Coastal hazard risk assessment for small islands: assessing the impact of climate change and disaster reduction measures on Ebeye (Marshall Islands)

Small island states around the world are among the areas most vulnerable to climate change and sea level rise. In this paper, we present results from an innovative methodology for a quantitative assessment of multiple hazards on coastal risks, driven by different hydro-meteorological events, and including the effects of climate change. Moreover, we take an additional step by including in the methodology the option to assess and compare the effectiveness of possible disaster risk reduction measures. The methodology is applied to a real case study at the island of Ebeye (the Republic of the Marshall Islands). An example is provided in which a rock revetment is implemented as a risk reduction measure for the island. Results show that yearly expected damages may increase, by the end of the century, by a factor of three to four, depending on the sea level rise scenario considered, while the number of yearly affected people may double. Putting a cap on the temperature increase (e.g. 1.5 vs. 2 °C) according to the Paris Agreement may reduce damages and number of affected people by about 20 and 15%, respectively. However, impacts for same warming levels can vary substantially among different emission scenarios. Disaster risk reduction measures can be useful for mitigating risks in current and future situations but should be incorporated within long-term adaptive planning for these islands.     

Use of passive sampling devices for monitoring and compliance checking of POP concentrations in water

Background

The state of the art of passive water sampling of (nonpolar) organic contaminants is presented. Its suitability for regulatory monitoring is discussed, with an emphasis on the information yielded by passive sampling devices (PSDs), their relevance and associated uncertainties. Almost all persistent organic pollutants (POPs) targeted by the Stockholm Convention are nonpolar or weakly polar, hydrophobic substances, making them ideal targets for sampling in water using PSDs. Widely used nonpolar PSDs include semi-permeable membrane devices, low-density polyethylene and silicone rubber.

Results and discussion

The inter-laboratory variation of equilibrium partition constants between PSD and water is mostly 0.2?C0.5 log units, depending on the exact matrix used. The sampling rate of PSDs is best determined by using performance reference compounds during field deployment. The major advantage of PSDs over alternative matrices applicable in trend monitoring (e.g. sediments or biota) is that the various sources of variance including analytical variance and natural environmental variance can be much better controlled, which in turn results in a reduction of the number of analysed samples required to obtain results with comparable statistical power.

Conclusion

Compliance checking with regulatory limits and analysis of temporal and spatial contaminant trends are two possible fields of application. In contrast to the established use of nonpolar PSDs, polar samplers are insufficiently understood, but research is in progress to develop PSDs for the quantitative assessment of polar waterborne contaminants. In summary, PSD-based monitoring is a mature technique for the measurement of aqueous concentrations of apolar POPs, with a well-defined accuracy and precision.     

The Dechlorination of H6CDD,OCDD and OCDF on an Alumina support: Elucidation of the isomer pattern by multi linear regression and thermodynamic data

The dechlorination of OCDD, OCDF and 1,2,3,4,7,8‐H₆CDD is studies on an alumina support impregnated with activated carbon, copper chloride and potassium chloride. There is a high correlation between the isomer pattern found after dechlorination and molecular structure properties. We also found a substantial correlation between the isomer pattern and the Gibbs free energy of formation of the individual isomers. This suggests a thermodynamically controlled process.     

Automated and continuous redox potential measurements in soil

Redox potential (Eh) describes the electrical state of a matrix. In soils, Eh is an important parameter controlling the persistence of many organic and inorganic compounds. A popular, but also criticized, manual measuring method makes use of a small tip of Pt placed on a copper wire that is placed in the soil; a reference electrode is placed in the same soil at a fixed distance. Fluctuations in redox potential values measured in the soil can be very large and depth-dependent. This will be overlooked when making single-point measurements. We developed the datalogger Hypnos 2.0 for continuous redox potential and temperature measurements at various depths in the soil and without disturbance of the site. Hypnos is field-deployable, relatively cheap, and runs on batteries. The datalogger can use a "sleep mode" between sampling events. In sleep mode, there is no constant voltage on the Pt wire or the reference electrode, but there is only a short pulse during sampling. We did not measure an effect of this short pulse on the measured redox potential. In sandy soils in mesocosms and in a salt marsh soil we measured changes in the Eh as large as from -400 to +100 mV within 4 d, and daily cycles of 200 mV. Both absolute redox potential values and their diurnal variations were depth-dependent. Because single redox measurements are insufficient in describing redox conditions in some soil systems, Hypnos can be a powerful tool when studying the effects of fluctuating redox conditions on metal availability and pollutant degradation.     

Spiking of performance reference compounds in low density polyethylene and silicone passive water samplers

A method for spiking performance reference compounds (PRCs) into low density polyethylene (LDPE) and silicone polymers is described. This method is based on equilibration of the polymers in aqueous/methanolic solutions of PRCs. Equilibration times range from minutes to hours for perdeuterated polyaromatic hydrocarbons (PAHs) and polychlorinated biphenyls (PCBs) with a hydrophobicity in the range 3.9 < logKow < 7.7. Best results were obtained for methanol-water ratios of 80/20 (v/v). The method allows for the use of PRCs for in situ calibration of the uptake kinetics of these solvent-free sampling phases in a similar way as for semipermeable membrane devices (SPMDs).     

Antibiotika als Umweltkontaminanten — Effekte auf Bodenbakterien

Goal and scope

Among the human and veterinary pharmaceuticals, antibiotics form an important group. Recent research addressed the environmental ‘side effects’ of antibiotics. Evidence for environmental effects of antibiotics has for example been found for the respiratory activity of soil microorganisms. In the present contribution, results of studies on the ecotoxicology of antibiotics that are based on the utilization of carbon substrates in so-called Biolog plates are summarized.

Methods, Results and Conclusions

The method of pollution-induced community tolerance (PICT) takes centre stage. PICT is based on the changes in community composition of environmental communities brought about by a toxicant, which lead to an overall increase in community tolerance to this toxicant. The suitability of such an increase in community tolerance as ecotoxicological endpoint had been the subject of several experiments. It was shown that effect testing of antibiotics requires supplementation of the communities with nutrients, and that the PICT method reveals antibiotic effects with a high specificity. In an application of PICT, effects of three classes of antibacterial compounds were investigated. Dose-response relationships were obtained for all substances, and effect concentrations were partly in the range of expected environmental concentrations. The possible risks of antibiotic use for an increase in the occurrence of antibiotic resistance genes in the environment are also touched upon, including the extent of natural resistance.

Outlook

Due to its specificity, the PICT method has shown to be a suitable ecotoxicological assay. Due to possible effects of tetracyclines on the structure of the soil microbial community, it is advised to use veterinary antibiotics with caution. The risks of an increase in the occurrence of antibiotic resistance in the environment should be investigated in more detail.     

Little effect of excessive biofouling on the uptake of organic contaminants by semipermeable membrane devices

The effects of water flow rate and antifouling agents on the extent of biofouling and on the uptake of non-polar organic contaminants by semipermeable membrane devices (SPMDs) were studied during four field experiments in the Western Wadden Sea. Biofouling densities on the sampler surface ranged from 0.3 to 16 g dry weight dm⁻². Water sampling rates were estimated from the dissipation rates of performance reference compounds (PRCs). The antifouling agents Irgarol and capsaicin (33 mg per ml triolein) had no noticeable effect on the extent of fouling, and caused only a 5–10% increase in the absorbed amounts. Enhanced flow rates had only a minimal effect on the amount of biofouling, but caused the water sampling rates to increase by a factor of 1.2–2. Increases in PRC-derived sampling rates were reflected by increases in the absorbed amounts for compounds that were in the linear uptake stage of the sampling process. The results imply (1) that extreme biofouling does not always result in reduced sampling rates, (2) that extreme biofouling does not preclude the existence of flow effects on the sampling rates, and (3) that differences in uptake rates are quantitatively reflected by the dissipation rates of PRCs.     

Application of the City Blueprint Approach to assess the challenges of water management and governance in Quito (Ecuador)

In this paper, we provide an assessment of the challenges of water, waste and climate change in the city of Quito by performing the City Blueprint Approach consisting of three assessment frameworks: (1) the Trends and Pressure Framework (TPF), (2) the City Blueprint Framework (CBF) and (3) the water Governance Capacity Framework (GCF). The TPF summarizes the main social, environmental and financial aspects that may affect urban water management. The CBF provides a clear overview of sustainable urban water management performance and its bottlenecks in municipalities and regions. The GCF comprises nine governance conditions which each consist of three indicators. The GCF provides insight in the most effective improvements to increase the governance capacity to address the identified urban water challenges. Our results show that poor wastewater treatment and long-term drinking water security are Quito’s main water challenges that may be jeopardized given the city’s rapid urbanization and economic pressure. The GCF analysis reveals that cooperation between stakeholders, implementing capacity and citizens’ awareness are the most important conditions for further development to find adequate solutions for Quito’s long-term drinking water security. We also suggest that more attention should be drawn to the transparency, accountability and participation principles. The results of Quito show that the City Blueprint Approach can serve as an affordable quick-scan to facilitate cities in their strategic planning to reach their sustainable development goals.