Heavy metal(loid)s in multiple media within a mussel mariculture area of Shangchuan Island, China: Partition, transfer and health risks.

Limited research has been conducted on the heavy metal (loid) (HM) exchanges among seawater, sediments and cultured mussels in mariculture areas. To determine the impacts of mussel mariculture on the transfer and risks of HMs in coastal environments, samples of seawater, sediments and cultured mussels from a typical mariculture area in the South China Sea were analysed. The logarithmic partition coefficients of sediment/water indicated that HMs were preferentially retained by sediments. There were relatively low ecological risks in mussel raft mariculture areas. Principal component analysis and correlation analysis revealed the influences of terrestrial input and ocean circulation on the HMs in seawater, and the bioaccumulation factors reflected the possible accumulation of HMs in seawater by cultured mussels. Mussel farming was the indirect source of HMs in sediments, and the biochemical processes of cultured mussels promoted the transfer and accumulation of HMs into sediments. Health risk assessment revealed that children were more susceptible than adults, and Cd, As and Cr were among the threatening elements. Nonetheless, the health risks that were possibly caused by the daily consumption of farmed mussels were still within safe limits. Thus, the potential pollution remediation and biomonitoring functions of mussel aquaculture in coastal water environments will be further studied in the future.

Responses of microeukaryotic community structure to a Phaeocystis globosa bloom in a semi-enclosed subtropical bay.

The occurrence of Phaeocystis globosa, a harmful algal bloom species in Chinese coastal waters, has significant impacts on marine organisms and poses a threat to the safety of coastal nuclear power plants. Although previous studies have established a close association between P. globosa blooms and the bacterial community, the relationship between the microeukaryotic community and P. globosa blooms remains poorly understood. In this study, the variations in the microeukaryotic community resulting from a P. globosa bloom were analyzed using 18S rRNA gene amplicon sequencing. The results indicated that the diversity of the microeukaryotic community during the bloom phase was significantly higher than that during the dissipation phase. The microeukaryotic community compositions varied significantly between the two phases of the P. globosa bloom. During the bloom phase, the dominant microeukaryotic was Viridiplantae, which was then replaced by Dinoflagellata during the dissipation phase. Co-occurrence network analysis showed that the relationship among the microeukaryotic community during the bloom phase was more complex than that during the dissipation phase, and the keystone taxa varied as the bloom progressed. Additionally, microeukaryotic community assembly was primarily driven by stochastic processes during the bloom phase based on the ß-nearest taxon distance, whereas it was driven by both deterministic processes and stochastic processes during the dissipation phase. Overall, our findings provide novel insight into the mechanisms and interactions involved in microeukaryotic community dynamics in environments disturbed by P. globosa blooms.

Source apportionment and human health risk of PAHs accumulated in edible marine organisms: A perspective of "source-organism-human".

Most PAHs produced by human activities can be absorbed and accumulated by edible organisms and pose a potential hazard to human health. However, the source apportionment and human health risk of PAHs accumulated in edible organisms remains largely unknown. Therefore, we conducted source analysis and health risk assessment based on the PAH concentrations in ten marine fish from coastal areas of Guangdong, China. Results showed that the pollution of PAHs in fish organisms was at "Minimally polluted" level, and that all marine fish had the ability to accumulate PAHs. Risk assessment indicated Carcinogenic risk of PAHs in four populations was at a "Cautionary risk" level, with urban children suffered the highest risk. Petroleum pollution, Coal and biomass combustion, and Marine transport emissions were identified as the main anthropogenic sources for PAHs in organisms, and Marine transport emissions accounted for the highest Carcinogenic risk. The Acceptable daily intake for all populations were far below their actual daily intake without causing "Cautionary risk". Our findings provide new insights into the source apportionment and health risk of PAHs from a "source-organism-human" perspective, and suggested that joint management of three anthropogenic sources would be an effective way to prevent the health risks of PAHs.

Coastal sediment heavy metal(loid) pollution under multifaceted anthropogenic stress: Insights based on geochemical baselines and source-related risks.

Contamination and risk assessments generally ignore the potential bias in results caused by the variation of background values at different spatial scales due to the spatial heterogeneity of sediments. This study aims to perform quantitative source-ecological risk assessment via establishing geochemical baselines values (GBVs) of heavy metal(loid)s (HMs) in Daya Bay, China. Cumulative frequency distribution (CFD) curves determined the GBVs of 12.44 (Cu), 30.88 (Pb), 69.89 (Zn), 0.06 (Cd), 47.85 (Cr), 6.80 (As), and 0.056 mg kg-1 (Hg), which were comparable to the background values of Guangdong Province surface soils, and implied a potential terrestrial origin of the coastal sediments. Principal component analysis (PCA) and positive matrix factorization (PMF) identified three sources (F1: natural processes; F2: anthropogenic impacts; F3: specific sources) with contributions of 51.7%, 29.2%, and 19.1%, respectively. The source-specific risk assessment revealed an ecological risk contribution potential of 73.8% for the mixed anthropogenic sources (F2 + F3) and only 26.2% for natural processes. Cd and Hg were the priority management of metallic elements, occupying 63.5% and 72.5% of the contribution weights of F2 and F3, respectively, which showed multi-level pollution potentials and ecological risk levels. The spatial distribution patterns demonstrated the hotspot features of HM pollution, and priority concerns should be given to the management of marine traffic and industrial point source pollution in Daya Bay. The results of the study provide a scientific approach and perspective for pollution treatment and risk management in the coastal environment.

[Characteristics, Source Analysis, and Health Risk Assessment of Polycyclic Aromatic Hydrocarbons (PAHs) Pollution in Marine Organisms from Estuaries of Changhua River in Hainan Province].

To assess the contamination by polycyclic aromatic hydrocarbons (PAHs) in organisms in the estuary of Changhua River in Hainan, we determined the content of 16 priority PAHs by gas chromatography and mass spectrometry (GC-MS). The composition, source, and potential edible risk of PAHs were studied. The results showed that the total PAHs of demersal fish (wet weight, same below), crustaceans, and pelagic fish were 5.52-787.98, 12.18-154.64, and 10.20-199.79 ng·g-1, respectively, and the average contents were 83.21, 64.72, and 89.48 ng·g-1, respectively. There were some differences in the content of PAHs in various organisms. The average content followed the order of pelagic fish > demersal fish > crustaceans. Compared with other areas in the country and abroad, the content of marine organisms'PAHs in the estuary of the Changhua River was above the medium level. The result of isomer characteristic ratio showed that the PAHs of 33 organisms mainly came from the combustion sources (petroleum combustion and biomass combustion) and petroleum sources. Moreover, demersal fish were greatly affected by combustion sources, while pelagic fish were greatly affected by petroleum sources. Human risk assessment indicated that the content of benzopyrene (BaP) was within the limits set by the European Union. Most of the organisms in the estuary of Changhua River were within the safe range of consumption, but the long-term consumption of these seafoods may pose a potential health risk (1.0×10-5≤ILCR<1.0×10-4).