Hans Sanderson

Effects of 25 pharmaceutical compounds to Lemna gibba using a seven-day static-renewal test

Antibiotics are known to have antichloroplastic properties, but their effects on aquatic higher plants are virtually unknown. In order to address this issue, 25 pharmaceuticals, including 22 antibiotics, were assessed for phytotoxicity to the aquatic higher plant Lemna gibba. A 7-d static-renewal test was used, and plants were treated with 0, 10, 30, 100, 300, and 1,000 microg/L of pharmaceutical-containing growth media. Phytotoxicity was assessed using multiple growth and biochemical endpoints. Effective concentration (EC)50, EC25, and EC10 values as well as tests for significant differences between treatments and controls lowest-observed-effect concentration (LOECs) were calculated for each endpoint. Twelve different classes of antibiotics were assessed; however, only members of the fluoroquinolone, sulfonamide, and tetracycline classes of antibiotics displayed significant phytotoxicity. The most toxic members of each of these classes tested were lomefloxacin, sulfamethoxazole, and chlortetracycline, with wet weight EC25 values of 38, 37, and 114 microg/L, respectively. Injury symptoms were comparatively uniform and consistent among chemical classes while degree of phytotoxicity varied considerably. Both of these criteria varied markedly between classes. Wet mass was consistently the most sensitive endpoint above 100 microg/L; conversely, frond number was the most sensitive below 100 microg/L. Pigment endpoints were significantly less sensitive than growth endpoints.

Comparative analysis of pharmaceuticals versus industrial chemicals acute aquatic toxicity classification according to the United Nations classification system for chemicals. Assessment of the (Q)SAR predictability of pharmaceuticals acute aquatic toxicity and their predominant acute toxic mode-of-action.

Pharmaceuticals have been reported to be ubiquitously present in surface waters prompting concerns of effects of these bioactive substances. Meanwhile, there is a general scarcity of publicly available ecotoxicological data concerning pharmaceuticals. The aim of this paper was to compile a comprehensive database based on OECDs standardized measured ecotoxicological data and to evaluate if there is generally cause of greater concern with regards to pharmaceutical aquatic toxicological profiles relative to industrial chemicals. Comparisons were based upon aquatic ecotoxicity classification under the United Nations Global Harmonized System for classification and labeling of chemicals (GHS). Moreover, we statistically explored whether the predominant mode-of-action (MOA) for pharmaceuticals is narcosis. We found 275 pharmaceuticals with 569 acute aquatic effect data; 23 pharmaceuticals had chronic data. Pharmaceuticals were found to be more frequent than industrial chemicals in GHS category III. Acute toxicity was predictable (>92%) using a generic (Q)SAR ((Quantitative) Structure Activity Relationship) suggesting a narcotic MOA. Analysis of model prediction error suggests that 68% of the pharmaceuticals have a non-specific MOA. Additionally, the acute-to-chronic ratio (ACR) for 70% of the analyzed pharmaceuticals was below 25 further suggesting a non-specific MOA. Sub-lethal receptor-mediated effects may however have a more specific MOA.

Adverse outcome pathways during early fish development: a conceptual framework for identification of chemical screening and prioritization strategies.

The fish early life-stage (FELS) test guideline (OECD 210 or OCSPP 850.1400) is the most frequently used bioassay for predicting chronic fish toxicity and supporting aquatic ecological risk assessments around the world. For each chemical, the FELS test requires a minimum of 360 fish and 1 to 3 months from test initiation to termination. Although valuable for predicting fish full life-cycle toxicity, FELS tests are labor and resource intensive and, due to an emphasis on apical endpoints, provide little to no information about chemical mode of action. Therefore, the development and implementation of alternative testing strategies for screening and prioritizing chemicals has the potential to reduce the cost and number of animals required for estimating FELS toxicity and, at the same time, provides insights into mechanisms of toxicity. Using three reference chemicals with well-established yet distinct adverse outcome pathways (AOPs) in early life stages of fish, we proposed FELS-specific AOPs as conceptual frameworks for identifying useful chemical screening and prioritization strategies. The reference chemicals selected as case studies were a cardiotoxic aryl hydrocarbon receptor agonist (2,3,7,8-tetrachlorodibenzo-p-dioxin), neurotoxic acetylcholinesterase inhibitor (chlorpyrifos), and narcotic surfactant (linear alkylbenzene sulfonate). Using qualitative descriptions for each chemical during early fish development, we developed generalized AOPs and, based on these examples, proposed a three-tiered testing strategy for screening and prioritizing chemicals for FELS testing. Linked with biologically based concentration-response models, a tiered testing strategy may help reduce the reliance on long-term and costly FELS tests required for assessing the hazard of thousands of chemicals currently in commerce.

Environmental Safety of the Use of Major Surfactant Classes in North America

This paper brings together over 250 published and unpublished studies on the environmental properties, fate, and toxicity of the four major, high-volume surfactant classes and relevant feedstocks. The surfactants and feedstocks covered include alcohol sulfate or alcohol sulfate (AS), alcohol ethoxysulfate (AES), linear alkylbenzene sulfonate (LAS), alcohol ethoxylate (AE), and long-chain alcohol (LCOH). These chemicals are used in a wide range of personal care and cleaning products. To date, this is the most comprehensive report on these substances chemical structures, use, and volume information, physical/chemical properties, environmental fate properties such as biodegradation and sorption, monitoring studies through sewers, wastewater treatment plants and eventual release to the environment, aquatic and sediment toxicity, and bioaccumulation information. These data are used to illustrate the process for conducting both prospective and retrospective risk assessments for large-volume chemicals and categories of chemicals with wide dispersive use. Prospective risk assessments of AS, AES, AE, LAS, and LCOH demonstrate that these substances, although used in very high volume and widely released to the aquatic environment, have no adverse impact on the aquatic or sediment environments at current levels of use. The retrospective risk assessments of these same substances have clearly demonstrated that the conclusions of the prospective risk assessments are valid and confirm that these substances do not pose a risk to the aquatic or sediment environments. This paper also highlights the many years of research that the surfactant and cleaning products industry has supported, as part of their environmental sustainability commitment, to improve environmental tools, approaches, and develop innovative methods appropriate to address environmental properties of personal care and cleaning product chemicals, many of which have become approved international standard methods.

Use of a (Quantitative) Structure–Activity Relationship [(Q)Sar] Model to Predict the Toxicity of Naphthenic Acids

Naphthenic acids (NA) are a complex mixture of carboxylic acids that are natural constituents of oil sand found in north-eastern Alberta, Canada. NA are released and concentrated in the alkaline water used in the extraction of bitumen from oil sand sediment. NA have been identified as the principal toxic components of oil sands process-affected water (OSPW), and microbial degradation of lower molecular weight (MW) NA decreases the toxicity of NA mixtures in OSPW. Analysis by proton nuclear magnetic resonance spectroscopy indicated that larger, more cyclic NA contain greater carboxylic acid content, thereby decreasing their hydrophobicity and acute toxicity in comparison to lower MW NA. The relationship between the acute toxicity of NA and hydrophobicity suggests that narcosis is the probable mode of acute toxic action. The applicability of a (quantitative) structure–activity relationship [(Q)SAR] model to accurately predict the toxicity of NA-like surrogates was investigated. The U.S. Environmental Protection Agency (EPA) ECOSAR model predicted the toxicity of NA-like surrogates with acceptable accuracy in comparison to observed toxicity values from Vibrio fischeri and Daphnia magna assays, indicating that the model has potential to serve as a prioritization tool for identifying NA structures likely to produce an increased toxicity. Investigating NA of equal MW, the ECOSAR model predicted increased toxic potency for NA containing fewer carbon rings. Furthermore, NA structures with a linear grouping of carbon rings had a greater predicted toxic potency than structures containing carbon rings in a clustered grouping.

Environmental Hazards of Sea-Dumped Chemical Weapons

Does the post-WWII burial at sea of chemical weapons still pose a human and environmental risk?

Impact of perfluorooctanoic acid on the structure of the zooplankton community in indoor microcosms

There is presently, a substantial amount of information being gathered concerning the environmental risk associated with the perfluorooctanoic acid (PFOA) compound. The aim of this paper was to determine a 35 day community no observable effect concentration (NOEC(community)) or lowest observable effect concentration (LOEC) for freshwater zooplankton exposed to PFOA during a study in 30 l indoor aquatic microcosms. Some significant (P < 0.01) temporal fluctuations in zooplankton abundance were observed, however, a NOEC(community) could not be calculated. LOEC for various species varied between 10 and 70 mg l(-1). According to LOEC values, the tentative order of descriptors sensitivity was as follows: Daphnia magna > richness > or = Cyclops canthocamptus staphylinus > Cyclops diaptomus>total zooplankton > or = Rotifera sp. The long term ecological significance of these temporal fluctuations could not be determined in this study, however, the overall study cessation analysis showed that the structure of the ecosystem was changed from a more diverse community dominated by larger species towards a less diverse community dominated by smaller more and robust species (P < 0.05). Additional chronic toxicity testing should also be addressed since these compounds are so persistent and recalcitrant.

Human health risk screening due to consumption of fish contaminated with chemical warfare agents in the Baltic Sea.

Chemical warfare agents (CWAs) have been disposed of in various fashions over the past decades. Significant amounts of CWA, roughly 11,000ton, have been dumped in the Baltic Sea east of the island Bornholm following the disarmament of Germany after World War II. This has caused concerns over potential human and environmental health risks, and resulted in restrictions on fishing in the dumpsite area. The purpose of this paper is to assess the potential indirect human health risks due to consumption of CWA-contaminated fish from the dumpsite area east of Bornholm. Earlier studies suggest that the fish community may be at risk from CWA exposure in the Bornholm basin. Moreover, elevated frequencies of lesions on fish caught in a CWA dumpsite in the Mediterranean Sea have been observed. The fish at the Mediterranean dumpsite had elevated total arsenic (As) concentrations in their tissue, and elevated total As levels were also observed in the sediment. Elevated total sediment As concentrations have also been recorded in CWA dumpsites in the Skagerrak and the Baltic Sea. Triphenylarsine and sulfur mustard gas (Yperite) are the CWAs with the greatest indirect human health risk potential. There are recognized uncertainties concerning Yperites and CWA-derived arsenicals fate and speciation in the environment, as well as their inherent toxicity, warranting caution and further site-specific environmental and human health risk assessments of CWAs dumped in the Bornholm basin.

Pesticide studies: replicability of micro/mesocosms.

The objective of this state-of-the-art review was to quantify the replicability of pesticide studies using micro/ mesocosms. Low interpretability of micro/mesocosm studies, and inconclusive and highly variable data, resulted in a discontinuation of the use of these studies for the registration of pesticides. Coefficients of variation, CV%, were calculated on the basis of data tables as a measure of statistical ‘effectiveness’ taken from the literature. The average CV in the investigated studies was 45%; larger out-door mesocosms averaged 51%, and smaller indoor micro/mesocosms averaged 32%. CVs on variables involving animals were higher than CVs on plant end-points, which in turn were higher than abiotic variables for all experiments. However, to enhance the interpretability and implementation of micro/mesocosm studies for pesticide registration, a number of context-dependent steps could be incorporated; 1) determine the appropriate experimental design and number of replicates by using power analysis, 2) Utilise advanced statistical analysis, such as probabilistic effect distribution and principal response curves, 4) report, preferably in quantitative terms using power analysis, the risk of Type II error. The author’s primary conclusion is that the level of CVs is context dependent and, therefore, it is not possible to suggest a generally acceptable level of CVs for all experiments. This has been suggested both directly and indirectly in the literature. Moreover, the number of insignificant (p > 0.05) results is high, 88% of all test biotic variables had no statistical significance. The average number of replicates were 3–4, which theoretically should yield significant effects at least at the highest test-concentration, then resulting in 75-66% insignificant results.

Power analysis as a reflexive scientific tool for interpretation and implementation of the precautionary principle in the European Union.

The diversity of interpretation, the subsequent lack of implementation, and the enforcement of the precautionary principle have been important issues in the European environmental discourse for the past five years. The European Commission published a communication on the Commission’s interpretation of the precautionary principle on February 2nd, 2000. However, the distinction between precaution and prevention is absent in the EU Commission’s interpretation, resulting in the communication’s lacking relevance for the precautionary principle. The important consequence of the precautionary concept in policy and decision-making is that it should not be based on an assumed certainty of the certainty of environmental knowledge — but rather on a certainty of the uncertainty of environmental knowledge. In other words, the regulation should, to a greater extent, be based on the management of uncertainty, and risk assessments should explicitly present and discuss related uncertainty and lack of knowledge. The management of uncertainty should be based on setting the acceptable level of risk of accepting a failure to reject the null hypothesis of no adverse effects (β). This is done by setting the required power (1-β) according to a socioeconomic cost-benefit analysis. Moreover, the acceptable ecological effect size (A) could also be seta priori which would have implications for the power of a study. Reversal of the burden of proof could be considered in order to resolve possible legal implications for the risk managers.