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As emerging pollutants, the environmental geochemistry of organophosphate esters (OPEs) in the coastal zone with multiple functional areas are still less recognized. This study investigated spatiotemporal distribution, sources and risks of 11 widely used OPEs in surface waters from seagoing rivers and multiple coastal functional areas of the Beibu Gulf. The results indicated that significantly higher ∑

Heavy metal pollution is a serious environmental problem in the marine ecosystem. Thereinto, marine transportation activities have gradually become an important source of heavy metals in seawater. However, the lack of studies on the temporal dynamics of seawater heavy metals in marine shipping areas has hindered our understanding of the sources and transport mechanisms of heavy metals in seawater of hectic shipping waters. Therefore, we investigated the interannual resolution variation of heavy metals in Porites lutea skeletons during the past 32 years under the rapid development of the shipping sector near Weizhou Island from the northern South China Sea. Results show that most heavy metal concentrations with higher coefficients of variation (≥100 %) in the Porites coral skeletons were higher than those in the uncontaminated or less anthropogenic waters. The results of principal component analysis and multiple linear regression showed that the interannual variations of Ni, V, Cr, Co, Zn, Cu, Mn, Fe and Mo were mainly impacted by marine oil extraction and oil spills generated by shipping activities, accounting for 51.58 %. The effect of sea surface temperature accounts for 13.44 %, and controls the interannual variations of Ba and Sr. The effect of industrial pollution accounts for 13.27 %, and explains the interannual variations of Cd and Y. The fuel consumption of marine shipping accounted for 8.76 %, explaining the interannual variations of Pb. The total contribution of anthropogenic activities reached 73.61 %. The interannual variation of heavy metals indicates that hectic marine shipping activities are the dominant cause of Ni, V, Pb, Cr, Co, Zn, Cu, Mn, Fe and Mo input to surface seawater around Weizhou Island. This provided valuable data for understanding the temporal dynamics and potential sources of heavy metals in the marine environment by using coral skeletons as a high-resolution recording vehicle.

As a natural laboratory for testing various paleoclimatological and paleoceanographic hypotheses, the Pliocene-Pleistocene stratigraphic sequence from a full-coring major scientific drilling (Well CK2 with total length: 928.75 m) in Yongle atoll of Xisha Islands, northern South China Sea was studied. The Petrography of studied section of the core was dominated by reef carbonate limestones which contain abundant shallow marine organisms, e.g., coralline algae, corals, and foraminifera, which almost consisted of pure carbonates and preserved the primary geochemical message since Pliocene. According to the isolation of Well CK2 and the provenance of elements, the systematic changes and abrupt points of isotope and element geochemical compositions (rare earth element parameters, SiO2 content, Al/Ti ratio, etc.) from coral reef carbonate record presented the elevated terrigenous influences related to the East Asian monsoon after ~2.6 Ma BP, as part of the Pliocene-Pleistocene climate transition. Our results demonstrated that the continental weathering controlled by the East Asian summer monsoon dominated the surface seawater compositions of study area before ~2.6 Ma BP, when the winter monsoon was not strong enough to exert significant influences. Then, the effects of eolian dust associated with the intensity of East Asian winter monsoon, the precipitation driven by summer monsoon, and the global temperature, which played different roles at different periods after ~2.6 Ma BP, should be considered. Our results confirmed that the potentials and significances of shallow-water carbonate deposition from coral reefs, and provided a unique perspective to shed light on the carbonate record of climate changes.

As one of the most abundant metals in heavy oils, Ni has suffered so notably increasing impacts from industrial and traffic activities that anthropogenic Ni emissions have altered natural geochemical processes. The coral Ni/Ca has become a reliable proxy for characterizing marine pollution, but this potential has been unexploited for highlighting oil pollution. Here, we utilized a high-resolution record of geochemical parameters (Ni/Ca, δ18O, and δ13C) in a Porites coral of an offshore island in the northern South China Sea to reconstruct of Ni distribution patterns in surface seawater from 1984 to 2015. The coral Ni/Ca ratios exhibit minor fluctuations, except for multiple mutation peaks (0.20 ± 0.42 μmol/mol) during the period from 1984 to 1993. The ratio was low and stable (0.10 ± 0.09 μmol/mol) from 1994 to 2008, and then increased rapidly with significant variations (1.60 ± 4.56 μmol/mol) from 2009 to 2015. The coral Ni/Ca ratios captured all significant Ni discharges, and this demonstrates its potential for recording oil spill episodes. The historical variations in the contributions of Ni indicate that industrial and traffic activities should be responsible for changes in the anthropogenic input. The leaks and consumptions of petroleum likely account for the primary Ni emission sources.

As a kind of tropical agricultural solid waste, cassava dregs had become a thorny nonpoint source pollution problem. This study investigated the feasibility of applying cassava dregs as a substitute for sucrose in biofloc technology (BFT) systems. Three types of biofloc systems (using three different carbon sources sucrose (BFT1), cassava dregs (BFT2) and enzyme-hydrolyzed cassava dregs (BFT3) respectively), and the control were constructed in this experiment in 200L tanks with a C/N ratio of 20/1. The comparison of the water quality indicators (The total ammonia nitrogen (TAN), nitrite (NO2--N), nitrate (NO3--N), chemical oxygen demand (COD)), biofloc for the above four groups was performed, and the results indicated that BFT3 showed greater potential to the formation of biofloc, which was beneficial for the water quality control. So the shrimp survival rate was the highest and the feed conversion rate was the lowest in BFT3. Besides, the high-throughput sequencing results showed that the relative abundance of heterotrophic bacteria in the top 30 dominant microbial communities in BFT3 was higher than those in BFT1 and BFT2 by 20.70% and 1.19%, respectively, which could decrease TAN to improve the water quality. Overall, the results had proved that the cassava dregs of enzymes hydrolysis could be used as an ideal and cheap carbon source in BFT.

Laboratory research has indicated that antibiotics had negative effects on coral growth by disturbing natural microbiota; however, no field studies have reported antibiotic contamination levels and their influence on coral growth in natural coral reef regions (CRRs). This study investigated antibiotic occurrence and sources in the surface water from CRRs that have suffered from rapid coral degradation and evaluated their risk to coral growth. These regions are in the South China Sea, including four coastal and two offshore CRRs. The results show that 13 antibiotics were detected in the coastal CRRs with concentrations ranging from 10−2–100 ng L−1, while 5 antibiotics occurred in offshore CRRs (300–950 km from the mainland), with concentrations ranging from 10−2 to 10−1 ng L−1. Their concentrations decreased gradually from the coast to offshore in the transport process. However, Yongxing Island, which is approximately 300 km from the mainland, was an exception with relatively higher concentrations than the surrounding reefs because of the ever-increasing human activity on the island. The presence of anthropogenic contaminants antibiotics in CRRs may be a potential risk to coral growth.

The contamination profiles of sixteen perfluoroalkyl substances (PFAS) were examined in coral reef fish samples collected from the South China Sea (SCS) where no information about this topic was available in the literature. The results revealed that six PFAS were found in coral reef fish samples from the SCS. Perfluorooctane sulfonate (PFOS) was the most predominant PFAS contaminant detected in most of the samples, with the highest concentration value of 27.05 ng/g wet weight (ww) observed in Cephalopholis urodelus. Perfluoroundecanoic acid (PFUnDA) and Perfluorotridecanoic acid (PFTrDA) were the second and third dominant PFAS, respectively. Mean PFOS concentrations in muscle of seven coral reef fish varied from 0.29 ng/g ww in Lethrinus olivaceus to 10.78 ng/g ww in Cephalopholis urodelus. No significant linear relationship was observed between PFOS levels and coral reef fish traits (length, weight) collected in this region. Average daily intake of PFOS for the seven coral reef fishes ranged from 0.79 ng/kg/d for Lethrinus olivaceus to 29.53 ng/kg/d for Cephalopholis urodelus. The hazard ratio (HR) values for human consumption of PFOS-contaminated coral reef fishes ranged from 0.04 to 1.48, with Cephalopholis urodelus having the highest HR value of 1.18 (higher than 1) among the species, indicating frequent consumption of Cephalopholis urodelus might pose potential health risk to local population. The present work have provided the first hand data of PFAS in coral reef fishes in the SCS and indirectly demonstrated the existence of low level PFAS pollution in the SCS in China.

International audience; In this research, magnetite and ethylenediamine-N,N'-disuccinic acid (EDDS) are used in a heterogeneous photo-Fenton system in order to find a new way to remove organic contaminants from water. Influence of different parameters including magnetite dosage, EDDS concentration, H2O2 concentration, and pH value were evaluated. The effect of different radical species including HO(·) and HO2(·)/O2(·-) was investigated by addition of different scavengers into the system. The addition of EDDS improved the heterogeneous photo-Fenton degradation of bisphenol A (BPA) through the formation of photochemically efficient Fe-EDDS complex. This effect is dependent on the H2O2 and EDDS concentrations and pH value. The high performance observed at pH 6.2 could be explained by the ability of O2(·-) to generate Fe(II) from Fe(III) species reduction. GC-MS analysis suggested that the cleavage of the two benzene rings is the first degradation step followed by oxidation leading to the formation of the benzene derivatives. Then, the benzene ring was opened due to the attack of HO(·) radicals producing short-chain organic compounds of low molecular weight like glycerol and ethylene glycol. These findings regarding the capability of EDDS/magnetite system to promote heterogeneous photo-Fenton oxidation have important practical implications for water treatment technologies.

A novel gas sensor composed of Pt nanoparticles-decorated hierarchical SnO2 nanostructures (Pt–SnO2) was synthesized via a facile dipping-precipitation strategy. Pt nanoparticles with small sizes (avg. 4 nm) were successfully dispersed onto our pre-synthesized 3D hierarchical SnO2 nanoflowers supports by using lysine as both capping and linking agents. The morphology, structure and composition of the as-prepared samples were characterized by means of field-emission scanning electron microscopy (FESEM), X-ray diffraction (XRD), transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS). Comparisons of the gas sensing performance between pure SnO2 and Pt–SnO2 nanocomposites revealed that after supporting Pt nanoparticles, the decorated sensor not only got an optimal working temperature of as low as 100 °C, but also exhibited faster response and recovery speeds and higher response than the pristine one at such low temperature. Moreover, good selectivity and excellent stability were also shown for the hybrid sensor. Sensing mechanisms were illustrated to help explain the strong spillover effect of the Pt nanoparticles and the Schottky barriers at the interface of metal and semiconductor, both of which facilitated the low temperature sensing performance. The Pt–SnO2 sensors are considered to be a promising candidate for trace environmental gas detections in practical use.

Scleractinian corals provide an excellent archive of geochemical proxies that allow the reconstruction of the oceanographic and climatic changes in the oceans. However, limited knowledge regarding the distribution coefficients (D) of trace metals between coral lattices and seawater has complicated efforts to obtain accurate quantitative data for seawater chemistry. Here we estimated the D values of five trace metals (Cu, Zn, Pb, Cd and Cr) for three coral species (Favia palauensis, Porites lutea, and Pavona decussata) and in situ seawater around Weizhou Island in the northern South China Sea. Despite several variations that could not be explained solely by species, our results were within the approved ranges of the previous reported estimates, and provide the most accurate D values for the these species to date. We also focused on the possible effects of surface seawater temperature (SST) on D vaules, finding no significant relationship. Nevertheless, the effects of SST, which could impact the distribution behavior of trace metals (especially Cd) should be paid more attention in the context of global climate change. The more precise D values for corals provided here represent important basic data for future research on coral reefs and expanded our knowledge of chemical signatures in biogenic lattices with regard to ocean composition.

The stabilization of heavy metals (zinc and chromium) and the degradation of organic pollutants during supercritical water (SCW) and supercritical water oxidation (SCWO) treatment of electroplating sludge (EPS) with a high iron content were studied. Experiments were performed in a batch reactor at temperatures in the range from 623.15 to 823.15 K with an oxygen coefficient (OE) from 0 to 2.0, a reaction time of 7 min and pressure of 25 MPa to examine the effect of the operation conditions. Chemical oxygen demand (COD) and total organic carbon (TOC) in raw sludge and liquid products under different reaction conditions were detected. The results indicated that more organic pollutant degradation occurred under supercritical conditions than in subcritical water. Additionally, as the temperature and amount of oxidant increased, the organic pollutant removal rate increased. In addition, the Zn and Cr removal efficiency from sludge was more than 98% under all conditions. Temperatures under 773.15 K had a positive effect, whereas the oxygen ratio was more significant than the other factors above 773.15 K. Furthermore, leaching toxicity tests of the heavy metals in solid products were conducted based on the toxicity characteristic leaching procedure (TCLP). All heavy metals showed greatly reduced leaching toxicity due to their stabilization. The Zn in the EPS is more easily converted into a solid product after SCWO treatment; however, Cr is more difficult to leach from the solid product. Oxides of iron, zinc, and chromium were detected by X-ray diffraction and an electron probe microanalyzer, and the yield of the oxides increased with increasing temperature and oxidant amount. Using the obtained data and analysis results, the effect of Fe on the stabilization of Zn and Cr was studied.

One-dimensional (1D) SnO2-coated ZnO nanowire (SnO2/ZnO NW) N-N heterojunctions were successfully constructed by an effective solvothermal treatment followed with calcination at 400 °C. The obtained samples were characterized by means of XRD, SEM, TEM, Scanning TEM coupled with EDS and XPS analysis, which confirmed that the outer layers of N-type SnO2 nanoparticles (avg. 4 nm) were uniformly distributed onto our pre-synthesized n-type ZnO nanowire supports (diameter 80~100 nm, length 12~16 μm). Comparisons of the gas sensing performances among pure SnO2, pure ZnO NW and the as-fabricated SnO2/ZnO NW heterojunctions revealed that after modification, SnO2/ZnO NW based sensor exhibited remarkably improved response, fast response and recovery speeds, good selectivity and excellent reproducibility to n-butylamine gas, indicating it can be used as promising candidates for high-performance organic amine sensors. The enhanced gas-sensing behavior should be attributed to the unique 1D wire-like morphology of ZnO support, the small size effect of SnO2 nanoparticles, and the semiconductor depletion layer model induced by the strong interfacial interaction between SnO2 and ZnO of the heterojunctions. The as-prepared SnO2/ZnO NW heterojunctions may also supply other novel applications in the fields like photocatalysis, lithium-ion batteries, waste water purification, and so on.

One-dimensional (1D) SnO2-coated ZnO nanowire (SnO2/ZnO NW) N-N heterojunctions were successfully constructed by an effective solvothermal treatment followed with calcination at 400 °C. The obtained samples were characterized by means of XRD, SEM, TEM, Scanning TEM coupled with EDS and XPS analysis, which confirmed that the outer layers of N-type SnO2 nanoparticles (avg. 4 nm) were uniformly distributed onto our pre-synthesized n-type ZnO nanowire supports (diameter 80~100 nm, length 12~16 μm). Comparisons of the gas sensing performances among pure SnO2, pure ZnO NW and the as-fabricated SnO2/ZnO NW heterojunctions revealed that after modification, SnO2/ZnO NW based sensor exhibited remarkably improved response, fast response and recovery speeds, good selectivity and excellent reproducibility to n-butylamine gas, indicating it can be used as promising candidates for high-performance organic amine sensors. The enhanced gas-sensing behavior should be attributed to the unique 1D wire-like morphology of ZnO support, the small size effect of SnO2 nanoparticles, and the semiconductor depletion layer model induced by the strong interfacial interaction between SnO2 and ZnO of the heterojunctions. The as-prepared SnO2/ZnO NW heterojunctions may also supply other novel applications in the fields like photocatalysis, lithium-ion batteries, waste water purification, and so on.

Passive air samplers (PAS) were deployed concurrently at 15 locations (nine urban sites and six rural sites) in Vietnam and exposed for approximately 6 weeks from June 26, 2012 to August 26, 2012 and from December 8, 2012 to February 8, 2013. The concentration, composition and enantiomeric signatures of the target compound and Air Mass Backward Trajectories of the 15 sampling sites are presented and discussed in this study. Relatively clean air mass from ocean and similar concentrations and composition of POPs between the south and north of Vietnam indicate that local emissions is most likely the major source of POPs in Vietnam. Technical DDT and technical HCH were widely used in Vietnam and corresponding quantitative data suggests the sporadic use. The preferential degradation of (+)-α-HCH was found in all sampling sites, which could be a regional characteristic of Vietnam. High trans-/cis-chlordane (TC/CC) ratios indicate the current use of technical chlordane for termite control. PCA estimated that main source of PCBs present in the atmosphere of Vietnam was uncontrolled discarded e-waste.