Identifying ecological production functions for use in ecosystem services-based environmental risk assessment of chemicals.

There is increasing research interest in the application of the ecosystem services (ES) concept in the environmental risk assessment of chemicals to support formulating and operationalising regulatory environmental protection goals and making environmental risk assessment more policy- and value-relevant. This requires connecting ecosystem structure and processes to ecosystem function and henceforth to provision of ecosystem goods and services and their economic valuation. Ecological production functions (EPFs) may help to quantify these connections in a transparent manner and to predict ES provision based on function-related descriptors for service providing species, communities, ecosystems or habitats. We review scientific literature for EPFs to evaluate availability across provisioning and regulation and maintenance services (CICES v5.1 classification). We found quantitative production functions for nearly all ES, often complemented with economic valuation of physical or monetary flows. We studied the service providing units in these EPFs to evaluate the potential for extrapolation of toxicity data for test species obtained from standardised testing to ES provision. A broad taxonomic representation of service providers was established, but quantitative models directly linking standard test species to ES provision were extremely scarce. A pragmatic way to deal with this data gap would be the use of proxies for related taxa and stepwise functional extrapolation to ES provision and valuation, which we conclude possible for most ES. We suggest that EPFs may be used in defining specific protection goals (SPGs), and illustrate, using pollination as an example, the availability of information for the ecological entity and attribute dimensions of SPGs. Twenty-five pollination EPFs were compiled from the literature for biological entities ranging from 'colony' to 'habitat', with 75% referring to 'functional group'. With about equal representation of the attributes 'function', 'abundance' and 'diversity', SPGs for pollination therefore would seem best substantiated by EPFs at the level of functional group.

Elaborations on the use of the ecosystem services concept for application in ecological risk assessment for soils.

This paper describes scientific developments that have raised awareness that changes in ecological risk assessment (ERA) methods are necessary. These changes have also been triggered by developments in environmental policies. This is illustrated by examples for The Netherlands and Europe. The ecosystem services concept seems to gain a central role in developments of new ERA methods. Main reasons for this are the integrative character of the concept, making it possible to integrate over environmental compartments or over environmental assessment methods, the concept's strength as communication tool and the possibility to value ecosystem services in economic terms. A method using ecosystem services in ERA is presented here in more detail, as an example. In this method assessment endpoints are derived from structures and processes in the ecosystem that are considered indispensable for the provision of particular ecosystem services. The approach facilitates fine-tuning ERA to specific land use demands.

Ecological vulnerability analysis: a river basin case study.

Assessing and quantifying ecosystem vulnerability is a key issue in site-specific ecotoxicological risk assessment. In this paper, the concept of vulnerability, particularly referred to aquatic ecosystems is defined. Sensitivity to stressors, susceptibility for exposure and recovery capability are described as component of vulnerability of biological communities. The potential for habitat changes must also be considered in ecosystem vulnerability assessment. A procedure based on the application of an ecosystem vulnerability index is proposed. The method allows the assessment of vulnerability of riverine ecosystems to multiple stressors. The procedure is applied to two river systems in northern Italy: River Serio, subject to strong human pressure, and River Trebbia, in semi-natural conditions, as reference system. Macrozoobenthos is chosen as the indicator community. The actual quality of River Serio was evaluated as the result of the multiple stressor pressure on the reference system. Values and limitations of the approach are discussed.

Ecological vulnerability in risk assessment--a review and perspectives.

This paper reviews the application of ecological vulnerability analysis in risk assessment and describes new developments in methodology. For generic non-site-specific assessments (e.g. for the requirements of most European directives on dangerous chemicals) risk is characterised just on the basis of the ratio between an effect indicator and an exposure indicator. However, when the actual risk for a specific ecosystem is desired, the concept of ecological vulnerability may be more appropriate. This calls for a change in thinking, from sensitivity at the organism level to vulnerability at higher organization levels, and thus forms the link from laboratory toxicology to field effects at population, community or ecosystem level. To do so, biological and ecological characteristics of the ecosystems under concern are needed to estimate the ecological vulnerability. In this review we describe different vulnerability analysis methods developed for populations (of a single species), communities (consisting of different populations of species) and ecosystems (community and habitat combined). We also give some examples of methods developed for socio-ecological systems. Aspects that all methods share are the use of expert judgment, the input of stakeholders, ranking and mapping of the results, and the qualitative nature of the results. A new general framework is presented to guide future ecological vulnerability analysis. This framework can be used as part of ecological risk assessment, but also in risk management. We conclude that the further quantification of ecological vulnerability is a valuable contribution to vulnerability assessment.

Strongly enhanced dissolution rate of fenofibrate solid dispersion tablets by incorporation of superdisintegrants.

In this study, it was shown that the incorporation of superdisintegrants in solid dispersion tablets containing a high drug load can strongly enhance the dissolution rate of the highly lipophilic drug fenofibrate. In addition, the dissolution rate was more increased when the superdisintegrant was incorporated in the drug containing solid dispersions than when it was physically mixed with the solid dispersions. The dissolution rate enhancement strongly depended on the type of superdisintegrants and increased in the order Polyplasdone XL-10

Biotransformation and pharmacokinetics of the antiplasmodial naphthylisoquinoline alkaloid dioncophylline A.

The biotransformation of the antiplasmodial naphthylisoquinoline alkaloid dioncophylline A by rat liver microsomes and its pharmacokinetics in male rats were studied. Incubation of dioncophylline A with rat liver microsomes resulted in the formation of the major metabolite 5'-O-demethyldioncophylline A, and a second minor metabolite, corresponding to the mass of an as yet unknown 4-hydroxydioncophylline A. Kinetic constants of the formation of 5'-O-demethyldioncophylline A were Km = 32 nmol and Vmax = 20 pmol min-1 mg-1). Administration of dioncophylline A at a dose of 6.67 mg kg-1 body weight to rats intravenously and orally (n = 4 per group) resulted in peak plasma levels of 0.84 and 0.11 microg ml-1, respectively. Levels of metabolites were below the limit of quantitation (LOQ). The following pharmacokinetic parameters of dioncophylline A were determined: oral bioavailability of 25%, plasma half-life of 2.5 h and partition volume of 8 l kg-1 body weight. Concentrations of dioncophylline A metabolites in all plasma and urine samples were below the limit of detection (LOD) and recovery of dioncophylline A in urine was very low, suggesting distribution into lipid rich tissues.

Within-trophic group interactions of bacterivorous nematode species and their effects on the bacterial community and nitrogen mineralization.

Knowledge of the interactions between organisms within trophic groups is important for an understanding of the role of biodiversity in ecosystem functioning. We hypothesised that interactions between bacterivorous nematodes of different life history strategies would affect nematode population development, bacterial community composition and activity, resulting in increased N mineralization. A microcosm experiment was conducted using three nematode species (Bursilla monhystera, Acrobeloides nanus and Plectus parvus). All the nematode species interacted with each other, but the nature and effects of these interactions depended on the specific species combination. The interaction between B. monhystera and A. nanus was asymmetrically competitive (0,-), whereas that between B. monhystera and P. parvus, and also A. nanus and P. parvus was contramensal (+, -). The interaction that affected microcosm properties the most was the interaction between B. monhystera and P. parvus. This interaction affected the bacterial community composition, increased the bacterial biomass and increased soil N mineralization. B. monhystera and P. parvus have the most different life history strategies, whereas A. nanus has a life history strategy intermediate to those of B. monhystera and P. parvus. We suggest that the difference in life history strategies between species of the same trophic group is of importance for their communal effect on soil ecosystem processes. Our results support the idiosyncrasy hypothesis on the role of biodiversity in ecosystem functioning.

Biodiversity effects on soil processes explained by interspecific functional dissimilarity.

The loss of biodiversity can have significant impacts on ecosystem functioning, but the mechanisms involved lack empirical confirmation. Using soil microcosms, we show experimentally that functional dissimilarity among detritivorous species, not species number, drives community compositional effects on leaf litter mass loss and soil respiration, two key soil ecosystem processes. These experiments confirm theoretical predictions that biodiversity effects on ecosystem functioning can be predicted by the degree of functional differences among species.