Simulating behavior of petroleum compounds during refinery effluent treatment using the SimpleTreat model.

Distribution and elimination of petroleum products can be predicted in aerobic wastewater treatment plants (WWTPs) using models such as multimedia fate model SimpleTreat. An advantage of the SimpleTreat model is that it only requires a few basic properties of a chemical in wastewater to calculate partitioning, biodegradation and ultimately emissions to air, surface water and produced sludge. The SimpleTreat model structure reflects a WWTP scheme.

Chemical pollution imposes limitations to the ecological status of European surface waters.

Aquatic ecosystems are affected by man-made pressures, often causing combined impacts. The analysis of the impacts of chemical pollution is however commonly separate from that of other pressures and their impacts. This evolved from differences in the data available for applied ecology vis-à-vis applied ecotoxicology, which are field gradients and laboratory toxicity tests, respectively.

Screening-Level Estimates of Environmental Release Rates, Predicted Exposures, and Toxic Pressures of Currently Used Chemicals.

We describe a procedure to quantify emissions of chemicals for environmental protection, assessment, and management purposes. The procedure uses production and use volumes from registration dossiers and combines these with Specific Environmental Release Category data. The procedure was applied in a case study.

Computational material flow analysis for thousands of chemicals of emerging concern in European waters.

Knowledge of exposure to a wide range of chemicals, and the spatio-temporal variability thereof, is urgently needed in the context of protecting and restoring aquatic ecosystems. This paper discusses a computational material flow analysis to predict the occurrence of thousands of man-made organic chemicals on a European scale, based on a novel temporally and spatially resolved modelling framework. The goal was to increase understanding of pressures by emerging chemicals and to complement surface water monitoring data.

Chemical fate of persistent organic pollutants in the arctic: Evaluation of simplebox.

Persistent organic pollutants (POPs) are of great concern for decades due to their persistence, bioaccumulation and long-range transport potential. Multimedia fate models are useful scientific and decision-support tools for predicting the chemical fate in the environment. The SimpleBox multimedia fate model (v4.

QSAR-Based Estimation of Species Sensitivity Distribution Parameters: An Exploratory Investigation.

Ecological risk assessments are hampered by limited availability of ecotoxicity data. The present study aimed to explore the possibility of deriving species sensitivity distribution (SSD) parameters for nontested compounds, based on simple physicochemical characteristics, known SSDs for data-rich compounds, and a quantitative structure-activity relationship (QSAR)-type approach. The median toxicity of a data-poor chemical for species assemblages significantly varies with values of the physicochemical descriptors, especially when based on high-quality SSD data (from either acute median effect concentrations or chronic no-observed-effect concentrations).

Species sensitivity distributions for use in environmental protection, assessment, and management of aquatic ecosystems for 12 386 chemicals.

The present study considers the collection and use of ecotoxicity data for risk assessment with species sensitivity distributions (SSDs) of chemical pollution in surface water, which are used to quantify the likelihood that critical effect levels are exceeded. This fits the European Water Framework Directive, which suggests using models to assess the likelihood that chemicals affect water quality for management prioritization. We derived SSDs based on chronic and acute ecotoxicity test data for 12 386 compounds.

Time-Integrative Passive sampling combined with TOxicity Profiling (TIPTOP): an effect-based strategy for cost-effective chemical water quality assessment.

This study aimed at demonstrating that effect-based monitoring with passive sampling followed by toxicity profiling is more protective and cost-effective than the current chemical water quality assessment strategy consisting of compound-by-compound chemical analysis of selected substances in grab samples. Passive samplers were deployed in the Dutch river delta and in WWTP effluents. Their extracts were tested in a battery of bioassays and chemically analyzed to obtain toxicity and chemical profiles, respectively.

A chemical activity approach to exposure and risk assessment of chemicals: Focus articles are part of a regular series intended to sharpen understanding of current and emerging topics of interest to the scientific community.

To support the goals articulated in the vision for exposure and risk assessment in the twenty-first century, we highlight the application of a thermodynamic chemical activity approach for the exposure and risk assessment of chemicals in the environment. The present article describes the chemical activity approach, its strengths and limitations, and provides examples of how this concept may be applied to the management of single chemicals and chemical mixtures. The examples demonstrate that the chemical activity approach provides a useful framework for 1) compiling and evaluating exposure and toxicity information obtained from many different sources, 2) expressing the toxicity of single and multiple chemicals, 3) conducting hazard and risk assessments of single and multiple chemicals, 4) identifying environmental exposure pathways, and 5) reducing error and characterizing uncertainty in risk assessment.

Quantitative structure-activity relationships for green algae growth inhibition by polymer particles.

After use and disposal of chemical products, many types of polymer particles end up in the aquatic environment with potential toxic effects to primary producers like green algae. In this study, we have developed Quantitative Structure-Activity Relationships (QSARs) for a set of highly structural diverse polymers which are capable to estimate green algae growth inhibition (EC50). The model (N = 43, R = 0.

The toxicity of plastic nanoparticles to green algae as influenced by surface modification, medium hardness and cellular adsorption.

To investigate processes possibly underlying accumulation and ecological effects of plastic nano-particles we have characterized their interaction with the cell wall of green algae. More specifically, we have investigated the influence of particle surface functionality and water hardness (Ca concentration) on particle adsorption to algae cell walls. Polystyrene nanoparticles with different functional groups (non-functionalized, -COOH and -NH) as well as coated (starch and PEG) gold nanoparticles were applied in these studies.

Towards the review of the European Union Water Framework Directive: Recommendations for more efficient assessment and management of chemical contamination in European surface water resources.

Water is a vital resource for natural ecosystems and human life, and assuring a high quality of water and protecting it from chemical contamination is a major societal goal in the European Union. The Water Framework Directive (WFD) and its daughter directives are the major body of legislation for the protection and sustainable use of European freshwater resources. The practical implementation of the WFD with regard to chemical pollution has faced some challenges.

Combining exposure and effect modeling into an integrated probabilistic environmental risk assessment for nanoparticles.

There is a growing need for good environmental risk assessment of engineered nanoparticles (ENPs). Environmental risk assessment of ENPs has been hampered by lack of data and knowledge about ENPs, their environmental fate, and their toxicity. This leads to uncertainty in the risk assessment.

SimpleBox 4.0: Improving the model while keeping it simple….

Chemical behavior in the environment is often modeled with multimedia fate models. SimpleBox is one often-used multimedia fate model, firstly developed in 1986. Since then, two updated versions were published.

Hierarchical Bayesian Approach To Reduce Uncertainty in the Aquatic Effect Assessment of Realistic Chemical Mixtures.

Species in the aquatic environment differ in their toxicological sensitivity to the various chemicals they encounter. In aquatic risk assessment, this interspecies variation is often quantified via species sensitivity distributions. Because the information available for the characterization of these distributions is typically limited, optimal use of information is essential to reduce uncertainty involved in the assessment.

A semi-empirical model for transport of inorganic nanoparticles across a lipid bilayer: implications for uptake by living cells.

Due to increasing application, release of nanoparticles (NPs) and nanomaterials into the environment becomes likely. Knowledge about NP uptake in organisms is crucial for risk assessment including estimations on the behavior of NPs based on their physicochemical properties. In the present study, the authors have applied current scientific knowledge to construct a mathematical model, which estimates the transport of NPs through a model biological membrane.

Definition and applications of a versatile chemical pollution footprint methodology.

Because of the great variety in behavior and modes of action of chemicals, impact assessment of multiple substances is complex, as is the communication of its results. Given calls for cumulative impact assessments, we developed a methodology that is aimed at expressing the expected cumulative impacts of mixtures of chemicals on aquatic ecosystems for a region and subsequently allows to present these results as a chemical pollution footprint, in short: a chemical footprint. Setting and using a boundary for chemical pollution is part of the methodology.

Simplifying modeling of nanoparticle aggregation-sedimentation behavior in environmental systems: a theoretical analysis.

Parameters and simplified model approaches for describing the fate of engineered nanoparticles (ENPs) are crucial to advance the risk assessment of these materials. Sedimentation behavior of ENPs in natural waters has been shown to follow apparent first order behavior, a 'black box' phenomenon that is insufficiently understood and therefore of limited applicability. Here we use a detailed Smoluchowski-Stokes model that accounts for homo- and heteroaggregation and sedimentation of ENPs and natural colloids (NCs), to simulate and interpret experimental ENP aggregation-sedimentation data.

The Flash Environmental Assessment Tool: worldwide first aid for chemical accidents response, pro action, prevention and preparedness.

The United Nations response mechanism to environmental emergencies requested a tool to support disaster assessment and coordination actions by United Nations Disaster Assessment and Coordination (UNDAC) teams. The tool should support on-site decision making when substantial chemical emissions affect human health directly or via the environment and should be suitable for prioritizing impact reduction management options under challenging conditions worldwide. To answer this need, the Flash Environmental Assessment Tool (FEAT) was developed and the scientific and practical underpinning and application of this tool are described in this paper.

Multimedia modeling of engineered nanoparticles with SimpleBox4nano: model definition and evaluation.

Screening level models for environmental assessment of engineered nanoparticles (ENP) are not generally available. Here, we present SimpleBox4Nano (SB4N) as the first model of this type, assess its validity, and evaluate it by comparisons with a known material flow model. SB4N expresses ENP transport and concentrations in and across air, rain, surface waters, soil, and sediment, accounting for nanospecific processes such as aggregation, attachment, and dissolution.

Rapid settling of nanoparticles due to heteroaggregation with suspended sediment.

Sedimentation of engineered nanoparticles (ENPs) has been studied mainly in artificial media and stagnant systems mimicking natural waters. This neglects the role of turbulence and heteroaggregation with sediment. The authors studied the apparent sedimentation rates of selected ENPs (cerium dioxide [CeO2 ], polyvinylpyrrolidone-capped silver [PVP-Ag], and silica-coated silver [SiO2 -Ag]) in agitated sediment-water systems resembling fresh, estuarine, and marine waters.