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.

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.

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.

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.

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%).

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.

Heavy metals in riverine/estuarine sediments from an aquaculture wetland in metropolitan areas, China: Characterization, bioavailability and probabilistic ecological risk.

Aquaculture wetlands, particularly those located within urban areas, are fragile ecosystems due to urban and aquaculture impacts. However, to date, there are no reports on the combined toxicity of heavy metal mixtures in aquatic biota in sediments from aquaculture wetlands in metropolitan areas. Thus, the characterization, bioavailability, and ecological probability risk of heavy metals were studied in the riverine/estuarine sediments of the Rongjiang River in an aquaculture wetland in Chaoshan metropolis, South China. In the study area, the average total concentrations (mg/kg) were 2.38 (Cd), 113.40 (Pb), 88.27 (Cr), 148.25 (Ni), 62.08 (Cu), 125.18 (Zn), 45,636.44 (Fe), and 797.18 (Mn), with the Cd pollution being regarded as extremely serious based on the enrichment factor (EF). There are two main sources of heavy metals in the study area; Ni, Pb, Zn, Fe and Mn are mainly from domestic waste, while Cr, Cd and Cu are possibly associated with industrial production activities. The bioavailability of most heavy metals accounted for more than 20% of the total concentration. The combined toxicity of heavy metal mixtures based on probabilistic risk assessment suggests that the surface sediments of the Rongjiang River and its estuary had a 15.71% probability of toxic effects on aquatic biota.

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.

Distribution, Multi-Index Assessment, and Sources of Heavy Metals in Surface Sediments of Zhelin Bay, a Typical Mariculture Area in Southern China.

The occurrence, multi-index assessment, and sources of heavy metals in surface sediments of Zhelin Bay were investigated. Average heavy metal concentrations (mg/kg) were 81.89 (Cr), 770.76 (Mn), 16.81 (Co), 62.25 (Ni), 96.30 (Cu), 162.04 (Zn), and 73.40 (Pb), with the concentrations of studied seven heavy metals being significantly higher than their corresponding background values. Geo-accumulation index (Igeo) and pollution load index (PLI) were implemented to assess degree of heavy metal contamination. The Igeo and PLI indicated that Cr, Mn, Co, Zn, and Pb were slightly polluted, and Cu and Ni were moderately polluted in the region. Potential ecological risk index (RI) and mean possible effect level (PEL) quotient were conducted to assess ecological risk. The RI and mean PEL quotient demonstrated that surface sediments of Zhelin Bay were slight ecological risks and exhibited a 21% probability of toxicity. Principal component analysis (PCA) combined with the correlation analysis (CA) and hierarchical cluster analysis (HAC) revealed that the heavy metal contamination in Zhelin Bay might originate from three type sources.

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.

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.

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.

Multi-index assessment of heavy metal contamination in surface sediments of the Pearl River estuary intertidal zone.

Surface sediments from 21 stations within the Pearl River estuary (PRE) intertidal zone were sampled for heavy metal contamination analysis. Average heavy metal concentrations (mg/kg) in the PRE intertidal zone were 118.5 (Cr), 860.4 (Mn), 19.5 (Co), 72.5 (Ni), 128.1 (Cu), 198.5 (Zn), and 73.0 (Pb), with the concentrations of Mn, Co, Ni, Cu, and Zn being significantly higher than their corresponding background values. The enrichment factor (EF) and geo-accumulation index (Igeo) reveal the same contamination status, with Pb, Ni, Co, Mn, and Cu showing slight to moderate contamination. Overall, the combined heavy metal concentration in the PRE intertidal surface sediments had a 24.7 % probability of toxic effects on aquatic biota based on the joint probabilistic risk (JPR) approach. Principal component analysis (PCA) coupled with the correlation analysis (CA) revealed that the heavy metal contamination in the PRE intertidal zone might originate from natural and anthropogenic sources.

Risk assessment of heavy metal and pesticide mixtures in aquatic biota using the DGT technique in sediments.

Heavy metals and pesticides (HMPs) are common contaminants due to their extensive use worldwide. Diffusive gradients in thin films (DGT) are a good method for measuring the bioavailable concentration of pollutants. This study represents the first evaluation of HMP toxicity in aquatic biota using the DGT technique in sediments. Zhelin Bay was selected as the case study site because it has been contaminated by pollutants. Nonmetric multidimensional scaling (NMS) analysis reveals that a diverse range of pollutants (V, Cr, Ni, Cu, Zn, As, Se, InHg, Mo, Cd, Sb, W, Pb, CLP, PYR) are mainly influenced by sediment characteristics. Assessment of single HMP toxicity found that the risk quotient (RQ) values for Mn, Cu, inorganic Hg (InHg), chlorpyrifos (CLP) and diuron (DIU) are significantly higher than 1, indicating that the adverse effects of these single HMPs should not be ignored. The combined toxicity of HMP mixtures based on probabilistic ecotoxicological risk assessment shows that Zhelin Bay surface sediments had a medium probability (54.6%) of toxic effects to aquatic biota.

Micro-CT and SEM investigation of sound absorption structure and chambers in the otoliths of Giant Panda fish species - Chinese Bahaba (Bahaba taipingensis).

As a critically endangered (CR) fish species, Chinese Bahaba is a unique "Giant Panda" fish species in China and has been listed among the national first-class wildlife protection animals and China's top 10 genetic resources of aquatic products since 2021. This fish species is of high commercial value because its swim bladder is commonly used in traditional Chinese medicine. Its otoliths are the sensory organs immersed in the endolymph for maintaining its balance and hearing. However, rare information has been reported on the sound absorption structure and chambers of otoliths of such "Giant Panda" fish. The big "C" groove was found in the fish's front sagittal otolith with the crystal cluster in the back sagittal otolith, the former of which is a 3D layered structure, that is constructed by elongated prismatic crystals. Besides, there are numerous small holes and adhesion material in this 3D layered structure, where many chambers were also found, indicating that some specific sounds may be captured by this structure and these chambers may then amplify such sounds at a certain wavelength. This finding could be of great importance for protecting and conserving this critically endangered species.

Application of diffusive gradients in thin films to determine rare earth elements in surface sediments of Daya Bay, China: Occurrence, distribution and ecotoxicological risks.

Known as burgeoning contaminants, the bioavailability of rare earth elements (REEs) can be determined using diffusive gradients in thin films (DGT). As Daya Bay (South China) has been under serious anthropogenic influences, the present study examined the distribution of REEs in surface sediments and their possible ecological risks in the bay. The range of DGT-labile concentrations of REEs (∑REEs) was from 5.67 µg/L to 8.41 µg/L, with an average of 7.34 µg/L. Results of assessment of single REE toxicity revealed that the risk quotient (RQ) values of Y, Ce and Yb were >1, indicating that their potential negative impacts on the nearby environment. However, analysis of the integral toxicity of REE mixtures through assessment of probabilistic ecotoxicological risks showed that there was a negligibly low probability of toxicity of PRE surface sediments to aquatic organisms in the study area.

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%).

Appraising ecotoxicological risk of mercury species and their mixtures in sediments to aquatic biota using diffusive gradients in thin films (DGT).

Mercury (Hg) is a global, persistent and inevitable pollutant, the toxicity of which is mostly reflected in its species including inorganic Hg (InHg) and methyl mercury (MeHg). Using diffusive gradients in thin films (DGT) is deemed as a reliable technique to determine the bioavailability of pollutants. This study is the first attempt to assess the integrated toxicity of mercury species mixtures in sediments to the aquatic biota based on the DGT technique. In the course, the Daya Bay under serious anthropogenic influences was selected as the study case. The results showed that the DGT concentrations of InHg and MeHg were detected as 0.30-1.93 µg/L and 0.28-1.94 µg/L respectively in the surface sediments collected from the Daya Bay. In terms of the toxicity of single mercury species, the risk quotient (RQ) values of InHg and MeHg significantly exceeded 1, indicating that the adverse effects of InHg and MeHg should not be ignored. In terms of the integrated toxicity of mercury species mixtures, the probabilistic biological risk assessment results demonstrate that Daya Bay features low (3.32%) probability of toxic effects in its surface sediments to the aquatic biota.

Rare earth elements in different trophic level marine wild fish species.

The presence of rare earth elements (REEs) in different trophic levels of wild fish species remains unknown. In this study, fish characteristics and distribution patterns of REEs at different trophic levels of wild fish species are studied for the first time. The northern coastal region of the South China Sea was selected as it has the highest fishing intensity in China. The concentrations of 15 REEs were measured in 14 marine wild fish species from this area. The total concentrations of REEs (ΣREEs) ranged from 1.02 to 178.55 µg/kg (wet weight). The average ratio of light REE (LREE) to heavy REE (HREE) was 13.04, indicating that the ∑REEs content was dominated by LREE. The distribution patterns demonstrated significant bioaccumulation of LREEs. The REE patterns of most of the fish species showed Ce, Gd, Tb, and Dy anomalies. Based on the estimated daily intake (EDI) levels, the consumption of these fish species poses a negligible risk to consumer health.