A novel cadmium detoxification pathway in Tri-spine horseshoe crab (Tachypleus tridentatus): A 430-million-years-ago organism.

Marine and intertidal heavy metal pollution has been a major concern in recent years. Tachypleus tridentatus has existed on earth for more than 430 million years. It has suffered a sharp decline in population numbers caused by environmental pollution and anthropogenic disturbance for almost 40 years. However, the effects of heavy metal pollution on juvenile T. tridentatus have not been reported. Here we show the mechanism of cadmium (Cd) detoxification in juvenile T. tridentatus using integrated antioxidant indexes and transcriptomic and metabolomic analysis. High Cd2+ concentration caused oxidative stress in juvenile T. tridentatus. The hazards increase with increasing Cd2+ concentration in juvenile T. tridentatus. Transcriptomics and metabolomics analyses concluded that high Cd2+ concentration resulted in the imbalance of glycerophospholipid metabolism in juvenile T. tridentatus to detoxify Cd. Our results offer a rationale for protective measures and further studies of heavy metal stress in T. tridentatus.

Ecotoxicological risk of antibiotics and their mixtures to aquatic biota with the DGT technique in sediments.

Antibiotics are emerging contaminants and widely used in human healthcare, livestock, and aquaculture. The toxicity posed by antibiotics and their mixtures in sediments depends on their bioavailability. Now, the bioavailability of organic materials can be determined accurately by the diffusive gradients in thin films (DGT) technique. This technique was used for the first time ever in this study to evaluate in detail the integral toxicity of antibiotics in sediments to aquatic biota. Zhelin Bay was selected as a case study, because it is the largest mariculture area in eastern Guangdong, South China. Two antibiotics, chlortetracycline (CTC) (A) and sulfachlorpyridazine (SCP), were detected at average concentrations of 2.83 and 1.14 ng/ml, respectively. The other fifteen antibiotics were undetectable. The single risk assessment based on the risk quotient (RQ) of CTC and SCP shows that a relatively low risk has occurred. After this careful assessment of probabilistic ecotoxicological risks, the combined toxicity of antibiotic mixtures (CTC and SCP) clearly indicates that the toxicity probability of surface sediments to aquatic organisms was relatively low (0.23%).

Risk on assessment of 15 REEs and mixtures by DGT in Songhua River system sediments of China's largest old industrial base.

Rare earth elements (REEs) are increasingly used in the high-tech sectors in the world and are therefore called burgeoning contaminants. As diffusive gradients in thin films (DGT) can be used to assess the bioavailability of inorganic matters, in this paper, we evaluated, for the first time, the ecotoxicology risks of REEs and their mixtures in river sediments of China's old industrial base by DGT. During our research, taking the Songhua River system (SRS) as an example, we detected its surficial sediments, of which the DGT-labile concentration of REEs (∑REEs) was 2.07-8.76 µg/L. As for the single toxicity, the risk quotient (RQ) values of Y at all sites were significantly greater than 1; while the values of Nd and Pr in some upstream reaches were all significantly greater than the threshold (1), indicating that these adverse effects of single REEs were not neglected. In terms of the combined toxicity of REEs mixtures, we carried out an assessment of the risks of probabilistic ecotoxicology, which showed that the SRS superficial sediments had a low probability of toxicity to aquatic organisms (0.54%).

A new method for estimating sedimental integrated toxicity of heavy metal mixtures to aquatic biota: a case study.

The existing methods of measuring combined toxicity of heavy metal mixtures in environment do not fully consider three major factors (i.e., number of heavy metal species, aquatic biota, all investigated sites as an entity). Herein, a new method named joint probabilistic risk (JPR) method is proposed for evaluating the combined toxicity of heavy metal mixtures to aquatic biota. In this new method, the above three factors are fully taken into account. In order to evaluate the feasibility of the new method, the Pearl River Estuary (PRE) is selected as a case study. Concentrations of heavy metals (Cd, Pb, Cr, Ni, Cu, and Zn) in surface sediments of PRE are investigated and toxic equivalent factors (TEFs) of these heavy metals are calculated. Based on TEFs, sedimental concentrations of heavy metals of PRE are converted to Cd toxic equivalent concentration (Cdeq), while the Cd toxicity data (Cdto) are extracted from the literature. The probability density curves for Cdeq and Cdto are constructed and the overlap area is quantified as 0.2497. This indicates that the surface sediments of PRE have a 24.97% probability of toxic effect towards aquatic biota. Finally, this new method is validated by two indirect methods of mERMq and mPELq.

Nonmetric multidimensional scaling and adverse effects on aquatic biota of polycyclic aromatic hydrocarbons in sediments: A case study of a typical aquaculture wetland, China.

Aquaculture wetlands, particularly those located within urban areas, are fragile ecosystems which are generally heavily impacted by urban and aquaculture activities. However, there are, to date, no reports on adverse effects related to polycyclic aromatic hydrocarbons (PAHs) in sediments from aquaculture wetlands in metropolitan areas. The characterization, sources, and incidence of adverse effects on aquatic biota of PAHs were studied in the riverine and estuarine sediments of the Rongjiang River in an aquaculture wetland in Chaoshan metropolis. The total PAH concentrations varied from 46.0 to 1665.2 ng/g (dry weight), with a mean of 246.4 ng/g, indicating lower concentrations than those of other comparable rivers and estuaries worldwide. High-molecular-weight PAHs were the major PAH species, with fluorene, benzo(b)fluoranthene, and benzo(a)pyrene as the dominant components. These PAHs are likely to be mainly derived from oil and coal/biomass combustion. Probability risk assessment indicated a moderate PAH ecological risk in the Rongjiang River and its estuary (RJE). Accordingly, a comprehensive management plan should be established to ensure sustainable aquaculture wetlands.

Bioaccessibilities and health implications of heavy metals in exposed-lawn soils from 28 urban parks in the megacity Guangzhou inferred from an in vitro physiologically-based extraction test.

This study focused on characterizing the oral bioaccessibilities and human health risks of eight heavy metals (Cd, Pb, Cr, Ni, Cu, Zn, Fe, and Mn) in surface-exposed lawn soils from 28 urban parks in Guangzhou. The physiologically-based extraction test (PBET) method was used to assess bioavailability (in gastric and intestinal phases) and human health risk was assessed via statistical modelling (carcinogenic risk assessment, hazard quotients and hazard indices). Mean bioaccessibilities of Cd, Pb, Cr, Ni, Cu, Zn, Fe, and Mn from all soil samples were 50.90 ± 17.67%, 5.81 ± 1.67%, 7.12 ± 3.24%, 17.91 ± 18.34%, 11.93 ± 2.88%, 34.33 ± 10.02%, 1.68 ± 0.48%, 26.71 ± 5.06%, respectively. The concentrations of most heavy metals were higher in the gastric phase, except for Cr and Ni which remained higher in the intestinal phase. Principal component analysis revealed that the bioaccessibilities of the heavy metals could be split into three groupings, based on the urban park of soil origin. The carcinogenic risk probabilities for Pb and Cr were under the acceptable level (< 1 × 10-4) for both adults and children. The hazard quotient and hazard index values indicated no significant risk of non-carcinogenic effects to children or adults exposed to Guangzhou urban park soils. This research will help inform further risk assessment and management of heavy metal contaminants in urban environments.

Bioaccessibility and human health implications of heavy metals in different trophic level marine organisms: A case study of the South China Sea.

This study investigated the total concentrations and bioaccessibility of heavy metals in edible tissues and trophic levels of 12 marine organism species in the South China Sea. The results were used to estimate health risks to humans. Of the heavy metals detected, nickel (Ni) was present at the highest concentrations, followed in descending, order by iron (Fe), zinc (Zn), manganese (Mn), chromium (Cr), copper (Cu), cadmium (Cd) and lead (Pb). Cd had the highest percentage bioaccessibility (61.91%). There were no correlations between log-transformed total metal concentrations and trophic level values, nor between log-transformed bioaccessibility metal concentrations and trophic level values. This indicates there is no biomagnification among these trace metals. The carcinogenic risk probabilities for Pb and Cr to urban and rural residents were below the acceptable level (< 1â€¯× 10-4). The target hazard quotient (THQ) value for each metal and the total THQ values for all metals studied indicated no significant risk of non-carcinogenic effects to urban and rural residents from consuming marine organisms from the South China Sea.

Contamination, Fractionation and Biological Risk Related to Metals in Surface Sediments from the Largest Deep Freshwater Lake in China.

The toxicity and mobility of metals in the environment are driven by their specific chemical forms and binding states. However, heavy metal fractionation in sediments from plateau deep lakes in China is rare. This study analyzed surface sediments collected from Fuxian Lake, the largest deep freshwater lake in China; parameters examined included total metal concentrations, chemical partitioning, and biological risk assessment. The average total concentrations (mg/kg) were 7.9 for Cd, 97.6 for Pb, 102.8 for Cr, 60.8 for Ni, 73.6 for Cu, and 112.9 for Zn; these levels were significantly higher than their corresponding background values. Cd was preferentially associated with the acid-soluble fraction; significant portions of the Pb, Cr, Ni, Cu, and Zn were mainly associated with the residual fractions. Overall, surface sediments of Fuxian Lake were associated with a 21% incidence of toxicity based on the mean effects range-median quotient. Cd was mainly at high or very high risk levels, and Cu and Zn were mainly at medium or high risk levels based on the risk assessment code (RAC).

Polycyclic Aromatic Hydrocarbons (PAHs) in Exposed-Lawn Soils from 28 Urban Parks in the Megacity Guangzhou: Occurrence, Sources, and Human Health Implications.

Polycyclic aromatic hydrocarbons (PAHs) in urban soils may pose a serious threat to human health via oral ingestion, dermal absorption, and particulate inhalation, especially in public parks and playgrounds, with children and senior citizens showing the highest susceptibility. Several studies have been undertaken identifying PAHs in urban soils, but no studies to date have assessed PAHs in urban parks, in particular in exposed-lawn soils. In recent decades, unprecedented rates of urbanization and industrialization in China have resulted in significant levels of urban environmental pollution. However, concentrations, sources, and the health risk associated with PAH exposure via urban park lawn soils in China remain unknown. The concentrations, sources, and health risk of exposure to 16 PAHs in surface-exposed lawn soils were studied in 28 urban parks in Guangzhou. Concentrations of Σ16PAHs ranged from 76.44 to 890.85 ng/g with a mean of 286.11 ng/g. PAH composition was mostly characterized by 2- and 4-ring PAHs in most sampling parks; Nap, Flua, Pyr, Phe, and Chr were the dominant constituents. Principle component analysis coupled with multivariate linear regression indicated that vehicular and coal combustion emissions contributed to 50.53 and 49.46% of PAHs in Guangzhou's urban park soils, respectively. Total cancer risk (TCR) analysis found that 22 parks (accounting for 78.57% total parks) designed for children's use and general-use park areas presented a potentially high risk (>1 × 10-4) for all users.

Fuzzy comprehensive assessment of heavy metals and Pb isotopic signature in surface sediments from a bay under serious anthropogenic influences: Daya Bay, China.

The fuzzy comprehensive assessment was undertaken to evaluate the marine sediment quality in Daya Bay, China based on the monitoring data of 2015 and China National Standard for Marine Sediment Quality (GB 18668-2002). The results demonstrated that the average metal concentrations (mg/kg) were 0.08 (Cd), 51.30 (Pb), 91.30 (Cr), 29.63 (Cu), 143.42 (Zn), 0.03 (Hg), and 7.31 (As), which were clearly higher with respect to their corresponding background values. Cr was the major pollutant based weight matrices calculated. Taken as whole, the membership degree of class I was a range from 0.65 to 1, suggesting that the marine sediment quality in Daya Bay belongs to class I. Pb stable isotopic analysis coupled with geographic information system (GIS) approach showed the sedimentary Pb mainly originated from petrochemical industry at northwest coast of Daya Bay.

Identification of heavy metal sources in the reclaimed farmland soils of the pearl river estuary in China using a multivariate geostatistical approach.

Heavy metals in the reclaimed farmland soils of the Pearl River Estuary in China have attracted much attention because of the health risk posed to local residents. The identification of heavy metal sources in these soils is necessary to reduce their health risk. Reclaimed farmland soil samples were collected from 144 sites in the Pearl River Estuary and the contents of heavy metals (Cd, Pb, Cr, Ni, Cu, and Zn) were determined. All these heavy metals showed concentrations substantially higher than their background values, indicating possible anthropogenic pollution. The results of a multivariate geostatistical method demonstrate that grouped Cd, Cr, and Cu were mainly controlled by chemical fertilizers. Grouped Pb and Zn were the most severely impacted by atmospheric deposition from Guangzhou and Foshan, and Ni was primarily impacted by electroplating factories' wastewater discharge.

Probabilistic risk assessment of microplastics on aquatic biota in coastal sediments.

As an emerging form of pollution, microplastic contamination of the coastal ecosystems is one of the world's most pressing environmental concerns. Coastal sediments have been polluted to varying degrees by microplastics, and their ubiquitous presence in sediments poses a threat to marine organisms. However, there is currently no ecological risk assessment of microplastics on aquatic biota in sediments. This study, for the first time, established a new procedure to evaluate the toxicity of microplastics on aquatic biota in sediments, based on the probabilistic risk assessment (PRA) concept. The choice of Zhelin Bay as the case study site was based on its severe pollution status. The average content of microplastics in the sediments of Zhelin Bay was 2054.17 items kg-1 dry weight, and these microplastics consisted of 46 different species. Microplastics in sediments exist in five different forms, with the film form being the main composition, and the majority of microplastics have particle sizes ranging from 100 to 500 µm. Correlation analysis (CA) reveals significant negative correlations between microplastic abundance, and Al2O3 and SiO2. The toxicity of microplastics, based on the PRA concept, suggests that Zhelin Bay surface sediments had a low probability (3.43%) of toxic effects on aquatic biota.

Environmental and dietary exposure to 24 polycyclic aromatic hydrocarbons in a typical Chinese coking plant.

Polycyclic aromatic hydrocarbons (PAHs), known for their health risks, are prevalent in the environment, with the coking industry being a major source of their emissions. To bridge the knowledge gap concerning the relationship between environmental and dietary PAH exposure, we explore this complex interplay by investigating the dietary exposure characteristics of 24 PAHs within a typical Chinese coking plant and their association with environmental pollution. Our research revealed Nap and Fle as primary dietary contaminants, emphasizing the significant influence of soil and atmospheric pollution on PAH exposure. We subjected our data to non-metric multidimensional scaling (NMDS), Spearman correlation analysis, Lasso regression, and Weighted Quantile Sum (WQS) regression to delve into this multifaceted phenomenon. NMDS reveals that dietary PAH exposure, especially within the high molecular weight (HMW) group, is common both within and around the coking plant. This suggests that meals prepared within the plant may be contaminated, posing health risks to coking plant workers. Furthermore, our assessment of dietary exposure risk highlights Nap and Fle as the primary dietary contaminants, with BaP and DahA raising concerns due to their higher carcinogenic potential. Our findings indicate that dietary exposure often exceeds acceptable limits, particularly for coking plant workers. Correlation analyses uncover the dominant roles of soil and atmospheric pollution in shaping dietary PAH exposure. Soil contamination significantly impacts specific PAHs, while atmospheric pollution contributes to others. Additionally, WQS regression emphasizes the substantial influence of soil and drinking water on dietary PAHs. In summary, our study sheds light on the dietary exposure characteristics of PAHs in a typical Chinese coking plant and their intricate interplay with environmental factors. These findings underscore the need for comprehensive strategies to mitigate PAH exposure so as to safeguard both human health and the environment in affected regions.

Metal Biological Enrichment Capacities, Distribution Patterns, and Health Risk Implications in Sea Bass (Lateolabrax japonicus).

Seabass (Lateolabrax japonicus) is a major aquacultured fish species worldwide. The bioconcentration, bioaccumulation, and biomagnification of metals in water, sediments, and commercial feed were investigated in L. japonicus from an aquaculture pond in the Pearl River Delta of South China. Aluminum (Al), chromium (Cr), manganese (Mn), iron (Fe), nickel (Ni), copper (Cu), zinc (Zn), arsenic (As), cadmium (Cd), and lead (Pb) were determined in the dorsal muscle, viscera, backbone, gill, and stomach contents of L. japonicus. The gill and stomach contents had higher levels of bioconcentration of most metals than other parts of fish. Based on the bioaccumulation factor, the gill and backbone exhibited the highest accumulation of Zn, while the viscera had the highest capacity to accumulate Cu. The mean biomagnification factor values exceeded for As in dorsal muscle, for Cu in the viscera, for Cr and Pb in the gill, and for Al, Cr, Fe, Cu, and Pb in the stomach contents, indicating efficient bioaccumulation from commercial feed and their habitat. Non-metric multidimensional scaling analysis revealed two groups that resulted from the accumulation of metals in various parts of L. japonicus. Moreover, health risk assessment indicated that no notable adverse health effects occurred from the ingestion of L. japonicus.

Impact assessment of human activities on resources of juvenile horseshoe crabs in Hainan coastal areas, China.

The booming coastal zone economy poses increasing anthropogenic threats to marine life and habitats. Using the endangered living fossil horseshoe crab (HSC) as an example, we quantified the intensity of various anthropogenic pressures along the coast of Hainan Island, China, and for the first time assessed their impact on the distribution of juvenile HSCs through a field survey, remote sensing, spatial geographic modeling, and machine learning methods. The results indicate that the Danzhou Bay needs to be protected as a priority based on species and anthropogenic pressure information. Aquaculture and port activities dramatically impact the density of HSCs and therefore be managed priority. Finally, a threshold effect between total, coastal residential, and beach pressure and the density of juvenile HSCs were detected, which indicates the need for a balance between development and conservation as well as the designation of suitable sites for the construction of marine protected areas.

Bioenrichment preference and human risk assessment of arsenic and metals in wild marine organisms from Dapeng (Mirs) Bay, South China Sea.

Bioenrichment preference of arsenic and metals in wild marine organisms has been scarcely considered. Twenty species including fishes, cephalopods, crustaceans, and bivalve mollusks were collected from Dapeng (Mis) Bay and analyzed for arsenic and metals. Through this study, we had obtained the following four main conclusions: (1) average concentrations of arsenic and metals (µg/kg, wet weight) in the aquatic organism samples were 48.7 for Cr, 1762.0 for Mn, 20,632.8 for Fe, 33.0 for Co, 119.5 for Ni, 3184.7 for Cu, 12,040.5 for Zn, 389.0 for As, 189.1 for Se, 144.4 for Cd, 15.0 for Hg, and 55.3 for Pb; (2) factor analysis (FA) revealed that the studied twenty species exhibited three types of arsenic and metal bioenrichment preference;(3) non-carcinogenic health risk assessment indicated insignificant health effects from marine organism consumption; (4) carcinogenic health risk assessment revealed an unacceptable risk from consumption of nine species, seven of which were crustaceans.

Nonmetric multidimensional scaling and probabilistic ecological risk assessment of trace metals in surface sediments of Daya Bay (China) using diffusive gradients in thin films.

This research is one main objective to assess combined toxicity of trace metal mixtures in aquatic biota in coastal sediments. Coastal sediments around the world are a major reservoir of trace metals from industrial wastewater discharge. Our case study site, Daya Bay in southern China, was selected because it has been under severe man-made impacts. Diffusive gradients in thin films (DGT) technique has proven to be a good method for measuring the bioavailability of trace metals. The bioavailability and distribution of trace metals in surface sediments were investigated along with their possible biological risks. The average bioavailable (DGT-labile) concentrations (µg/L) were 0.44 (V), 0.51 (Cr), 52.49 (Mn), 0.10 (Co), 1.36 (Ni), 0.74 (Cu), 14.53 (Zn), 0.97 (As), 0.14 (Se), 6.73 (Mo), 0.17 (Cd), 0.27 (Sb), 0.10 (W), and 1.32 (Pb). Nonmetric multidimensional scaling (NMS) is a robust multivariate ordination method that makes no assumptions about the distribution of the underlying data. NMS was used to explore that DGT-labile concentrations of trace metals were influenced by sediment properties. NMS results indicated that most DGT- labile trace metals influenced by sediment properties. Risk assessment of single trace metal toxicity revealed that risk quotient (RQ) values for Mn, Cu, Zn and Pb significantly exceeded 1, demonstrating that the toxic effects of these trace metals should be not ignored. The probabilistic ecological risk assessment for integral toxicity of one mixture of 14 trace metals revealed that Daya Bay surface sediments had a low probability (9.04 %) of adverse effects on aquatic biota.

Probabilistic ecotoxicological risk assessment of heavy metal and rare earth element mixtures in aquatic biota using the DGT technique in coastal sediments.

Heavy metals (HMs) are routine contaminants due to their extensive use worldwide. Rare earth elements (REEs) are emerging contaminants because of their global exploitation for use in the high-tech sector. Diffusive gradients in thin films (DGT) are an effective method for measuring the bioavailable component of pollutants. This study represents the first assessment of the mixture toxicity of HMs and REEs in aquatic biota using the DGT technique in sediments. Xincun Lagoon was chosen as the case study site because it has been contaminated by pollutants. Nonmetric multidimensional scaling (NMS) analysis reveals that a wide variety of pollutants (Cd, Pb, Ni, Cu, InHg, Co, Y, La, Ce, Pr, Nd, Sm, Eu, Gd, Dy, Ho, Er, Tm, and Yb) are primarily impacted by sediment characteristics. Appraisal of single HM-REE toxicity reveals that the risk quotient (RQ) values for Y, Yb and Ce notably exceeded 1, demonstrating that the adverse effects of these single HMs and REEs should not be ignored. The combined toxicity of HM-REE mixtures in terms of probabilistic ecological risk assessment shows that the Xincun surface sediments had a medium probability (31.29%) of toxic effects on aquatic biota.

Bioavailability and health risk assessment of Zn and Cd in edible tissues of two typical shellfish species using in vitro gastrointestinal digestion.

Dynamic extraction of edible tissues of Jinjiang oyster (Crassostrea rivularis) and Flower clam (Paphia undulata) was conducted using a fully biomimetic digestion (in vitro) method. The impact of different cooking methods on the bioavailability of Zn and Cd in the edible shellfish tissues was analyzed, and the human health risk of Zn and Cd was evaluated. The results show that the gastric biomimetic extractions of Zn and Cd in unheated samples of C. rivularis and P. undulata were higher than those in the intestinal biomimetic extraction. The extraction patterns of cooked samples were consistent with those of raw samples. The bioavailability of Zn and Cd in cooked samples of C. rivularis was 94.9% and 82.5%, respectively, indicating increased Zn bioavailability but decreased Cd bioavailability compared to the raw samples. The bioavailability of Zn and Cd in cooked samples of P. undulata was 85.1% and 83.0%, respectively, both of which decreased compared to the raw samples. Consumption of C. rivularis can provide 21.0% to 34.2% of the daily required Zn intake, while consumption of P. undulata can provide 3.8% to 6.4%. The intake of Cd from both shellfish species is below the monthly tolerable intake recommended by FAO/WHO. Consuming cooked C. rivularis can increase the intake of Zn and decrease the intake of Cd.

Rare earth elements in sediments from a representative Chinese mariculture bay: Characterization, DGT-based bioaccessibility, and probabilistic ecological risk.

Rare earth elements (REEs) are emerging contaminants due to their worldwide exploitation in the high-technology sector. Aquaculture systems, particularly those located within coastal areas, are fragile ecosystems due to anthropogenic impacts regarding urban and aquaculture activities. However, to date, there are no reports on the combined toxicity of rare earth element (REE) mixtures on aquatic biota in sediments from coastal aquaculture systems. In this study, the combined toxicity of REE mixtures based on probabilistic risk assessment indicated that the surface sediments of Zhelin Bay had a 1.86% probability of toxic effects on aquatic biota. The average value of total REEs (TREEs) was 297.37 µg/g, with light REEs representing the major part. A factor analysis (FA)-geographic information system (GIS)-based approach coupled with correlation analysis (CA) revealed that the REEs are derived from anthropogenic sources through fluvial processes.