ECOSM-a new joint project for assessing environmental risks of poorly soluble compounds used in cosmetics-project presentation

This article reports on the second Young Environmental Scientists Meeting that was hosted from 28 February to 2 March 2011 by the Institute for Environmental Research at RWTH Aachen University, Germany. This extraordinary meeting was again initiated and organized by the Student Advisory Council under the umbrella of Society of Environmental Toxicology and Chemistry Europe. A movie about the meeting and the abstracts of poster and platform presentations are freely available as supplemental material of this article.     

Scenarios of global bioenergy production: The trade-offs between agricultural expansion, intensification and trade

Increased future demands for food, fibre and fuels from biomass can only be met if the available land and water resources on a global scale are used and managed as efficiently as possible. The main routes for making the global agricultural system more productive are through intensification and technological change on currently used agricultural land, land expansion into currently non-agricultural areas, and international trade in agricultural commodities and processed goods. In order to analyse the trade-offs and synergies between these options, we present a global bio-economic modelling approach with a special focus on spatially explicit land and water constraints as well as technological change in agricultural production. For a global bioenergy demand scenario reaching 100 ExaJoule (EJ) until 2055 we derive a required rate of productivity increase on agricultural land between 1.2 and 1.4 percent per year under different land allocation options. A very high pressure for yield increase occurs in Sub-Saharan Africa and the Middle East, even without additional bioenergy demand. Moreover, we analyse the implicit values (shadow prices) of limited water resources. The shadow prices for bioenergy are provided as a metric for assessing the trade-offs between different land allocation options and as a link between the agricultural and energy sector.     

Attitudes and perceptions of indigenous fishermen towards marine resource management in Kuna Yala,Panama

The Kuna are a strong and independent culture, however outside influences are imposing growing pressure on their people. Overpopulation and large-scale overfishing are among the most severe threats. The Kuna have developed their own management strategies to address these pressing issues. This study presents local perceptions and attitudes towards marine resource management of six indigenous fishing communities in Kuna Yala, Panama. Results highlight significant general and comparative differences in fishermen's attitudes and perceptions based on socio-cultural structures of communities, occupation and role in local decision-making. The level of cultural survival in communities was a strong indicator for different priorities and attitudes. Differences were also evident based on the level of marine resources used for income generation. Participation in local decision-making processes had positive impacts on levels of knowledge and information, and fostered critical thinking among participants. In addition, the results also denoted that conservation and development were more effective in the long term if the host population could develop strategies and plans for biodiversity conservation. Ownership and empowerment were strong indicators that influenced local livelihood to promote sustainable use of marine resources.     

An occupational chemical priority list for future life cycle assessments

A chemical priority list is presented to screen and identify relevant chemicals, for which more detailed and industrial-sector specific quantitative exposure, risk and life-cycle assessments should be completed. A list of 38 solvents were ranked according to the framework of the LCA toxicity model, USEtox, and according to the framework proposed by the UNEP/SETAC working group on Indoor Exposure Assessment in LCA. An additional method, based on a risk assessment (RA) framework, was used to examine the robustness of the priority rank. Under both schemes dichloromethane, ethanol, formaldehyde, hexane and toluene all rank in the top ten positions. These chemicals are currently relevant with regard to health effects on a population level. Some of these chemicals are known as hazardous, while others, such as ethanol, have a low toxicity but were prioritized because of their extensive use and high exposure levels. This study attempts to combine the knowledge and methods of the LCA and occupational hygiene communities in assessing health impacts. It provides a consistent and transparent method for rapid comparative assessments of different chemicals and identifies the chemicals and workplaces that will require more thorough investigations.     

Effect of food concentration and type of diet on <Emphasis Type="Italic">Acartia </Emphasis>survival and naupliar development

We have performed life table experiments to investigate the effects of different food types and concentrations on the larval development and survival up to adulthood of Acartia tonsa. The food species offered comprised a wide taxonomic spectrum: the pigmented flagellates Isochrysis galbana, Emiliania huxleyi, Rhodomonas sp., Prorocentrum minimum, the diatom Thalassiosira weissflogii, grown on medium offering enriched macronutrient concentrations and the ciliate Euplotes sp. initially cultured on Rhodomonas. For the ciliate species, also the functional response was studied. In order to avoid limitation by mineral nutrients, food algae have been taken from the exponential growth phase of the nutrient replete cultures. The suitability of Rhodomonas as a food source throughout the entire life cycle was not a surprise. However, in contrast to much of the recent literature about the inadequacy or even toxicity of diatoms, we found that also Thalassiosira could support Acartia-development through the entire life cycle. On the other hand, Acartia could not complete its life cycle when fed with the other food items, Prorocentrum having adverse effects even when mixed with Rhodomonas and Thalassiosira. Isochrysis well supported naupliar survival and development, but was insufficient to support further development until reproduction. With Emiliania and Euplotes, nauplii died off before most of them could reach the first copepodite stages. Acartia-nauplii showed a behavioral preference for Euplotes-feeding over diatom feeding, but nevertheless Euplotes was an insufficient diet to complete development beyond the naupliar stages.     

Progress in herbicide determination with the thylakoid bioassay

Chloroplast thylakoids are used as biological units to determine herbicides in different kinds of water samples as well as in aqueous extracts of compost, soil or food samples. The thylakoid bioassy shows clearly inhibition of fluorescence yield in the presence of photosystem II specific herbicides. Due to this method the ecotoxicological effect of samples with unknown pollutants can be tested fast and cost effective. It has been proven that all photosynthetic active compounds are recorded at the same time because only additive interactions occur. Therefore, the contamination level can be expressed as cumulative parameter for photosystem II active substances. Application was improved clearly by the addition of the radical scavenger sodium ascorbate to the isolation media and by a higher concentration of the measuring medium. A new data evaluation method is described yielding in a lower detection limit of 0.4 μg diuron/1. The guidelines for the quality of water for human consumption with an allowable concentration of pesticides in groups is 0,5 μg/1 [1,2] and can be controlled with the thylakoid bioassay without performing any preconcentration steps.     

Rise of toxic cyanobacterial blooms in temperate freshwater lakes: causes,correlations and possible countermeasures

The progressive degradation of surface freshwater quality due to the mass proliferation of toxic cyanobacterial blooms is of growing global concern. The occurrence of cyanobacterial blooms is not a new phenomenon. However, a global increase in the frequency, duration, and distribution of toxic cyanobacterial blooms could be observed in the past decades. Evidence suggests that this trend might be attributed to a complex interplay of direct and indirect anthropogenic influences. The underlying causes and interrelations for this development have not been fully clarified. Nonetheless, all evidence points to the fact that mitigation of toxic cyanobacterial blooms will be a key challenge of the twenty-first century. This review addresses the underlying causes for the increased incidence of toxic cyanobacteria in temperate freshwater lakes and attempts to reveal possible reciprocities between bloom promoting factors. Selected approaches for the prevention of toxic cyanobacterial blooms as well as the mitigation of their potential negative impacts on humans will be presented.     

Dietary intake of hexabromocyclododecane diastereoisomers (α-, β-, and γ-HBCD) in the Belgian adult population

A study was performed to assess exposure of the Belgian population to HBCD diastereoisomers. Measurements of HBCD were performed by UPLC-MS/MS, on 45 composite samples from 5 major food groups: dairy (products), meat (products), eggs, fish (products) and a group of “other” products. The medium bound estimated average daily intake (EDI) of ΣHBCD in the Belgian population was 0.99 ng kg⁻¹ bw d⁻¹. The diastereoisomer contribution to the mean EDI showed a predominance of γ-HBCD at 67%, followed by α-HBCD at 25% and 8% for β-HBCD. These results are consistent with the pattern found in the two food groups contributing the most to the EDI: meat (products) and the group of “other” products. Anyway, it has to be noted that diastereomeric distribution of HBCD can change due to bioisomerisation in biological material. Levels of HBCD diastereoisomers found in Belgian food samples of animal origin were low in comparison with those found in other EU countries and the resulting EDI was substantially below the proposed thresholds.     

The OECD validation program of the H295R steroidogenesis assay: Phase 3. Final inter-laboratory validation study

Background, goals, and scope

In response to increasing concerns regarding the potential of chemicals to interact with the endocrine system of humans and wildlife, various national and international programs have been initiated with the aim to develop new guidelines for the screening and testing of these chemicals in vertebrates. Here, we report on the validation of an in vitro assay, the H295R steroidogenesis assay, to detect chemicals with the potential to inhibit or induce the production of the sex steroid hormones testosterone (T) and 17??-estradiol (E2) in preparation for the development of an Organization for Economic Cooperation and Development (OECD) test guideline.

Methods

A previously optimized and pre-validated protocol was used to assess the potential of 28 chemicals of diverse structures and properties to validate the H295R steroidogenesis assay. These chemicals are comprised of known endocrine-active chemicals and ??negative?? chemicals that were not expected to have effects on the targeted endpoints, as well as a number of test chemicals with unknown modes of action at the level of the steroidogenic pathway. A total of seven laboratories from seven countries participated in this effort. In addition to effects on hormone production, confounding factors, such as cell viability and possible direct interference of test substances with antibody-based hormone detection assays, were assessed. Prior to and during the conduct of exposure experiments, each laboratory had to demonstrate that they were able to conduct the assay within the margin of predefined performance criteria.

Results

With a few exceptions, all laboratories met the key quality performance parameters, and only 2% and 7% of all experiments for T and E2, respectively, were excluded due to exceedance of these parameters. Of the 28 chemicals analyzed, 13 and 14 tested affected production of T and E2, respectively, while 11 and 8 did not result in significant effects on T and E2 production, respectively. Four and six chemicals produced ambiguous results for effects on T and E2 production, respectively. However, four of these cases each for T and E2 were associated with only one laboratory after a personnel change occurred. Significant interference of test chemicals with some of the antibody-based hormone detection systems occurred for four chemicals. Only one of these chemicals, however, significantly affected the ability of the detection system to categorize the chemical as affecting E2 or T production.

Discussion and conclusions

With one exception, the H295R steroidogenesis assay protocol successfully identified the majority of chemicals with known and unknown modes of interaction as inducers or inhibitors of T and E2 production. Thus it can be considered a reliable screen for chemicals that can alter the production of sex steroid hormones. One of the remaining limitations associated with the H295R steroidogenesis assay protocol is the relatively small basal production of E2 and its effect on quantifying the decreased production of this hormone with regard to the identification of weak inhibitors. An initial comparison of the data produced in this study with those from in vivo studies from the literature demonstrated the potential of the H295R steroidogenesis assay to identify chemicals affecting hormone homeostasis in whole organisms. Particularly promising was the lack of any false negatives during the validation and the very low number of false positives (1 out of 28 chemicals for each T and E2).

Perspectives

Based on the results obtained during this validation study and the accordingly revised test protocols, an OECD draft test guideline was developed and submitted to the OECD working group of the national coordinators of the test guidelines program (WNT) for comments in December 2009.