavy metal pollution, the effectiveness of using Mussel Watch is beyond any reasonable doubts. The challenge is the development of more accurate methodologies for of heavy metal data interpretation, and the precision of the biomonitoring studies using bivalves as biomonitors, whether in coastal or freshwater ecosystems. Lastly, inclusion of human health risk assessment of heavy metals in commercial bivalves would make the research papers of high public interest.

Trophic transfer of pollutants within two intertidal rocky shore ecosystems in different biogeographic regions of South Africa

Tsitsikamma and Sheffield Beach are two relatively pristine sites along the South African east coast representing warm temperate and subtropical biogeographic rocky shore intertidal ecosystems, respectively. Stable isotopes (δ¹⁵N and δ¹³C), metals and organochlorine pesticides (OCPs) were measured in 38 intertidal components to study biomagnification or biodilution of metals and OCPs in these marine food webs. Comparison of the four species common to both sites revealed that the highest Al, Fe and OCP concentrations were measured in intertidal organisms from Sheffield Beach and was attributed to diffuse input into the nearshore marine environment sources via estuaries and groundwater. All other metals were higher in intertidal organisms from Tsitsikamma and were attributed to the metal-rich phytoplankton blooms during upwelling events. There was no correlation between metal and OCP accumulation and dietary source (δ¹³C) or trophic level (δ¹⁵N). The application of trophic magnification factors (TMFs) using a relatively short benthic food chain indicated biomagnification for As, Cd, Cu, Se and Zn and biodilution of OCPs at both sites. Since these food chains represent only a small portion of the intertidal ecosystems we found limited evidence of biomagnification or biodilution of metals and OCPs across species. This was attributed to different dietary sources in the same food web and similar trophic levels being occupied by the same species in different food chains. We found that food web composition rather than temperature-based biogeographical distribution influenced trophic transfer of metals and OCPs.

Polycyclic aromatic hydrocarbons (PAHs) in marine organisms from two fishing grounds, South Yellow Sea, China: Bioaccumulation and human health risk assessment

Sediment and marine organism samples collected from Haizhou Bay and Lusi fishing ground in South Yellow Sea, China were analysed for polycyclic aromatic hydrocarbons (PAHs). The concentrations of 16 PAHs in marine organisms ranged from 127.43 to 350.53 ng/g dry weight (dw, Haizhou Bay fishing ground) and from 86.37 to 213.02 ng/g dw (Lusi fishing ground). The dominant compounds were 2- and 3-ring PAHs in marine organism tissues. The main PAH sources were found to be coal combustion. Specific habitat, feeding habit, trophic level and environmental differences may affect the PAH levels in marine organisms in our study area. The biota-sediment accumulation factor (BSAF) decreased with increasing PAH log K_ow and BSAF values might differ in response to various environmental conditions and species. The excess cancer risk from PAH-contaminated seafood consumption was slightly higher than the guideline value (10^-6), but much lower than the priority risk level (10^-4).

Silver Nanoparticles in Zebrafish (Danio rerio) Embryos: Uptake, Growth and Molecular Responses

Silver nanoparticles (AgNPs) are widely used in commercial applications as antimicrobial agents, but there have recently been increasing concerns raised about their possible environmental and health impacts. In this study, zebrafish embryos were exposed to two sizes of AgNP, 4 and 10 nm, through a continuous exposure from 4 to 96 h post-fertilisation (hpf), to study their uptake, impact and molecular defense responses. Results showed that zebrafish embryos were significantly impacted by 72 hpf when continuously exposed to 4 nm AgNPs. At concentrations above 0.963 mg/L, significant in vivo uptake and delayed yolk sac absorption was evident; at 1.925 mg/L, significantly reduced body length was recorded compared to control embryos. Additionally, 4 nm AgNP treatment at the same concentration resulted in significantly upregulated hypoxia inducible factor 4 (HIF4) and peroxisomal membrane protein 2 (Pxmp2) mRNA expression in exposed embryos 96 hpf. In contrast, no significant differences in terms of larvae body length, yolk sac absorption or gene expression levels were observed following exposure to 10 nm AgNPs. These results demonstrated that S4 AgNPs are available for uptake, inducing developmental (measured as body length and yolk sac area) and transcriptional (specifically HIF4 and Pxmp2) perturbations in developing embryos. This study suggests the importance of particle size as one possible factor in determining the developmental toxicity of AgNPs in fish embryos.

Effective removal matrix interferences by a modified QuEChERS based on the molecularly imprinted polymers for determination of 84 polychlorinated biphenyls and organochlorine pesticides in shellfish samples

A modified quick, easy, cheap, effective, rugged, and safe (QuEChERS) procedure combined with GC-MS/MS detection approach using a dynamic multiple reaction monitoring (DMRM) mode was successfully applied for the simultaneous analysis of 84 polychlorinated biphenyls (PCBs) and organochlorine pesticides (OCPs) in shellfish samples. The novel molecular imprinted polymers (MIPs) were synthesized by precipitation polymerization and characterized by Scanning electron microscopy, Brunauer-Emmett-Teller, Fourier transform infrared spectra and adsorption experiment. The MIPs exhibited good adsorption capability to pigment coextractives in shellfish samples without the loss of analytes compared with other sorbents. Under optimal conditions, spiked experiments in sinonovacula, mussel, and clam at 10.0-100.0 μg/kg concentrations showed excellent recoveries ranging from 70% to 120% for all analytes with the relative standard deviations of <10%. The developed method showed good linearity with the correlation coefficient above 0.9980, and the limits of quantification were in the range of 0.01-9.02 μg/kg. The developed QuEChERS procedure combined with GC-MS/MS was successfully applied to 84 PCBs and OCPs residues detection in shellfish samples.

Sources of elevated heavy metal concentrations in sediments and benthic marine invertebrates of the western Antarctic Peninsula

Antarctica is one of the least anthropogenically-impacted areas of the world. Metal sources to the marine environment include localised activities of research stations and glacial meltwater containing metals of lithogenic origin. In this study, concentrations of nine metals (Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb, Zn) were examined in three species of benthic invertebrates collected from four locations near Rothera Research Station on the western Antarctic Peninsula: Laternula elliptica (mudclam, filter feeder), Nacella concinna (limpet, grazer) and Odontaster validus (seastar, predator and scavenger). In addition, metals were evaluated in sediments at the same locations. Metal concentrations in different body tissues of invertebrates were equivalent to values recorded in industrialized non-polar sites and were attributed to natural sources including sediment input resulting from glacial erosion of local granodioritic rocks. Anthropogenic activities at Rothera Research Station appeared to have some impact on metal concentrations in the sampled invertebrates, with concentrations of several metals higher in L. elliptica near the runway and aircraft activities, but this was not a trend that was detected in the other species. Sediment analysis from two sites near the station showed lower metal concentrations than the control site 5 km distant and was attributed to differences in bedrock metal content. Differences in metal concentrations between organisms were attributed to feeding mechanisms and habitat, as well as depuration routes. L. elliptica kidneys showed significantly higher concentrations of eight metals, with some an order of magnitude greater than other organs, and the internal structure of O. validus had significantly higher Ni. This study supports previous assessments of N. concinna and L. elliptica as good biomonitors of metal concentrations and suggests O. validus as an additional biomonitor for use in future Antarctic metal monitoring programs.

Enrichment and contamination level of trace metals in the Mediterranean marine sediments of Spain

Coastal ecosystems are heavily polluted by human activities. These pollutants reach the aquatic environment and accumulate in the sediment. Among the chemical pollutants, metals represent a notable hazard since they are not biodegradable and have the capability to bioaccumulate, resulting in toxic effects in both the short and long term. In this study, the content of metals and As in marine sediments of the Spanish Mediterranean coast was determined. A total of four annual sampling campaigns were carried out along the Valencian Community coastline, where the presence of eight trace elements (Cr, Cd, Ni, Pb, Cu, Hg, Zn and As) was determined. In this area, the presence of the contaminants is due to both natural and anthropogenic sources. The results obtained allowed, first, to establish nearness Reference Values of the area under study, second, to use several pollution indices (Contamination Factor, Enrichment Factor, Geoaccumulation Factor, Nemerow Pollution Index, and Modified Pollution Index) to determine contamination levels in the area, and finally to select the best index to apply in this coastal zone. The best indices to use in this region are EF and MPI since both take into consideration the natural contributions of the elements studied. The results revealed that according to the index used only two studied zones are classified as Heavily and Severely polluted. The remaining zones (between 25 and 29%) were classified as Moderately or Moderately to Heavily polluted and most of the zones (63% to 100%) were classified as Unpolluted/Low Polluted and Unpolluted/Slightly Polluted. The outcomes obtained with this work indicate that in general, the Valencian coast does not present significant levels of pollution due to the studied trace elements.

Fluoxetine suppresses the immune responses of blood clams by reducing haemocyte viability, disturbing signal transduction and imposing physiological stress

The antidepressant fluoxetine (FLX), a selective serotonin reuptake inhibitor, is widely prescribed for the treatment of depression and anxiety disorders. Nowadays, measurable quantities of FLX have been frequently detected in the aquatic ecosystems worldwide, which may pose a potential threat to aquatic organisms. Although the impacts of FLX exposure on immune responses are increasingly well documented in mammals, they remain poorly understood in aquatic invertebrates. Therefore, to gain a better understanding of the ecotoxicological effects of FLX, the impacts of waterborne FLX exposure on the immune responses of blood clam, Tegillarca granosa, were investigated in this study. Results obtained showed that both cellular and humoural immune responses in T. granosa were suppressed by exposure to waterborne FLX, as indicated by total counts of haemocytes (THC), phagocytic rate, and activities of superoxide dismutases (SOD) and catalase (CAT), suggesting that waterborne FLX renders blood clams more vulnerable to pathogen challenges. To ascertain the mechanisms explaining how waterborne FLX affects immune responses, haemocyte viabilities, intracellular Ca²⁺ levels, in vivo concentrations of neurotransmitters, physiological stress conditions (as indicated by in vivo concentrations of cortisol), and expressions of key regulatory genes from Ca²⁺ and neurotransmitter signal transduction, as well as immune-related signalling pathways, were examined after 10 days of FLX exposure by blood clams via 1, 10 and 100 μg/L waterborne FLX. The results obtained indicated that immune response suppression caused by waterborne FLX could be due to (i) inhibited haemocyte viabilities, which subsequently reduce the THC; (ii) altered intracellular Ca²⁺ and neurotransmitter concentrations, which lead to constrained phagocytosis; and (iii) aggravated physiological stress, which thereafter hampers immune-related NFκB signalling pathways.

Preliminary study and first evidence of presence of microplastics and colorants in green mussel, Perna viridis (Linnaeus, 1758), from southeast coast of India

Pollution by microplastics (MPs) is currently a global problem in the coastal and marine environment. Transfer of MPs from land to sea and their inclusion in the food web has a significant adverse effect on the marine life and human health. The present study was carried out at the fishing harbour of Chennai, southeast coast of India. The possible MPs were isolated from the soft tissues of the commercially important bivalve Perna viridis and examined by microscopic and DXR Raman spectroscopic methods. The MPs were identified as to be polystyrene polymers in the soft tissues. This investigation revealed that size and color are the major factors affecting the bioavailability of MPs to bivalves in the study area. The presence of colorants in organisms revealed an anthropogenic origin through the use of a wide array of applications. Hence, coastal zones are a hotspot for pollution by MPs, and filter feeding bivalves are at the highest risk. Therefore, further studies are required to understand the accumulation rates and residence time of MPs across the food webs.

Differential effects of β-glucan on oxidative stress, inflammation and copper transport in two intestinal regions of large yellow croaker Larimichthys crocea under acute copper stress

The aim of the present study was to evaluate investigate the effects of β-glucan on oxidative stress, inflammation and copper transport in two intestinal regions of large yellow croaker under acute copper stress. Fish were injected with β-glucan at a dose of 0 or 5 mg kg^-1 body weight on 6, 4 and 2 days before exposed to 0 and 368 μg Cu L^-1 for 48 h. Biochemical indicators (MDA, Cu content, MTs protein levels, Cu/Zn-SOD, CAT and iNOS activities), gene expressions of oxidative stresses (Cu/Zn-SOD, CAT, Nrf2, MTs and MTF-1), inflammatory responses (NF-κB, iNOS, IL-1β, IL-6 and TNF-α) and Cu transporters (ATP7A, ATP7B and CTR1) were determined. In the anterior intestine, β-glucan increased MTs levels, activities of Cu/Zn-SOD, CAT and iNOS, mRNA levels of MTs, CAT, iNOS, ATP7A and ATP7B, and reduced Cu content and CTR1 gene expression to inhibite Cu-induced MDA. But β-glucan had no effect on inflammatory gene expressions. In the mid intestine, β-glucan increased activities of Cu/Zn-SOD and iNOS, mRNA levels of Cu/Zn-SOD, CAT and iNOS to maintain MDA content. However, unlike the anterior intestine, β-glucan had no effect on Cu transporter gene expressions. Furthermore, transcription factors (Nrf2, NF-κB and MTF-1) paralleled with their target genes in the mid intestine, but no correlation was observed between NF-κB and IL-1β and TNF-α gene expressions in the anterior intestine. In conclusion, our results unambiguously showed that β-glucan induced oxidative stress, inflammation and copper transport were varied between the anterior and mid intestines of fish under Cu stress.

Integrated assessment of heavy metal pollution using transplanted mussels in eastern Guangdong, China

Heavy metal contamination has been widely studied in coastal areas around the world. However, integrative studies of heavy metals pollution by monitoring and characterizing sediments, organisms, and biomarkers as well as their holistic interactions are rare. Here, we selected a developed coastal area in eastern Guangdong, China as the study field. Heavy metal analysis (both in sediment and mussel) and biomarker tests, including neutral red retention time test (NRRT) and micronuclei (MN) test, were employed in the current research. Anthropogenic activities influenced the heavy metal levels in sediments. Significant relationships (p < 0.05) were observed in the concentrations of Cd, Cu, and Zn between sediments and transplanted mussel, and significant relationships (p < 0.05) were also observed in between the concentrations of Cd, Cu, and Zn in sediments and the NRRT of mussel. The potential ecological risk index (RI) of sediments significantly correlated with NRRT (R = -0.991, p < 0.05). In Hao River, where the highest RI of sediments was found, the highest MN frequency and the lowest NRRT in mussels were detected simultaneously. The results indicated that the heavy metal pollution might cause subcellular toxic and genotoxic effects on mussels, especially for those from polluted areas (i.e., Hao River). The present study suggests that the transplanted green-lipped mussels are suitable for assessing heavy metal pollution, especially for Cd, Cu, and Zn.

Trace metals and macroelements in mussels from Chinese coastal waters: National spatial patterns and normalization

Metal contamination is one of the most ubiquitous and complex problems in the Chinese coastal environment. To explore the large-scale spatial patterns of bioavailable metals, we sampled three major mussels, including 784 blue mussels (Mytilus edulis Linnaeus, 1758) of 14 sites, 224 hard-shelled mussels (Mytilus unguiculatus Valenciennes, 1858) of 4 sites, and 392 green mussels (Perna viridis (Linnaeus, 1758)) of 7 sites, ranging from temperate to tropical coastlines of China, during August and September 2015. The concentrations of macroelements (Na, K, Ca, Mg, and P) and toxic trace metals (Ag, Cd, Cr, Cu, Ni, Pb, Ti, and Zn) in the mussel's whole soft tissues were determined. Among the four Chinese coastal basins, Cd, Ti and Cr in the mussel tissues were the highest at Bohai Sea (BS) and Yellow Sea (YS), and Cu, Ni, Pb and Ag in the mussel tissues were the highest at East China Sea (ECS) and South China Sea (SCS). Zinc concentrations in mussels from YS were significantly higher than those from the other regions. Given the variability of environmental conditions such as salinity and nutrients, we further normalized the measured tissue metal concentrations with tissue Na and P levels. After Na normalization as the salinity proxy, the variability of Cd, Cu, Zn, Ag, and Ni was reduced. Trace elements accumulation in the mussel tissues was significantly related to both macroelements (Na or P) and body dry weight. The present study demonstrated that nonlinear optimization of different elements was necessary in assessing metal bioaccumulation patterns in marine mussels at a large spatial scale.

Distribution and risk assessment of trace metals in sediments from Yangtze River estuary and Hangzhou Bay, China

The Yangtze River estuary (YRE) and Hangzhou Bay (HZB) is of environmental significance because of the negative impact from industrial activities and rapid development of aquaculture on the south bank of HZB (SHZB) in recent years. This study investigated the distribution and risk assessments of trace metals (Cr, Cu, Zn, Hg, Pb, and Cd) accumulated in surface sediments by sampling in YRE, outer and south HZB. Copper and Zn concentration (avg. 35.4 and 98.7 mg kg^-1, respectively) in surface sediments were generally higher than the background suggesting a widespread of Cu and Zn in the coastal area of Yangtze River Delta. High concentrations of Cu (~ 42 mg kg^-1), Zn (~ 111 mg kg^-1), Cd (~ 0.27 mg kg^-1), and Hg (~ 0.047 mg kg^-1) were found in inner estuary of YRE and decreased offshore as a result of terrestrial input and dilution effect of total metal contents by "cleaner" sediments from the adjacent sea. In outer HZB, accumulation of terrestrial derived metal has taken place near the Zhoushan Islands. Increase in sediment metal concentration from the west (inner) to the east (outer) of SHZB gave rise to the input of fine-grained sediments contaminated with metals from outer bay. According the results from geoaccumulation index, nearly 75% of samples from YRE were moderately polluted (1.0 < I _geo < 2.0) by Cd. Cadmium and Hg contributed for 80~90% to the potential ecological risk index in the YRE and HZB, with ~ 72% sites in HZB under moderate risk (150 ≤ RI < 300) especially near Zhoushan Islands.

Bioaccumulation of metals in juvenile rainbow trout (oncorhynchus mykiss) via dietary exposure to blue mussels

The potential for metals to bioaccumulate in aquatic species, such as fish, via trophic level transfer was investigated. An in vivo experiment was set up in a flow-through system in which juvenile rainbow trout were fed blue mussels collected from a Class A pristine site and an effluent-impacted river estuary, over a period of 28 days. Selected elements (As, Cd, Cr, Co, Cu, Fe, Pb, Mn, Mo, Ni, Se, Sn, V, Zn) were determined in the mussels and fish tissues (muscle and skin) collected at 0, 14 and 28 days. This study reveals the occurrence of metals in mussels sampled in the Irish marine environment and highlights the bioaccumulation potential of metals in fish tissues via trophic transfer. All 14 monitored metals were determined in the mussels collected from both sites and mussels collected from the effluent-impacted site contained three times more Co, Mo, Sn and V than the mussels collected from the Class A site. Following a 28-day dietary exposure, concentrations of As and Se (fish muscle), and Pb, Se and Zn (fish skin), were significantly greater in fish feeding on contaminated mussels compared to those with a regular fish feed diet. The significance of metal detection and bioaccumulation in the mussel and fish tissues, highlights the potential for metal exposure to humans through the food chain. As fish are recommended as a healthy and nutritious food source, it is important to fully understand metal bioaccumulation in commercially important aquatic species and ensure the safety of human consumers.

Laser-Induced Breakdown Spectroscopy for Rapid Discrimination of Heavy-Metal-Contaminated Seafood Tegillarca granosa

Tegillarca granosa samples contaminated artificially by three kinds of toxic heavy metals including zinc (Zn), cadmium (Cd), and lead (Pb) were attempted to be distinguished using laser-induced breakdown spectroscopy (LIBS) technology and pattern recognition methods in this study. The measured spectra were firstly processed by a wavelet transform algorithm (WTA), then the generated characteristic information was subsequently expressed by an information gain algorithm (IGA). As a result, 30 variables obtained were used as input variables for three classifiers: partial least square discriminant analysis (PLS-DA), support vector machine (SVM), and random forest (RF), among which the RF model exhibited the best performance, with 93.3% discrimination accuracy among those classifiers. Besides, the extracted characteristic information was used to reconstruct the original spectra by inverse WTA, and the corresponding attribution of the reconstructed spectra was then discussed. This work indicates that the healthy shellfish samples of Tegillarca granosa could be distinguished from the toxic heavy-metal-contaminated ones by pattern recognition analysis combined with LIBS technology, which only requires minimal pretreatments.

In-situ synthesis of reduced graphene oxide/gold nanoparticles modified electrode for speciation analysis of copper in seawater

In this paper, reduced graphene oxide/gold nanoparticle/Nafion (rGO/AuNP/Nafion) modified electrode was fabricated through in-situ synthesis and used for determination of copper ions in strong salt electrolyte (0.5M NaCl) by differential pulse anodic stripping voltammetry (DPASV). This in-situ synthesis procedure was based on the ion-exchange and electrochemical reduction. The use of rGO provided a larger electrode surface and the presence of more active sites, while electron transfer was accelerated by incorporating AuNPs. Nafion was utilized as a cation exchange polymer in which rGO and AuNPs could be tightly attached to the electrode surface. The physical and electrochemical characterizations of the as-prepared modified electrode were studied by transmission electron microscopy (TEM), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS) and cyclic voltammetry. AuNPs with diameter of 5-10nm on rGO decorated in the gold electrode surface were observed. Under the optimal conditions, the rGO/AuNP/Nafion electrode had a linear response to copper ions in the concentrations range from 20nM to 1μM (R² = 0.998), with the lowest detectable concentration of 8nM and the detection limit of 4nM (S/N = 3). Additionally, this electrode was successfully applied to the speciation analysis of copper (free, dissolved and total) in seawater.

Pre-acclimation to low copper mitigated immunotoxic effects in spleen and head-kidney of large yellow croaker (Pseudosciaena crocea) when exposed subsequently to high copper

The hypothesis tested in this study was that Cu pre-acclimation would mitigate high Cu induced immunotoxic effects in large yellow croaker Pseudosciaena crocea. To the end, fish were pre-acclimation to 0 and 84μg CuL^-1 for 48h and then exposed to 0 and 420μg CuL^-1 for another 48h. Survival rate, Cu content, ROS, NO, activities and mRNA levels of inflammatory genes (iNOS and COX-2), and gene expressions of transcription factor NF-κB and its inhibitor IκBα were determined in spleen and head-kidney of large yellow croaker. Cu pre-acclimation significantly reduced mortality of fish exposed to 420μg CuL^-1. Cu pre-acclimation triggered the up-regulation of both enzyme activities and express levels of iNOS and COX-2 in spleen under 420μg CuL^-1 exposure, resulting in remarkable reduction of Cu content and ROS in this tissue. Contrast to spleen, iNOS activity remained unchanged but the mRNA level of iNOS increased, and the mRNA level of COX-2 remained constant though COX-2 activity enhanced in head-kidney, suggesting iNOS and COX-2 may be modulated by Cu at a post-transcriptional level. In this process, NF-κB/IκBα signaling molecules may play a vital role in the transcriptional activation of inflammatory genes in both spleen and head-kidney. In conclusion, low Cu pre-acclimation alleviated high Cu induced immunotoxicity in spleen and head-kidney of large yellow croaker by enhancing the activities and mRNA levels of inflammatory genes.

Bioaccumulation and biomagnification of short and medium chain polychlorinated paraffins in different species of fish from Liaodong Bay, North China

Chlorinated paraffins (CPs) are highly complex technical mixtures, and the short chain chlorinated paraffins (SCCPs) are classed as persistent and have been included in the Stockholm Convention. However, there have been few studies of SCCPs and medium chain chlorinated paraffins (MCCPs) and their bioaccumulation and biomagnification in different species of fish. The present study investigated the levels, congener group profiles, bioaccumulation, and biomagnification of SCCPs and MCCPs in different species of fish from Liaodong Bay, North China. The ranges for the ΣSCCP and ΣMCCP concentrations were 376.3-8596 ng/g lipid weight (lw) and 22.37-5097 ng/g lw, respectively. The logarithms of bioaccumulation factors of ΣSCCPs ranged from 4.69 to 6.05, implying that SCCPs bioaccumulated in the fish. The trophic magnification factor of ΣSCCPs was 2.57, indicating that SCCPs could biomagnify in fish. Carbon chain length, the numbers of chlorine atoms, and octanol/water partition coefficients of the SCCPs and MCCPs might be important factors affecting the bioaccumulation of these chemicals in fish. The risk posed to human health by consumption of fish containing SCCPs was low. New SCCPs with nine carbons (C₉) were detected in fish in this study.

Blue mussels (Mytilus edulis spp.) as sentinel organisms in coastal pollution monitoring: A review

The blue mussel (Mytilus spp.) is widely used as a bioindicator for monitoring of coastal water pollution (mussel watch programs). Herein we provide a review of this study field with emphasis on: the suitability of Mytilus spp. as environmental sentinels; uptake and bioaccumulation patterns of key pollutant classes; the use of Mytilus spp. in mussel watch programs; recent trends in Norwegian mussel monitoring; environmental quality standards and background concentrations of key contaminants; pollutant effect biomarkers; confounding factors; particulate contaminants (microplastics, engineered nanomaterials); climate change; harmonization of monitoring procedures; and the use of deployed mussels (transplant caging) in pollution monitoring. Lastly, the overall state of the art of blue mussel pollution monitoring is discussed and some important issues for future research and development are highlighted.

Assessment of trace metal accumulation in native mussels (Brachidontes rodriguezii) from a South American temperate estuary

The present work provides the first results in heavy metal bioaccumulation in the autochthonous mussel Brachidontes rodriguezii from the Bahía Blanca Estuary (Argentina), one of the most important coastal environments of South America, subjected to different anthropogenic pressure. The study is based on the detection of Cd, Cu, Pb, Mn, and Fe in mussels' soft tissue and sediments' fine fraction by means of inductively coupled plasma atomic emission spectroscopy (ICP-OES), in order to analyze the potential relationship between both components of the aquatic system. Additionally, different indices are calculated with the purpose of obtaining detailed data. The heavy metal burden in mussels varied seasonally, showing a clearer pattern for the stations located in the internal area of the estuary. Metals exhibited maximum values in summer and to a lesser extent in winter, followed by a decrease during spring. Multiple international guideline assessment allowed classifying the area as moderately polluted, including a low range for Cd and medium for Cu and Pb. Moreover, the average detected levels were within the measured ranges in other coastal areas. Regarding human health, trace metal content in mussels met the national and international standards for safe consumption.

Sub-lethal effects of cadmium and copper on RNA/DNA ratio and energy reserves in the green-lipped mussel Perna viridis

This study aims to test if RNA/DNA ratio and various energy reserve parameters (i.e., glycogen, lipid, protein content and total energy reserves) are sensitive biomarkers for indicating stresses induced by metal contaminants in the green-lipped mussel Perna viridis, a common organism for biomonitoring in Southeast Asia. This study was, therefore, designed to examine the effects of cadmium (Cd) and copper (Cu) on these potential biomarkers in two major energy storage tissues, adductor muscle (AM) and hepatopancreas (HP), of P. viridis after sub-lethal exposure to either metal for 10 days. The results showed that neither Cd nor Cu treatments affected the RNA/DNA ratio, glycogen and protein contents in AM and HP. As the most sensitive biomarker in P. viridis, the total lipid content in both AM and HP was significantly decreased in the treatment of 5μg Cu/L and 0.01-0.1μgCd/L, respectively. However, soft-tissue body burdens of Cu or Cd did not significantly correlate with each of the four biomarkers regardless of the tissue type. In addition, AM generally stored more glycogen than HP, whereas HP stored more lipids than AM. We proposed that multiple biomarkers may be employed as an integrated diagnostic tool for monitoring the health condition of the mussels.

Spatial-temporal trend and health implications of polycyclic aromatic hydrocarbons (PAHs) in resident oysters, South China Sea: A case study of Eastern Guangdong coast

Spatial and temporal distributions of polycyclic aromatic hydrocarbons (PAHs) were investigated in Eastern Guangdong coast, China. Total PAH concentrations in oysters ranged from 231 to 1178ng/g with a mean concentration of 622ng/g dry weight. Compared with other bays and estuaries, PAH levels in oysters were moderate. Spatial distribution of PAHs was site specific, with relatively high PAH concentrations observed in Zhelin Bay and Kaozhouyang Bay. Based on the Spearman test analysis, only PAH concentration in oysters from Jiazi Harbor showed a significant increasing trend (P<0.05). Three-ring PAHs were the most abundant, accounting for 54.2%-88.4% of total PAHs. Diagnostic ratios suggested that PAHs were derived mainly from petroleum origin. BaP and ∑4PAH concentrations were well within the European Union limits (5ng/g and 30ng/g wet weight, respectively). The incremental lifetime cancer risks (ILCR) for PAHs were <10(-5), indicating that the adverse health risks associated with oyster consumption in this area were minimal.

Residual levels of rare earth elements in freshwater and marine fish and their health risk assessment from Shandong, China

The total concentrations of rare earth elements (ΣREE) were quantified in 251 samples from 10 common species of freshwater and marine fish in seventeen cities of Shandong, China. ΣREE obtained from the freshwater fish ranged from 34.0 to 37.9ngg(-1) (wet weight) and marine fish from 12.7 to 37.6ngg(-1). The ratio of LREE to HREE was 13.7:1 and 10:1 for freshwater and marine fish, respectively. This suggests that freshwater fish exhibit greater REE concentrations than marine fish and the biological effects of LREE are higher than HREE. Results revealed a similar REE distribution pattern between those fish and coastal sediments, abiding the "abundance law". The health risk assessment demonstrated the EDIs of REEs in fish were significantly lower than the ADI, indicating that the consumption of these fish presents little risk to human health.

Health risk assessments of heavy metal exposure via consumption of marine mussels collected from anthropogenic sites

A total of 40 marine mussel Perna viridis populations collected (2002-2009) from 20 geographical sites located in two busy shipping lanes namely the Straits of Malacca (10 sites; 16 populations) and the Straits of Johore (8 sites; 21 populations) and three populations (2 sites) on the east coast of Peninsular Malaysia, was determined for Cd, Cu, Fe, Ni, Pb and Zn concentrations. In comparison with the maximum permissible limits (MPLs) set by existing food safety guidelines, all metal concentrations found in all the mussel populations were lower than the prescribed MPLs. In terms of the provisional tolerable weekly intake prescribed by the Joint FAO/WHO Expert Committee on Food Additives (JECFA) and oral reference doses (ORDs) by the USEPA, all the studied metals (except for Pb) were unlikely to become the limiting factors or unlikely to pose a risk for the consumption of the mussel populations. The estimated daily intake (EDI) for average level mussel (ALM) and high level mussel (HLM) consumers of mussels was found to be lower than the ORD guidelines for Cd, Cu, Fe, Ni and Zn. Furthermore, the target hazard quotient (THQ) was found to be less than 1 for ALM consumers but higher than 1 for HLM consumers in some sites. Therefore, there were no potential human health risks to the ALM consumers of the mussels. However, for Pb THQ values, the Pb levels in some mussel populations could create a health risk problem. Present results indicate that the consumption amounts of mussels should be limited for minimizing potential health risks of heavy metals to the HLM consumers.

Health risks of polycyclic aromatic hydrocarbons via fish consumption in Haimen bay (China), downstream of an e-waste recycling site (Guiyu)

Guiyu, China has been one of the largest e-waste recycling sites of the world for more than 20 years. Abundant data show that local dwellers there suffered from severe health risks from e-waste contaminants. In this study, polycyclic aromatic hydrocarbons (PAHs) were used as candidates to test the contamination levels and their possible adverse effects on residents in Haimen Bay, the estuary of Lian River (less than 30km from Guiyu), which has been totally neglected. The concentrations of 16PAHs were determined in collected marine fish with a median ΣPAH concentration of 1478ng/g (wet weight), and the contamination may be mainly influenced by Lian River runoff, specifically from Guiyu. The lifetime excess cancer risk for local dwellers was much higher than the serious risk level (10(-4)). More seriously, outflows of PAHs from the e-waste recycling site (Guiyu) seemed to exert health risks of a much larger scale of population downstream.

Metal bioaccumulation in consumed marine bivalves in Southeast Brazilian coast

This work aimed to investigate metal bioaccumulation by mussels (Perna perna) and Lion's Scallop (Nodipecten nodosus) farmed in tropical bays, in order to estimate spatial and temporal variation in the exposure to these elements, as well as human health risk. The concentration of each measured element was considered for this evaluation, using maximum residue level (MRL) in foods established by the Brazilian (ANVISA), American (USFDA) and European Communities (EC) legislations. Values for estimated daily ingestion (EDI) were determined for metals intake through mussel and scallop consumption. These estimates were compared with the reference value of (PTDI) proposed by World Health Organization (WHO). Trace elements concentration was measured on ninety mussels P. perna (tissue) and ninety Lion's Scallop N. nodosus (muscle and gonad) reared in four different tropical areas of the Southeast Brazilian coast, between 2009 and 2010. Zinc (Zn), Iron (Fe), Copper (Cu), Manganese (Mn), Chrome (Cr), Nickel (Ni), Cadmium (Cd) and Lead (Pb) concentrations were measured by flame atomic absorption spectrometry after acid mineralization. Cd and Mn were more efficiently bioaccumulated by scallops than mussels and the opposite was found for Fe, Cu and Ni. Guanabara Bay and Sepetiba Bay were considered the most impacted between ecosystems studied. Higher Cd values in Arraial do Cabo in the other sites studied were associated with upwelling that occurs in the region. Consumption of both species cannot be considered safe, because the Cu and Cr concentrations, in accordance with the limits established by the Brazilian Agency (ANVISA). On the other hand, any EDI value exceeded the corresponding value of the PTDI, proposed by World Health Organization (WHO).

Linking trace element variations with macronutrients and major cations in marine mussels Mytilus edulis and Perna viridis

Marine mussels have long been used as biomonitors of contamination of trace elements, but little is known about whether variation in tissue trace elements is significantly associated with those of macronutrients and major cations. The authors examined the variability of macronutrients and major cations and their potential relationships with bioaccumulation of trace elements. The authors analyzed the concentrations of macronutrients (C, N, P, S), major cations (Na, Mg, K, Ca), and trace elements (Al, V, Mn, Fe, Co, Ni, Cu, Zn, As, Se, Mo, Cd, Ba, Pb) in the whole soft tissues of marine mussels Mytilus edulis and Perna viridis collected globally from 21 sites. The results showed that 12% to 84% of the variances in the trace elements was associated with major cations, and the tissue concentration of major cations such as Na and Mg in mussels was a good proxy for ambient seawater concentrations of the major cations. Specifically, bioaccumulation of most of the trace elements was significantly associated with major cations, and the relationships of major cations with trace cations and trace oxyanions were totally opposite. Furthermore, 14% to 69% of the variances in the trace elements were significantly associated with macronutrients. Notably, more than half of the variance in the tissue concentrations of As, Cd, V, Ba, and Pb was explained by the variance in macronutrients in one or both species. Because the tissue macronutrient concentrations were strongly associated with animal growth and reproduction, the observed coupling relationships indicated that these biological processes strongly influenced the bioaccumulation of some trace elements. The present study indicated that simultaneous quantification of macronutrients and major cations with trace elements can improve the interpretation of biomonitoring data.

Distribution of persistent organic pollutants (POPs) in cultured mussels from the Croatian coast of the Adriatic Sea

In this study we investigated the distribution of 7 organochlorine pesticides (OCPs) and 17 polychlorinated biphenyl (PCBs) congeners in the edible tissue of the blue mussels (Mytilusgalloprovincialis) collected at 15 shellfish breeding farms and 1 harvesting area along the Croatian Adriatic coast. All analyzed OCPs were found in all samples (0.011-1.47 ng g(-)(1) w.wt.). Concentrations of PCB congeners in positive samples ranged between 0.007 and 7.66 ng g(-)(1) w.wt. The most abundant compounds were γ-HCH, PCB-138 and PCB-153. Overall levels of PCBs and OCPs were in the lower end of the concentration ranges reported in literature. Significant differences of all contaminants were recorded between seasons, with higher values in the warmer part of the year. Results of the evaluation of the risks to human health associated with consumption of the mussels containing organic contaminants suggest that the levels of these compounds in mussels do not pose any threat for consumers of cultivated mussels.

Residues and chiral signatures of organochlorine pesticides in mollusks from the coastal regions of the Yangtze River Delta: source and health risk implication

The residues and enantiomeric fractions of organochlorine pesticides (OCPs) were measured in 11 mollusk species collected from the coastal areas along the Yangtze River Delta to evaluate the status, potential sources, and health risks of pollution in these areas. The concentrations of DDTs, HCHs, and chlordanes ranged from 6.22 to 398.19, 0.66-7.11, and 0.14-4.08 ng g(-1) based on wet weight, respectively; DDTs and HCHs have the highest values, globally. The DDTs increased and the HCHs decreased compared to historical data. Both the box-and-whisker plots and the one-way ANOVA tests indicated that the OCP levels varied little between sampling locations and organism species. The compositions of the DDTs and HCHs suggested a cocktail input pattern of fresh and weathered technical products. The comparative EF values for the α-HCH between the sediments and mollusks, as well as the lack of any discernible difference in the relative proportions of HCH isomers among different species from the same sampling site implied that the HCH residues in the mollusks came directly from the surrounding environment. However, the biotransformation of DDTs in mollusks cannot be precluded. The assessments performed based on several available guidelines suggested that although no significant human health risks were associated with the dietary intake of OCPs, the concentrations of DDTs exceeded the maximum residual limits of China and many developed nations. Moreover, an increased lifetime cancer risk from dietary exposure to either DDTs or HCHs remains a possibility. Because non-racemic OCP residues are common in the mollusk samples, our results suggest a need to further explore the levels and toxicity of the chiral contaminants in mollusks and other foodstuff to develop the human risk assessment framework based on chiral signatures.

The source of natural and anthropogenic heavy metals in the sediments of the Minjiang River Estuary (SE China): implications for historical pollution

Two sedimentary cores in the Minjiang River estuary (SE China) are documented for grain size, clay minerals, heavy metals, magnetic parameters and Pb isotopes to investigate the source and historical variation of heavy metals. The MJK9 core was collected outside of the Minjiang River estuary, and the core is composed of mixed sediments, of which ~70% from the Yangtze River and 30% from the Minjiang River. It is thus difficult to be used for tracing the human activity along the Minjiang River. In contrast, the sediments of MJK16 core which was collected in a nearshore area are primarily from the Minjiang River. The enrichment factors of the sediments were <1.5, indicating minor pollution. The results indicate that the sediments of the MJK16 core have Cu and Pb concentrations increasing since 1980, associated with the increase of magnetic mineral concentration and (206)Pb/(207)Pb and (206)Pb/(208)Pb of the sediments. We compared the Pb isotopic compositions between our results and those for the deposit mining in the Minjiang River basin, and aerosols and coal dust in south China, and considered that Pb in the sediments of the MJK16 core was derived primarily from weathered rocks as well as industrial emission (e.g. coal combustion). The sediments have anthropogenic Pb concentrations ranging from 6% in 1950 to 23.7% in 2010, consistent with the impact of rapid urban and industrial development in China.

Metals in sediments and mangrove oysters (Crassostrea rhizophorae) from the Caroni Swamp, Trinidad

Metals can have significant impacts on inhabitants of mangrove swamps as well as consumers of mangrove-associated fauna. Yet, for several Caribbean islands, assessments regarding the impact of metals on such ecosystems are particularly sparse. The present study investigated the distribution and potential impact of Cd, Cr, Cu, Ni, Pb and Zn in the Caroni Swamp, Trinidad and Tobago's largest mangrove ecosystem. Surface sediments and mangrove oysters (Crassostrea rhizophorae) from 10 sites in the swamp were analysed for the 6 identified metals. The concentration ranges (in μg/g dry wt.) of metals in sediments from Caroni Swamp were: Zn (113.4-264.6), Cr (27-69.7), Ni (10.7-41.1) and Cu (11-40.7). Based on Canadian Sediment Quality Guidelines (CSQGs), metals in sediments posed a low to medium risk to aquatic life. The concentration ranges (in μg/g wet wt.) for metals in Crassostrea rhizophorae tissues were: Zn (123.2-660), Cu (4.2-12.3), Ni (0.1-5.5), Pb (0.1-0.9), Cr (0.2-0.3) and Cd (0.1-0.2). Multiple evaluations indicated that zinc posed a potential threat to the health of oyster consumers. Information from this study is vital for managing the Caroni Swamp, safeguarding the health of consumers of shellfish on this Caribbean island and serving as a useful baseline for future local and regional risk assessments.

Organochlorine pesticide contamination in marine organisms of Yantai coast, northern Yellow Sea of China

To evaluate the contamination of organochlorine pesticides (OCPs) in marine organisms and their potential health risk on consumers in the northern Yellow Sea of China, mollusks, wild shrimps, and crabs were collected from the Yantai coast, and the OCP contents in the samples were analyzed and compared. The results indicate that all the samples have been contaminated by OCPs, and OCP concentrations varied in individual species and in sampling sites. Among the studied OCPs, ∑HCH and ∑DDT concentrations ranged from 0.91 to 13.92 ng g(-1) and from 10.16 to 411.19 ng g(-1), respectively. Meretrix was highly enriched with HCHs, while the highest DDT concentration was found in Crassostrea. For the OCP isomers, β-HCH was the predominant isomer of HCHs, and p,p'-DDE concentration was much higher than other isomers of DDTs. The concentrations of other OCPs (HCB, t-CHL, endrin, and mirex) were relatively low. For the shrimp and crab samples, Alpheus distinguendus samples accumulated a higher level of HCHs but lower DDTs than Oratosquilla aratoria and Carcinoplax vestitus in all sampling areas. HCHs in the samples of contrast area were not significantly lower than that of the sewage outfall area and port area, whereas DDTs in the samples of contrast area were relatively lower than that of the other two areas. Generally, all the OCP contents in the samples are in the range of the edible hygienic criteria except the total concentration of DDTs in Crassostrea.