Joop L. M. Hermens

Bio: Joop L. M. Hermens is an academic researcher from Utrecht University. The author has contributed to research in topics: Solid-phase microextraction & Acute toxicity. The author has an hindex of 65, co-authored 221 publications receiving 12985 citations. Previous affiliations of Joop L. M. Hermens include University of Amsterdam & Swiss Federal Institute of Aquatic Science and Technology.

Modes of action in ecotoxicology: their role in body burdens, species sensitivity, QSARs, and mixture effects.

Abstract: In contrast to the general research attitude in the basic sciences, environmental sciences are often goal-driven and should provide the scientific basis for risk assessment procedures, cleanup, and precautionary measures and finally provide a decision support for policy and management. Hence, the prominent role of mechanistic studies in ecotoxicology is not only to understand the impact of pollutants on living organisms but also to deduce general principles for the categorization and assessment of effects. The goal of this review is, therefore, not to provide an exhaustive coverage of modes of toxic action and their underlying biochemical mechanisms but rather to discuss critically the application of this knowledge in ecotoxicological risk assessment. Knowing the mechanism or, at least, the mode of toxic action is indispensable for developing descriptive and predictive models in ecotoxicology. This review seeks to show the crucial role of target sites, interactions with the target site(s), and mechanisms ...

Determination of octanol/water partition coefficients for hydrophobic organic chemicals with the “slow‐stirring” method

Abstract: Experimental data are presented on octanol/water partition coefficients for 70 hydrophobic organic chemicals that were determined with a “slow-stirring” method. With this method, log Kow values can be obtained relatively easily, with high reproducibility and low standard deviations. For compounds with log Kow values of less than 4.5, the experimental data agree well with literature data based on the classical shake-flask method. For more hydrophobic compounds, deviations occur because of the formation of octanol emulsions in the shake-flask procedure. In general, there is reasonable agreement with literature data obtained by reversed-phase HPLC or the generator-column method, although substantial deviations do occur for some individual compounds, especially the higher-chlorinated ortho-substituted polychlorinated biphenyl (PCB) congeners. For chlorobenzenes, chloroanilines and PCBs, substituent constants (π) are calculated. With these π values, partition coefficients for these compounds can be estimated simply by calculation.

Equilibrium sampling devices.

Abstract: These devices are part of an emerging strategy for monitoring exposure to hydrophobic organic chemicals.

The Challenge of Micropollutants in Aquatic Systems

Abstract: The increasing worldwide contamination of freshwater systems with thousands of industrial and natural chemical compounds is one of the key environmental problems facing humanity. Although most of these compounds are present at low concentrations, many of them raise considerable toxicological concerns, particularly when present as components of complex mixtures. Here we review three scientific challenges in addressing water-quality problems caused by such micropollutants. First, tools to assess the impact of these pollutants on aquatic life and human health must be further developed and refined. Second, cost-effective and appropriate remediation and water-treatment technologies must be explored and implemented. Third, usage and disposal strategies, coupled with the search for environmentally more benign products and processes, should aim to minimize introduction of critical pollutants into the aquatic environment.

Adverse outcome pathways: A conceptual framework to support ecotoxicology research and risk assessment

Abstract: Ecological risk assessors face increasing demands to assess more chemicals, with greater speed and accuracy, and to do so using fewer resources and experimental animals. New approaches in biological and computational sciences may be able to generate mechanistic information that could help in meeting these challenges. However, to use mechanistic data to support chemical assessments, there is a need for effective translation of this information into endpoints meaningful to ecological risk-effects on survival, development, and reproduction in individual organisms and, by extension, impacts on populations. Here we discuss a framework designed for this purpose, the adverse outcome pathway (AOP). An AOP is a conceptual construct that portrays existing knowledge concerning the linkage between a direct molecular initiating event and an adverse outcome at a biological level of organization relevant to risk assessment. The practical utility of AOPs for ecological risk assessment of chemicals is illustrated using five case examples. The examples demonstrate how the AOP concept can focus toxicity testing in terms of species and endpoint selection, enhance across-chemical extrapolation, and support prediction of mixture effects. The examples also show how AOPs facilitate use of molecular or biochemical endpoints (sometimes referred to as biomarkers) for forecasting chemical impacts on individuals and populations. In the concluding sections of the paper, we discuss how AOPs can help to guide research that supports chemical risk assessments and advocate for the incorporation of this approach into a broader systems biology framework.

Canonical correspondence analysis and related multivariate methods in aquatic ecology

Abstract: Canonical correspondence analysis (CCA) is a multivariate method to elucidate the relationships between biological assemblages of species and their environment. The method is designed to extract synthetic environmental gradients from ecological data-sets. The gradients are the basis for succinctly describing and visualizing the differential habitat preferences (niches) of taxa via an ordination diagram. Linear multivariate methods for relating two set of variables, such as twoblock Partial Least Squares (PLS2), canonical correlation analysis and redundancy analysis, are less suited for this purpose because habitat preferences are often unimodal functions of habitat variables. After pointing out the key assumptions underlying CCA, the paper focuses on the interpretation of CCA ordination diagrams. Subsequently, some advanced uses, such as ranking environmental variables in importance and the statistical testing of effects are illustrated on a typical macroinvertebrate data-set. The paper closes with comparisons with correspondence analysis, discriminant analysis, PLS2 and co-inertia analysis. In an appendix a new method, named CCA-PLS, is proposed that combines the strong features of CCA and PLS2.