Interlaboratory Comparison of Extractable Organofluorine Measurements in Groundwater and Eel (Anguilla rostrata): Recommendations for Methods Standardization.

Research on per- and polyfluoroalkyl substances (PFAS) frequently incorporates organofluorine measurements, particularly because they could support a class-based approach to regulation. However, standardized methods for organofluorine analysis in a broad suite of matrices are currently unavailable, including a method for extractable organofluorine (EOF) measured using combustion ion chromatography (CIC). Here, we report the results of an international interlaboratory comparison. Seven laboratories representing academia, government, and the private sector measured paired EOF and PFAS concentrations in groundwater and eel (Anguilla rostrata) from a site contaminated by aqueous film-forming foam. Among all laboratories, targeted PFAS could not explain all EOF in groundwater but accounted for most EOF in eel. EOF results from all laboratories for at least one replicate extract fell within one standard deviation of the interlaboratory mean for groundwater and five out of seven laboratories for eel. PFAS spike mixture recoveries for EOF measurements in groundwater and eel were close to the criterion (±30%) for standardized targeted PFAS methods. Instrumental operation of the CIC such as replicate sample injections was a major source of measurement uncertainty. Blank contamination and incomplete inorganic fluorine removal may introduce additional uncertainties. To elucidate the presence of unknown organofluorine using paired EOF and PFAS measurements, we recommend that analysts carefully consider confounding methodological uncertainties such as differences in precision between measurements, data processing steps such as blank subtraction and replicate analyses, and the relative recoveries of PFAS and other fluorine compounds.

Effects of simulated environmental discharges of the salmon lice pesticides deltamethrin and azamethiphos on the swimming behaviour and survival of adult Northern shrimp (Pandalus borealis).

Swimming behaviour was investigated in adult egg-carrying northern shrimp (Pandalus borealis) exposed to dilute concentrations of the pesticides Alpha Max® (active ingredient deltamethrin) and Salmosan® (active ingredient azamethiphos) used to control parasitic copepods in salmon aquaculture. These treatments are applied topically within fish nets or well boats. Following a short treatment period, the pesticides are directly discharged to sea, exposing non-target organisms such as P. borealis to diluted concentrations of these chemicals. Locomotor activity was measured continuously in individual shrimp over several days within which they were exposed to treatments of diluted AlphaMax® or Salmosan®. Dilutions were based on modelling and dispersion studies from the literature and were considered environmentally realistic for greater than 1 km from point of discharge. 24 h continuous flow treatments were delivered within a 3.5-day monitoring period to observe the timeline of events following the release of treatment water, addressing questions of temporal responses in locomotor activity, recognising key time points of significant events and assessing the survival capacity of the shrimp. Exposure of shrimp to 1 ng l-1 deltamethrin triggered an immediate increase in swimming activity which reduced in intensity over the following 22 h leaving all shrimp either moribund or dead. A further exposure trial exposing shrimp to 0.2 ng l-1 deltamethrin (nominal) showed an increase in activity at the start of exposure that continued throughout the 24 h delivery, returning to previous levels by the end of the 3.5-day monitoring period. All these shrimps survived for at least four weeks after exposure, putting the threshold concentration of deltamethrin leading to immobility or death in adult P. borealis within this study at greater than 0.2 ng l-1 (nominal) and less than 1 ng l - 1 (measured). Exposure of P. borealis to azamethiphos at 30 ng l-1 induced several periods of significantly increased activity within the first 10 h of exposure and an extended period of reduced activity during post exposure, though no morbidity was observed with this treatment. No significant increase in activity or morbidity was observed in shrimp during a water vehicle control assessment. Shrimps exposed to a combination of 30 ng l-1 azamethiphos and 1 ng l-1 deltamethrin broadly followed the response pattern shown by shrimp exposed to 1 ng l-1 deltamethrin alone. Pesticide residues were not detected in post exposure tissue analyses for either chemical. The potential ecological significance of increased swimming activity at the start of pesticide exposures is discussed.

Effects on Life-History Traits of Hypogastrura viatica (Collembola) Exposed to Imidacloprid Through Soil or Diet.

Collembola (springtails) are important members of soil communities worldwide by contributing to degradation of organic matter. In nature, Collembola might be exposed to the neonicotinoid insecticide imidacloprid, which is fairly persistent in soil. We exposed the widespread Hypogastrura viatica to imidacloprid through soil or food and monitored the animals during exposure and a post exposure period. We recorded effects on life-history traits affecting individual fitness, that is, mortality, behavioral activity, several reproduction traits, and molting frequency. Exposure through soil led to a concentration-dependent mortality, while the mortality from dietary exposure possibly reflected reduced feeding activity. The body burden of imidacloprid in the Collembola did not differ between treatments. We found no sign of recovery in behavioral activity following exposure in either experiment. The egg production of H. viatica was not significantly affected by imidacloprid at 0.01 mg/kg dry soil but showed a tendency to reduce number of eggs per batch and reduced hatching success. At higher concentrations, reproduction was close to, or completely, stopped. The molting frequency decreased during exposure, while in the post exposure period, we saw milder effects at the highest concentrations, suggesting elimination through molting or reduced toxic response as a result of reduced feeding activity. Overall, H. viatica was more sensitive to imidacloprid than previously studied Collembola, which highlights the importance of considering species sensitivities when risk-assessing soil environments. Environ Toxicol Chem 2021;40:3111-3122. © 2021 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC.

Within-Body Distributions and Feeding Effects of the Neonicotinoid Insecticide Clothianidin in Bumblebees (Bombus terrestris).

Bumblebees can be exposed to neonicotinoid pesticides through nectar and pollen collected from treated crops, which can cause lethal and sublethal effects in these nontarget pollinators. However, the body distribution of the compound after exposure to neonicotinoids in bumblebees is not well studied. Bumblebee colonies (Bombus terrestris, n = 20) were exposed to field-realistic concentrations of clothianidin through artificial nectar (3.6-13 µg/L) for 9 d. Comparison of the nominal with the measured exposure in nectar indicated good compliance, confirming the applicability of the method. When quantified, clothianidin showed a concentration-dependent occurrence in the head and body of workers (head: <0.2-2.17 µg/kg; body: <0.2-3.17 µg/kg), and in the body of queens (<0.2-2.49 µg/kg), although concentrations were below those measured in the nectar (bioaccumulation factor = 0.2). Exposure to clothianidin did not affect mortality nor brood production, nor did it have a statistically significant effect on nectar consumption and size of food storage. However, visual inspection suggests higher nectar consumption of nectar with low clothianidin content compared with nectar with no or high clothianidin content. Our results show that dietary clothianidin is taken up in bumblebees, but does not bioaccumulate to elevated levels compared with exposure. Still, clothianidin may elicit responses that affect feeding behavior of the pollinator B. terrestris, although our endpoints were not significantly affected. Environ Toxicol Chem 2021;40:2781-2790. © 2021 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC.

Assessing Stress Resilience After Smolt Transportation by Waterborne Cortisol and Feeding Behavior in a Commercial Atlantic Salmon (Salmo salar) Grow-Out Recirculating Aquaculture System.

Sampling protocols and water quality sensors have been developed to assess fish health and welfare in recirculating aquaculture systems (RASs). Still, the use of fish-based non-invasive welfare indicators, reflecting the physiological state of the fish, is limited in this type of system. Cortisol, the major stress-coping hormone in fish, diffuses through the gills. Consequently, waterborne cortisol is a potential fish-based non-invasive welfare indicator in RAS. However, its use in commercial rearing systems is sparse. In this study, we evaluated water cortisol levels and feeding behavior as welfare indicators of newly inserted smolt in a commercial RAS for harvest size Atlantic salmon. The RAS consisted of two parallel fish rearing raceways, raceways 1 and 2, sharing the same water treatment with common outlets and inlets. The smolts were inserted in raceway 1 while salmon that have been in the system for 6 months or more were kept in raceway 2. The smolt insertion period was 3 days. Samples for water cortisol levels were withdrawn the day before, 1 and 3 days after the smolt insertion period. Smolt insertion resulted in elevated water cortisol concentrations in the entire system, with the highest values in raceway 1, one day after smolt insertion. Estimated cortisol production in newly inserted smolt decreased over time, was similar to what has been reported in salmon adapting to experimental tanks. Feeding behavior indicated that the appetite was not fully resumed in the newly inserted smolts, while the appetite of fish in raceway 2 was unaffected by smolt insertion. These results, obtained in a highly intensive commercial RAS, suggest that waterborne cortisol together with feeding behavior can be used as indicators for adaptive processes associated with stress resilience in farmed fish. Thus, they are promising non-invasive indicators for assessing the impact of potential stressors on fish welfare in this type of rearing system.

A Multiple Life-History Trait-Based and Time-Resolved Assessment of Imidacloprid Effects and Recovery in the Widely Distributed Collembolan Folsomia quadrioculata.

Life-history traits determine individual fitness and the fate of populations. Imidacloprid, a widely used neonicotinoid insecticide, which persists in soil for more than 100 d at biologically relevant levels, may affect nontarget and ecologically important species, such as collembolans. In the present study, we determined the sublethal effects of short-term imidacloprid exposure and postexposure recovery in the collembolan Folsomia quadrioculata, which occurs abundantly across the northern hemisphere. We assessed survival, egg production, and hatching success in adult springtails exposed for 14 d through the diet to imidacloprid, followed by a 28-d postexposure phase. Survival and hatching success were high throughout the experiment in all the treatments, with no clear concentration dependence. However, egg production declined during the exposure phase and nearly stopped between 8 and 14 d in all the treatments (except the control) but resumed during the postexposure phase. Moreover, the resumption of egg production showed a concentration-dependent delay. Our findings suggest that low imidacloprid exposures can restrict reproduction, with potentially severe consequences for the population, notwithstanding the partial recovery in egg production. Environ Toxicol Chem 2021;40:139-147. © 2020 SETAC.

Occurrence and trophic transport of organic compounds in sedimentation ponds for road runoff.

Sedimentation ponds have been shown to accumulate several groups of contaminants, most importantly polycyclic aromatic compounds (PACs) and metals. But also, other urban organic pollutants have shown to be present, including polybrominated diphenyl ethers (PBDEs), organophosphate compounds (OPCs) and benzothiazoles (BTs). This investigation aimed at determining the occurrence of these four groups of contaminants in sedimentation ponds and determine their transport from water/sediment to organisms. PACs, including alkylated PACs, PBDEs; OPCs and BTs were determined in water, sediment, plants, dragonfly larvae and fish from two sedimentation ponds and one reference site. Fish were analysed for PAC metabolites. Overall, higher concentrations of all four pollutant groups were detected in water and sediment from sedimentation ponds compared to two natural lakes in rural environments (reference sites). The concentration difference was highest in sediments, and >20 higher concentration was measured in sedimentation ponds (3.6-4.4 ng/g ww) compared to reference (0.2 ng/g ww) for sum BDE6. For PACs and PBDEs a clear transport from water/sediment to organisms were observed. Fish were the highest trophic level organism (3.5-5) in our study, and all four pollutant groups were detected in fish. For PBDEs a trophic biomagnification (TMF) was found both in sedimentation ponds and reference, but higher concentrations in all matrices were measured in sedimentation ponds. TMF was not calculated for PACs since they are metabolised by vertebrates, but a transfer from water/sediment to organisms was seen. For BTs and OPCs, no consistent transfer to plants and dragonfly larvae could be seen. One OPC and two BTs were detected in fish, but only in fish from sedimentation ponds. It is therefore concluded that sedimentation ponds are hotspots for urban and traffic related contaminants, of which especially PACs and PBDEs are transferred to organisms living there.

Effects of exposing shrimp larvae (Pandalus borealis) to aquaculture pesticides at field relevant concentrations, with and without food limitation.

Anti-parasitic drugs used in the aquaculture industry are discharged to the sea after treatment of salmon. In this study, the effects of azamethiphos (AZA) in the Salmosan® formulation and deltamethrin (DEL) in the Alpha Max® formulation, have been assessed in Northern shrimp larvae (Pandalus borealis) when administered both separately and in combination. The exposure concentrations were 100 ng/L for AZA and 2 ng/L for DEL, each representing a 1000-fold dilution of the prescribed concentrations for salmon. These two chemicals were combined at these concentrations to give a third treatment (AZA + DEL). When larvae were exposed for two hours on the first, second and third days post hatch (dph), significantly increased mortality and reduced swimming activity were observed for larvae from the DEL and combined AZA + DEL treatments 4 dph, though not in larvae from the AZA treatment. A single pulse exposure, delivered on the first day post hatch, caused similar effects on mortality and swimming activity 4 dph as the three-pulse exposure. Mortality was driven by the presence of DEL in both experiments, with no amplification or reduction of effects observed when DEL and AZA were combined. Larvae were observed for 13 days following the single pulse exposure, with food limitation introduced as an additional stressor on day 4. In the DEL and AZA + DEL treatments mortality continued to increase regardless of food level, with no larvae completing development to stage II. The overriding toxicity of DEL masked any potential effects the reduced food ration may have exerted. Swimming activity was lower for AZA treated larvae than Control larvae 13 dph, when both groups were fed daily, though no other significant changes to mortality, development to stage II, feeding rate or gene expression were observed. Food limited Control and AZA larvae had lower swimming activity and feeding rate than daily fed Control larvae, with expression of pyruvate kinase and myosin genes also downregulated. However, there was no negative effect on survival or successful development to stage II in these treatments. In addition, mesencephalic astrocyte-derived neurotropic factor was downregulated in food limited Control larvae when compared with the daily fed Controls. Results from this study together with reported estimates of dispersion plume concentrations of discharged pesticides indicate that toxic concentrations of deltamethrin could reach shrimp larvae several kilometers from a treated salmon farm.

Concentration and Distribution of Naphthenic Acids in the Produced Water from Offshore Norwegian North Sea Oilfields.

Naphthenic acids (NAs) constitute one of the toxic components of the produced water (PW) from offshore oil platforms discharged into the marine environment. We employed liquid chromatography (LC) coupled to high-resolution mass spectrometry with electrospray ionization (ESI) in negative mode for the comprehensive chemical characterization and quantification of NAs in PW samples from six different Norwegian offshore oil platforms. In total, we detected 55 unique NA isomer groups, out of the 181 screened homologous groups, across all tested samples. The frequency of detected NAs in the samples varied between 14 and 44 isomer groups. Principal component analysis (PCA) indicated a clear distinction of the PW from the tested platforms based on the distribution of NAs in these samples. The averaged total concentration of NAs varied between 6 and 56 mg L-1, among the tested platforms, whereas the concentrations of the individual NA isomer groups ranged between 0.2 and 44 mg L-1. Based on both the distribution and the concentration of NAs in the samples, the C8H14O2 isomer group appeared to be a reasonable indicator of the presence and the total concentration of NAs in the samples with a Pearson correlation coefficient of 0.89.

Detection of tris(2,3-dibromopropyl) phosphate and other organophosphorous compounds in Arctic rivers.

The flame-retardant tris(2,3-dibromopropyl) phosphate (TDBrPP) was in the 1970s banned for uses in textiles that may be in contact with the skin, owing to strong suspicions that the substance was a human carcinogen. The substance is looked for but rarely detected in samples from the built and natural environments, but there are indications that TDBrPP is still in use. Here, we report the measurement of a polymer-water partition coefficient (Kpw) for two types of silicone rubber (SR), allowing quantitative estimation of freely dissolved concentrations of TDBrPP by passive sampling in water. We found levels of 100 to 200 pg/L in two Arctic rivers that were sampled during a 2014-2015 survey of contamination using passive samplers in Norwegian and Russian rivers draining into the Barents Sea. We also report the widespread presence of other organophosphorus flame retardants in this survey of eight rivers that drain into the Barents Sea.

Whole-Organism Transcriptomic Analysis Provides Mechanistic Insight into the Acute Toxicity of Emamectin Benzoate in Daphnia magna.

Emamectin benzoate (EMB) is an antisea lice chemical widely used in the aquaculture that may also unintentionally affect nontarget crustaceans in the environment. Although the adverse effects of this compound are well documented in various species, the full modes of action (MoAs) are still not well characterized. The current study was therefore conducted to characterize the MoAs of EMB and link perturbations of key toxicological pathways to adverse effects in the model freshwater crustacean Daphnia magna. Effects on molting and survival were determined after 48 h exposure to EMB, whereas global transcriptional changes and the ecdysone receptor (EcR) binding potency was determined to characterize the MoA. The results showed that the molting frequency and survival of D. magna decreased in a concentration-dependent manner, and the observed changes could not be attributed to direct interactions with the EcR. Major MoAs such as activation of glutamate-gated chloride channels and gamma-aminobutyric acid signaling, disruption of neuroendocrine regulation of molting, perturbation of energy homeostasis, suppression of DNA repair and induction of programmed cell death were observed by transcriptional analysis and successfully linked to the adverse effects. This study has demonstrated that acute exposure to intermediate and high pM levels of EMB may pose hazards to nontarget crustaceans in the aquatic environment.

Environmental fate and effects of novel quorum sensing inhibitors that can control biofilm formation.

The formation of bacterial biofilms can have negative impacts on industrial processes and are typically difficult to control. The increase of antibiotic resistance, in combination with the requirement for more environmentally focused approaches, has placed pressure on industry and the scientific community to reassess biofilm control strategies. The discovery of bacterial quorum sensing, as an important mechanism in biofilm formation, has led to the development of new substances (such as halogenated thiophenones) to inhibit the quorum sensing process. However, there are currently limited data regarding the biodegradability or ecotoxicity of these substances. To assess the environmental fate and effects of thiophenones capable of quorum sensing inhibition, candidate substances were first identified that have potentially high biodegradability and low ecotoxicity using quantitative structure activity relationships. Subsequent confirmatory hazard assessment of these substances, using a marine alga and a marine crustacean, indicated that these estimates were significantly under predicted with acute toxicity values more than three orders of magnitude lower than anticipated combined with limited biodegradability. Therefore, although these quorum sensing inhibitors appear a promising approach to control biofilms, they may also have environmental impacts on certain aquatic organisms.

Evaluation of the sensitivity, responsiveness and reproducibility of primary rainbow trout hepatocyte vitellogenin expression as a screening assay for estrogen mimics.

Vitellogenin (Vtg) induction in primary fish hepatocytes has been proposed as an in vitro screening assay for ER agonists and antagonists, but has not yet been used extensively as a high-throughput screening tool due to poor reproducibility, sensitivity and overall feasibility. The present work has evaluated the role of seasonal variation, normalization, optimal culture and assay conditions on the sensitivity, responsiveness and reproducibility of in vitro vtg gene mRNA and protein expression in rainbow trout (Oncorhynchus mykiss) primary hepatocytes using the xenoestrogen 17α-ethynylestradiol (EE2) as a test chemical. The results show that primary hepatocytes display a relatively high individual and seasonal variation in both Vtg mRNA and protein induction potential, although less variance was observed in assay sensitivity. Data normalization of assay response to maximum (3 nM EE2) and minimum (DMSO) Vtg production dramatically reduced this variance and led to improved assay reproducibility. A time-dependent response was observed both for mRNA and protein expression, reaching maximum Vtg induction after 96 h of exposure, although reproducible concentration response curves for both Vtg mRNA and protein could be obtained already after 48 h. A need for chemical re-exposure of the hepatocytes was identified to be important for sustaining exposure concentrations in extended studies (>48 h), whereas different plate formats (96, 24 or 6 wells) did not affect the bioassay performance. In conclusion, standardization of hepatocyte bioassay and test conditions as well as data-normalization procedures are proposed to be instrumental for more consistent and comparable results in future use of this in vitro assay.