Environmental implications and nanotechnological advances in octocrylene-enriched sunscreen formulations: A comprehensive review

Ultraviolet (UV) radiation is a major contributor to skin aging, cancer, and other detrimental health effects. Sunscreens containing FDA-approved UV filters, like avobenzone, offer protection but suffer from photodegradation and potential phototoxicity. Encapsulation, antioxidants, and photostabilizers are strategies employed to combat these drawbacks. Octocrylene, an organic UV filter, utilizes nanotechnology to enhance sun protection factor (SPF). This review examines recent literature on octocrylene-enriched sunscreens, exploring the interplay between environmental impact, nanotechnological advancements, and clinical trial insights. A critical focus is placed on the environmental consequences of sunscreen use, particularly the potential hazards UV filters pose to marine ecosystems. Research in the Mediterranean Sea suggests bacterial sensitivity to these filters, raising concerns about their integration into the food chain. This review aims to guide researchers in developing effective strategies for photostabilization of UV filters. By combining encapsulation, photostabilizers, and antioxidants, researchers can potentially reduce phototoxic effects and contribute to developing more environmentally friendly sunscreens.

UV filters in everyday cosmetic products, a comparative study

Today, UV filters are found as contaminants in a variety of biological fluids and environment, e.g. in vegetable crops and surface water. This is because UV filters are widely used in everyday products. In this context, we focused this study on cosmetic products, in order to assess the importance of this source of contamination. The study of 742 cosmetic products, excluding actual sunscreen products, but including hygiene, personal care and make-up products and perfumes revealed that the most common UV filters present are butyl methoxydibenzoylmethane (90 products or 12.1% of products tested), octyl methoxycinnamate (75 products or 10.1% of products tested), octocrylene (62 products or 8.3% of products tested), octyl salicylate (43 products or 5.8% of products tested) and titanium dioxide (33 products or 4.4% of products tested). Very few UV filters are found in the hygiene products (only in 12 shampoos/conditioners and in 2 shower gels) and deodorants and toothpastes are completely free of them. Conversely, make-up and perfumes are frequently formulated with at least one UV filter. Seventy-five of the two hundred and forty-four (or 30.7%) skincare products studied contained at least one UV filter. 49.1 of the makeup products studied and 74.3% of perfumes contained it.

Increasing exposure to the UV filters octocrylene and 2-ethylhexyl salicylate in Germany from 1996 to 2020: Human biomonitoring in 24-h urine samples of the German Environmental Specimen Bank (ESB)

The UV filters octocrylene (OC) and 2-ethylhexyl salicylate (EHS) are commonly used in sunscreens and frequently detected in environmental media. However, knowledge on human exposures is scarce. In this human biomonitoring (HBM) study, we analyzed concentrations of exposure biomarkers specific to OC (CPAA, DOCCA, 5OH-OC) and EHS (5OH-EHS, 5oxo-EHS, 5cx-EPS) in 24-h urine samples (n = 420) from the German Environmental Specimen Bank (ESB). These samples were collected from German students (20-29 years; 30 males/30 females per year) between 1996 and 2020 (4-year intervals; collection in winter). We found continuously increasing OC and EHS exposures (Jonckheere-Terpstra; p < 0.001) documented by very few to no samples with concentrations of the most sensitive biomarkers CPAA and 5cx-EPS above the limit of quantification (LOQ) in 1996 (5 % and 0 %, respectively) and reaching 100 % and 93 % above the LOQ in 2016, with median concentrations of 4.79 and 0.071 µg/L, respectively. In 2020, biomarker concentrations slightly decreased to 3.12 µg/L CPAA (97 %>LOQ) and 0.060 µg/L 5cx-EPS (88 %>LOQ). This general trend was confirmed by the other biomarkers, however at lower detection rates. Based on metabolite excretion in the 24-h urine samples and human toxicokinetic data, we calculated maximum daily intakes (DI) of 17 µg/(kg bw * d) OC and 59 µg/(kg bw * d) EHS. Based on a derived no-effect level (DNEL) of 0.8 mg/(kg bw * d), the OC exposures of individuals in our study did not indicate any health risk. Similarly, for EHS all biomarker concentrations were well below the HBM-I values of 12 µg/L 5OH-EHS and 11 µg/L 5cx-EPS. Our data proves the general applicability of specific OC and EHS metabolites for HBM in the general population and shows clearly increasing exposures. Higher (co-)exposures must be expected in populations with increased sunscreen use such as (summer) vacationers, children and outdoor workers.

Biomarkers activity in Oreochromis niloticus under sub-chronic exposure to a UV filters ternary mixture

The behavior of organic UV filters in aquatic ecosystems and living organisms raises concern. For the first time, biochemical biomarkers were evaluated in the liver and brain of juvenile Oreochromis niloticus exposed to 0.001 and 0.5 mg L^-1 of a benzophenone-3 (BP-3), octyl methoxycinnamate (EHMC), and octocrylene (OC) mixture for 29 days. Before the exposure, the stability of these UV filters was investigated using liquid chromatography. The experiment with aeration in the aquarium showed a high percentage of concentration reduction (%) after 24 h: 62 ± 2 for BP-3, 96 ± 6 for EHMC, and 88 ± 2 for OC versus 5 ± 4 for BP-3, 8 ± 7 for EHMC, and 2 ± 3 for OC when without aeration. These results defined the bioassay protocol. The stability of the filters concentrations after being stored in PET flasks and subjected to freezing and thawing cycles was also verified. In PET bottles, the BP-3, EHMC, and OC presented concentration reductions of 8 ± 1, 28 ± 7 and 25 ± 5 respectively, after 96 h storage and four freezing cycles. In falcon tubes the concentration reductions observed were 47 ± 2 for BP-3, >95 ± 1 for EHMC and 86 ± 2 for OC after 48 h and two cycles. The 29 days of sub-chronic exposure indicated the occurrence of oxidative stress through the enhanced lipid peroxidation (LPO) levels for the groups exposed to both bioassay concentrations. The catalase (CAT), glutathione-S-transferase (GST), and acetylcholinesterase (AChE) activities did not show significant alterations. The genetic adverse effects were analyzed in erythrocytes of fish exposed to 0.001 mg L^-1 of the mixture by comet and micronucleus biomarkers and no significant damage was observed.

Beach showers as sources of contamination for sunscreen pollution in marine protected areas and areas of intensive beach tourism in Hawaii, USA

In 2019, sands in nearby runoff streams from public beach showers were sampled on three islands in the State of Hawaii and tested for over 18 different petrochemical UV filters. Beach sands that are directly in the plume discharge of beach showers on three of the islands of Hawaii (Maui, Oahu, Hawai'i) were found to be contaminated with a wide array of petrochemical-based UV-filters that are found in sunscreens. Sands from beach showers across all three islands had a mean concentration of 5619 ng/g of oxybenzone with the highest concentration of 34,518 ng/g of oxybenzone at a beach shower in the Waikiki area of Honolulu. Octocrylene was detected at a majority of the beach shower locations, with a mean concentration of 296.3 ng/g across 13 sampling sites with the highest concentration of 1075 ng/g at the beach shower in Waikiki. Avobenzone, octinoxate, 4-methylbenzylidene camphor and benzophenone-2 were detected, as well as breakdown products of oxybenzone, including benzophenone-1, 2,2'-dihydroxy-4-methoxybenzophenone, and 4-hydroxybenzophenone. Dioxybenzone (DHMB) presented the highest concentration in water (75.4 ng/mL), whereas octocrylene was detected in all water samples. Some of these same target analytes were detected in water samples on coral reefs that are adjacent to the beach showers. Risk assessments for both sand and water samples at a majority of the sampling sites had a Risk Quotient > 1, indicating that these chemicals could pose a serious threat to beach zones and coral reef habitats. There are almost a dozen mitigation options that could be employed to quickly reduce contaminant loads associated with discharges from these beach showers, like those currently being employed (post-study sampling and analysis) in the State of Hawaii, including banning the use of sunscreens using petrochemical-based UV filters or educating tourists before they arrive on the beach.

Octocrylene exposure impairs mouse oocyte quality by inducing spindle defects and mitochondria dysfunction

One of organic ultraviolet (UV) filters, Octocrylene (OCL), is mainly used in various cosmetic products, which is being frequently detected in soil, sediment, aquatic systems and food chain. There is evidence confirmed the reproductive toxicity of OCL in Japanese medaka. However, less was known about the effects of OCL exposure on oocyte quality. Here, we investigated the impacts of OCL on mouse oocyte maturation and quality by exposing oocytes to OCL in vitro at concentrations of 8, 22, 30, 40 and 50nM. The results showed that OCL markedly reduced mouse oocyte germinal vesicle breakdown (GVBD) at 50nM and polar body extrusion (PBE) rates at 40 and 50nM. OCL exposure further disrupted spindle assembly and chromosome alignment, finally inducing aneuploid. Mitochondrial function was also damaged by OCL exposure, leading to ROS overproduction and apoptosis in oocytes. Moreover, OCL treatment impaired the distribution of cortical granules and sperm binding ability of oocytes. In summary, these data demonstrated that OCL could disturb the oocyte meiotic maturation and reduce oocyte quality.

Review of the environmental fate and effects of two UV filter substances used in cosmetic products

Sunscreens containing UV filters, such as octocrylene (OCR) and butyl-methoxydibenzoylmethane (BMDBM), have been increasingly used to protect human skin against UV radiation. Both substances have been detected in monitoring studies in the freshwater and marine environment, and there has been concern about potential effects on aquatic organisms. In the present work, the environmental fate and occurrence, bioaccumulation and ecotoxicity including endocrine effects of OCR and BMDBM are reviewed focusing on the aquatic environment. The two UV filters have low water solubilities and a high sorption potential. The available data indicate that OCR is poorly biodegradable. BMDBM lacks anaerobic and inherent biodegradability. However, it was biodegraded to variable degrees in simulation studies. Measured concentrations in the freshwater and marine environment were found to vary considerably between sites, depending on the extent of recreational activities or wastewater discharges. While the bioconcentration factor of OCR in fish is below the threshold value for bioaccumulation according to EU REACH, the available data for BMDBM do not allow a definitive conclusion on its bioaccumulation potential. Analysis of the aquatic toxicity data showed that data quality was often limited, e.g. in the case of effect concentrations substantially exceeding maximum achievable dissolved concentrations. Up to their limit of water solubility, OCR and BMDBM showed no toxicity to microorganisms, algae, and corals, and no acute toxicity to daphnids and fish. In chronic daphnid tests, OCR was highly toxic, whereas BMDBM lacked toxicity. Reliable water-sediment toxicity tests are required to further evaluate possible effects on benthic invertebrates. The available data do not provide evidence for endocrine effects of the two UV filters on fish. In order to assess potential environmental risks caused by OCR and BMDBM, a validated exposure model for estimating direct emission of UV filters into the aquatic environment and data from systematic, longer-term monitoring studies are needed.

Sunscreen filter octocrylene is a potential obesogen by acting as a PPARγ partial agonist

Octocrylene (OC) is an extensively prescribed organic ultraviolet B filter used in sunscreen products. Due to its extensive use, a significant level of OC is detected in marine and freshwater environments. Notably, the bioaccumulation of OC in aquatic biota may affect human health. In this study, the effect of OC on metabolism was investigated using the adipogenesis model of human bone marrow mesenchymal stem cells (hBM-MSCs). OC promoted adiponectin production during adipogenesis in hBM-MSCs compared to the vehicle-treated control (EC₅₀, 29.6 μM). In target identification, OC directly bound to peroxisome proliferator-activated receptor (PPAR) γ (Ki, 37.8 μM). OC-bound PPARγ also significantly recruited nuclear receptor coactivator proteins SRC-1 (EC₅₀, 54.1 μM) and SRC-2 (EC₅₀, 58.6 μM). In the molecular docking simulation study, the optimal ligand-binding mode of OC suggested that OC is a PPARγ partial agonist. A competitive analysis with a PPARγ full agonist pioglitazone revealed that OC acted as a PPARγ partial agonist. OC altered the gene transcription profile of lipid-metabolism associated enzymes in normal human keratinocytes, primarily exposed human cells after the application of sunscreens. In conclusion, OC is a potential metabolic disrupting obesogen.

A burning issue: The effect of organic ultraviolet filter exposure on the behaviour and physiology of Daphnia magna

Ultraviolet (UV) filters are compounds utilized in many manufacturing processes and personal care products such as sunscreen to protect against UV-radiation. These highly lipophilic compounds are emerging contaminants of concern in aquatic environments due to their previously observed potential to bioaccumulate and exert toxic effects in marine ecosystems. Currently, research into the toxic effects of UV filter contamination of freshwater ecosystems is lacking, thus the present study sought to model the effects of acute and chronic developmental exposures to UV filters avobenzone, oxybenzone and octocrylene as well as a mixture of these substances in the freshwater invertebrate, Daphnia magna, at environmentally realistic concentrations. Median 48-hour effect and lethal concentrations were determined to be in the low mg/L range, with the exception of octocrylene causing 50% immobilization near environmental concentrations. 48-hour acute developmental exposures proved to behaviourally impair daphnid phototactic response; however, recovery was observed following a 19-day post-exposure period. Although no physiological disruptions were detected in acutely exposed daphnids, delayed mortality was observed up to seven days post-exposure at 200 μg/L of avobenzone and octocrylene. 21-day chronic exposure to 7.5 μg/L octocrylene yielded complete mortality within 7 days, while sublethal chronic exposure to avobenzone increased Daphnia reproductive output and decreased metabolic rate. 2 μg/L oxybenzone induced a 25% increase in metabolic rate of adult daphnids, and otherwise caused no toxic effects at this dose. These data indicate that UV filters can exert toxic effects in freshwater invertebrates, therefore further study is required. It is clear that the most well-studied UV filter, oxybenzone, may not be the most toxic to Daphnia, as both avobenzone and octocrylene induced behavioural and physiological disruption at environmentally realistic concentrations.

Reproductive toxicity and estrogen activity in Japanese medaka (Oryzias latipes) exposed to environmentally relevant concentrations of octocrylene

The growing use of octocrylene (OC) in sunscreens has posed a great threat to aquatic organisms. In the present study, to assess its reproductive toxicity and mechanism, paired Japanese medaka (Oryzias latipes) (F0) were exposed to OC at nominal concentrations of 5, 50, and 500 μg/L for 28 d. Significant increases were observed in the gonadosomatic index (GSI) and hepatosomatic index (HSI) of F0 medaka at 500 μg/L OC (p < 0.05) without significant differences in fecundity. The fertility was significantly decreased at all treatments (p < 0.05). Significant increases in the percent of mature oocytes were observed at 5 and 500 μg/L OC, in which contrary to the percent of spermatozoa (p < 0.05). The plasma sex hormones and vitellogenin levels significantly increased in males at all treatments and in females at 50 and 500 μg/L OC (p < 0.05). In addition, the levels of fshβ and lhβ in the brains and the levels of fshr, lhr and cyp17α in the gonads were significantly upregulated in males at all treatments (p < 0.05), in line with those of ar, erα, erβ and cyp19β in the brains of male and female. The upregulation of vtg in male and female livers was observed only at 500 μg/L OC and upregulation of star and hsd3β was observed in testis at all treatments (p < 0.05). Continued exposure to OC significantly induced increases in the time to hatching, morphological abnormality rates, and cumulative death rates of F1 embryos, inconsistent with body length of F1 larvae (p < 0.05). Therefore, the responses of the exposed fish at the biochemical and molecular levels indicated reproductive toxicity and estrogenic activity of OC, providing insights into the mechanism of OC.

Systemic availability of lipophilic organic UV filters through dermal sunscreen exposure

BACKGROUND

Chemical UV filters are common components in sunscreens and cosmetic products and used to protect the skin against harmful effects of sunlight like sunburn. However, the effectiveness of sunscreens in the prevention of skin cancer is in some parts still controversial. Meanwhile, questions about negative effects of the chemical UV filters on human health arise and request an effective risk assessment. Real-life exposure data in humans after application of these products are still rare. Thus, we explored whether and to what extent UV filters are absorbed through the skin into the human body.

MATERIAL AND METHODS

Plasma and urine samples from 20 healthy volunteers were collected before, during and after a real-life exposure scenario (1st application: 2 mg/cm²; 2nd and 3rd (after 2 and 4 h): 1 mg/cm² each) using a commercial sunscreen formulation for one day. These samples were analyzed for their content of the currently prominent UV filters octocrylene and avobenzone as well as 2-cyano-3,3-diphenylacrylic acid (CDAA) as the main octocrylene metabolite by using different liquid chromatography electrospray-ionization tandem mass spectrometric procedures.

RESULTS

Following dermal sunscreen exposure, avobenzone, octocrylene and CDAA reached concentrations up to 11 μg/L, 25 μg/L and 1352 μg/L in plasma. In urine detection rates of avobenzone and octocrylene were low while CDAA showed a high detection rate and reached up to 5207 μg/g creatinine. Kinetic models could be fitted for octocrylene and CDAA in plasma and CDAA in urine. Concentration peaks were reached between 10 and 16 h after first application and half-life periods were in the range of 1.5 to 2 days. The lipophilic UV filter octocrylene and its metabolite CDAA showed a much slower elimination than other more hydrophilic UV filters. Concordantly, the metabolite CDAA in particular showed a markedly increased renal excretion over the whole sampling period and indicated high internal exposure to OC.

DISCUSSION

Real-life sunscreen usage leads to considerable bioavailability of organic UV filters and their metabolites which is rarely seen for other environmental exposures. A combined monitoring of the parent compound and its metabolites is important to fully address internal exposure to the UV filter in humans. Considering the kinetic profiles a prolonged systemic release due to depot formation in skin and a potential accumulation through multi-day exposure is presumed. High in-vivo loads call for a critical toxicological assessment of the UV filters and their metabolites.

Quantification of prominent organic UV filters and their metabolites in human urine and plasma samples

Monitoring human exposure to chemical UV filters is essential for an accurate assessment of the health risk caused by the resorbed compounds. We developed different procedures for the determination of the prominent UV filters octocrylene (OC), avobenzone (AVO) and 2-ethylhexyl salicylate (EHS) as well as for two OC and EHS metabolites in human urine and OC, AVO and 2-cyano-3,3-diphenylacrylic acid (CDAA) in plasma samples using liquid chromatography-tandem mass spectrometry (LC-MS/MS). Since the development of a multi-method for all analytes proved to be difficult, three different procedures were established for the determination of AVO, OC and its metabolite CDAA in urine and plasma as well as for EHS and its metabolite 5-hydroxy-EHS in urine. The methods have been validated with good sensitivity, precision and accuracy. The procedures were satisfactorily applied to the determination of the target compounds in human samples collected from volunteers after sunscreen application. These new analytical procedures can provide information on the internal exposure to the UV filters OC, AVO and EHS, which has been little studied.

An environmental risk assessment of three organic UV-filters at Lac Bay, Bonaire, Southern Caribbean

Although organic UV filters (OUVFs) benefit human health by preventing skin burns and cancer, several studies revealed that organic UV filters can induce developmental and reproductive toxicity to aquatic organisms. Discharge of OUVFs occurs predominantly at marine recreational hotspots, such as Lac Bay, Bonaire, and is predicted to increase significantly due to growing tourism worldwide. Unfortunately, there is no insight what the current and future discharge of OUVF at Lac Bay is. Therefore, this study aimed to 1) measure concentrations and estimate the risk of specific OUVFs to different nursery habitats at Lac Bay, and 2) compare measured and predicted concentration based risk assessment outcome. Results showed that at least one of the three nurseries at Lac Bay had a potential for adverse effects. Furthermore, predicted environmental concentrations of UV filter discharge can be applied to gain more insight in the order of extent of OUVF discharge by marine tourism.

Occurrence and assessment of the risk of ultraviolet filters and light stabilizers in Victorian estuaries

This reconnaissance study was undertaken to examine the occurrence of common ultraviolet filters (UVF) and light stabilizers (UVLS), and preservatives in four different estuaries in Port Philip Bay, Victoria, for the first time. In total, 11 UV filters, 10 UV stabilizers, 12 preservatives and a metabolite, and one fragrance were screened in grab samples of water and sediment using a combination of solid phase extraction and gas and liquid chromatography mass spectrometry measurement techniques. In that context, 16 of the UVF and UVLS and 5 of the preservatives screened were observed in water and/or sediment samples. There are no marine water quality guideline values for any of the fragrances, preservatives and UV filters and light stabilizers in Australia's current national water quality guidelines, so potential risk was assessed using the risk quotient (RQ) and toxic unit (TU) concepts. In that context, only two chemicals (OC and EHMC) had both an RQ above 1 and a log₁₀TU above - 3, suggesting that few of the screened chemicals would have posed an individual, short-term risk to organisms in the waters studied at the time of sampling. However, the detection of common UV filters, such as 4MBC, EHMC, OC and the common preservatives 2-PE, MP, and PB in these Victorian estuaries highlights that the existence of personal care products in the environment is not just an issue for more densley populated countries in the northern hemisphere, but also potentially of concern in Australia. And, in that context, more sampling campaigns in Port Philip Bay are of paramount importance to assess the potential risk posed by these compounds to aquatic ecosystems.

Diurnal variations in personal care products in seawater and mussels at three Mediterranean coastal sites

The presence of personal care products (PCPs) in the marine environment is of major concern. PCPs, UV filters, and musks can enter the marine environment indirectly through wastewater or directly via recreational activities. We conducted this study to document patterns in the occurrence of seven PCPs at three coastal sites impacted by recreational activities during 1 day. The study focused on diurnal variations in these seven PCPs in seawater and indigenous mussels. In seawater, UV filters showed diurnal variations that mirrored variations in recreational activities at the sites. Ethylhexyl methoxycinnamate (EHMC) and octocrylene (OC) water concentrations increased from under the limit of quantification in the morning to 106 and 369 ng/L, respectively, when recreational activities were the highest. In mussels, diurnal variations in OC were observed, with the lowest concentrations recorded in the morning and then increasing throughout the day. As Mytilus spp. are widely used as sentinels in coastal pollution monitoring programs (mussel watch), our findings on diurnal variations could enhance sampling recommendations for recreational sites impacted by PCPs.

Ozonation of the oxybenzone, octinoxate, and octocrylene UV-filters: Reaction kinetics, absorbance characteristics, and transformation products

UV-filters (UVFs) are active ingredients in personal care products that protect skin from exposure to UV light. Environmentally-relevant concentrations of UVFs have recently been linked to toxicity in aquatic organisms, necessitating research into improved UVF removal in water/wastewater treatment. Here, we investigated ozonation of the three most commonly employed UVFs: octinoxate (OMC), octocrylene (OC), and oxybenzone (OXY). Specific second-order rate constants for UVF reaction with ozone were identified as follows: OMC, 5.25×10⁴M^-1s^-1; OC, 1.58M^-1s^-1; OXY (neutral), 3.80×10²M^-1s^-1; and, OXY (anion), 1.51×10⁶M^-1s^-1. These kinetic parameters indicated that OMC and OXY undergo significant (2-log or greater) transformation for typical ozone exposures in disinfection processes; however, minimal oxidation is expected for OC. UV absorbance mapping was employed to characterize the loss of UVF activity (i.e., absorbance across the UV-A, UV-B, and UV-C ranges) during ozonation. These 4-dimensional maps also confirmed ozone attack mechanisms, namely reaction at phenolate (OXY) and olefin (OMC, OC) groups. Primary transformation products from these reactions were identified for all three UVFs of concern. For OC and OXY, the benzophenone structure is conserved, suggesting that transformation products retain toxicity concerns.

Neurotoxic effect of active ingredients in sunscreen products, a contemporary review

Sunscreen application is the main strategy used to prevent the maladies inflicted by ultraviolet (UV) radiation. Despite the continuously increasing frequency of sunscreen use worldwide, the prevalence of certain sun exposure-related pathologies, mainly malignant melanoma, is also on the rise. In the past century, a variety of protective agents against UV exposure have been developed. Physical filters scatter and reflect UV rays and chemical filters absorb those rays. Alongside the evidence for increasing levels of these agents in the environment, which leads to indirect exposure of wildlife and humans, recent studies suggest a toxicological nature for some of these agents. Reviews on the role of these agents in developmental and endocrine impairments (both pathology and related mechanisms) are based on both animal and human studies, yet information regarding the potential neurotoxicity of these agents is scant. In this review, data regarding the neurotoxicity of several organic filters: octyl methoxycinnamate, benzophenone-3 and −4, 4-methylbenzylidene camphor, 3-benzylidene camphor and octocrylene, and two allowed inorganic filters: zinc oxide and titanium dioxide, is presented and discussed. Taken together, this review advocates revisiting the current safety and regulation of specific sunscreens and investing in alternative UV protection technologies.

Accumulation and effects of the UV-filter octocrylene in adult and embryonic zebrafish (Danio rerio)

Wide application of the UV-filter octocrylene (OC) in cosmetics leads to contamination of the aquatic environment, but effects of OC remain unclear. Here we determine bioaccumulation and molecular effects of OC. Adult male zebrafish were exposed to 22, 209 and 383 μg/L and embryos to 69, 293 and 925 μg/L OC. OC accumulated in fish up to 17 μg/g. Calculated BCF varied between 41 and 136. Microarray analysis in brain and liver following exposure to 383 μg/L OC revealed alteration of 628 and 136 transcripts, respectively. Most prominent GO processes included developmental processes, organ development, hematopoiesis, formation of blood vessels, blood circulation, fat cell differentiation and metabolism. Validation by RT-qPCR in brain and liver of adult fish and embryos included a series of genes. Blood levels of 11-ketotestosterone were not altered. The transcriptomics data suggest that OC mainly affects transcription of genes related to developmental processes in the brain and liver as well as metabolic processes in the liver.