A new method to study biodegradation kinetics of organic trace pollutants by activated sludge

A reliable prediction of the behaviour of organic trace compounds in activated sludge plants requires an accurate input of the biodegradation kinetics. Often these kinetics are extrapolated from the results of standardised biodegradation tests. However, these tests generally are not designed to yield kinetic information and do not reflect the conditions in activated sludge plants. To overcome these problems a new test method was developed which is referred to as a 'by-pass' test. The test methodology is explained and examples are given for three compounds: the C(12)-homologue of linear alkylbenzene sulfonate, nitrilotriacetic acid and toluene. More experience with the test is required, particularly with respect to selection of the proper test settings, which are compound related. The test is a suitable tool in a research environment, for example to investigate the effect of plant operational parameters on the biodegradation kinetics.     

Framing climate uncertainty: socio-economic and climate scenarios in vulnerability and adaptation assessments

Scenarios have become a powerful tool in integrated assessment and policy analysis for climate change. Socio-economic and climate scenarios are often combined to assess climate change impacts and vulnerabilities across different sectors and to inform risk management strategies. Such combinations of scenarios can also play an important role in enabling the interaction between experts and other stakeholders, framing issues and providing a means for making explicit and dealing with uncertainties. Drawing on experience with the application of scenarios to climate change assessments in recent Dutch research, the paper argues that scenario approaches need to be matched to the frames of stakeholders who are situated in specific decision contexts. Differentiated approaches (top-down, bottom-up and interactive) are needed to address the different frames and decision-making contexts of stakeholders. A framework is proposed to map scenarios and decision contexts onto two dimensions: the spatial scale of the context and the starting point of approach used in scenario development (top-down, bottom-up or incident-driven). Future climate and socio-economic scenario development will be shaped by the need to become better aligned with multiple interacting uncertainties salient to stakeholders.     

Assessing the impact of microfinance programming on children: an evaluation from post‐tsunami Aceh

This paper presents an evaluation of the long‐term impact of microfinance programmes on Acehnese children during the post‐tsunami recovery. The study, conducted from June to August 2010, examined the impact of microfinance programming six years after the tsunami. The sample consisted of 185 microfinance participants, with a comparison group of 192 individuals who did not participate in microfinance programmes. All respondents were parents, interviewed through a structured survey. The study used four child protection indicators—diet, health, childcare and education—in contrast to traditional repayment rate indicators. The primary results were insignificant with respect to all four child protection indicators, suggesting that, with respect to these indicators, there was no long‐term difference between the impact of microfinance on beneficiaries' children and non‐beneficiaries' children. These findings signify a need for microfinance actors to move beyond traditional indicators of economic success to evaluate the social changes microfinance programmes are presumed to effect.     

Integrating Strategic Environmental Assessment with Industry Planning: A Case Study of the Pasquai-Porcupine Forest Management Plan,Saskatchewan, Canada

Strategic environmental assessment (SEA) is gaining widespread recognition as a tool for integrating environmental considerations in policy, plan, and program development and decision-making. Notwithstanding the potential of SEA to improve higher-order decision processes, there has been very little attention given to integrating SEA with industry planning practices. As a result, the benefits of SEA have yet to be fully realized among industrial proponents. That said, SEA practice is ongoing, albeit informally and often under a different label, and is proving to be a valuable tool for industry planning and decision-making. Based on a case study of the Pasquai-Porcupine forest management plan in Saskatchewan, Canada, this paper illustrates how an integrated approach to SEA can contribute to industry environmental decision-making and can enhance the quality and deliverability of industry plans.     

Vitellogenin content in European eel (Anguilla anguilla) in Flanders, Belgium

As part of a large-scale monitoring program of bioaccumulating contaminants in the European eel (Anguilla anguilla) in Flanders (Belgium), we investigated potential effects of xenoestrogens in these fish. The present paper describes the results of the plasma vitellogenin (VTG) content, measured in 142 eels sampled at 20 different locations, in relation to the internal pollution levels. To validate the blood VTG assays, a small number of eels (n=8) was exposed to 10 microg ethinylestradiol/l (EE2) for 9 days. In this experiment, VTG was detected as a protein with a molecular weight of 214 kDa and confirmed by Western blotting. Compared with the solvent controls, significantly higher concentrations of VTG were measured in EE2 exposed eel. However, the VTG content was relatively low compared with other fish species exposed to high concentrations of estrogens. The plasma VTG content of eels from the field study was very low, despite a very high internal load of endocrine disrupters. These results, together with previously published studies, suggest that immature yellow European eel might not be the best sentinel species to study the effects of estrogenic compounds on VTG levels of wild fish populations.     

Identification of chemical hazards for terrestrial plants in the regulatory context: Comparison of OECD and ISO guidelines

Standardized test protocols are used in the regulatory context for identifying the hazardous properties of chemicals, wastes, and contaminated materials. This paper compares the relevance of two guidelines measuring effects on terrestrial plants, the OECD TG 208 and the ISO TG 22030 and presents the scientific basis for a recent decision of the European Chemicals Agency (ECHA) under the European chemicals regulation REACH. If there are no specific phytotoxicity alerts, both guidelines are considered suitable for assessing long-term hazards, providing that a sufficient number of species is included in the OECD protocol, the recommended minimum number is six, which offer a reasonably broad selection of species to account for interspecies sensitivity. The proposed methodology, based on a combination of probabilistic assessments using Monte Carlo analysis, can be adapted for supporting similar decisions under specific regulatory processes; for example, for assessing contaminated soils or pesticides’ applications.     

Degradation of Isobutanal at High Loading Rates in a Compost Biofilter

Abstract

Biofiltration has been increasingly used for cleaning waste gases, mostly containing low concentrations of odorous compounds. To expand the application area of this technology, the biofiltration of higher pollutant loading rates has to be investigated. This article focuses on the biodegradation of isobutanal (IBAL) in a compost biofilter (BF) at mass loading rates between 211 and 4123 g/m³/day (30– 590 ppm_v). At mass loading rates up to 785 g/m³/day, near 100% removal efficiencies could be obtained. However, after increasing the loading rate to 1500–1900 g/m³/day, the degradation efficiency decreased to 62–98%. In addition, a pH decrease and production of isobutanol (IBOL) and isobutyric acid (IBAC) were observed. This is the first report showing that an aldehyde can act as electron donor as well as acceptor in a BF. To study the effects of pH, compost moisture content, and electron acceptor availability on the biofiltration of IBAL, IBOL, and IBAC, additional batch and continuous experiments were performed. A pH of 5.2 reduced the IBAL degradation rate and inhibited the IBOL degradation, although adaptation of the microorganisms to low pH was observed in the BFs. IBAC was not degraded in the batch experiments. High moisture content (51%) initially had no effect on the IBOL production, although it negatively affected the IBAL elimination increasingly during a 21–day time–course experiment. In batch experiments, the reduction of IBAL to IBOL did not decrease when the amount of available electron acceptors (oxygen or nitrate) was increased. The IBAL removal efficiency at higher loading rates was limited by a combination of nutrient limitation, pH decrease, and dehydration, and the importance of each limiting factor depended on the influent concentration.