Surface sediments from intertidal Bohai Bay were sampled for the geochemical and environmental assessment of six trace metals (Cd, Cr, Cu, Ni, Pb and Zn). Results indicate that sediment grain size plays an important role in controlling the distribution and fractionation of them. Metal concentrations in clayey silt sediments are all clearly higher than in sand and silty sand ones. Cd and Pb in clayey silt sediments are more mobile than in sand and silty sand ones. Two sediment quality guidelines and two geochemical normalization methods (index of geoaccumulation and enrichment factor) were used to judge the potential risk and accumulation of metals. According to the mean probable effects level quotient, the combination of studied metals may have a 21% probability of being toxic. The sediments with high fraction of clay and silt have been contaminated by trace metals to various degrees, among which Cr contributes the most to contamination.

Fish accumulate several trace elements in muscle, gills and liver, however studies also indicate that metals can be excreted through bile. Since metal contamination leads to modifications in bile composition, biliary excretion offers an alternative way to evaluate the presence of trace-elements. Bile is easier to obtain than other organs and presents a simpler matrix, making it easier for chemical pre-treatment. To verify if bile can be useful as a biomonitoring tool for metal contamination, liver and bile trace element concentrations were determined and correlated. The Artificial Neural Networks statistical technique was used to verify if liver trace-element quantification could be substituted by bile analysis. Results show that significant correlations were obtained between trace elements in bile and liver and the ANN validated the hypothesis that certain trace-elements in bile could be utilized instead of liver trace-elements. Further studies in this field are of interest to further validate this biomarker.

Land use (and land management) change is seen as the primary factor responsible for changes in sediment and nutrient delivery to water bodies. Understanding how sediment and nutrient (or constituent) concentrations vary with land use is critical to understanding the current and future impact of land use change on aquatic ecosystems. Access to appropriate land-use based water quality data is also important for calculating reliable load estimates using water quality models. This study collated published and unpublished runoff, constituent concentration and load data for Australian catchments. Water quality data for total suspended sediments (TSS), total nitrogen (TN) and total phosphorus (TP) were collated from runoff events with a focus on catchment areas that have a single or majority of the contributing area under one land use. Where possible, information on the dissolved forms of nutrients were also collated. For each data point, information was included on the site location, land use type and condition, contributing catchment area, runoff, laboratory analyses, the number of samples collected over the hydrograph and the mean constituent concentration calculation method. A total of ∼750 entries were recorded from 514 different geographical sites covering 13 different land uses. We found that the nutrient concentrations collected using “grab” sampling (without a well defined hydrograph) were lower than for sites with gauged auto-samplers although this data set was small and no statistical analysis could be undertaken. There was no statistically significant difference (p<0.05) between data collected at plot and catchment scales for the same land use. This is most likely due to differences in land condition over-shadowing the effects of spatial scale. There was, however, a significant difference in the concentration value for constituent samples collected from sites where >90% of the catchment was represented by a single land use, compared to sites with <90% of the upstream area represented by a single land use. This highlights the need for more single land use water quality data, preferably over a range of spatial scales. Overall, the land uses with the highest median TSS concentrations were mining (∼50,000mg/l), horticulture (∼3000mg/l), dryland cropping (∼2000mg/l), cotton (∼600mg/l) and grazing on native pastures (∼300mg/l). The highest median TN concentrations are from horticulture (∼32,000μg/l), cotton (∼6500μg/l), bananas (∼2700μg/l), grazing on modified pastures (∼2200μg/l) and sugar (∼1700μg/l). For TP it is forestry (∼5800μg/l), horticulture (∼1500μg/l), bananas (∼1400μg/l), dryland cropping (∼900mg/l) and grazing on modified pastures (∼400μg/l). For the dissolved nutrient fractions, the sugarcane land use had the highest concentrations of dissolved inorganic nitrogen (DIN), dissolved organic nitrogen (DON) and dissolved organic phosphorus (DOP). Urban land use had the highest concentrations of dissolved inorganic phosphorus (DIP). This study provides modellers and catchment managers with an increased understanding of the processes involved in estimating constituent concentrations, the data available for use in modelling projects, and the conditions under which they should be applied. Areas requiring more data are also discussed.

The current status of mercury concentrations in the Gulf of Mexico (GOM) were assessed using the Mussel Watch Program (MWP) contaminant monitoring data, which is based on the analysis of oyster tissue and sediment samples. In both matrices, tHg and MeHg concentrations varied broadly. Significant concentration differences (p<0.05) between the sub-regions of the eastern, central and western Gulf were observed with maximum concentrations (hotspots) found at specific sites all across the Gulf. Compared to the Food and Drug Administration’s action level in seafood, maximum mercury values were low. Based on the long-term MWP data, tHg in tissues show fairly static temporal trends along the central and western Gulf coast, while strong decreasing trends were observed in the eastern Gulf. However, the presence of mercury hotspots indicates that mercury is still a concern in the GOM. The results complement existing information to further the understanding of mercury distributions in the GOM.

The search for alternative indicators of disease-risk from non-enteric pathogens at the beach revealed high densities of targeted bacteria. To explain the high numbers of potential non-enteric pathogens, Staphylococcus aureus and Pseudomonas aeruginosa, in beach sand, we investigated factors affecting their survival and distribution, as well as those of a potential fecal indicator, Clostridium perfringens. Results indicated greater S. aureus and P. aeruginosa survival and proliferation in sterile beach sand, than seawater, with diminished numbers upon exposure to natural micro-predators. C. perfringens remained relatively consistent with initial numbers. Intermediate sand particles (850μm–2mm) constituted the major micro-niche; creating implications for beach classification programs. Colonization of sterile sand boxes at the beach by S. aureus and P. aeruginosa confirmed the filtering action (>100×) of beach sand. The use of these potential pathogens in periodic sanitary evaluation of beach sand quality is indicated, regardless of the factors influencing their abundance.

The occurrence of persistent organic pollutants (POPs) as polychlorinated biphenyls (PCBs), organochlorine pesticides (OCPs) and polybrominated diphenyl ethers (PBDE) in crabs Hepatus pudibundus and Callinectesdanae was assessed from two different places inside of the Santos Bay and Moela Island near one of the most economically important metropolitan areas in Southern Brazil. Among POPs analyzed, ∑PCBs (222–923ngg⁻¹lipid weight) and ∑DDTs (154–410ngg⁻¹lw) exhibited the highest concentrations in the crabs. ∑HCHs ranged from 10.3 to 30.9ngg⁻¹lw and were found in all individuals. Other OCPs found in lower concentration was Mirex (7.6–41.6ngg⁻¹lw) and HCB (5.83–16.9ngg⁻¹lw). ∑PBDEs (24.1ngg⁻¹lw) were only found in one male individual from the species C. danae collected near to the submarine sewage of Santos. Male crabs showed higher POP concentrations than female crabs for those two species.

Photolysis rates of phenanthrene as a function of ionic strength (salinity), oxygen levels and humic acid concentrations were measured in aqueous solution over the range of conditions found in fresh to marine waters. Photolysis followed first order kinetics, with an estimated photodegradation half-life in sunlight in pure water of 10.3±0.7h, in the mid-range of published results. Photolysis rate constants decreased by a factor of 5 in solutions with humic acid concentrations from 0 to 10mgCL⁻¹. This decrease could be modeled entirely based on competitive light absorption effects due to the added humics. No significant ionic strength or oxygen effects were observed, consistent with a direct photolysis mechanism. In the absence of significant solution medium effects, the photodegradation lifetime of phenanthrene will depend only on solar fluxes (i.e. temporal and seasonal changes in sunlight) and not vary with a freshwater to marine environment.

Ballast water exchange processes facilitate the dispersal and unnatural geographic expansion of phytoplankton, including harmful algal bloom species. From 2005 to 2010, over 45,000 vessels (∼8000 annually) travelled across Galveston Bay (Texas, USA) to the deep-water ports of Houston (10th largest in the world), Texas City and Galveston. These vessels (primarily tankers and bulkers) discharged ∼1.2×10⁸metrictons of ballast water; equivalent to ∼3.4% of the total volume of the Bay. Over half of the ballast water discharged had a coastwise origin, 96% being from US waters. Galveston Bay has fewer non-indigenous species but receives a higher volume of ballast water discharge, relative to the highly invaded Chesapeake and San Francisco Bays. Given the magnitude of shipping traffic, the role of Galveston Bay, both as a recipient and donor region of non-indigenous phytoplankton species is discussed here in terms of the invasibility risk to this system by way of ballast water.

The 2010–2011 wet season was one of extreme weather for the State of Queensland, Australia. Major rivers adjacent to the Great Barrier Reef (GBR) were discharging at rates 1.5 to >3 times higher than their long term median. Exposure to photosystem II herbicides has been routinely monitored over a period of up to 5years at 12 inshore GBR sites. The influence of this wet season on exposure to photosystem II herbicides was examined in the context of this long-term monitoring record and during flood plume events in specific regions. Median exposures expressed as diuron equivalent concentration were an average factor of 2.3 times higher but mostly not significantly different (p<0.05) to the median for the long-term monitoring record. The herbicides metolachlor and tebuthiuron were frequently detected in flood plume waters at concentrations that reached or exceeded relevant water quality guidelines (by up to 4.5 times).

There is an urgent need to develop reliable biomarkers of environmental hypoxia exposure in marine organisms in order to assess the ecological impacts of the marked increase in coastal hypoxia worldwide. Full-length hypoxia-inducible factor HIF-1α and HIF-2α cDNAs were cloned and characterized from dragonet Callionymus valenciennei, a representative epibenthic teleost inhabiting hypoxic areas in Tokyo Bay, to evaluate the potential utility of their transcript levels as biomarkers of environmental hypoxia exposure. HIF-1α and HIF-2α transcript levels in the livers of dragonet collected from hypoxic sites in Tokyo Bay were increased several-fold over those collected from nonhypoxic areas. Further, HIF-1α and HIF-2α mRNA levels were increased in dragonet livers after 7days exposure to hypoxia in a controlled laboratory experiment, and they declined to control levels within 24h of restoration to normoxic conditions. Our findings suggest HIF-1α and HIF-2α transcript levels are potentially useful biomarkers of environmental hypoxia exposure.