publishedVersion

The longitudinal dispersion coefficient (LDC) of river pollutants is considered as one of the prominent water quality parameters. In this regard, numerous research studies have been conducted in recent years, and various equations have been extracted based on hydrodynamic and geometric elements. LDC’s estimated values obtained using different equations reveal a significant uncertainty due to this phenomenon’s complexity. In the present study, the crow search algorithm (CSA) is applied to increase the equation’s precision by employing evolutionary polynomial regression (EPR) to model an extensive amount of geometrical and hydraulic data. The results indicate that the CSA improves the performance of EPR in terms of R² (0.8), Willmott’s index of agreement (0.93), Nash–Sutcliffe efficiency (0.77), and overall index (0.84). In addition, the reliability analysis of the proposed equation (i.e., CSA) reduced the failure probability (Pf) when the value of the failure state containing 50 to 600 m²/s is increasing for the Pf determination using the Monte Carlo simulation. The best-fitted function for correct failure probability prediction was the power with R² = 0.98 compared with linear and exponential functions.

Anti-sea lice pesticides, used in the salmonid aquaculture industry, are a growing environmental concern due to their potential to adversely affect non-target crustaceans. Azamethiphos and deltamethrin are two bath treatment pesticides used on salmon farms in Norway, however, limited information is available on their impact on European lobster (Homarus gammarus) larvae in the Norwegian marine environment. Here, we firstly report the lethal (LC50) and effective (EC50) concentrations of azamethiphos and deltamethrin for stage I and stage II larvae, following 1-h exposures. Using a hydrodynamic model, we also modelled the dispersal of both compounds into the marine environment around selected Norwegian farms and mapped the potential impact zones (areas that experience LC50 and EC50 concentrations) around each farm. Our data shows that azamethiphos and deltamethrin are acutely toxic to both larval stages, with LC50 and EC50 values below the recommended treatment concentrations. We also show that the azamethiphos impact zones around farms were relatively small (mean area of 0.04–0.2 km2), however deltamethrin impact zones covered much larger areas (mean area of 21.1–39.0 km2). These findings suggest that deltamethrin poses a significant risk to European lobster in the Norwegian marine environment while the impact of azamethiphos may be less severe. | publishedVersion

Anti-sea lice pesticides, used in the salmonid aquaculture industry, are a growing environmental concern due to their potential to adversely affect non-target crustaceans. Azamethiphos and deltamethrin are two bath treatment pesticides used on salmon farms in Norway, however, limited information is available on their impact on European lobster (Homarus gammarus) larvae in the Norwegian marine environment. Here, we firstly report the lethal (LC₅₀) and effective (EC₅₀) concentrations of azamethiphos and deltamethrin for stage I and stage II larvae, following 1-h exposures. Using a hydrodynamic model, we also modelled the dispersal of both compounds into the marine environment around selected Norwegian farms and mapped the potential impact zones (areas that experience LC₅₀ and EC₅₀ concentrations) around each farm. Our data shows that azamethiphos and deltamethrin are acutely toxic to both larval stages, with LC₅₀ and EC₅₀ values below the recommended treatment concentrations. We also show that the azamethiphos impact zones around farms were relatively small (mean area of 0.04–0.2 km²), however deltamethrin impact zones covered much larger areas (mean area of 21.1–39.0 km²). These findings suggest that deltamethrin poses a significant risk to European lobster in the Norwegian marine environment while the impact of azamethiphos may be less severe.

Anti-sea lice pesticides, used in the salmonid aquaculture industry, are a growing environmental concern due to their potential to adversely affect non-target crustaceans. Azamethiphos and deltamethrin are two bath treatment pesticides used on salmon farms in Norway, however, limited information is available on their impact on European lobster (Homarus gammarus) larvae in the Norwegian marine environment. Here, we firstly report the lethal (LC50) and effective (EC50) concentrations of azamethiphos and deltamethrin for stage I and stage II larvae, following 1-h exposures. Using a hydrodynamic model, we also modelled the dispersal of both compounds into the marine environment around selected Norwegian farms and mapped the potential impact zones (areas that experience LC50 and EC50 concentrations) around each farm. Our data shows that azamethiphos and deltamethrin are acutely toxic to both larval stages, with LC50 and EC50 values below the recommended treatment concentrations. We also show that the azamethiphos impact zones around farms were relatively small (mean area of 0.04–0.2 km2), however deltamethrin impact zones covered much larger areas (mean area of 21.1–39.0 km2). These findings suggest that deltamethrin poses a significant risk to European lobster in the Norwegian marine environment while the impact of azamethiphos may be less severe. | publishedVersion

Per- and polyfluoroalkyl substances (PFASs) are today considered important constituents of the continuously growing substance group of persistent contaminants of emerging environmental concern (PCEC). Here, we report for the first time the concentrations of 12 relevant PFASs in 28 marine water samples from the Saudi Arabian coastal waters of the Red Sea. The sum levels of 12 PFASs (Σ12 PFAS) in surface seawater ranged from <LOQ to 956 ngL−1. For the reference background site of this study, Σ12 PFAS levels ranged from <LOQ to 10.9 ng/L. The highest PFAS levels have been found in Al-Arbaeen and Al-Shabab, two lagoons continuously receiving treated sewage effluents. PFHxA, PFHxS, and 6:2 FTS were the most prevalent PFASs with relatively high concentrations. Discharge of municipal and industrial wastewaters is considered an important source of PFASs. The pattern of PFASs observed here suggests that the usage of PFAS-containing aqueous film-forming foams (AFFFs) is a potential additional source for these compounds in Al-Arbaeen and Al-Shabab lagoons. However, a systematic elucidation of local PFASs sources is needed. Contamination of the Red Sea waters with PFASs poses a potential imminent risk to the marine environment of the Red Sea and ultimately may even affect the health of human consumers through the consumption of local seafood | publishedVersion

publishedVersion | Per- and polyfluoroalkyl substances (PFASs) are today considered important constituents of the continuously growing substance group of persistent contaminants of emerging environmental concern (PCEC). Here, we report for the first time the concentrations of 12 relevant PFASs in 28 marine water samples from the Saudi Arabian coastal waters of the Red Sea. The sum levels of 12 PFASs (Σ12 PFAS) in surface seawater ranged from <LOQ to 956 ngL−1. For the reference background site of this study, Σ12 PFAS levels ranged from <LOQ to 10.9 ng/L. The highest PFAS levels have been found in Al-Arbaeen and Al-Shabab, two lagoons continuously receiving treated sewage effluents. PFHxA, PFHxS, and 6:2 FTS were the most prevalent PFASs with relatively high concentrations. Discharge of municipal and industrial wastewaters is considered an important source of PFASs. The pattern of PFASs observed here suggests that the usage of PFAS-containing aqueous film-forming foams (AFFFs) is a potential additional source for these compounds in Al-Arbaeen and Al-Shabab lagoons. However, a systematic elucidation of local PFASs sources is needed. Contamination of the Red Sea waters with PFASs poses a potential imminent risk to the marine environment of the Red Sea and ultimately may even affect the health of human consumers through the consumption of local seafood

This paper presents the first acute toxicity data of the natural insecticide spinosad in amphibians. The sensitivity of two neotropical sympatric anuran species, Boana pulchella and Rhinella arenarum, to spinosad-based formulation Tracer™ was evaluated. Lethal effects are reported in tadpoles of B. pulchella stage 25 between 2.81 and 35.44 mg spinosad/L, while for the same concentration range no lethal effects were detected in tadpoles of R. arenarum of the same stage. In addition, Tracer™ produced sublethal effects at the individual level on the swimming activity, morphology (growth and presence of abnormalities), and development of B. pulchella from 2.81 to 5.78 mg spinosad/L, while in R. arenarum effects were only detected in the swimming activity and growth from 2.78 and 6.22 mg/L, respectively. At the biochemical level, Tracer™ produced inhibition of different enzymatic activities, among them, catalase activity at 2.81 mg spinosad/L, glutathione S- transferase activity from 2.81 to 2.98 mg spinosad/L, and acetylcholinesterase activity at 2.81 mg spinosad/L. These findings allow us to conclude that B. pulchella is more sensitive than R. arenarum to spinosad-based formulation Tracer™. The effects demonstrated here are not consistent with those expected since spinosad is supposed to be an environmental healthy alternative. This paper provides useful and necessary information to implement regulations on the use of new compounds entering the market and its associated risks. | Instituto de Recursos Biológicos | Fil: Bahl, María Florencia. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Departamento de Química. Centro de Investigaciones del Medio Ambiente; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. | Fil: Brodeur, Celine Marie Julie. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Recursos Bilológicos; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. | Fil: Salgado Costa, Carolina. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Departamento de Química. Centro de Investigaciones del Medio Ambiente; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. | Fil: D'Andrea, María Florencia. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Recursos Bilológicos; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. | Fil: Sansiñena, Jesica Alejandra. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Departamento de Química. Centro de Investigaciones del Medio Ambiente; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. | Fil: Marino, Damián José. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Departamento de Química. Centro de Investigaciones del Medio Ambiente; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. | Fil: Natale, Guillermo S. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Departamento de Química. Centro de Investigaciones del Medio Ambiente; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina.

This paper presents the first acute toxicity data of the natural insecticide spinosad in amphibians. The sensitivity of two neotropical sympatric anuran species, Boana pulchella and Rhinella arenarum, to spinosad-based formulation Tracer™ was evaluated. Lethal effects are reported in tadpoles of B. pulchella stage 25 between 2.81 and 35.44 mg spinosad/L, while for the same concentration range no lethal effects were detected in tadpoles of R. arenarum of the same stage. In addition, Tracer™ produced sublethal effects at the individual level on the swimming activity, morphology (growth and presence of abnormalities), and development of B. pulchella from 2.81 to 5.78 mg spinosad/L, while in R. arenarum effects were only detected in the swimming activity and growth from 2.78 and 6.22 mg/L, respectively. At the biochemical level, Tracer™ produced inhibition of different enzymatic activities, among them, catalase activity at 2.81 mg spinosad/L, glutathione S- transferase activity from 2.81 to 2.98 mg spinosad/L, and acetylcholinesterase activity at 2.81 mg spinosad/L. These findings allow us to conclude that B. pulchella is more sensitive than R. arenarum to spinosad-based formulation Tracer™. The effects demonstrated here are not consistent with those expected since spinosad is supposed to be an environmental healthy alternative. This paper provides useful and necessary information to implement regulations on the use of new compounds entering the market and its associated risks. | Fil: Bahl, Maria Florencia. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Centro de Investigaciones del Medio Ambiente - Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Investigaciones del Medio Ambiente; Argentina | Fil: Brodeur, Celine Marie Julie. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata; Argentina. Instituto Nacional de Tecnología Agropecuaria. Centro de Investigación de Recursos Naturales. Instituto de Recursos Biológicos; Argentina | Fil: Salgado Costa, Carolina. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Centro de Investigaciones del Medio Ambiente - Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Investigaciones del Medio Ambiente; Argentina | Fil: D'andrea, María Florencia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata; Argentina. Instituto Nacional de Tecnología Agropecuaria. Centro de Investigación de Recursos Naturales. Instituto de Recursos Biológicos; Argentina | Fil: Sansiñena, Jesica Alejandra. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Centro de Investigaciones del Medio Ambiente - Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Investigaciones del Medio Ambiente; Argentina | Fil: Marino, Damian Jose Gabriel. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Centro de Investigaciones del Medio Ambiente - Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Investigaciones del Medio Ambiente; Argentina | Fil: Natale, Guillermo Sebastian. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Centro de Investigaciones del Medio Ambiente - Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Investigaciones del Medio Ambiente; Argentina

peer reviewed | Humpback whales (Megaptera novaeangliae) from the Southern Hemisphere carry information on persistent organic pollutants (POPs) from their feeding zones in Antarctica to their breeding grounds, making this species a sentinel of contaminants accumulation in the Southern Ocean. This study aimed to evaluate driving factors, namely feeding areas, trophic level, and sex, affecting POP concentrations in the blubber of humpback whales breeding off Mozambique and off Ecuador. Biopsies of free-ranging humpback whales including blubber and skin were collected in 2014 and 2015 from Ecuador (n = 59) and in 2017 from Mozambique (n = 89). In both populations, HCB was the major contaminant followed by DDTs > CHLs > PCBs > HCHs > PBDEs. POP concentrations were significantly higher in males compared to females. HCB, DDTs, HCHs and PBDEs were significantly different between whales from the Mozambique population and the Ecuador population. Sex and feeding habits were important driving factors accounting for POP concentrations in Ecuador whales. The whales from our study had some of the lowest POP concentrations measured for humpback whales in the world. These whales fed predominantly on krill as reflected from the low δ13C and δ15N values measured in the skin. However, the isotopic niches of whales from Mozambique and Ecuador did not overlap indicating that the two populations are feeding in different areas of the Southern Ocean. | EXPOSURE OF HUMPBACK WHALES FROM THE SOUTHERN HEMISPHERE TO PERSISTENT ORGANIC POLLUTANTS: INFLUENCE OF THEIR ISOTOPIC NICHE, SEX AND AGE DETERMINED BY EPIGENETICS

Humpback whales (Megaptera novaeangliae) from the Southern Hemisphere carry information on persistent organic pollutants (POPs) from their feeding zones in Antarctica to their breeding grounds, making this species a sentinel of contaminants accumulation in the Southern Ocean. This study aimed to evaluate driving factors, namely feeding areas, trophic level, and sex, affecting POP concentrations in the blubber of humpback whales breeding off Mozambique and off Ecuador. Biopsies of free-ranging humpback whales including blubber and skin were collected in 2014 and 2015 from Ecuador (n = 59) and in 2017 from Mozambique (n = 89). In both populations, HCB was the major contaminant followed by DDTs > CHLs > PCBs > HCHs > PBDEs. POP concentrations were significantly higher in males compared to females. HCB, DDTs, HCHs and PBDEs were significantly different between whales from the Mozambique population and the Ecuador population. Sex and feeding habits were important driving factors accounting for POP concentrations in Ecuador whales. The whales from our study had some of the lowest POP concentrations measured for humpback whales in the world. These whales fed predominantly on krill as reflected from the low δ¹³C and δ¹⁵N values measured in the skin. However, the isotopic niches of whales from Mozambique and Ecuador did not overlap indicating that the two populations are feeding in different areas of the Southern Ocean.

An interlaboratory comparison exercise was conducted to assess the consistency of microplastic quantification across several laboratories. The test samples were prepared by mixing one liter seawater free of plastics, microplastics made from polypropylene, high- and low-density polyethylene, and artificial particles in two plastic bottles, and analyzed concurrently in 12 experienced laboratories around the world. The minimum requirements to quantify microplastics were examined by comparing actual numbers of microplastics in these sample bottles with numbers measured in each laboratory. The uncertainty was due to pervasive errors derived from inaccuracies in measuring sizes and/or misidentification of microplastics, including both false recognition and overlooking. The size distribution of microplastics should be smoothed using a running mean with a length of >0.5 mm to reduce uncertainty to less than ±20%. The number of microplastics <1 mm was underestimated by 20% even when using the best practice for measuring microplastics in laboratories. | publishedVersion

An interlaboratory comparison exercise was conducted to assess the consistency of microplastic quantification across several laboratories. The test samples were prepared by mixing one liter seawater free of plastics, microplastics made from polypropylene, high- and low-density polyethylene, and artificial particles in two plastic bottles, and analyzed concurrently in 12 experienced laboratories around the world. The minimum requirements to quantify microplastics were examined by comparing actual numbers of microplastics in these sample bottles with numbers measured in each laboratory. The uncertainty was due to pervasive errors derived from inaccuracies in measuring sizes and/or misidentification of microplastics, including both false recognition and overlooking. The size distribution of microplastics should be smoothed using a running mean with a length of >0.5 mm to reduce uncertainty to less than ±20%. The number of microplastics <1 mm was underestimated by 20% even when using the best practice for measuring microplastics in laboratories.

Embargo until 22 Feb 2021 | Adverse impacts of marine litter is documented on >1400 species, including marine megafauna (fish, birds, sea turtles and mammals). The primary impacts include ingestion and entanglement, and there is increasing concern about chemical contamination via ingestion. Numerous survey approaches and monitoring programs have been developed and implemented around the world. They may aim to provide data about parameters such as species distribution and interactions with anthropogenic activities. During the Sixth International Marine Debris Conference, a session was dedicated to the tools and constraints in monitoring interactions between litter and megafauna. In the present paper, we summarize 7 case studies which discuss entanglement and ingestion including macro- and micro-debris in several taxa and across multiple geographic regions. We then discusses the importance of tools and standardizing methods for assessment and management purposes, in the context of international environmental policies and marine litter strategies. | acceptedVersion

Adverse impacts of marine litter is documented on >1400 species, including marine megafauna (fish, birds, sea turtles and mammals). The primary impacts include ingestion and entanglement, and there is increasing concern about chemical contamination via ingestion. Numerous survey approaches and monitoring programs have been developed and implemented around the world. They may aim to provide data about parameters such as species distribution and interactions with anthropogenic activities. During the Sixth International Marine Debris Conference, a session was dedicated to the tools and constraints in monitoring interactions between litter and megafauna. In the present paper, we summarize 7 case studies which discuss entanglement and ingestion including macro- and micro-debris in several taxa and across multiple geographic regions. We then discusses the importance of tools and standardizing methods for assessment and management purposes, in the context of international environmental policies and marine litter strategies.

Adverse impacts of marine litter is documented on >1400 species, including marine megafauna (fish, birds, sea turtles and mammals). The primary impacts include ingestion and entanglement, and there is increasing concern about chemical contamination via ingestion. Numerous survey approaches and monitoring programs have been developed and implemented around the world. They may aim to provide data about parameters such as species distribution and interactions with anthropogenic activities. During the Sixth International Marine Debris Conference, a session was dedicated to the tools and constraints in monitoring interactions between litter and megafauna. In the present paper, we summarize 7 case studies which discuss entanglement and ingestion including macro- and micro-debris in several taxa and across multiple geographic regions. We then discusses the importance of tools and standardizing methods for assessment and management purposes, in the context of international environmental policies and marine litter strategies.

In oil spill models, vertical mixing due to turbulence is commonly modelled by random walk. If the eddy diffusivity varies with depth, failing to take the derivative of the diffusivity into account in the random walk scheme will lead to incorrect results. Depending on the diffusivity profile, the result may be either over- or underprediction of the amount of surfaced oil. The importance of using consistent random walk schemes has been known for decades in, e.g., the plankton modelling community. However, it appears not to be common knowledge in the oil spill community, with inconsistent random walk schemes appearing even in recent publications. We demonstrate and quantify the error due to inconsistent random walk, using a simplified oil spill model, and two different diffusivity profiles. In the two cases considered, a commonly used inconsistent scheme predicts respectively 54% and 202% the amount of surface oil, compared to a consistent scheme. | publishedVersion

In oil spill models, vertical mixing due to turbulence is commonly modelled by random walk. If the eddy diffusivity varies with depth, failing to take the derivative of the diffusivity into account in the random walk scheme will lead to incorrect results. Depending on the diffusivity profile, the result may be either over- or underprediction of the amount of surfaced oil. The importance of using consistent random walk schemes has been known for decades in, e.g., the plankton modelling community. However, it appears not to be common knowledge in the oil spill community, with inconsistent random walk schemes appearing even in recent publications. We demonstrate and quantify the error due to inconsistent random walk, using a simplified oil spill model, and two different diffusivity profiles. In the two cases considered, a commonly used inconsistent scheme predicts respectively 58% and 176% the amount of surface oil, compared to a consistent scheme.

Oil-related aggregates (ORAs) may contribute to the fate of oil spilled offshore. However, our understanding about the impact of diatoms and associated bacteria involved in the formation of ORAs and the fate of oil compounds in these aggregates is still limited. We investigated these processes in microcosm experiments with defined oil dispersions in seawater at 5 °C, employing the Arctic diatom Fragilariopsis cylindrus and its associated bacterial assemblage to promote ORA formation. Accumulation of oil compounds, as well as biodegradation of naphthalenes in ORAs and corresponding water phases, was enhanced in the presence of diatoms. Interestingly, the genus Nonlabens was predominating the bacterial communities in diatom-supplemented microcosms, while this genus was not abundant in other samples. This work elucidates the relevance of diatom biomass for the formation of ORAs, microbial community structures and biodegradation processes in chemically dispersed oil at low temperatures relevant for Arctic conditions. | acceptedVersion

Oil-related aggregates (ORAs) may contribute to the fate of oil spilled offshore. However, our understanding about the impact of diatoms and associated bacteria involved in the formation of ORAs and the fate of oil compounds in these aggregates is still limited. We investigated these processes in microcosm experiments with defined oil dispersions in seawater at 5 °C, employing the Arctic diatom Fragilariopsis cylindrus and its associated bacterial assemblage to promote ORA formation. Accumulation of oil compounds, as well as biodegradation of naphthalenes in ORAs and corresponding water phases, was enhanced in the presence of diatoms. Interestingly, the genus Nonlabens was predominating the bacterial communities in diatom-supplemented microcosms, while this genus was not abundant in other samples. This work elucidates the relevance of diatom biomass for the formation of ORAs, microbial community structures and biodegradation processes in chemically dispersed oil at low temperatures relevant for Arctic conditions.

The objective of this paper is to provide a simple extension of the much-used gravity spreading model for oil on calm water to account for the spreading behavior of waxy crude oils in cold waters – including the observed retardation and eventual termination of spreading at certain oil film thicknesses. This peculiar behavior is not predicted by traditional spreading models for oil on calm water (i.e. viscous-gravity spreading models), but may occur due to non-Newtonian oil properties caused by precipitation of wax at low temperatures. To clarify the spreading behavior of such oils, SINTEF has conducted a series of laboratory experiments with a range of waxy oil mixtures. The present paper contains analyses of data from these experiments, including favorable comparisons with calculations by a proposed improved surface spreading model. | Spreading of waxy Crude Oils on calm weather | acceptedVersion

The objective of this paper is to provide a simple extension of the much-used gravity spreading model for oil on calm water to account for the spreading behavior of waxy crude oils in cold waters – including the observed retardation and eventual termination of spreading at certain oil film thicknesses. This peculiar behavior is not predicted by traditional spreading models for oil on calm water (i.e. viscous-gravity spreading models), but may occur due to non-Newtonian oil properties caused by precipitation of wax at low temperatures. To clarify the spreading behavior of such oils, SINTEF has conducted a series of laboratory experiments with a range of waxy oil mixtures. The present paper contains analyses of data from these experiments, including favorable comparisons with calculations by a proposed improved surface spreading model.