Undifferentiated versus retinoic acid-differentiated SH-SY5Y cells in investigation of markers of neural function in toxicological research.

The SH-SY5Y human neuroblastoma cell line is a standard in vitro experimental model of neuronal-like cells used in neuroscience and toxicological research. These cells can be differentiated into mature neurons, most commonly using retinoic acid (RA). Despite differences in characteristics, both undifferentiated and differentiated SH-SY5Y cells are used in research. However, due to uncertainties regarding the expression of specific markers of neural function in each culture, there is no definite conclusion on which culture is better suited for (neuro)toxicological and/or neuroscience investigations. To address this dilemma, we investigated the basal expression/activity of the key elements of acetylcholine, dopamine, serotonin, and GABA neurotransmitter pathways, along with the elements involved in exocytosis of neurotransmitters, and neuron electrophysiological activity in undifferentiated and in RA-differentiated SH-SY5Y cells using a six-day differentiation protocol. Our findings revealed that both SH-SY5Y cell types are functionally active. While undifferentiated SH-SY5Y cells exhibited greater multipotency in the expression of tested markers, most of those markers expressed in both cell types showed higher expression levels in RA-differentiated SH-SY5Y cells. Our results suggest that the six-day differentiation protocol with RA induces maturation, but not differentiation of the cells into specific neuron phenotype. The greater multipotency of undifferentiated cells in neural markers expression, together with their higher sensitivity to xenobiotic exposure and more simple cultivation protocols, make them a better candidate for high throughput toxicological screenings. Differentiated neurons are better suited for neuroscience researches that require higher expression of more specific neural markers and the specific types of neural cells.

Getting More Ecologically Relevant Information from Laboratory Tests: Recovery of Lemna minor After Exposure to Herbicides and Their Mixtures.

Recovery after exposure to herbicides-atrazine, isoproturon, and trifluralin-their binary and ternary mixtures, was studied under laboratory conditions using a slightly adapted standard protocol for Lemna minor. The objectives of the present study were (1) to compare empirical to predicted toxicity of selected herbicide mixtures; (2) to assess L. minor recovery potential after exposure to selected individual herbicides and their mixtures; and (3) to suggest an appropriate recovery potential assessment approach and endpoint in a modified laboratory growth inhibition test. The deviation of empirical from predicted toxicity was highest in binary mixtures of dissimilarly acting herbicides. The concentration addition model slightly underestimated mixture effects, indicating potential synergistic interactions between photosynthetic inhibitors (atrazine and isoproturon) and a cell mitosis inhibitor (trifluralin). Recovery after exposure to the binary mixture of atrazine and isoproturon was fast and concentration-independent: no significant differences between relative growth rates (RGRs) in any of the mixtures (IC10Mix, 25Mix, and 50Mix) versus control level were recorded in the last interval of the recovery phase. The recovery of the plants exposed to binary and ternary mixtures of dissimilarly acting herbicides was strictly concentration-dependent. Only plants exposed to IC10Mix, regardless of the herbicides, recovered RGRs close to control level in the last interval of the recovery phase. The inhibition of the RGRs in the last interval of the recovery phase compared with the control level is a proposed endpoint that could inform on reversibility of the effects and indicate possible mixture effects on plant population recovery potential.

Safety and efficacy of a feed additive consisting of monensin sodium (Coxidin®) for chickens for fattening, chickens reared for laying, turkeys for fattening and turkeys reared for breeding (Huvepharma N.V.).

Following a request from the European Commission, EFSA was asked to deliver a scientific opinion on the safety and efficacy of monensin sodium (Coxidin®) as a coccidiostat for chickens for fattening, chickens reared for laying, turkeys for fattening and turkeys reared for breeding. The additive currently on the market complies with the existing conditions of authorisation. The FEEDAP Panel concluded that Coxidin® remains safe for turkeys for fattening (up to 16 weeks) and extends this conclusion to turkeys reared for breeding (up to 16 weeks). The Panel was not in the position to confirm that the current maximum authorised level of 125 mg monensin sodium/kg complete feed remains safe for chickens for fattening and chickens reared for laying. The use of monensin sodium from Coxidin® at the corresponding maximum authorised/proposed use levels in the target species is safe for the consumer. The existing maximum residue levels (MRLs) for poultry tissues ensure consumer safety. No withdrawal time is necessary. Both formulations of Coxidin® pose a risk by inhalation. The formulation with wheat bran as a carrier was neither irritant to the skin nor a skin sensitiser but it was irritant to the eyes. In the absence of data, no conclusions could be made on the potential of the formulation containing calcium carbonate to be irritant to skin and eyes and to be a skin sensitiser. The use of monensin sodium from Coxidin® in complete feed for the target species poses no risk for the terrestrial compartments and for sediment. No risk for groundwater is expected. For chickens for fattening the risk for aquatic compartment cannot be excluded, but no risks are expected for the other animal categories. There is no risk of secondary poisoning. Coxidin® is efficacious in controlling coccidiosis at a level of 100 mg/kg complete feed for chickens for fattening and at 60 mg/kg complete feed for turkeys for fattening. These conclusions are extended to chickens reared for laying and turkeys reared for breeding. The Panel noted that there are signs of development of resistance of Eimeria spp. to monensin sodium.

Safety and efficacy of a feed additive consisting of narasin (Monteban® G100) for chickens for fattening (Elanco GmbH).

Following a request from the European Commission, EFSA was asked to deliver a scientific opinion on the safety and efficacy of the coccidiostat narasin (Monteban® G100) for chickens for fattening. In a previous opinion, uncertainties remained on the identification and characterisation of the non-genetically modified production strain of the active substance narasin. The Panel could not conclude either on the safety of Monteban® G100 for chickens for fattening or on the efficacy of the additive at the minimum applied concentration. The FEEDAP Panel excluded risks for environment but the risk for sediment compartment could not be assessed. The applicant provided supplementary information to cover the data gaps and substituted the narasin production strain from Streptomyces spp. NRRL 8092 to Streptomyces spp. NRRL B-67771. The information submitted to taxonomically identify the production strain did not allow to assign it to any described microbial species. Based on the information provided, the Panel concluded that the use of Monteban® G100 did not raise safety concerns as regards the production strain for the target animal, consumer, user and environment. The Panel concluded that 70 mg narasin/kg complete feed was safe for chickens for fattening with a margin of safety of 1.4; narasin from Monteban® G100 was unlikely to increase shedding of Salmonella Enteritidis, Salmonella Typhimurium and Campylobacter jejuni. Narasin, when used in chickens for fattening at 70 mg/kg feed, was not expected to pose a risk to the aquatic compartment and to sediment, while a risk for the terrestrial compartment could not be excluded. No risk for groundwater was expected, nor for secondary poisoning via the terrestrial food chain, but the risk of secondary poisoning via the aquatic food chain could not be excluded. The Panel concluded that 60 mg narasin/kg feed was efficacious in controlling coccidiosis in chickens for fattening.

Assessment of the feed additive consisting of diclazuril (Clinacox® 0.5%) for chickens for fattening and chickens reared for laying for the renewal of its authorisation (Elanco GmbH).

Following a request from the European Commission, EFSA was asked to deliver a scientific opinion on the safety and efficacy of diclazuril (Clinacox® 0.5%) as a coccidiostat for chickens for fattening and chickens reared for laying. The additive currently on the market complies with the existing conditions of authorisation. The additive remains safe for the target species and the consumer under the authorised conditions of use. The additive is irritant to skin, eyes and respiratory tract but is not a skin sensitiser. Exposure by inhalation cannot be excluded. The FEEDAP Panel cannot conclude on the safety for the environment of diclazuril from Clinacox® 0.5% due to lack of data. Diclazuril from Clinacox® 0.5% at a concentration of 1 mg diclazuril/kg complete feed has the potential to control coccidiosis in chickens for fattening. This conclusion is extended to chickens reared for laying. Development of resistance to diclazuril of field Eimeria spp. strains isolated from chickens should be monitored.

Safety and efficacy of a feed additive consisting of salinomycin sodium (Sacox®) for rabbits for fattening (Huvepharma N.V.).

Following a request from the European Commission, EFSA was asked to deliver a scientific opinion on the safety and efficacy of the coccidiostat salinomycin sodium (Sacox®) for rabbits for fattening. The EFSA Panel on Additives and Products or Substances used in Animal Feed (FEEDAP) concluded that the use of salinomycin sodium (SAL-Na) from Sacox® does not raise safety concerns for the target species, consumers, users and the environment with regard to the production strain. In the absence of adequate tolerance studies, the FEEDAP Panel could not conclude on the safety of SAL-Na from Sacox® for rabbits for fattening. The FEEDAP Panel concluded that the additive is safe for the consumer when it is used at the proposed maximum level of 25 mg SAL-Na/kg complete feed for rabbits and a withdrawal period of 1 day is respected. The following maximum residue limits (MRL) are proposed for the marker residue compound salinomycin (SAL): 0.2 and 0.03 mg SAL/kg for liver and kidney, respectively. The additive is not irritant to skin and eyes but should be considered a potential dermal and respiratory sensitiser. A risk for inhalation toxicity could not be excluded. The use of the SAL-Na from Sacox® in feed for rabbits for fattening up to the highest proposed level will not pose a risk for the terrestrial and aquatic compartment and ground water. The risk of secondary poisoning can be excluded for worm-eating birds and mammals, while it cannot be excluded for fish-eating birds and mammals. The FEEDAP Panel concludes that SAL-Na from Sacox® at the minimum concentration of 20 mg SAL-Na/kg complete feed has the potential to control coccidiosis in rabbits for fattening. Development of resistance to SAL-Na of field Eimeria spp. strains isolated from rabbits for fattening should be monitored.

Safety for the environment of a feed additive consisting of semduramicin sodium (Aviax 5%) for chickens for fattening (Phibro Animal Health s.a.).

Following a request from the European Commission, the EFSA Panel on Additives and Products or Substances used in Animal Feed (FEEDAP) was asked to deliver a scientific opinion on the safety for the environment of the coccidiostat semduramicin sodium (Aviax 5%) when used in feed for chickens for fattening. The additive Aviax 5% is intended to be used as a coccidiostat in feed for chickens for fattening at a level of 20-25 mg semduramicin sodium/ kg complete feed. The safety and efficacy of the additive was evaluated by the FEEDAP Panel in 2018 and 2022. In those opinions it was concluded that the additive is safe for the target species and consumer, while no conclusions could be made on the irritancy of Aviax 5% to skin and eye and on the potential for dermal and respiratory sensitisation. Regarding the safety for the environment, the Panel concluded that a risk for the terrestrial compartment could not be excluded. Based on new data submitted, no risk is expected from the use of the additive in animal nutrition at the proposed conditions of use for the terrestrial compartment. The previous conclusions of the FEEDAP Panel on the safety of the additive for the environment can be updated as follows: the use of semduramicin sodium from Aviax 5% in feed for chickens for fattening up to 25 mg/kg complete feed does not pose a risk for groundwater nor for aquatic, terrestrial and sediment compartments.

Safety for the environment of a feed additive consisting of diclazuril (Coxiril®) for chickens reared for laying and pheasants (Huvepharma NV).

Following a request from the European Commission, EFSA was asked to deliver a scientific opinion on the safety for the environment of diclazuril (Coxiril®) as a coccidiostat feed additive for chickens reared for laying and pheasants. In its previous assessments, the Panel on Additives and Products or Substances used in Animal Feed (FEEDAP) could not reach a final conclusion on the risk resulting from the use of diclazuril in acid soil from Coxiril®. On the basis of the new data provided, the FEEDAP Panel updates the previous conclusions as follows: no risk is expected for the terrestrial compartment and for sediment when diclazuril is used in chickens reared for laying and to pheasants at the proposed condition of use (in both acidic and non-acidic soils). No concern for groundwater is expected for both acidic and non-acidic soils. Due to the lack of data, no conclusions can be drawn for the aquatic compartment. Diclazuril does not have the potential for bioaccumulation; therefore, a risk of secondary poisoning is unlikely.

Safety and efficacy of a feed additive consisting of halofuginone hydrobromide (STENOROL®) for chickens for fattening and turkeys for fattening/reared for breeding (Huvepharma N.V.).

Following a request from the European Commission, EFSA was asked to deliver a new scientific opinion on the coccidiostat halofuginone hydrobromide (STENOROL®) when used as a feed additive for chickens for fattening and turkeys for fattening/reared for breeding. The Panel on Additives and Products or Substances used in Animal Feed (FEEDAP) concludes that the safety for turkeys for fattening established in its previous opinion can be extended to turkeys for breeding up to 12 weeks of age. Based on the new data provided on the safety for consumer, environment and efficacy, the Panel updates its previous conclusions as follows: halofuginone hydrobromide is not genotoxic. Applying an uncertainty factor of 100 to the lowest no observed adverse effect level (NOAEL) of 0.03 mg/kg body weight (bw) per day, an acceptable daily intake (ADI) of 0.3 µg halofuginone/kg bw is established. The chronic exposure of consumers to residues of halofuginone would amount to 6-19% of the ADI after 3 days of withdrawal. Therefore, the Panel considers that the additive is safe for the consumer of tissues obtained from chickens for fattening and turkeys for fattening fed the additive at a maximum level of 3 mg/kg complete feed at a 3-day withdrawal time. For control purposes, the Panel recommends the setting of the following maximum residue limits (MRLs): liver, 50 µg/kg; kidney, 40 µg/kg; muscle, 3 µg/kg; skin/fat, 10 µg/kg wet tissue. Based on an updated environmental risk assessment, no concern for groundwater is expected. Halofuginone is unlikely to bioaccumulate and the risk of secondary poisoning is not likely to occur. No safety concerns are expected for terrestrial and aquatic environments. The additive has the potential to control coccidiosis in chickens for fattening and turkeys for fattening/reared for breeding up to 12 weeks of age at a minimum level of 2 mg/kg complete feed.

Safety and efficacy of a feed additive consisting of copper(II)-betaine complex for all animal species (Biochem Zusatzstoffe Handels- und Produktionsges. mbH).

Following a request from the European Commission, the EFSA Panel on Additives and Products or Substances used in Animal Feed (FEEDAP Panel) was asked to deliver a scientific opinion on the safety and efficacy of a copper(II)-betaine complex as nutritional feed additive for all animal species. Based on the results of a tolerance study carried out in chicken, the FEEDAP Panel concluded that the additive is safe for chickens for fattening when used up to the current maximum authorised levels of copper in feed; this conclusion was extrapolated to all animal species and categories at the respective maximum copper levels in complete feed authorised in the European Union. The FEEDAP Panel concluded that the use of the copper(II)-betaine complex in animal nutrition at the maximum copper levels authorised for the animal species poses no concern to the safety of consumers. Regarding the safety for the environment, the use of the additive in feed for terrestrial animals and land-based aquaculture is considered safe under proposed conditions of use. The data available do not allow the conclusion to be made on the safety of the additive for marine sediment when it is used in sea cages. The additive is not a skin irritant, but it is an irritant to the eyes. Due to the traces of nickel, the additive is considered to be a respiratory and skin sensitiser. The Panel could not conclude on the efficacy of the product.

Safety and efficacy of a feed additive consisting of a zinc(II)-betaine complex for all animal species (Biochem Zusatzstoffe Handels- und Produktionsges. mbH).

Following a request from the European Commission, EFSA was asked to deliver a scientific opinion on the safety and efficacy of a zinc(II)-betaine complex as nutritional additive for all animal species. The EFSA Panel on Additives and Products or Substances used in Animal Feed (FEEDAP) concluded that the additive is safe for chickens for fattening. This conclusion could be extrapolated to all animal species and categories provided that the maximum authorised levels in the EU for total zinc in feed are not exceeded. The FEEDAP Panel concluded that the use of the zinc(II)-betaine complex in animal nutrition is of no concern for consumer safety provided that the maximum authorised total zinc levels in feed are respected. The additive is considered to be a skin and respiratory sensitiser due to the presence of nickel; it is irritant to the eyes, but not to the skin. The use of the additive in animal nutrition for terrestrial animals and land-based aquaculture at the proposed use levels is considered safe for terrestrial and aquatic ecosystems. The available data do not allow the conclusion to be made on the safety of the additive for the marine sediment when it is used in sea cages. Based on the deposition of zinc in edible tissues/organs in chickens for fattening, the FEEDAP Panel concluded that the additive is a source of bioavailable zinc, comparable to the standard inorganic zinc source, and therefore, the additive is efficacious in meeting the birds zinc requirements. This conclusion can be extrapolated to all animal species and categories.

Assessment of caffeine neurotoxicity using novel biomarkers of neural function in SH-SY5Y cells - Is there a need for environmental concern?

Worldwide usage of caffeine results in its constant release into the aquatic environment and growing concerns related to associated risks. We assessed (neuro)toxicity of environmentally relevant concentrations of caffeine, using novel biomarkers of neural function in SH-SY5Y cells and markers of general toxicity also in HepG2 cells. The RQ-PCR analyses showed that caffeine disturbs the expression of genes encoding several key elements of neurotransmitter pathways, with the most prominent responses observed for serotonin receptor 3A, dopamine receptor D2, monoamine oxidase B and GABA-transaminase. Expression of genes encoding synaptotagmin 10 involved in exocytosis of neurotransmitters and ATPase Na+/K+ transporting subunit alpha 3 was also disturbed. Caffeine stimulated the activity of monoamine oxidase, while cytotoxicity and effects on mitochondrial membrane potential were not observed. Our study points out the new possible molecular targets of caffeine and suggests that the raising concerns related to its growing environmental presence are justified.

Safety and efficacy of a feed additive consisting of butylated hydroxytoluene (BHT) for all animal species (Katyon Technologies Limited).

Following a request from the European Commission, the Panel on Additives and Products or Substances used in Animal Feed (FEEDAP) was asked to deliver a scientific opinion on the safety and efficacy of butylated hydroxytoluene (BHT) as a feed additive for all animal species. The additive BHT is considered safe for chickens for fattening and weaned piglets at the maximum proposed concentration of 150 mg/kg complete feed. This conclusion is extended to chickens reared for laying and extrapolated to pigs for fattening. In the absence of data, no conclusion on the safety for the other target species could be drawn. The exposure of the consumer to BHT from tissues and products of animals fed the additive ranged from 1% to 3% of the acceptable daily intake (ADI). The FEEDAP Panel concluded that the use of BHT as a feed additive at the proposed conditions of use is of no concern for the safety of the consumers. Exposure of the user to BHT via inhalation is likely; however, the Panel is not in the position to conclude on the potential inhalation toxicity of the additive. BHT is a skin and eye irritant, no conclusions can be drawn on the potential of the additive to be a skin sensitiser. In the absence of data, the FEEDAP Panel cannot conclude on the safety of BHT for the environment. The additive BHT is considered an efficacious antioxidant in feedingstuffs for all animal species.

Safety and efficacy of a feed additive consisting of butylated hydroxytoluene (BHT) for all animal species (Lanxess Deutschland GmbH).

Following a request from the European Commission, the Panel on Additives and Products or Substances used in Animal Feed (FEEDAP) was asked to deliver a scientific opinion on the safety and efficacy of butylated hydroxytoluene (BHT) as a feed additive for all animal species. The additive BHT is considered safe for chickens for fattening and weaned piglets at the maximum proposed concentration of 150 mg/kg complete feed. This conclusion is extended to chickens reared for laying and extrapolated to pigs for fattening. In the absence of data, no conclusion on the safety for the other target species could be drawn. The exposure of the consumer to BHT from tissues and products of animals fed the additive ranged from 1% to 3% of the acceptable daily intake (ADI). The FEEDAP Panel concluded that the use of BHT as a feed additive at the proposed conditions of use is of no concern for the safety of the consumers. Exposure of the user to BHT via inhalation is likely; however, the Panel is not in the position to conclude on the potential inhalation toxicity of the additive. BHT is a skin and eye irritant, no conclusions can be drawn on the potential of the additive to be a skin sensitiser. In the absence of data, the FEEDAP Panel cannot conclude on the safety of BHT for the environment. The additive BHT is considered an efficacious antioxidant in feedingstuffs for all animal species.

Safety and efficacy of a feed additive consisting of ethoxyquin (6-ethoxy-1,2-dihydro-2,2,4-trimethylquinoline) for all animal species (FEFANA asbl).

Ethoxyquin is synthetised from p-phenetidine, a possible mutagen, which remains in the additive as an impurity at concentrations of < 2.5 mg/kg additive. Ethoxyquin is considered safe for all animal species at the proposed inclusion level of 50 mg/kg complete feed. However, owing the presence of p-phenetidine, no safe level of the additive in feed for long-living and reproductive animals could be identified. The FEEDAP Panel derived a health-based guidance value of 0.006 mg ethoxyquin dimer (EQDM)/kg bw per day and applied it to the sum of ethoxyquin and its transformation products. A maximum total concentration of 50 mg ethoxyquin/kg complete feed for all animal species, except dairy ruminants, would not pose a risk for the consumer. However, in the absence of data on p-phenetidine residues in tissues and products of animal origin, no conclusion on the safety for the consumer could be drawn. The conclusions on consumer safety assume that the maximum total concentration of 50 mg EQ/kg feed is expressed as the sum of EQ, EQDM, EQI and DHEQ. Exposure of the unprotected user to p-phenetidine via inhalation should be minimised. No safety concerns for groundwater are expected. It is not possible to conclude on the safety of EQ for the terrestrial compartment. A risk for the aquatic compartment cannot be excluded when ethoxyquin is used in terrestrial animals. Unacceptable risk is not expected for freshwater sediment-dwelling organisms. A risk of secondary poisoning via the terrestrial food chain is not expected, whereas a risk via the aquatic food chain cannot be excluded. No concerns for aquatic organisms are expected for ethoxyquin used in fish farmed in land-based system, a risk cannot be excluded for marine sediment dwelling organisms when ethoxyquin is used in sea-cages. Ethoxyquin is considered efficacious in the range 25-50 mg/kg complete feed.

Safety of a feed additive consisting of semduramicin sodium (Aviax 5%) for chickens for fattening (Phibro Animal Health s.a.).

Following a request from the European Commission, the Panel on Additives and Products or substances used in Animal Feed (FEEDAP Panel) was asked to deliver a scientific opinion on the safety of the coccidiostat Aviax 5% (semduramicin sodium) when used in feed for chickens for fattening. In a previous assessment, the FEEDAP Panel could not conclude on the taxonomical identification of the production strain at species level and on the absence of genetic determinants for antimicrobial resistance. In addition, the Panel could not conclude on the safety for the target animals and could not set maximum residue limits to protect consumers. Regarding the safety for the environment, although the use of the additive was considered safe for the terrestrial compartment, a risk for the aquatic compartment and for groundwater pollution could not be excluded. Based on the new data provided, the FEEDAP Panel concludes that there are no safety concerns for the target animals, consumer, user and environment regarding the production strain of semduramicin sodium. Based on the results in the tolerance trial, the FEEDAP Panel concludes that the additive is safe for chickens for fattening up to the maximum recommended level (25 mg/kg complete feed), but no margin of safety can be established. The use of semduramicin sodium at a maximum level of 25 mg/kg complete feed for chickens for fattening is safe for consumers with no withdrawal time. Based on the new data provided and the current requirements for environmental risk assessment, the use of semduramicin sodium from Aviax 5% in feed for chickens for fattening up to 25 mg/kg complete feed does not pose a risk for groundwater nor for aquatic and sediment compartments, while a risk for the terrestrial compartment cannot be excluded. The bioaccumulation and the risk for secondary poisoning are considered to be low.

One planet: one health. A call to support the initiative on a global science-policy body on chemicals and waste.

The chemical pollution crisis severely threatens human and environmental health globally. To tackle this challenge the establishment of an overarching international science-policy body has recently been suggested. We strongly support this initiative based on the awareness that humanity has already likely left the safe operating space within planetary boundaries for novel entities including chemical pollution. Immediate action is essential and needs to be informed by sound scientific knowledge and data compiled and critically evaluated by an overarching science-policy interface body. Major challenges for such a body are (i) to foster global knowledge production on exposure, impacts and governance going beyond data-rich regions (e.g., Europe and North America), (ii) to cover the entirety of hazardous chemicals, mixtures and wastes, (iii) to follow a one-health perspective considering the risks posed by chemicals and waste on ecosystem and human health, and (iv) to strive for solution-oriented assessments based on systems thinking. Based on multiple evidence on urgent action on a global scale, we call scientists and practitioners to mobilize their scientific networks and to intensify science-policy interaction with national governments to support the negotiations on the establishment of an intergovernmental body based on scientific knowledge explaining the anticipated benefit for human and environmental health.

Application of General Unified Threshold Models of Survival Models for Regulatory Aquatic Pesticide Risk Assessment Illustrated with an Example for the Insecticide Chlorpyrifos.

Mathematical models within the General Unified Threshold models of Survival (GUTS) framework translate time-variable chemical exposure information into expected survival of animals. The GUTS models are species and compound specific and explicitly describe the internal exposure dynamics in an organism (toxicokinetics) and the related damage and effect dynamics (toxicodynamics), thereby connecting the external exposure concentration dynamics with the simulated mortality or immobility over time. In a recent scientific opinion on toxicokinetic-toxicodynamic (TKTD) models published by the European Food Safety Authority (EFSA), the GUTS modeling framework was considered ready for use in the aquatic risk assessment for pesticides and aquatic fauna. The GUTS models are suggested for use in risk assessment, if they are sufficiently validated for a specific substance-species combination. This paper aims to illustrate how they can be used in the regulatory environmental risk assessment for pesticides for a specific type of refinement, that is, when risks are triggered by lower tiers in acute as well as in chronic risk assessment and mortality or immobility is the critical endpoint. This approach involves the evaluation of time-variable exposure regimes in a so-called "Tier-2C" assessment. The insecticide chlorpyrifos was selected as an example compound because a large data set was available. The GUTS models for 13 different freshwater arthropods and 8 different theoretical aquatic exposure profiles were used to calculate a series of GUTS-based risk estimates, including exposure profile-specific multiplication factors leading to 50% mortality or immobility at the end of the tested profile (LP50/EP50) as "margins of safety." To put the use of GUTS models within the tiered aquatic risk assessment into perspective, GUTS models for the 13 aquatic arthropods were also used to predict the environmental risks of a measured chlorpyrifos exposure profile from an experimental ditch study (Tier-3 approach), and the results are discussed in the context of calibration of the tiered approach. Integr Environ Assess Manag 2021;17:243-258. © 2020 The Authors. Integrated Environmental Assessment and Management published by Wiley Periodicals LLC on behalf of Society of Environmental Toxicology & Chemistry (SETAC).

Safety for the environment of a feed additive consisting of nicarbazin (Coxar®) for use in turkeys for fattening (Huvepharma N.V.).

Following a request from the European Commission, the Panel on Additives and Products or substances used in Animal Feed (FEEDAP Panel) was asked to deliver a scientific opinion on the safety for the environment of the coccidiostat Coxar® (nicarbazin) when used in feed for turkeys for fattening. In previous assessments, the FEEDAP Panel could not conclude on the safety of Coxar® for the environment due to concerns on 4,40-dinitrocarbanilide (DNC, one of the moieties of nicarbazin). On the basis of the new data provided, the FEEDAP Panel updates its previous conclusions on the safety of Coxar® for the environment as follows: The use of nicarbazin from Coxar® in complete feed for turkeys does not pose a risk for the terrestrial and aquatic compartment and in sediment. No concern for groundwater is expected. The bioaccumulation potential of nicarbazin in the environment is low.

Effect-Directed Analysis of Progestogens and Glucocorticoids at Trace Concentrations in River Water.

Effect-based monitoring is increasingly applied to detect and-in conjunction with chemical analysis-to identify endocrine-disrupting compounds (EDCs) in the environment. Although this approach of effect-directed analysis has been successfully demonstrated for estrogenicity and androgenicity, data on progestogens and glucocorticoids driving endocrine disruption are quite limited. We investigated progestogenic and glucocorticoid activities in Danube River water receiving untreated wastewater from Novi Sad, Serbia. After a 2-step fractionation, all fractions were tested with reporter gene bioassays for agonistic and antagonistic hormonal responses at progestogenic and glucocorticoid hormone receptors as well as with target and nontarget analytical screening of active fractions by liquid chromatography-high-resolution mass spectrometry. Due to masking by cytotoxic mixture components, the effects could not be detected in the raw water extract but were unraveled only after fractionation. Target chemical screening of the fraction that was active in the progesterone receptor (PR) assay revealed that progesterone and megestrol acetate were predominant drivers of PR-mediated activity along with medroxyprogesterone, dihydrotestosterone, androsterone, and epiandrosterone. Hydrocortisone was detected at sub-ng/L concentration in the active fraction in the glucocorticoid receptor (GR) assay but could not explain a significant fraction of the observed GR activity. The present study indicates that effect-based monitoring is a powerful tool to detect EDCs in the aquatic environment but that fractionation may be required to avoid masking effects of mixture components. Future effect-directed analysis studies are required to better understand the occurrence of EDCs and masking compounds in different lipophilicity windows, to finally reduce fractionation requirements for monitoring to a smart clean-up. Environ Toxicol Chem 2019;39:189-199. © 2019 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals, Inc. on behalf of SETAC.