A simplified index to quantify the irritation/corrosion potential of chemicals - Part II: Eye.

Eye irritation is a key human health endpoint assessed by in vitro and in vivo methods. One of the commonly used scoring methods to quantify the eye irritation potential of chemicals is the Modified Maximum Average Score (MMAS). It is dependent on the eye irritation effects (e.g. corneal opacity) originally proposed by Draize and then partially adopted by the OECD TG 405. These scores are not always fully reported in regulatory dossiers and lead to several drawbacks, 1) the difficulty to translate MMAS into a classification within the existing EU CLP/UN GHS criteria, 2) the absence of corrosion (serious eye damage), and 3) the dependency on input parameters which are usually not required under the OECD TGs (e.g. eye surface area). This study determined if classification can be driven by a maximum of two observed effects thereby simplifying the scoring calculation. The Simplified Irritation Index (SIIEYE), based only on corneal opacity and conjunctival redness, was developed using validated studies representing multiple chemical groups. A correlation was observed between the MMAS and the SIIEYE allowing harmonisation of the classification for the existing data. This index proved to be useful in the development of in silico model.

A simplified index to quantify the irritation/corrosion potential of chemicals - Part I: Skin.

Skin irritation is a key human health endpoint assessed by in vitro and in vivo methods. The OECD TG 404 guideline (in vivo) is based on erythema and oedema translated semi-quantitatively into Draize scores, providing hazard statements for substance classification following EUCLP/UNGHS criteria. Draize scores require quantitation from subjective in vivo observations, to obtain a scoring index, the Primary Irritation Index (PII). However, it is not recognised under REACH due to translating difficulties, notably the cut-off limit for classification and non-inclusion of corrosive effects. The aim of this study was to determine if classification can be driven by just one of the observed effects, erythema only, to create a Simplified Irritation Index (SIISKIN). This simplifies the scoring calculation and reduces subjectivity. A quantitative approach with cut-off limits is thus proposed for classification. Substances can be classified as non-irritant, potentially irritant, irritant, or corrosive. The Simplifed Irritation Index (SIISKIN) is based on validated studies, representing multiple chemical groups. A significant correlation between SIISKIN and the harmonised classification was observed, and a proportionate relationship between the SIISKIN and the corresponding PII. The index proved to be useful in the development of an in silico model.

Application of screening tools for environmental hazard and risk to support assessment and subsequent prioritization of effluent discharges from the oil and gas industry.

Assessment and management of effluent discharges are key to avoiding environmental deterioration. Often compliance with discharge regulations and permits is based on a limited set of chemical parameters, while information on whole effluent hazardous properties (toxicity, bioaccumulation potential, persistence) and environmental risks is lacking. The need to collect those data and to become more effective in quickly identifying high-risk activities, without extensive laboratory testing, has led to the development of screening tools to complement information on chemical composition. A simple, Tier 1 screening "toolbox" is proposed which is comprised of solid-phase microextraction with gas chromatographic (SPME-GC) analysis, the in-vitro ecotoxicity assay Microtox, and a simple weathering assay. When combined with dilution modeling, screening-level risk assessments can be performed, providing additional lines of evidence to support a weight of evidence type of analysis. Application of the toolbox enables prioritization of discharges that may be deemed to require higher tier assessment. The toolbox was trialed on a number of produced water samples collected from offshore oil and gas facilities and effluents from petroleum processing and manufacturing sites. In contrast to what has been reported for petroleum products, results showed only moderate correlation between bioavailable hydrocarbons (bHCs) and toxicity, which might be related to the possible presence of toxic contaminants from other chemical classes or to methodological issues such as suboptimal conditions during transport. The methods employed were quick, inexpensive, and simple to conduct. They require relatively small volumes of sample, which is especially advantageous when evaluating discharges from remote offshore facilities. The toolbox adds valuable information on whole effluent properties to existing data, for example, on chemical composition, which can improve understanding of which discharges are more likely to pose a risk to the environment and so require further investigation or risk management. Integr Environ Assess Manag 2021;17:1025-1036. © 2021 Shell International B.V. Integrated Environmental Assessment and Management published by Wiley Periodicals LLC on behalf of Society of Environmental Toxicology & Chemistry (SETAC).

Re-evaluation of target lipid model-derived HC5 predictions for hydrocarbons.

The target lipid model (TLM) has been previously applied to predict the aquatic toxicity of hydrocarbons and other nonionic organic chemicals and for deriving the concentrations above which 95% of species should be protected (HC5 values). Several concerns have been identified with the TLM-derived HC5 when it is applied in a substance risk assessment context. These shortcomings were addressed by expanding the acute and chronic toxicity databases to include more diverse taxonomic groups and increase the number of species. The TLM was recalibrated with these expanded databases, resulting in critical target lipid body burdens and acute-to-chronic ratios that met the required guidelines for using species sensitivity distributions in substance risk assessment. The HC5 equation was further revised to consider covarying model parameters. The calculated HC5 values derived from the revised TLM framework were validated using an independent data set for hydrocarbons comprising 106 chronic values across plants, invertebrates, and fish. Assuming a sum binomial distribution, the 95% confidence limit for a 5% failure is between 0.8 and 9.2%. Eight chronic values fell below the HC5, corresponding to an excursion of 7.5%, which falls within the expected uncertainty bounds. Thus, calculated HC5s derived from the revised TLM framework were found to be consistent with the intended protection goals. Environ Toxicol Chem 2018;37:1579-1593. © 2018 SETAC.

A Review of the Environmental Degradation, Ecotoxicity, and Bioaccumulation Potential of the Low Molecular Weight Polyether Polyol Substances.

"Polyalkylene glycol" is the name given to a broad class of synthetic organic chemicals which are produced by polymerization of one or more alkylene oxide (epoxide) monomers, such as ethylene oxide (EO) and propylene oxide (PO), with various initiator substances which possess amine or alcohol groups. A generalization of this polymerization reaction is illustrated in Fig. 1.

Critical micelle concentration values for different surfactants measured with solid-phase microextraction fibers.

The amphiphilic nature of surfactants drives the formation of micelles at the critical micelle concentration (CMC). Solid-phase microextraction (SPME) fibers were used in the present study to measure CMC values of 12 nonionic, anionic, cationic, and zwitterionic surfactants. The SPME-derived CMC values were compared to values determined using a traditional surface tension method. At the CMC of a surfactant, a break in the relationship between the concentration in SPME fibers and the concentration in water is observed. The CMC values determined with SPME fibers deviated by less than a factor of 3 from values determined with a surface tension method for 7 out of 12 compounds. In addition, the fiber-water sorption isotherms gave information about the sorption mechanism to polyacrylate-coated SPME fibers. A limitation of the SPME method is that CMCs for very hydrophobic cationic surfactants cannot be determined when the cation exchange capacity of the SPME fibers is lower than the CMC value. The advantage of the SPME method over other methods is that CMC values of individual compounds in a mixture can be determined with this method. However, CMC values may be affected by the presence of compounds with other chain lengths in the mixture because of possible mixed micelle formation. Environ Toxicol Chem 2016;35:2173-2181. © 2016 SETAC.

Comprehensive review of several surfactants in marine environments: Fate and ecotoxicity.

Surfactants are a commercially important group of chemicals widely used on a global scale. Despite high removal efficiencies during wastewater treatment, their high consumption volumes mean that a certain fraction will always enter aquatic ecosystems, with marine environments being the ultimate sites of deposition. Consequently, surfactants have been detected within marine waters and sediments. However, aquatic environmental studies have mostly focused on the freshwater environment, and marine studies are considerably underrepresented by comparison. The present review aims to provide a summary of current marine environmental fate (monitoring, biodegradation, and bioconcentration) and effects data of 5 key surfactant groups: linear alkylbenzene sulfonates, alcohol ethoxysulfates, alkyl sulfates, alcohol ethoxylates, and ditallow dimethyl ammonium chloride. Monitoring data are currently limited, especially for alcohol ethoxysulfates and alkyl sulfates. Biodegradation was shown to be considerably slower under marine conditions, whereas ecotoxicity studies suggest that marine species are approximately equally as sensitive to these surfactants as freshwater species. Marine bioconcentration studies are almost nonexistent. Current gaps within the literature are presented, thereby highlighting research areas where additional marine studies should focus.

From Bioavailability Science to Regulation of Organic Chemicals.

The bioavailability of organic chemicals in soil and sediment is an important area of scientific investigation for environmental scientists, although this area of study remains only partially recognized by regulators and industries working in the environmental sector. Regulators have recently started to consider bioavailability within retrospective risk assessment frameworks for organic chemicals; by doing so, realistic decision-making with regard to polluted environments can be achieved, rather than relying on the traditional approach of using total-extractable concentrations. However, implementation remains difficult because scientific developments on bioavailability are not always translated into ready-to-use approaches for regulators. Similarly, bioavailability remains largely unexplored within prospective regulatory frameworks that address the approval and regulation of organic chemicals. This article discusses bioavailability concepts and methods, as well as possible pathways for the implementation of bioavailability into risk assessment and regulation; in addition, this article offers a simple, pragmatic and justifiable approach for use within retrospective and prospective risk assessment.

European Chemicals Agency dossier submissions as an experimental data source: refinement of a fish toxicity model for predicting acute LC50 values.

As a result of the stringent data requirements of the Registration, Evaluation, Authorisation, and Restriction of Chemicals (REACH) regulation, a vast amount of ecotoxicological data has become available through the dissemination portal of the European Chemicals Agency (ECHA). As of April 2014, the database contained 12,439 unique substances from 47,909 dossiers. This vast database could be used to refine existing, or to create new, non-testing methods, such as quantitative structure-activity relationships (QSARs). Acute fish toxicity data were mined from the ECHA database using the eChemPortal; after filtering for single organic substances, 1159 experimental data points remained, representing 564 compounds. To evaluate the quality and accessibility of this data, the authors used the data to refine and improve an existing QSAR. The reliability of the data submitted to the ECHA database, as well as the effectiveness of the Klimisch scoring system, were assessed by comparing the refined QSAR with established QSAR benchmarks. The model developed meets all Organisation for Economic Co-operation and Development principles, has strong internal (leave-one-out internally cross-validated correlation coefficient [Q(2)(LOO)] = 0.91) and external (external coefficient of determination (predicted vs experimental [test set])) validation statistics, and can provide reliable fish median lethal concentration (LC50) predictions for non-polar narcotics. Although some issues with dossier misinformation were discovered, it was found that the ECHA dissemination portal is a valuable and reliable data source. When queried using the eChemPortal, chemical dossiers containing reliable data could be found quickly. The ECHA dissemination portal holds great potential for future QSAR development and improvement, such as updating QSARs within the Ecological Structure-Activity Relationships (ECOSAR) program.

PETRORISK: a risk assessment framework for petroleum substances.

PETRORISK is a modeling framework used to evaluate environmental risk of petroleum substances and human exposure through these routes due to emissions under typical use conditions as required by the European regulation for the Registration, Evaluation, Authorization and Restriction of Chemicals (REACH). Petroleum substances are often complex substances comprised of hundreds to thousands of individual hydrocarbons. The physicochemical, fate, and effects properties of the individual constituents within a petroleum substance can vary over several orders of magnitude, complicating risk assessment. PETRORISK combines the risk assessment strategies used on single chemicals with the hydrocarbon block approach to model complex substances. Blocks are usually defined by available analytical characterization data on substances that are expressed in terms of mass fractions for different structural chemical classes that are specified as a function of C number or boiling point range. The physicochemical and degradation properties of the blocks are determined by the properties of representative constituents in that block. Emissions and predicted exposure concentrations (PEC) are then modeled using mass-weighted individual representative constituents. Overall risk for various environmental compartments at the regional and local level is evaluated by comparing the PECs for individual representative constituents to corresponding predicted no-effect concentrations (PNEC) derived using the Target Lipid Model. Risks to human health are evaluated using the overall predicted human dose resulting from multimedia environmental exposure to a substance-specific derived no-effect level (DNEL). A case study is provided to illustrate how this modeling approach has been applied to assess the risks of kerosene manufacture and use as a fuel.

What contribution do detergent fatty alcohols make to sewage discharges and the marine environment?

To investigate the potential sources of fatty alcohols arriving at a WWTP and entering the receiving waters, a study was conducted at Treborth North Wales using compound specific stable isotope mass spectrometry (¹³C and ²H). Samples were collected from soils, marine sediments, detergents used in the catchment and in the WWTP. Total fatty alcohol concentrations decreased in the liquid phases through the treatment works with the majority of the compounds accumulating in the sludge (biosolids). Natural plant based detergents have δ¹³C values between -26 and -32‰ while petroleum-based detergents occupy a range between -25 and -30‰. The corresponding δ²H values are -250‰ for natural sourced materials and -50‰ for oil-based detergents which enable these two sources to be separated. The influent to the WWTP contained fatty alcohols which originated mainly from faecal sources and natural surfactants (∼75%) with a smaller amount potentially derived from petroleum-based surfactants (∼25%). The effluents from the WWTP contained mainly short chain compounds with a chain length less than C¹6. Their δ²H stable isotope signature was different to the other potential sources examined and suggests bacterial synthesis during the treatment processes. The sludge had relatively high concentrations of fatty alcohols as would be expected from their low water solubility. The stable isotopic signatures were consistent with a mixture of faecal and detergent sources. The sludge in this area is routinely spread on agricultural land as a fertiliser and may find its way back into the sea via land runoff. On the basis of the mean discharge rates and the mean C12 concentration in the effluent, this WWTP would contribute ∼300 g day⁻¹ to the receiving waters. The marine sediment samples had short chain fatty alcohols that are typical of marine production and with stable isotope values that indicate exclusive marine production for the C14 potentially mixed with terrestrial sources for the C16 and C18 compounds. Therefore, the fatty alcohols in the marine sediments are not the same as those that were discharged in the liquid effluent and these fatty alcohols were not the ones that entered the works through the influent but were synthesised or recycled within the works.