Environmental Toxicology and Chemistry最新文献

A critical element for understanding measured concentrations and predicting exposure levels of UV filters (UVFs) in recreational waters relates to mass released from sunscreen products applied to skin during swimming and bathing. A probabilistic mass transfer kinetic model was developed to estimate distributions of the mass of five organic UVFs released during individual swim events with sunscreen. The model incorporates the ratios of different demographics and distributions of their total skin areas, adjusted to account for body areas to which sunscreens are not typically applied or do not contact water. The resulting distribution of skin areas is combined with distributions of sunscreen application rates and UVF levels in sunscreen products to generate a distribution of UVF masses on skin that are exposed to water with the fraction released to water calculated using a first-order equation describing the kinetics of release. The predicted median mass released during a swim event was 112 mg for oxybenzone, 32.6 mg for avobenzone, 23.5 mg for octocrylene, 47.7 mg for homosalate and 7.59 mg for octisalate. As proof of principle, the model was used to repeat previous modelling at Prophète Beach, which resulted in predicted median values for oxybenzone and avobenzone within a factor of three of the reported measured environmental concentrations.

Alternative approaches to traditional animal testing are being promoted to support regulatory chemical risk assessments for environment and human health. The Organisation for Economic Development (OECD) has validated some in vitro test methods, but these methods are often suitable only for mono-constituent chemicals with a limited range of physicochemical properties. Most in vitro test methods are not suitable for poorly soluble, (semi)volatile, or multi-constituent chemical substances without significant methodological adaptations. In particular, substance of Unknown or Variable composition, Complex reaction products or Biological materials (UVCBs), including hydrocarbon UVCBs and petroleum substances (PS), can pose serious challenges for in vitro (eco)toxicity testing due to their complexity and variable chemical compositions. The choice of dosing method will depend on the purpose of the test as well as the physicochemical properties of the test substance. It remains difficult to establish and maintain stable exposures of PS in in vitro test systems due to different factors, including (1) the high surface area to volume ratios of multi-well plates that promotes sorption, (2) the open test wells that allow (semi)volatile constituents to escape or contaminate neighbouring plate wells, (3) the difficulty to analytically confirm exposure in small testing volumes and (4) the presence of lipids and proteins in biological media which bind PS constituents. This review maps the currently used dosing methods for hydrophobic and/or (semi)volatile chemicals and UVCBs in in vitro tests for environment and human health hazard assessments and outlines approaches and modifications to overcome various testing challenges associated with these test substances. Finally, research gaps are identified and recommendations made for future development of in vitro assays for UVCBs.

Exposure of fish early life stages to polycyclic aromatic hydrocarbons (PAHs) causes negative impacts on development of teleost fish, which can be exacerbated by rising global temperatures. This study investigated the combined effects of exposure to oil water accommodated fractions from the spill that affected the Brazilian northeast and rising temperatures on early development of the zebrafish Danio rerio. Exposure to PAHs caused developmental delay and increased frequency of malformations at 16.47 and 32.95 μg-∑PAHt L-1 at 28 °C, 30 °C, and 32 °C. Incomplete mandible development was not verified after PAH exposure at 28 °C but increased with increasing temperatures. Increased frequency of malformations included thrombosis, deformed heart, pericardial and yolk-sac edemas and spinal kyphosis. Heart rates increased with increasing temperature in control larvae and with increasing PAH concentrations at 28 °C and 30 °C, but not at 32 °C. Total length, eye and swim bladder area of larvae at 168 hr post-fertilization (hpf) decreased with increasing PAH concentrations and increasing temperatures, indicating an additive interaction. Acetylcholinesterase (AChE) activity in control larvae increased with increasing temperatures and decreased with increasing PAH concentrations. Combined exposure to PAHs and temperature elevation intensified developmental delays and teratogenic outcomes, posing additional threats to the viability of Danio rerio early life stages. Results indicate that temperature effects should be considered in oil spill risk assessments under climate change scenarios.

Globally, there has been a push for the development of new approach methods that refine, reduce, and replace animal use in toxicity testing. A large source of this animal use is whole-effluent toxicity testing, which is widely employed in regulation to determine the toxicity of effluents. The rainbow trout acute lethality test is one of the most widely used in North America for this purpose, as it empirically and irrefutably demonstrates effluent toxicity. Despite its strengths, this test is an ideal candidate for replacement due to its frequent use. One replacement is the RTgill-W1 assay, which uses a rainbow trout gill cell line to assess the toxicity of effluent samples. Despite its promise, the RTgill-W1 assay has rarely been investigated for its potential in replacing the rainbow trout acute lethality test. This study assessed the toxicity of pulp and paper mill effluents using the RTgill-W1 assay. Sixty-two effluents were sourced from 3 separate mills with a total of 5 unique sampling locations; an additional 8 effluents were created by mixing effluents together. Of the 70 effluents, 50 were assessed with both the rainbow trout acute lethality test and the RTgill-W1 assay. Twenty of these caused >50% mortality to the rainbow trout and >50% decline in cell viability. An additional 3 effluents caused a >50% decline in cell viability. In effluents causing >50% mortality and a decline in cell viability, there was a strong correlation in toxicity (r = 0.786, p <0.001). The alamarBlue endpoint was more sensitive in filtered effluents (p <0.001). The effluent matrix did not influence the test endpoints, but NH3 was observed to cause significant vacuolation of the cells. Overall, these results are promising for the implementation of the RTgill-W1 assay as a replacement to the rainbow trout acute lethality test for pulp mill effluents.

Freshwater bodies worldwide are experiencing salinization, often with severe ecological consequences. An underexplored topic in freshwater salinization research is the potential for waterbodies to stratify their incoming salty water (due to its higher density) and the effects this stratification may have on freshwater organisms. We conducted a mesocosm experiment to test whether salt stratification can occur in small freshwater bodies and its ecological consequences. We created salt-stratified mesocosms by piping salty water down to the bottom of a 1200-L mesocosm and examined the duration of the created stratification. We discovered that salt stratification in mesocosms can last for several weeks. We then compared the habitat selection and survival of two species of freshwater snails (the native pouch snail, Physa acuta, and invasive banded mystery snail, Viviparus georgianus) when exposed to the presence or absence of salt stratification, crossed with the presence or absence of predation cues (i.e.,, crushed conspecifics). Mystery snails preferred the bottom habitats, regardless of the presence of salt or predator cues, and consequently suffered near total mortality in the salt stratified mesocosms (97% survival without salt vs. 3% survival with). In contrast, the pouch snails reduced their use of the bottom habitat in response to both stratified salt and predator cues While they still suffered mortality in the salt-stratified mesocosms, it was much less than the mystery snails. (82% survival without salt vs. 47% survival with salt). These results suggest that the stratification of salt pollution in freshwater bodies can persist for prolonged periods and differentially affect freshwater species as a result of their habitat preferences.

The phenolic compound 3-trifluoromethyl-4'-nitrophenol (TFM) is used as a lampricide, applied to rivers and streams to control populations of invasive sea lamprey (Petromyzon marinus) in the Great Lakes. 3-Trifluoromethyl-4'-nitrophenol is used to selectively target larval sea lamprey because of their limited capacity to detoxify it. The tissue TFM accumulation impairs mitochondrial adenosine triphosphate production by uncoupling oxidative phosphorylation, leading to energy depletion and death. Sea lamprey tolerance to TFM is greater in the summer, but the underlying mechanism(s) are unresolved. The present study tested the hypothesis that an increased capacity of sea lamprey to eliminate TFM at warmer temperatures increases their tolerance to TFM. Acute toxicity tests demonstrated that the 12-hr median lethal concentration (LC50) of TFM steadily increased by approximately 1.5-fold as water temperature rose from 7 to 28 °C. When lamprey were acclimated to one of three temperatures (6, 12, 24 °C) and exposed to an identical TFM concentration (i.e., 12-hr LC25 at 12 °C), muscle and liver TFM concentrations were approximately 30% and 36% lower in lamprey acclimated to 24 °C, suggesting more effective elimination of TFM at warmer temperatures. Calculations of the TFM steady state concentration and elimination half-life (t1/2) in the liver and muscle following TFM exposure suggested that they have a greater capacity to eliminate TFM in warmer water. We propose that the sea lamprey's capacity to detoxify TFM is greater at higher temperatures, preventing internal concentrations from reaching lethal levels during acute (9-12 hr) TFM exposure of similar duration to field applications. We also propose that water temperature, in addition to water pH and alkalinity, be considered when determining TFM application concentration used to optimize sea lamprey treatment effectiveness.

The potential impact of imidacloprid on human and environmental health has been the topic of recent research. The present study conducted an unprecedented scientometric analysis of the insecticide imidacloprid, encompassing all articles addressing it, to provide an overview of studies that detect and analyze its effects. Scientific publications were obtained from the Web of Science™, and after manually reviewing all titles, abstracts, and methods, articles related to imidacloprid were selected for analysis. The results were analyzed using the Microsoft Office Excel®, VosViewer, and R programs, the last one using the 'Bibliometrix' package. A total of 5,485 articles were written by 16,224 authors with an H-index of 128, suggesting a relevant impact factor for this line of research. Over time, the research has had thematic changes: in the first decade (1991-2001), it was most related to the actions of this insecticide in the target organisms, and in the last decade (2012-2022), there has been an increase in studies on ways to detect this insecticide in different matrices and its toxicity. The increase in the frequency of the keyword "toxicity" demonstrates that researchers have concentrated on understanding the effects of this insecticide, particularly on bees. Researchers have invested more in detecting the presence of imidacloprid in water and its consequences for non-target organisms. However, it is still necessary to invest in research and technologies to remediate the presence of these compounds in surface waters, soils, and sediments, minimizing the chronic exposure of non-target organisms.

Persistence, defined as the resistance of chemicals to environmental degradation, is a central criterion in regulatory hazard assessments under the European Union Registration, Evaluation, Authorisation, and Restriction of Chemicals and Labelling and Packaging regulations. It determines both long-term exposure potential and the reversibility of environmental contamination. The Organisation for Economic Co-operation and Development (OECD) Test Guideline (TG) 309, which assesses aerobic mineralisation in surface water, is a cornerstone method for deriving degradation half-lives used in Persistence and very Persistent (P/vP) classifications. However, despite its regulatory status, TG 309 suffers from significant variability in outcomes, raising concerns over its reliability, reproducibility, and suitability for determining an intrinsic property. This article reviews the European regulatory framework and critically examines inoculum properties (e.g.,, source, suspended solids, total and dissolved organic carbon, microbial density, pH, seasonality) and technical factors (e.g.,, inoculum storage, temperature, test concentration, adaptation vs. cometabolism) that influence test results. While research has identified several parameters affecting biodegradation kinetics, many studies deviate from regulatory conditions, limiting their applicability (e.g.,, pre-exposed inoculum, sediment addition, test temperature…). Current evidence highlights the so-called "lottery effect," whereby even readily biodegradable substances may sometimes be classified as Persistent, undermining the test's regulatory robustness. It is concluded that no set of universally relevant conditions currently ensures reproducible determination of Persistence as an intrinsic property. This uncertainty poses significant regulatory challenges, particularly as new hazard classes such as PMT/vPvM expand the scope of Persistence assessments. Research is urgently needed to clarify the role of microbial population dynamics, inoculum sources, and organic carbon composition, and to explore possible refinements that could reduce test variability while maintaining regulatory acceptability.

On-shore produced water (PW) spills can impair soil quality. To provide a practical tool for evaluating efficacy of PW contaminated soil remediation, a seed germination test was developed. This research included three experimental phases. In the first phase, seed germination of two native grasses, Brewster sideoats grama (BSG), and Santiago silver bluestem (SSB), were investigated in 10 d tests with uncontaminated soils. Based on performance, BSG was selected for subsequent phases. In phase two, seed germination tests were performed on field soil spiked with dilutions of PW. A parallel sodium chloride (NaCl) solution prepared at the same chloride concentration as the PW was tested for comparison. Soil electrical conductivity (EC) was used to characterize salt stress. Results indicated similar seed germination inhibition in PW and NaCl treatments. In phase three, exposure to PW and NaCl solutions spiked to field soil was repeated at lower dilutions. Soil exposures to dilutions of a 10 mM solution of a remediation agent, prussian yellow (PY), alone and combined with PW and NaCl were also tested. In addition to soil EC, free cyanide concentrations were determined to assess potential PY photo-dissociation. Results indicated that PY alone did not inhibit seed germination. Further, addition of PY to PW or NaCl did not increase toxicity with low and variable levels of free cyanide reported in soil. These findings support PY use in soil remedial applications. Despite the wide range of potential contaminants in PW, the primary determinant of toxicity was attributed to salinity under the tested conditions. Further work is needed to assess if native grass seed germination tests are predictive of revegetation success in the field.

Evidence supports the presence of a second major source of 2,3,7,8-tetrachlorodibenzo-p-dioxin (2,3,7,8-TCDD) to the Lower Passaic River (LPR) at river mile 12-12.5, identified as the former Givaudan facility in Clifton, New Jersey. Using sediment chemistry and high-resolution dated cores, Garvey et al. (2011) identified an anomalous DDT + DDE (dichlorodiphenyltrichloroethane + dichlorodiphenyldichloroethylene) to 2,3,7,8-TCDD ratio near Givaudan that suggests an upstream source of 2,3,7,8-TCDD. This study integrates these same data with (1) chemical production at Givaudan and the former Diamond Alkali chemical plant in Newark, New Jersey located at river mile 3.5, (2) wastewater infrastructure and combined sewer overflow bypass events, (3) river flow and hydrodynamic models of upstream transport, (4) and estimated 2,3,7,8-TCDD discharged to the LPR. The increase in 2,3,7,8-TCDD and the anomalous DDT + DDE to 2,3,7,8-TCDD ratio observed in late 1950s to early 1960s sediments between river mile (RM) 10 and 12 coincides with increasing 2,4,5-trichlorophenol (2,4,5-TCP) usage (source of 2,3,7,8-TCDD) at both facilities, but the chemical signatures at RM 10-12 do not match Diamond. River flows prior to the drought in the late 1960s limited the upstream extent of transport, making transport from Diamond unlikely to be responsible for the increase in 2,3,7,8-TCDD at RM 10-12. Records show frequent high-volume diversions of the municipal sewer through a bypass at RM 11.5 during this period, resulting in the discharge of large volumes of Givaudan's wastewater. Estimates of the mass of 2,3,7,8-TCDD discharged from Givaudan are comparable to literature-based estimates of discharges from Diamond. These results provide compelling evidence that Givaudan is a second major source of 2,3,7,8-TCDD and accounts for a significant fraction of the 2,3,7,8-TCDD in the LPR.