Integrated toxicity evaluation of metals in sediments of Jiaozhou Bay (China): Based on biomarkers responses in clam Ruditapes philippinarum exposed to sediment extracts

Evaluation of the chronic toxicity of bisphenol A and bisphenol AF to sea cucumber Apostichopus japonicus after long-term single and combined exposure at environmental relevant concentration

Bisphenols are emerging endocrine disrupting pollutant, and several studies have reported that they are already ubiquitous in various environmental matrices and intend to deposit in sediment. The primary sources of bisphenols are river and sewage discharge. Sea cucumber (Apostichopus japonicus), a typical deposit feeder, is one of the most important commercial marine species in Aisa. However, the effects of the bisphenol A (BPA) and its analogues bisphenol AF (BPAF) on sea cucumber was unclear. In this study, we carried out field survey in major sea cucumber farming areas in northern China, with the aim of determining which bisphenol analogue is the major bisphenol contamination in this aquaculture area. The results showed that the presence of BPAF was detected in four sampling sites (Dalian, Tangshan, Laizhou, and Longpan). The mean level of BPAF in Laizhou sediment samples was the highest which reached to 9.007 ± 4.702 μ g/kg. Among the seawater samples, the BPAF only have been detected in the samples collected at Longpan. (0.011 ± 0.003 μ g/L). Furthermore, we conducted an experiment to evaluate the single and combined toxicity of BPA and BPAF on sea cucumbers. The concentrations were informed by the findings based on the results of field research. (0.1, 1.0, and 10 μ g/L). After exposure, the body weight gain, and specific growth rate showed no significant changes (P > 0.05). We observed the histological alterations in respiratory tree of treated sea cucumbers including the fusion and detachment of lining epithelial tissue, and increase of lumen space. However, the catalase (CAT), malondialdehyde (MDA), and glutathione (GSH) activity was not significantly changed (P > 0.05). We evaluated the effects of BPA and BPAF through calculating the integrated biomarker response index (IBR), and the results indicated that the toxicity of combined treatment was higher than single treatment. Additionally, BPAF exposure to A. japonicus was more toxic than BPA.

The physiological response of the clam Ruditapes philippinarum and scallop Chlamys farreri to varied concentrations of microplastics exposure

Microplastics (MPs) pollution's impact on the marine ecosystem is widely recognized. This study compared the effects of polyethylene (PE) and polyethylene terephthalate (PET) on two bivalve species, Ruditapes philippinarum (clam) and Chlamys farreri (scallop), at two particle concentrations (10 and 1000 μg/L). MPs were found in the digestive glands and gills of both species. Although clearance rates showed no significant changes, exposure to different MPs caused oxidative stress, energy disruption, and lipid metabolism disorders in both clam and scallop. Histopathological damage was observed in gills and digestive glands. IBR values indicated increasing toxicity with concentration, with PET being more toxic than PE. WOE model suggested increasing hazard with concentration, highlighting higher PET toxicity on clam digestive glands. In contrast, PE hazard increased in gills, showing different species responses. R. philippinarum exhibited higher sensitivity to MPs than C. farreri, providing insights for assessing ecological risk under realistic conditions and stress conditions.

The ban on the sale of new petrol and diesel cars: Can it help control prospective marine pollution of polycyclic aromatic hydrocarbons (PAHs) in Shandong Province, China?

The constantly increasing amount of road vehicles causes massive exhaust emissions of pollutants, including polycyclic aromatic hydrocarbons (PAHs), necessitating a global responsibility to implement the policy of the ban on the sale of new petrol and diesel cars. Here, we assessed the policy control efficiency on marine pollution of PAHs in China through scenario modeling and prediction models, based on pollution monitoring, risk assessment, and source apportionment of PAHs in typical bays of Shandong Province. The results showed that in 2021, the pollution risk levels were relatively low (HI: 0.008-0.068, M-ERM-Q: 0.001-0.016, IBR: 1.23-2.69, ILCR: 8.11 ×10-6-1.99 ×10-5), and PAHs were mainly derived from traffic emissions (24.9%-35.2%), coal combustion (25.2%-32.9%), petroleum (17.2%-28.9%), and biomass combustion (17.6%-22.8%). In 2050, the predicted decrease of pollution risk values after the implementation of the policy was significant (12%-26%), and the gap between 2021 and 2050 was also significantly huge (18%-85%) without considering possible substitution of conventional energy. Collectively, this study built systematic approaches for assessing prospective marine pollution of PAHs. However, due to the particularity of Shandong Province, i.e., its national predominance of conventional energy consumption, the policy may be more effective when it comes to other coastal areas worldwide, calling for a larger scale research.

Assessment of toxic metal pollution in Yueqing Bay and the extent of metal-induced oxidative stress in Tegillarca granosa raised in this water

Yueqing Bay is an important economic shellfish culture zone in Zhejiang Province, China. However, increased pollution in the water caused by toxic metals has led to the bioaccumulation of toxic metals in cockles such as Tegillarca granosa, and the consequence of toxic metal-associated toxicity in these animals. This study aimed to assess the concentration of toxic metals in the water and sediment in four different sites (Baisha, Qingjiang, Nanyue, and Wengyang) within Yueqing Bay and to evaluate the extent of metal bioaccumulation in T. granosa raised in the aquaculture farms located within the four sites, as well as the changes in biomarkers in T. granosa in response to the metals. The assessment was carried out at two different times of the year, January and July. The water and sediment samples taken from the aquaculture farms in Baisha (S1), Qingjiang (S2) and Nanyue (S3) were found to have a comprehensive toxic metal pollution index (Pc) <1, indicating that these farms were not polluted. However, the water and sediment samples taken from the aquaculture farm in Wengyang (S4) had a Pc between 1 and 2, indicating mild toxic metal pollution. The edible risk assessments (HQ) of T. granosa in all four farms were <1, and therefore, these cockles could be considered safe for human consumption. The toxic metal enrichment in T. granosa exhibited a strong correlation with the toxic metal content in the sediment. In all four farms, CAT and SOD activity levels in the visceral mass of T. granosa were higher than those found in the foot, and a significantly higher level of CAT activity was detected in July compared with January. Similarly, MDA and H2O2 contents in the visceral mass were also higher in July than in January. Tegillarca granosa individuals taken from S4 and S3 farms exhibited significantly higher levels of metallothionein (MT) mRNA and MDA compared with individuals from S1 and S2 farms. Furthermore, the levels of MDA and MT mRNA showed significant positive correlations with Cd, Cr, Hg, and Cu. Elevation of lipid peroxidation in these cockles coincided with increasing levels of endogenous antioxidants. The visceral mass of T. granosa and its MDA level could be used as a tissue indicator and a biochemical marker, respectively, for detecting toxic metal pollution. MT mRNA might also be used as a molecular marker of toxic metal pollution. The integrated biomarker response version 2 (IBRv2) values of the four aquaculture farms in Yueqing Bay showed the order S4 > S3 > S2 > S1, indicating that S4 had the most serious metal-induced stress. Furthermore, the IBRv2 values correlated with the Nemerow composite index (Pc) for all the cockles examined. Thus, as far as the contamination of aquaculture farms in Yueqing Bay by toxic metals is concerned, the aquaculture farm in Wengyang (S4) was mildly contaminated by toxic metals. However, the contamination was relatively low, presenting a low risk for the local population of T. granosa.

Tissue-based trace element pollution of clam Ruditapes philippinarum in China: Hotspot identification and multiple nonlinear analysis

Considering the complexity of coastal and estuarine systems, a great challenge of environmental health assessment is to distinguish between natural and anthropogenically induced stress. Quantification of trace element accumulation in the tissues of sedentary bivalves with subsequent hotspot identification is important to assess the pollution status. The present study conducted a nationwide mapping of bioavailable macro- and trace elements in a widely distributed biomonitoring clam Ruditapes philippinarum from China. Ag, As, Cd, Cr, Cu, and Zn concentrations in the clams showed similar levels as those documented previously in mussels, but were lower than those in oysters at similar sites from China. Notably, the total As concentrations in clams at Xinkai Estuary and Beibu Bay were relatively higher than those at other sites in China. After normalization by tissue biomass, salinity (Na) and nutrient (P), some hotspots were identified with high pollution of trace elements at Liaodong Bay of Bohai Sea, Gold Beach of Qingdao, Dongling Port of Yellow Sea, Hangzhou Bay and adjacent coasts of East China Sea, and Pearl River Estuary and Beibu Bay of South China Sea. This study demonstrated that most trace elements had a path-dependent effect of biomass, except for Cd which showed an indirect pathway of AgNi related accumulation. Results showed significant correlations between Cd, Zn, Ag and Ni, and between Pb/Cr and Ti in clams. After mass normalization, all trace elements displayed significantly positive correlations with Na or P. Simultaneously, the clam biomass played an intermediary role in trace element accumulation in non-linear patterns related to salinity and nutrient. These results are important in evaluating the composite ambiguous information of the historical data of trace element biomonitoring.

An integrated approach using chemical ecological risk assessment and multi-integrated biomarker indexes approach to assess pollution: A case study of Ruditapes philippinarum in four bays on the Shandong Peninsula in China

Considering the ecological risks of polycyclic aromatic hydrocarbons (PAHs) to the marine environment, it is urgent to find scientific and effective monitoring methods. In this study, an integrated approach combining chemical ecological risk assessment and multi-integrated biomarker indexes approach was used to assess the marine environment. Samples included seawater, sediments, and clam Ruditapes philippinarum were collected from four bays on the Shandong Peninsula, China in the four seasons of 2019. The concentrations, composition, potential sources, and ecological risk of PAHs were investigated in seawater and sediments. Risk quotient (RQ) and sediment quality guidelines (SQGs) were calculated to assess the ecological risks of PAHs in seawater and sediment, respectively. And then, clam Ruditapes philippinarum's multi-level biological response, including its ethoxyresorufin-O-deethylase (EROD), glutathione S-transferase (GST), superoxide dismutase (SOD), lipid peroxidation (LPO), and acetylcholinesterase (AChE) were investigated in-depth, by which multi-integrated biomarker indexes approach were calculated to evaluate marine environmental quality. Taken together, the results showed that the concentration of PAHs was in good agreement with the response of biomarkers, and the usefulness of the combined use of chemical ecological risk assessment and integrated biomarker indexes to assess PAHs pollution was verified.

Molecular characterization of a novel p38 MAPK cDNA from Cyclina sinensis and its potential immune-related function under the threat of Vibrio anguillarum

The p38 mitogen-activated protein kinase (MAPK) is one important member of MAPK family and reported to serve a predominant function in regulating innate immunity after the occurrence of certain infection. In the present study, one novel p38 MAPK gene was acquired from Cyclina sinensis based on the RNA-seq analysis and designated as Csp38 MAPK. This novel gene contained a full length of 1781 bp, 1104 bp of which was deemed as open reading frames and gave rise to a peptide of 367 amino acids with a predicted molecular weight of 42.31 KDa. A conserved serine/threonine protein kinase (S_Tkc) region along with a Thr-Gly-Tyr motif was discovered in the deduced sequence. According to the phylogenetic analysis, there was a close relationship between this kinase and Meretrix petechialis p38 MAPK. As for the expression pattern, this newly-identified Csp38 MAPK was ubiquitously distributed in several tissues throughout the body but with varied abundance. After the challenge of Vibrio anguillarum, both the transcription and phosphorylation level of Csp38 MAPK in hemolymph were coordinately altered with a time-dependent manner. Besides, with the application of double strand RNA homologous to myeloid differentiation factor 88 (MyD88) of C. sinensis, the activation of Csp38 MAPK was found to obviously decrease in hemolymph after the pathogen stimulation. Hence, our experimental data presented evidence for the potential involvement of p38 MAPK in response to bacterial invaders in C. sinensis, possibly facilitating the understanding for pathogen-induced innate immunity in clams.

Evaluating environmental impact of STP effluents on receiving water in Beijing by the joint use of chemical analysis and biomonitoring

To evaluate the environmental impact of receiving water from the Qinghe River sewage treatment plant (STP) effluents in Beijing, we collected sediments and Bellamya aeruginosa (Up-site, Discharge-site, and Down-site) both in 2017 and 2018 and analyzed the samples via chemical analysis, biological responses and transcriptomics. In two years of data, our biological results showed that AChE activities presented different degrees of influence on B. aeruginosa captured at sampling points of the STP compared to control sites (P < 0.05). Additionally, indicators of the antioxidant system (e.g., SOD, CAT, GST, EROD activity) and MDA content were significantly increased in the whole tissue at the Up-site of the STP. Integration of the assessed biomarkers using the integrated biomarker response (IBR) index ranked the environmental impact at sites as Up-site > Discharge-site > Down-site. In terms of the transcriptome data, B. aeruginosa collected from the Discharge-site of the STP showed greater transcriptomic response than it did from all other sites. KEGG pathway analysis revealed that sewage significantly altered the expression of genes involved in xenobiotics by cytochrome P450, drug metabolism-cytochrome P450, glutathione metabolism, oxidative phosphorylation, citrate (TCA) cycle, glycolysis/gluconeogenesis, apoptotic and Parkinson's disease. The concentrations of 34 organic pollutants (17 PAHs, 10 PAEs, 7 EDCs) were measured. The chemical concentrations of pollutants decreased from Up-site to Down-site and were well correlated with enzyme activity, IBR, and transcriptomic results. Our results demonstrated that the combined use of chemical analysis, biological responses and transcriptome data is necessary to validate the efficacy of a battery of biomarkers chosen to detect environmental stress due to pollution.

Biomonitoring of polycyclic aromatic hydrocarbons (PAHs) from Manila clam Ruditapes philippinarum in Laizhou, Rushan and Jiaozhou, bays of China, and investigation of its relationship with human carcinogenic risk

This study examined the marine environment and seafood safety using chemical monitoring and multiple biomarkers. Samples were collected from three bays on the Shandong Peninsula in China, Laizhou, Rushan and Jiaozhou, in March, May, August, and October of 2018 and 2019. The polycyclic aromatic hydrocarbon (PAH) concentrations in sediments and tissue samples from the clam Ruditapes philippinarum and multiple biomarkers were measured. All the sampling sites were found to be medium-PAH-contaminated areas (100-1000 ng/g d.w.). According to the correlation analysis, ethoxyresorufin-o-deethylase (EROD) and superoxide dismutase (SOD) activity in the clam's digestive gland were sensitive to PAHs (p < .05), but the incremental lifetime cancer risk (ILCR) was lower than the priority risk level (10^-4) at most sampling sites. EROD, SOD and acetylcholinesterase activity exhibited significant correlations with the ILCR values (p < .01), suggesting that they may serve as good indicators for assessing safe seafood consumption levels for human beings.

Geochemical Composition of the Lomé Lagoon Sediments, Togo: Seasonal and Spatial Variations of Major, Trace and Rare Earth Element Concentrations

The concentrations of major, trace (TE), and rare earth (REE) elements and their seasonal and spatial distribution were studied on the fine fraction (<63 µm) of the sediments of the Lomé lagoons (West Lake, East Lake, and Lake Bè). The sediments were collected on a total of nine sampling sites (three per Lake) during two campaigns (dry season and rainy season). The quality of the sediments was assessed on the basis of the enrichment factor (EF) and the labile or non-residual fraction (NRF) in relation to the values recommended for the quality of the sediments (Sediment Quality Guidelines, SQG). The distribution of rare earth elements shows enrichments in light rare earths superior to those of heavy rare earth elements during any season. Positive Ce anomalies are less noticeable and less variable between seasons than Eu anomalies. La/Yb ratios are positively correlated with the percentage of Al and Fe oxides and with the percentage of fine fractions. The main bearing phases of rare earth elements are, therefore, Al and Fe oxides and the finest fractions of the sediments. The concentrations of trace elements vary little, according to the seasons, but show strong variations from one element to another. The degrees of enrichment obtained are moderate for Bi, Cr, Ga, Mo, Pb, Sn, and Zn (1.5 < EF < 5) to significant for As, Cd, and Sb (5 < EF < 20) for all sites of Lake Bè. For the sites of West Lake, the degrees of enrichment obtained are moderate for As, Cd, Cu, Mo, and Pb (1.5 < EF < 5) to a significance for As, Bi, Cd, Pb, Sb, Sn, and Zn (5 < EF < 20). Only the East Lake sites show high degrees of enrichment for elements such as Sb and Sn (20 < EF < 40). Trace elements (TE) such as As, Cd, Cu, and Ni have total concentrations within the range of variation of the SQG concentrations (particularly Probable Effect Level (PEL) and Effect Range Median (ERM)), whereas Cr, Pb, and Zn total concentrations are higher. The ranking of priority sites with respect to the sediment contamination is determined according to ERM and PEL quotients in relation to the probability of toxicity for benthic organisms. For almost all the sites, the priority is lowest to medium-low with regard to As, Cd, and Cu and medium-high (Cr and Ni) to highest (Pb and Zn), particularly for the East and West Lakes. Moreover, the NRF can represent significant percentages of the total TE concentrations: 5% to 15% for As, Bi, Ni, V, Mo, and Sc, 15% to 25% for Co, Cu, and Sr, 25% to 40% for Pb and Zn and, lastly, 47% to 55% for Cd.

A verification of correlation between chemical monitoring and multi-biomarker approach using clam Ruditapes philippinarum and scallop Chlamys farreri to assess the impact of pollution in Shandong coastal area of China

Biogeochemical monitoring coupled with multi-biomarker approach were performed for the assessment of marine environment, using clam Ruditapes philippinarum and scallop Chlamys farreri to indicate contamination status in sediments and seawater respectively. The bivalves were collected from three stations, Jiaozhou Bay, Rushan Bay and Laizhou Bay, of Shandong coastal area. A series of contaminants (PAHs and TBBPA) and biomarkers (AhR, EROD, GST, SOD, GPx, CAT, DNA damage) were measured. Multi-biomarker pollution index (MPI) and integrated biomarker response (IBR) were carried out to evaluate contamination status and both indexes showed that Rushan Bay was most polluted, where the pollution level of sediments reached "highly polluted" in August, followed by Jiaozhou Bay and Rushan Bay which reached "lightly polluted". The correlation of IBR values with contaminants' concentrations was verified through the Pearson correlation coefficient (p < 0.05), consolidating this scientific assessment method for marine environment.

Biomarkers responses of the clam Anomalocardia flexuosa in sediment toxicity bioassays using dredged materials from a semi-arid coastal system

Few test organisms are employed for sediment toxicity assessments in Tropical regions, including Brazil. We assessed the ability of the clam Anomalocardia flexuosa to respond to contamination in sediment bioassays using dredging materials of a semi-arid region (Ceará State, NE Brazil), with attention to sublethal responses. Sediments were collected during and after dredging (survey 1 and 2, respectively) and animals exposed in laboratory over 28 days, with responses measured at 7 days. Bioaccumulation of contaminants was determined in whole-body soft tissues as a metric of bioavailability, and biomarkers' changes were monitored in terms of enzymes of phase I and II metabolism, acetylcholinesterase (AChE), and antioxidant responses, lipid peroxidation (LPO) and DNA damage (strand breaks). Clams accumulated aliphatic (AHs) and aromatic hydrocarbons (PAHs), and linear alkylbenzenes (LABs) compared to control conditions (day 0), with increased amounts of As, Cd, Cu, and Zn observed in some samples. The enzyme glutathione S-transferase was enhanced in animals exposed to samples, indicating activation of phase II metabolism. Changes observed in glutathione peroxidase (GPx), glutathione reductase (GR), LPO and strand breaks were related to oxidative stress. AChE enzymatic activity also changed, as an indicator of neurotoxicity caused by sediment exposure. The computed integrated biomarker response index (IBR) ranked sites according to the contamination status and proximity to its sources. Correlations found for biomarkers and bioaccumulation of hydrocarbons indicated the influence of harbor activities, effluent discharges, and urban runoff on the sediment pollution of Mucuripe Bay. Data also showed that SQGs are unable to predict bioaccumulation and subchronic effects. Based on our results we consider that biomarkers responses in A. flexuosa are important endpoints to be applied in sediment toxicity bioassays in tropical regions.