Selected trace elements (As, Cr, Zn, Cu, Cd, Co, Pb and Ni) in 76 surface sediment samples collected from the rivers and the intertidal zone of Jiaozhou Bay (JZB) were evaluated to assess their environmental background values in the JZB catchment. Overall, the sediment quality in the area meets the China Marine Sediment Quality criteria. The background values (ranges) of the elements As, Cr, Zn, Cu, Cd, Co, Pb and Ni were, respectively, 8.28 (4.10–12.46), 67.96 (38.40–97.52), 56.80 (16.42–196.51), 19.13 (5.71–64.06), 0.10 (0.02–0.42), 6.51 (2.08–20.40), 17.97 (12.26–55.84) and 20.69 (10.43–30.95)mg/kg. The background values of most of the trace elements were lower than those in Chinese soil, the upper continental crust, global shales and global preindustrial sediments. The results may assist in defining future coastal and river management measures specifically targeted at monitoring trace element contamination in the JZB catchment.

PURPOSE OF REVIEW: Mangroves are under increasing heavy metal (HM) pollution pressure from human activities because of the rapid industrialization and urbanization in coastal areas. Field and laboratory experiments showed that the tolerance of mangrove plants to HM stress is normally a mixture of metal avoidance and scavenging of reactive oxygen species (ROS). In this review, related studies during the past few decades on the accumulation and tolerance of mangrove to HMs have been synthesized. RECENT FINDINGS: In mangroves, metal accumulation mainly occurred at the root level with restricted transport to the aerial portions of the plant. The common founded HMs, such as copper, zinc, cadmium, chromium, and mercury, generally showed high bioconcentration factor in roots, while the concentration factors for these metals in leaves were usually much lower than one. The limited translocation of the toxic metals to the aerial parts renders the mangrove plants a high endurance ability to high levels of HM stress. To protect the cellular components from oxidative damage by HMs, mangroves have developed both enzymatic and nonenzymatic antioxidant mechanisms to scavenge the ROS. In some circumstances, the changes of antioxidative enzyme activity were usually in accordance with the changes of toxic metal concentrations in plant tissues. However, the responses of antioxidative enzymes in mangroves to HM stress varied with plant species, metal type, and concentration, as well as the duration of the treatment time. More toxicity tests are needed with early life stages of mangroves to determine threshold effect concentrations under more realistic conditions.

To date, very little or no data exist in literature for some brominated flame retardants (BFRs) and polychlorinated biphenyls in Queensland sediments. These pollutants were measured in the sediments along the Brisbane River estuary. The target compounds were regularly detected in measurable concentrations: PBDEs=33.3–97.8% (n=45), PCBs=94.1–100% (n=51) and HBCDs=79–98% (n=48). Consistently, >90% of the observed ∑8PBDE concentration was attributed to BDE-209. Mean PBDE levels (ng/g dry wt.) were: 4.4±3.2 (∑8PBDE) and 4.4±3.0 (BDE-209) across 22 sampling sites. The mean ∑7PCB and ∑HBCD were 5.4±4.5 and 1.0±1.5ng/g dry wt. respectively. The 25% (α-HBCD), 8% (β-HBCD) and 67% (γ-HBCD) diastereoisomer contributions observed were consistent with values reported in the literature. Contaminant levels are fairly distributed along the River and were generally low compared to similar studies around the world.

Eutrophication causes the major impact in the coastal waters of the state of Yucatan. In general, loss of water quality and biological communities and massive development of toxic microorganisms are some of the consequences of this phenomenon. To reveal changes in species composition and cell abundance of the taxocoenosis of epibenthic dinoflagellates before and after a harmful algal bloom event in the water column that lasted about 150days (August–December 2011) in the Dzilam – San Crisanto area (northern Yucatan Peninsula, southeastern Gulf of Mexico) were the main objectives of the present study. In August 2011 and September 2012, sampling along 20 transects perpendicular to the coastline along the entire northern Yucatan coast, starting from 20 sampling sites from El Cuyo in the east to Celestún in the west, at a distance of 50, 150 and 250m from the coast, was carried out. Physicochemical characteristics measured before and after the bloom were within the ranges previously reported in the study area. Salinity was the most stable characteristic, with mean values of 36.25 and 36.42 in 2011 and 2012, respectively. Phosphates were the only parameter that showed a wide range with higher values before the bloom (0.03–0.54μM/l). A total of 168 macrophyte (seaweeds and seagrasses), sponge and sediment samples (105 in 2011 and 63 in 2012) that included associated microphytobenthos were taken by snorkeling from 0.7 to 5m depth. Six substrate types were distinguished: Chlorophyta, Phaeophyceae, Rhodophyta, Angiospermae (seagrasses), Demospongiae (sponges) and sediment. Chlorophytes dominated the collected samples: 38 samples in 2011 and 23 in 2012. Avrainvillea longicaulis f. laxa predominated before the bloom and Udotea flabellum after it. In total, 25 epibenthic dinoflagellate species from 11 genera were found. The genus Prorocentrum was the most representative in terms of the number of species. The highest total dinoflagellate cell abundances were observed in the sites with different types of macrophytes (up to 2441cells/g substrate wet weight in 2011 and up to 1068cells/g in 2012). The lowest cell densities were observed in the areas with scarce or no macrophytes on sandy seafloor. Before the bloom, Prorocentrum rhathymum (up to 4995cells/g) and P. cf. sipadanensis (up to 5275cells/g) were the most abundant, and after the bloom the latter was dominant (up to 3559cells/g); in 2012, both variety of substrates and dinoflagellate cell abundance diminished. A canonical correspondence analysis revealed significant relationships between the physicochemical variables and epiphytic/benthic dinoflagellate species either before or after the bloom. The pelagic bloom resulted in the loss of substrate for epiphytic dinoflagellates, which caused replacement of the dominant species and a decrease in cell abundance of the whole taxocoenosis.

Elevation in toxic trace metal concentration found in coastal sediments in recent years (2013–2016) increased the risk to the aquaculture industry in south Hangzhou bay. This study assessed the main factors controlling the metal distribution and mobility in sediments by sampling from 20 sites along the bank. Spatial distribution and cluster analysis indicated that Cd, As, Hg and Sb attributed to anthropogenic terrestrial sources; while Cr, Co, Cu, Ni, Zn, and Pb, carried by fine-grained sediments and accumulated on tidal flat, were inputted from marine sources. High mobility of Cd was expected because of its considerable proportion (~50%) associated with the acid extractable fraction. Pb, Cu and Co in redox sensitive fraction should also be taken into concern in management of reclaimed area affected by tide. Risk assessments by potential ecological risk index (PERI) emphasised the importance of further monitor and proper treatment of 4 terrestrial generated metals in sediments.

The present experimental study was to characterize the adsorption behavior of 17 α-ethyl estradiol (EE2) onto marine sediment in both the single and binary solute systems. Stepwise spiking was innovatively performed to better understand the competition effects. Adsorption of EE2 on the marine sediment can be well fitted by the Freundlich model with an affinity coefficient (KF) varying from 15.8 to 39.8L/kg. It was significantly influenced by SOM and the particle properties. Co-presence of BPA brought about a significant competition effect on the adsorption of EE2, leading to a reduced EE2 adsorption. The competitive effect imposed by EE2 to BPA, however, was even more serious owing probably to the large molecular structure and high hydrophobicity of EE2. The sediment sample with the highest SOM and SSA presented a mild competition effect, while the sediment with the lowest SOM and largest particle size exhibited the most serious competition effect.

The concentrations of 16 metals were assessed in snoek(Thyrsites atun; n=20) and yellowtail (Seriola lalandi; n=37) sampled from the West and South-East coasts of South Africa. Variability was observed at both small (Al, Cr, Hg, Pb, Mn and Cu) and large (As and Cu) spatial scales while inter-specific examination revealed diverse metal concentrations in snoek (Higher levels: Cr, Mn, Co, Hg and Pb) and yellowtail (higher levels: Fe and Cu). Zn, As and Hg were positively correlated with yellowtail size with no such correlations in snoek. Mean concentrations of As (0.61mg·kg−1; 0.98mg·kg−1), Cd (0.008mg·kg−1; 0.004mg·kg−1), Hg (0.27mg·kg−1; 0.16mg·kg−1) and Pb (0.009mg·kg−1; 0.005mg·kg−1) for snoek and yellowtail respectively were within regulatory guidelines. However, 10% (n=2) of snoek exceeded Hg maximum allowable limit, suggesting caution and further investigation. Overall, two meals (150g) per week of snoek or larger yellowtail (12–15kg) can be safe for human (adult) consumption.

The aim of the present study was to evaluate the hazard from shipwrecks on communities by a holistic approach taking into account different effects on biological communities. Multibeam and Remotely Operated Vehicles surveys recorded ecological assessment of fish and benthic species on three shipwrecks flooded during the Second World War on Maërl beds habitats in the strait of Sicily. Pollution levels of a wide range of chemicals of ecotoxicological concern were also measured in sediments and in fish species from different trophic levels. Statistical analysis evidenced significant differences among pollutant levels between both sediments and fish collected in shipwreck sites and controls. Concerning fish, significant effects due to the vessel's cargo type and flooding position are recorded. In spite of that, our results underline that shipwrecks are also a hotspots of biodiversity and a habitat for preservation strategies in marine ecosystems that need to be monitored.

The Environmental Protection Agency (USEPA) has identified Benzene, Toluene, Ethylbenzene, and Xylene (BTEX) as hazardous air pollutants. In this study, BTEX sampling was conducted at 20 sites during summer 2015 and winter 2016 in Yazd. Concentrations of BTEX were analyzed using a gas chromatograph with a flame ionization detector (GC-FID). In addition, ozone formation potential (OFP) and the health risks of BTEX were calculated. Spatial mapping was accomplished using the Kriging method. The obtained concentrations of total BTEX ranged from 8 to 560 μg/m3. The highest average individual values belonged to toluene and xylene (38 ± 42 and 41 ± 45 μg/m3, respectively). Seasonal variation showed a downward trend from summer to winter. The peak BTEX emissions occurred in the evenings, due to rush hour traffic and meteorological factors. Spatial analysis showed that the maximum levels of BTEX occurred on high traffic roads or near fuel stations. Significant correlation coefficients between benzene and other BTEX compounds revealed that BTEX were emitted from main sources including gasoline vehicles and stations. The mean ratio of toluene/benzene (T/B) in summer (1.8) was more than winter (1.4). The seasonal changes in T/B ratio possibly were attributed to photochemistry, meteorology, and emission aspects. The OFP values were 720 ± 729 and 375 ± 319 μg/m3 in summer and winter, respectively. OFPs, ranked maximum to minimum, were as follows: xylene > toluene > ethylbenzene > benzene. Although the values of the non-cancer risk of BTEX were under permissible recommended level, a cancer risk still exists because of high values of airborne benzene.

This study tested robustness of mathematically defined species sensitivity with manipulation of disturbance gradient coverage by datasets on two different pressures and two depth zones of the central Baltic Sea. The results indicate large differences of sensitivity values for the same species when depth range changed. After addition of samples from impacted sites to the control datasets, estimated sensitivity values decreased for half of analysed species. Sensitivity of tolerant species appeared to be highly dependent on the coverage of disturbance gradient by the dataset, while sensitive species were highly robust to this effect. Although pressure type and coverage of disturbance gradient by the dataset was important, sensitivity changes were primarily linked to the altered environmental conditions. It is suggested that sensitivity values based on natural variability of pre-selected communities will better integrate the role of important environmental factors and increase robustness of discrimination between disturbed and undisturbed sites.