Long-term trends and short-term variability of water quality in Skive Fjord, Denmark – nutrient load and mussels are the primary pressures and drivers that influence water quality

Nineteen years of monitoring data from the eutrophic Skive Fjord, Denmark were examined for linkages to external pressures and drivers, including nutrient inputs, meteorology and stocks of blue mussels. Linkages were examined by: 1) time-series analysis to document effects of nutrient reduction programs, 2) Pearson Rank correlations, 3) multivariate statistical analysis (PLS) to identify water quality variables with high predictability and their linkages to pressures, and 4) regression analysis to quantify relationships between pressures and water quality. Freshwater input, nitrogen load and phosphorus load showed decreasing trends through the period 1984–2002. The load reductions were only partially translated into trends in water quality: phosphorus decreased in most seasons, while total nitrogen decreased during winter and spring only. Phosphorus concentration had the highest predictability (explained by seasonal temperature variation) followed by transparency, silicate, tot-N, chlorophyll-a, primary productivity, phytoplankton diversity and phytoplankton turnover. The variation in pressures other than nutrient input confounded the relations between loads and water quality. High biomass of mussels led to reduced chlorophyll-a and increased transparency, while short-term variability in water column mixing led to changes in chlorophyll-a due to nutrient entrainment and coupling to benthic mussels.     

The economic value of water use: implications for implementing the Water Framework Directive in Scotland

The European Union Water Framework Directive (WFD) enshrines several economic principles in pursuit of 'good ecological status' for Europe's waters and rationalising water use in society. The implicit principle of maximising the social value from use of a scarce resource is reminiscent of the debate about treating water as an economic good, which has competing uses in society. This paper locates the debate about the economic value of water in the requirements of WFD. Specifically, we consider the implications of national reporting requirements for the economic characterisation report that stress the identification of relative value derived from use. As part of the Scottish contribution to the UK reporting exercise, we use a range of secondary data sources to derive economic values for water on a sector basis. We suggest whether the implications of different water values can be followed through in the WFD.     

A Priori Typology-Based Prediction of Benthic Macroinvertebrate Fauna for Ecological Classification of Rivers

We evaluated a simple bioassessment method based on a priori river typology to predict benthic macroinvertebrate fauna in riffle sites of rivers in the absence of human influence. Our approach predicted taxon lists specific to four river types differing in catchment area with a method analogous to the site-specific RIVPACS-type models. The reference sites grouped in accordance with their type in NMS ordination, indicating that the typology efficiently accounted for natural variation in macroinvertebrate assemblages. Compared with a null model, typology greatly increased the precision of prediction and sensitivity to detect human impairment and strengthened the correlation of the ratio of observed-to-expected number of predicted taxa (O/E) with the measured stressor variables. The performance of the typology-based approach was equal to that of a RIVPACS-type predictive model that we developed. Exclusion of rarest taxa with low occurrence probabilities improved the performance of both approaches by all criteria. With an increasing inclusion threshold of occurrence probability, especially the predictive model sensitivity first increased but then decreased. Many common taxa with intermediate type-specific occurrence probabilities were consistently missing from impacted sites, a result suggesting that these taxa may be especially important in detecting human disturbances. We conclude that if a typology-based approach such as that suggested by the European Union’s Water Framework Directive is required, the O/E ratio of type-specific taxa can be a useful metric for assessment of the status of riffle macroinvertebrate communities. Successful application of the approach, however, requires biologically meaningful river types with a sufficient pool of reference sites for each type.     

Quantitative catchment profiling to apportion faecal indicator organism budgets for the Ribble system, the UK's sentinel drainage basin for Water Framework Directive research

Under the EU Water Framework Directive (WFD) 20/60/EC and the US Federal Water Pollution Control Act 2002 management of water quality within river drainage basins has shifted from traditional point-source control to a holistic approach whereby the overall contribution of point and diffuse sources of pollutants has to be considered. Consequently, there is a requirement to undertake source-apportionment studies of pollutant fluxes within catchments. The inclusion of the Bathing Water Directive (BWD), under the list of 'protected areas' in the WFD places a requirement to control sources of faecal indicator organisms within catchments in order to achieve the objectives of both the BWD (and its revision - 2006/7/EC) and the WFD. This study was therefore initiated to quantify catchment-derived fluxes of faecal indicator compliance parameters originating from both point and diffuse sources. The Ribble drainage basin is the single UK sentinel WFD research catchment and discharges to the south of the Fylde coast, which includes a number of high profile, historically non-compliant, bathing waters. Faecal indicator concentrations (faecal coliform concentrations are reported herein) were measured at 41 riverine locations, the 15 largest wastewater treatment works (WwTWs) and 15 combined sewer overflows (CSOs) across the Ribble basin over a 44-day period during the 2002 bathing season. The sampling programme included targeting rainfall-induced high flow events and sample results were categorised as either base flow or high flow. At the riverine sites, geometric mean faecal coliform concentrations showed statistically significant elevation at high flow compared to base flow. The resultant faecal coliform flux estimates revealed that over 90% of the total organism load to the Ribble Estuary was discharged by sewage related sources during high flow events. These sewage sources were largely related to the urban areas to the south and east of the Ribble basin, with over half the load associated with the relatively small subcatchment of the River Douglas. The majority of this load was attributed to two WwTWs that discharge through a common outfall close to the tidal limit of this catchment. Budgets adjusted to accommodate the impact of proposed UV disinfection of these effluents showed that the load from these sources would be reduced significantly during base flow conditions. However, during high flow events loads would still remain high due to the operation of storm sewage overflows from stormwater retention tanks. The study identified untreated storm sewage spills from urban infrastructure and WwTW stormwater retention tanks as the dominant component of the high flow flux of faecal indicators to receiving waters of the Fylde coast and the associated bathing waters.     

Food web assessments in the Baltic Sea: Models bridging the gap between indicators and policy needs

Ecosystem-based management requires understanding of food webs. Consequently, assessment of food web status is mandatory according to the European Union’s Marine Strategy Framework Directive (MSFD) for EU Member States. However, how to best monitor and assess food webs in practise has proven a challenging question. Here, we review and assess the current status of food web indicators and food web models, and discuss whether the models can help addressing current shortcomings of indicator-based food web assessments, using the Baltic Sea as an example region. We show that although the MSFD food web assessment was designed to use food web indicators alone, they are currently poorly fit for the purpose, because they lack interconnectivity of trophic guilds. We then argue that the multiple food web models published for this region have a high potential to provide additional coherence to the definition of good environmental status, the evaluation of uncertainties, and estimates for unsampled indicator values, but we also identify current limitations that stand in the way of more formal implementation of this approach. We close with a discussion of which current models have the best capacity for this purpose in the Baltic Sea, and of the way forward towards the combination of measurable indicators and modelling approaches in food web assessments. Supplementary InformationThe online version contains supplementary material available at 10.1007/s13280-021-01692-x.     

Disentangling the ecosystem service ‘flood regulation’: Mechanisms and relevant ecosystem condition characteristics

Riverine floods cause increasingly severe damages to human settlements and infrastructure. Ecosystems have a natural capacity to decrease both severity and frequency of floods. Natural flood regulation processes along freshwaters can be attributed to two different mechanisms: flood prevention that takes place in the whole catchment and flood mitigation once the water has accumulated in the stream. These flood regulating mechanisms are not consistently recognized in major ecosystem service (ES) classifications. For a balanced landscape management, it is important to assess the ES flood regulation so that it can account for the different processes at the relevant sites. We reviewed literature, classified them according to these mechanisms, and analysed the influencing ecosystem characteristics. For prevention, vegetation biomass and forest extent were predominant, while for mitigation, the available space for water was decisive. We add some aspects on assessing flood regulation as ES, and suggest also to include flood hazard into calculations.     

Is the trajectory of European Union environmental policy less certain?

ABSTRACT

The core themes and research questions of this volume, centred on the nature of environmental policy change in the European Union (EU), are laid out. An original heuristic framework to capture different dimensions, mechanisms and processes of policy change is presented. In order to contextualise the current situation, where EU policy scope has reached maturity and faces an uncertain future trajectory, EU environmental politics is divided into particular eras, looking closely at the nature of change in each period. This volume interrogates the extent to which change has occurred, the conditions or context within which it did/did not take place and the implications arising from stasis or change. The contributions to the volume are introduced and placed into the context of the broader trajectory of EU environmental policy.     

Scientific basis of dissolved organic carbon limitation for landfilling of municipal treatment sludge – Is it attainable and justifiable?

This study evaluated the scientific and technical basis of the dissolved organic carbon (DOC) limitation imposed on municipal sludge for landfilling, mainly for assessing the attainability of the implemented numerical level. For this purpose, related conceptual framework was analyzed, covering related sewage characteristics, soluble microbial products generation, and substrate solubilization and leakage due to hydrolysis. Soluble COD footprint was experimentally established for a selected treatment plant, including all the key steps in the sequence of wastewater treatment and sludge handling. Observed results were compared with reported DOCs in other treatment configurations. None of the leakage tests performed or considered in the study could even come close to the prescribed limitation. All observed results reflected 10–20 fold higher DOC levels than the numerical limit of 800 mg/kg (80 mg/L), providing conclusive evidence that the DOC limitation imposed on municipal treatment sludge for landfilling is not attainable, and therefore not justifiable on the basis of currently available technology.     

Determination of toxic metals in discarded Liquid Crystal Displays (LCDs)

This study focused on the determination of the toxic metal content of Liquid Crystal Displays (LCDs) present in various Waste Electrical and Electronic Equipment (WEEE). The main objective was the identification and quantification of toxic metals detected in LCD panels. An experimental procedure which involved dismantling, shredding, pulverization, digestion and chemical analysis was followed for the sorting, separation and analysis of LCD monitors from various electronic devices that are currently on the market. Nine selected devices were examined, originated from four different types of e-waste (WEEE); TVs, computers, mobile phones and tablets. Eleven metals were measured in all examined samples. In addition, concentration values of chromium (Cr), cadmium (Cd), lead (Pb) and mercury (Hg) were compared with the respective limits set by the RoHS 2002/95/EC Directive that was recently renewed by the 2012/19/EU recast. The comparison revealed that the examined toxic metals on LCD panels did not exceed the limits set by the European Union (EU). Furthermore, when results were compared to the TTLC regulatory limits it was revealed that in three samples As concentrations were higher than the limit. Finally, when the TCLP test was implemented the aforementioned samples did not exhibit proportionally elevated values in their leachates.     

基于SEVESOⅢ指令对某市工业企业危险性进行评估

参考欧盟SevesoⅢ指令,结合区域风险评估的方法,对江苏省某市31家工业企业源于工业事故的潜在危险性进行评估。评估时综合考察工业企业储存(包括输入、输出)危险物质的种类及数量,以及工业企业危险的生产工艺流程,基于SevesoⅢ指令对企业的危险性进行分级。通过改进SevesoⅢ指令工业企业危险性评估方法(如用连续分类法代替阈值法等),采用工业危险性指数(ⅡH)表征工业企业的危险性,并对ⅡH进行排序。结果表明,该市工业企业的ⅡH值范围在0-1,其中低危险或无危险企业(ⅡH<0.5)24家;中度危险企业(0.5≤ⅡH<1.0)6家;重度危险企业(ⅡH=1.0)1家。通过本研究,实践并改进了工业企业危险性评估的方法,为环境风险管理提供方法支持,以预防工业事故和环境灾害的发生。