Application of biomarkers for improving risk assessments of chemicals under the Water Framework Directive: a case study

To answer the requirement of the European Commission's Water Framework Directive (WFD) for biological-effects endpoints to classify the ecological health of aquatic ecosystems, we propose the biomarker response index (BRI). The BRI, based on a suite of biomarkers at different levels of biological response at the individual level, provides an integrated relative measure of the general health status of coastal invertebrates. Using the BRI, the health of mussels (Mytilus edulis) from 10 estuaries classified by the Environment Agency of England and Wales under the WFD was compared. Eight sites were healthier than predicted and two showed a similar health status to that of the predicted point-source pollution risk classification. Results indicate that the BRI offers a potential measure of organism health that can be used in monitoring under the WFD as an additional aid to reduce uncertainty in defining risk classification and to provide better evidence of existing impact.     

Alkylphenols in marine environments: Distribution monitoring strategies and detection considerations

The presence of alkylphenols (APs) in coastal and marine ecosystems is not as well-documented as it is in freshwater ecosystems. This paper reviews reported concentrations of alkylphenol ethoxylates (APEOs) and APs in seawater, sediments and organisms of marine environments such as estuaries, coastal lagoons, bights, harbours or deep sea in order to study their distribution. Overall contamination of marine aquatic compartments by APs and APEOs has been observed, while coastal areas in the vicinity of wastewater discharges are more impacted than deep sea environments, but to a lesser extent than freshwater sites. Sediments act as sinks for APs and APEOs, especially around wastewater discharge sites. Reported AP concentrations in marine organisms are higher in bivalves and gastropods than in fishes. As nonylphenols and octylphenols are estrogenomimetic, biological responses induced in marine organisms are discussed. Finally, we describe the cell bioassay approach for the biodetection of APs.     

On the relevance of meiobenthic research for policy-makers

The need for scientific advice to manage the aquatic environment in an ecosystem context has never been greater. Many assessments of ecosystem state and change use inadequate data on non-conspicuous, non-target organisms. These include meiofauna, a diverse group of small-sized organisms (<1 mm) that live in a range of terrestrial and aquatic environments. Meiobenthic research published between 2007 and 2011 has failed to underpin ecosystem management and conservation practices. This is partly because of the belief amongst decision-makers and the public that microscopic organisms beyond our normal range of perception are ecologically unimportant. Methodological limitations related to the taxonomic identification of small-sized organisms and the narrow scope of many contemporary meiofauna studies are also to blame. This article explores ways in which meiobenthologists can improve the impact and uptake of their research.     

Evaluation and application of dialysis porewater samplers for microbiological studies at sediment-water interfaces

The equilibrium diffusion technique has become a valuable tool for ecological and biogeochemical studies in aquatic environments. In sediment ecosystems, changes in concentration of microbial metabolites with increasing depth can be determined dependably and reproducibly with this technique. Since the permeation characteristics of the membranes employed are crucial, selecting the proper membrane requires knowledge about its behavior under conditions which prevail in the natural environment. Thirteen polymer sheets were evaluated comparing permeation terms for biogeochemically relevant solutes, biodegradability, and mechanical strength. Cellulose-based dialysis membranes are most satisfactory when employed in low temperature anoxic environments. For this membrane, correction terms were calculated to account for diffusion losses during retrieval and sampling. Optimal incubation times can now be predicted from experimentally determined permeation coefficients for several porewater solutes. Dialysis porewater samplers (DPS) have been successfully applied during more than 100 independent experiments for the collection of interstitial water from surface sediments. DPS were used for water depths as deep as 290 meters.     

Pb-derived ages for the reconstruction of terrestrial contaminant history into the Mexican Pacific coast: Potential and limitations

²¹⁰Pb is widely used for dating recent sediments in the aquatic environment; however, our experiences working in shallow coastal environments in the Pacific coast of Mexico have demonstrated that the potential of ²¹⁰Pb for reliable historical reconstructions might be limited by the low ²¹⁰Pb atmospheric fallout, sediment mixing, abundance of coarse sediments and the lack of ¹³⁷Cs signal for ²¹⁰Pb corroboration. This work discusses the difficulties in obtaining adequate sedimentary records for geochronological reconstruction in such active and complex settings, including examples of ²¹⁰Pb geochronologies based on sediment profiles collected in two contrasting areas coastal areas (mudflats associated to coastal lagoons of Sinaloa State and the continental shelf of the Gulf of Tehuantepec), in which geochemical data was used to support the temporal frame established and the changes in sediment supply recorded in the sediment cores which were related to the development of land-based activities during the last century.     

Differences between Humic Substances from Riverine,Estuarine, and Marine Environments Observed by Fluorescence Spectroscopy

Sixteen samples of fulvic acids and XAD‐4 fractions of riverine, estuarine, coastal, and open ocean origin have been studied by emission and synchronous molecular fluorescence spectroscopy. Certain features of the molecular fluorescence are related to the nature, the content, and the origin of those aquatic humic substances (HS). Riverine HS appear several times richer in fluorophores than marine HS, which can be well observed by emission fluorescence spectroscopy. Synchronous‐scan spectra of fulvic acids and of XAD‐4 fractions from the aquatic environments studied, emphasized the quality differences of their fluorophores. These features are useful as tracers of humic substances related with their natural environment source or even with their anthropogenic origin.     

Impact of repository depth on residence times for leaking radionuclides in land-based surface water

The multiple scales of landscape topography produce a wide distribution of groundwater circulation cells that control the hydro-geological environments surrounding geological repositories for nuclear waste. The largest circulation cells tend to discharge water into major river reaches, large freshwater systems or the nearby Baltic Sea. We investigated numerically the release of radionuclides from repositories placed in bedrock with depths between 100 to 2000 meters in a Swedish coastal area and found that leakage from the deeper positions emerges primarily in the major aquatic systems. In effect, radionuclides from the deeper repositories are more rapidly transported towards the Sea by the stream system compared to leakage from more shallow repositories. The release from the shallower repositories is significantly retained in the initial stage of the transport in the (superficial) landscape because the discharge occurs in or near low-order streams with high retention characteristics. This retention and residence time for radioactivity in the landscape control radiological doses to biota and can, thus, be expected to constitute an essential part of an associated risk evaluation.     

Simplification bias: lessons from laboratory and field experiments on flow through aquatic vegetation

We present a critical analysis of experimental findings on vegetation–flow–sediment interactions obtained through both laboratory and field experiments on tidal and coastal environments. It is well established that aquatic vegetation provides a wide range of ecosystem services (e.g. protecting coastal communities from extreme events, reducing riverbank and coastal erosion, housing diverse ecosystems), and the effort to better understand such services has led to multiple approaches to reproduce the relevant physical processes through detailed laboratory experiments. State-of-the-art measurement techniques allow researchers to measure velocity fields and sediment transport with high spatial and temporal resolution under well-controlled flow conditions, yielding predictions for hydrodynamic and sediment transport scenarios that depend on simplified or bulk vegetation parameters. However, recent field studies have shown that some simplifications on the experimental setup (e.g. the use of rigid elements, a single diameter, a single element height, regular or staggered layout) can bias the outcome of the study, by either hiding or amplifying some of the relevant physical processes found in natural conditions. We discuss some observed cases of bias, including general practices that can lead to compromises associated with simplified assumptions. The analysis presented will identify potential pathways to move forward with laboratory and field measurements, which could better inform predictors to produce more robust, universal and accurate predictions on flow–vegetation–sediment interactions. © 2020 John Wiley & Sons, Ltd.     

Porosity and hydraulic conductivity estimation of the basaltic aquifer in Southern Syria by using nuclear and electrical well logging techniques

An alternative approach using nuclear neutron-porosity and electrical resistivity well logging of long (64 inch) and short (16 inch) normal techniques is proposed to estimate the porosity and the hydraulic conductivity (K) of the basaltic aquifers in Southern Syria. This method is applied on the available logs of Kodana well in Southern Syria. It has been found that the obtained K value by applying this technique seems to be reasonable and comparable with the hydraulic conductivity value of 3.09 m/day obtained by the pumping test carried out at Kodana well. The proposed alternative well logging methodology seems as promising and could be practiced in the basaltic environments for the estimation of hydraulic conductivity parameter. However, more detailed researches are still required to make this proposed technique very performed in basaltic environments.     

Assessing sound exposure from shipping in coastal waters using a single hydrophone and Automatic Identification System (AIS) data

Underwater noise from shipping is a growing presence throughout the world's oceans, and may be subjecting marine fauna to chronic noise exposure with potentially severe long-term consequences. The coincidence of dense shipping activity and sensitive marine ecosystems in coastal environments is of particular concern, and noise assessment methodologies which describe the high temporal variability of sound exposure in these areas are needed. We present a method of characterising sound exposure from shipping using continuous passive acoustic monitoring combined with Automatic Identification System (AIS) shipping data. The method is applied to data recorded in Falmouth Bay, UK. Absolute and relative levels of intermittent ship noise contributions to the 24-h sound exposure level are determined using an adaptive threshold, and the spatial distribution of potential ship sources is then analysed using AIS data. This technique can be used to prioritize shipping noise mitigation strategies in coastal marine environments.     

A simple method for locating the fresh water-salt water interface using pressure data

Salt water intrusion is a key issue in dealing with exploitation, restoration, and management of fresh ground water in coastal aquifers. Constant monitoring of the fresh water-salt water interface is necessary for proper management of ground water resources. This study presents a simple method to estimate the depth of the fresh water-salt water interface in coastal aquifers using two sets of pressure data obtained from the fresh and saline zones within a single borehole. This method uses the density difference between fresh water and saline water and can practically be used at coastal aquifers that have a relatively sharp fresh water-salt water interface with a thin transition zone. The proposed method was applied to data collected from a coastal aquifer on Jeju Island, Korea, to estimate the variations in the depth of the interface. The interface varied with daily tidal fluctuations and heavy rainfall in the rainy season. The estimated depth of the interface showed a good agreement with the measured electrical conductivity profile.     

Spatio-temporal comparisons of imposex status and tissue organotin concentration in the whelk Reishia clavigera collected along the coasts of Dapeng Bay and Daya Bay,Shenzhen, China

Organotin compounds (OTs) have caused widespread adverse effects on marine organisms. As no local restrictions on OT-based antifouling paints have been implemented in China, high concentrations of OTs still occur in coastal environments. In this study, we measured the imposex status and tissue concentrations of OTs in the whelk Reishia clavigera collected along the coast of Dapeng Bay and Daya Bay of Shenzhen, China in 2013. Our results showed that all female whelks suffered from the onset of imposex. The highest concentration of total OTs was 27,756 μg kg⁻¹ dry weight in the samples collected from Shuitousha. Triphenyltin was the most predominant residue, accounting for more than 97.8% of total OTs across all sites. Compared with the results from previous studies, the marine environment of this region is still heavily contaminated with OTs. Therefore, a tightened control is necessary to regulate the use and release of OTs in China.     

Innovative Contaminant Mass Flux Monitoring in an Aquifer Subject to Tidal Effects

Exposure from groundwater contamination to aquatic receptors residing in receiving surface water is dependent upon the rate of contaminated groundwater discharge. Characterization of groundwater fluxes is challenging, especially in coastal environments where tidal fluctuations result in transient groundwater flows towards these receptors. This can also be further complicated by the high spatial heterogeneity of subsurface deposits enhanced by anthropogenic influences such as the mixing of natural sediments and backfill materials, the presence of subsurface built structures such as sheet pile walls or even occurrence of other sources of contaminant discharge. In this study, the finite volume point dilution method (FVPDM) was successfully used to characterize highly transient groundwater flows and contaminant mass fluxes within a coastal groundwater flow system influenced by marked tides. FVPDM tests were undertaken continuously for more than 48 h at six groundwater monitoring wells, in order to evaluate groundwater flow dynamics during several tide cycles. Contaminant concentrations were measured simultaneously which allowed calculating contaminant mass fluxes. The study highlighted the importance of the aquifer heterogeneity, with groundwater fluxes ranging from 10⁻⁷ to 10⁻³ m/s. Groundwater flux monitoring enabled a significant refinement of the conceptual site model, including the fact that inversion of groundwater fluxes was not observed at high tide. Results indicated that contaminant mass fluxes were particularly higher at a specific monitoring well, by more than three orders of magnitude, than at other wells of the investigated aquifer. This study provided crucial information for optimizing further field investigations and risk mitigation measures.     

Cone Penetrometer Tests and HydroPunch® Sampling: A Screening Technique for Plume Definition

Cone penetrometer tests and HydroPunch® sampling were used to define the extent of volatile organic compounds in ground water. The investigation indicated that the combination of these techniques is effective for obtaining ground water samples for preliminary plume definition. HydroPunch samples can be collected in unconsolidated sediments and the analytical results obtained from these samples are comparable to those obtained from adjacent monitoring wells. This sampling method is a rapid and cost-effective screening technique for characterizing the extent of contaminant plumes in soft sediment environments. Use of this screening technique allowed monitoring wells to be located at the plume boundary, thereby reducing the number of wells installed and the overall cost of the plume definition program.     

Occurrence of estrogen-like substances in the marine environment of the Northern Mediterranean Sea

Evidence has been presented that a number of environmental agents perturbs the function of the sex hormone signalling pathways in marine animals.

In this work the estrogenic/antiestrogenic activity of coastal marine water samples from five sites of the Northern Mediterranean Sea was assayed using a recombinant Saccharomyces cerevisiae yeast strain (RMY326 ER-ERE) transfected with the human estrogen receptor . Extraction of potential EDCs from seawater was performed in columns packed with XAD-2 resins.

The estrogenic activity was calculated as percentage of the activity of 17β-estradiol (10 nM) and it ranged from 4.8% and 59.03%, significantly depending on sampling site (p = 0.0013) and season (p < 0.05). Antagonistic activity of extracts was also detected and the percentage of inhibition of estradiol-dependent β-galactosidase induction ranged to 52.8%. These results point the reliability of the yeast assay as a first level screening test to assess the quality of aquatic environments.     

Anthropogenic organic contaminants in water, sediments and benthic organisms of the mangrove-fringed Segara Anakan Lagoon, Java, Indonesia

Segara Anakan, a mangrove-fringed coastal lagoon in Indonesia, has a high diversity of macrobenthic invertebrates and is increasingly affected by human activities. We found >50 organic contaminants in water, sediment and macrobenthic invertebrates from the lagoon most of which were polycyclic aromatic compounds (PACs). Composition of PACs pointed to petrogenic contamination in the eastern lagoon. PACs mainly consisted of alkylated PAHs, which are more abundant in crude oil than parent PAHs. Highest total PAC concentration in sediment was above reported toxicity thresholds for aquatic invertebrates. Other identified compounds derived from municipal sewage and also included novel contaminants like triphenylphosphine oxide. Numbers of stored contaminants varied between species which is probably related to differences in microhabitat and feeding mode. Most contaminants were detected in Telescopium telescopium and Polymesoda erosa. Our findings suggest that more attention should be paid to the risk potential of alkylated PAHs, which has hardly been addressed previously.     

Mapping water quality and substrate cover in optically complex coastal and reef waters: an integrated approach

Sustainable management of coastal and coral reef environments requires regular collection of accurate information on recognized ecosystem health indicators. Satellite image data and derived maps of water column and substrate biophysical properties provide an opportunity to develop baseline mapping and monitoring programs for coastal and coral reef ecosystem health indicators. A significant challenge for satellite image data in coastal and coral reef water bodies is the mixture of both clear and turbid waters. A new approach is presented in this paper to enable production of water quality and substrate cover type maps, linked to a field based coastal ecosystem health indicator monitoring program, for use in turbid to clear coastal and coral reef waters. An optimized optical domain method was applied to map selected water quality (Secchi depth, Kd PAR, tripton, CDOM) and substrate cover type (seagrass, algae, sand) parameters. The approach is demonstrated using commercially available Landsat 7 Enhanced Thematic Mapper image data over a coastal embayment exhibiting the range of substrate cover types and water quality conditions commonly found in sub-tropical and tropical coastal environments. Spatially extensive and quantitative maps of selected water quality and substrate cover parameters were produced for the study site. These map products were refined by interactions with management agencies to suit the information requirements of their monitoring and management programs.     

ANN application for prediction of atmospheric nitrogen deposition to aquatic ecosystems

The occurrences of increased atmospheric nitrogen deposition (ADN) in Southeast Asia during smoke haze episodes have undesired consequences on receiving aquatic ecosystems. A successful prediction of episodic ADN will allow a quantitative understanding of its possible impacts. In this study, an artificial neural network (ANN) model is used to estimate atmospheric deposition of total nitrogen (TN) and organic nitrogen (ON) concentrations to coastal aquatic ecosystems. The selected model input variables were nitrogen species from atmospheric deposition, Total Suspended Particulates, Pollutant Standards Index and meteorological parameters. ANN models predictions were also compared with multiple linear regression model having the same inputs and output. ANN model performance was found relatively more accurate in its predictions and adequate even for high-concentration events with acceptable minimum error. The developed ANN model can be used as a forecasting tool to complement the current TN and ON analysis within the atmospheric deposition-monitoring program in the region.