Combined toxic effects of polystyrene microplastic and benzophenone-4 on the bioaccumulation, feeding, growth, and reproduction of Daphnia magna.

The potential toxicity of microplastics (MPs) and UV filter Benzophenone-4 (BP4) to aquatic organisms has caused widespread concern among the public. However, the combined effects of MPs and BP4 on aquatic organisms are not well understood. This study sought to examine the combined impacts of 10 µg/L BP4, 1 mg/L Polystyrene (PS, 10 µm), and a mixture of both on the feeding, behavior, growth, and reproduction of Daphnia magna (D. magna) over a period of 21 days. The results showed that the combined exposure led to a reciprocal facilitation of bioaccumulation, along with a decrease in the second antenna beats frequency in D. magna. While the co-exposure did not change the body size or growth rate of D. magna, it did affect their feeding efficiency, leading to a decrease in Chlorella ingestion within a 24-hour period. Furthermore, there was a high occurrence of malformations in two generations of D. magna exposed to BP4 and PS. The combined exposure also negatively affected reproductive parameters, such as the cumulative number of neonates and the days of first brood, suggesting a decline in overall reproductive success possibly due to feeding inhibition, with available energy potentially being redistributed between reproduction and growth in the daphnids. Co-exposure to BP4 and PS also led to elevated levels of Reactive Oxygen Species (ROS), Malonydialdehyde (MDA), and Glutathione (GSH) levels, as well as mRNA levels related to reproduction, growth, and detoxification in D. magna. Overall, this study delved into the consequences of BP4 and PS on bioaccumulation, feeding, behavior, growth, and reproduction, demonstrating that simultaneous exposure to BP4 and PS could pose a synergistic ecological hazard, potentially threatening aquatic organisms. These findings are critical and should be taken into account for accurate environmental risk assessments.

Benzophenone-4 inhibition in marine diatoms: Physiological and molecular perspectives.

Benzophenone-4 (BP-4), a widely utilized organic ultraviolet (UV) filter, is recognized as a pseudo-persistent contaminant in aquatic environments. To elucidate the effects and mechanisms of BP-4 on marine diatoms, an investigation was conducted on the growth rate, photosynthetic pigment content, photosynthetic parameters, antioxidant enzyme activity, malondialdehyde (MDA) levels, cellular structure, and transcriptome profile of the model species, Phaeodactylum tricornutum. The results showed a pronounced inhibition of algal growth upon exposure to BP-4, with a 144 h-EC50 value of 201 mg·L-1. In addition, BP-4 exposure resulted in a significant reduction in biomass, disruption of cell membrane integrity, and increased MDA accumulation, with levels escalating 3.57-fold at 125 mg·L-1 of BP-4. In the BP-4-treated samples, 1556 differentially expressed genes (DEGs) were identified, of which 985 were upregulated and 571 were downregulated. Gene ontology and KEGG pathway enrichment analysis revealed that the carbon fixation and carbon metabolism processes in P. tricornatum were disrupted in response to BP-4 exposure, along with excessive reactive oxygen species (ROS) production. The upregulation of genes associated with photosynthetic pigment (chlorophyll and carotenoids) synthesis, phospholipid synthesis, ribosome biogenesis, and translation-related pathways may be regarded as a component of P. tricornatum's tolerance mechanism towards BP-4. These results provide preliminary insights into the toxicity and tolerance mechanisms of BP-4 on P. tricornatum. They will contribute to a better understanding of the ecotoxicological impacts of BP-4 on the marine ecosystem and provide valuable information for elimination of BP-4 in aquatic environment by bioremediation.

Removal of benzophenone-4 via chlorination and advanced oxidation processes in aqueous solution: kinetics, by-product identification, and mechanistic studies.

Benzophenone-4 (BP-4) is one of the UV filters widely used in personal care products (PCPs). BP-4 has been identified as an emergent contaminant detected in influent and effluent of wastewater treatment plants (WWTPs) at high concentrations showing that conventional treatment is unable to remove it, subsequently, the presence of BP-4 in surface water is inevitable. In this study, we focus on the degradation of this compound by chlorine, and we report the efficiency of its removal from water by applying two advanced oxidation processes UV/TiO2 and UV/H2O2 aiming to achieve a superior mineralization result. The study was performed in purified water (pH = 6.5, temperature = 25 °C) with an initial concentration of BP-4 similar to that detected in WWTPs (10 mg/L). The results showed that 76% of BP-4 was degraded after 80 min of reaction with chlorine leading to the formation of one by-product persistent in the solution. The oxidation by UV/TiO2 and UV/H2O2 led to a total removal of BP-4 and their generated by-products after 50 and 10 min of reactions, respectively. The kinetic study showed that BP-4 degradation by UV/H2O2 and UV/TiO2 followed pseudo-first-order reaction kinetics and the apparent rate constants (kapp) were determined to be 0.48 min-1 and 0.08 min-1, respectively. The degradation of BP-4 by chlorine followed first-order reaction kinetics with kapp = 0.02 min-1. The identification of by-product structures was performed using liquid chromatography with electrospray ionization and tandem mass spectrometry (MS/MS. The fragmentation of BP-4 and by-product ions at different collision energies allowed to propose the pathways of degradation and to predict the toxicity using a silico toxicity program which confirmed a higher toxicity of all generated by-products.

Novel CuCo2O4 Composite Spinel with a Meso-Macroporous Nanosheet Structure for Sulfate Radical Formation and Benzophenone-4 Degradation: Interface Reaction, Degradation Pathway, and DFT Calculation.

A series of CuCo2O4 composite spinels with an interconnected meso-macroporous nanosheet morphology were synthesized using the hydrothermal method and subsequent calcination treatment to activate peroxymonosulfate (PMS) for benzophenone-4 (BP-4) degradation. As-prepared CuCo2O4 composite spinels, especially CuCo-H3 prepared by adding cetyltrimethylammonium bromide, showed superior reactivity for PMS activation. In a typical reaction, BP-4 (10.0 mg/L) was almost completely degraded in 15 min by the activation of PMS (200.0 mg/L) using CuCo-H3 (100.0 mg/L), with only 9.2 µg/L cobalt leaching detected. Even after being used six times, the performance was not influenced by the lower leaching of ions and surface-absorbed intermediates. The possible interface mechanism of PMS activation by CuCo-H3 was proposed, wherein a unique interconnected meso-macroporous nanosheet structure, strong interactions between copper and cobalt, and cycling of Co(II)/Co(III) and Cu(I)/Cu(II) effectively facilitated PMS activation to generate SO4•- and •OH, which contributed to BP-4 degradation. Furthermore, combined with intermediates detected by liquid chromatography quadrupole time-of-flight mass spectrometry and density functional theory calculation results, the degradation pathway of BP-4 involving hydroxylation and C-C bond cleavage was proposed.

Catalytic use of TiO2 nanowires in the photodegradation of Benzophenone-4 as an active ingredient in sunscreens.

Water contamination has compromised the quality of this resource during the last years with the presence of persistent organic pollutants. Because of the resistance of these compounds to degradation, several advance oxidation techniques have been proposed. In this study, we report the employment of an advance oxidation technique in the degradation of benzophenone-4 (BP-4), using TiO2 as catalyst, which was obtained following a fast-hydrothermal method. TiO2 nanowires (TiO2NWs) were fully characterized considering the morphology, elemental composition, oxidation states, vibrational modes and crystalline structure with SEM and TEM, EDS, XPS, FTIR and XRD, respectively. The photocatalytic degradation was carried out using a home-made photoreactor under slightly acidic conditions achieving an average of 90% removal. It was determined that the photocatalysis is the most probable route of degradation since the photolysis or catalysis procedures produce negligible contributions. An apparent kinetic constant of 1.29 × 10-2 min-1 was determined, according to a pseudo-first order reaction.

Degradation of benzophenone-4 in a UV/chlorine disinfection process: Mechanism and toxicity evaluation.

This study investigated the degradation of benzophenone-4 (BP-4) in a UV/chlorine disinfection process, with chlorination and UV disinfection as comparisons. With a degradation efficiency of 80% after 10 s, the UV/chlorine process significantly enhanced the degradation of BP-4. However, a rebound of 36% of the initial concentration was observed in the UV/chlorine process ([free active chlorine (FAC)]0:[BP-4]0 = 1:1, pH = 7). The same tendency appeared under the addition of alkalinity, Cl-, and humic acid (HA). This work interpreted this interesting kinetic tendency from the perspective of mechanism. In fact, the transformation between the chlorinated product P1 and BP-4 was reversible under certain conditions. The inhomogeneous charge distribution of the CCl bond in P1 led to the photolytic dechlorination of P1. This transformation caused an increase in BP-4 concentration. In addition, the increase in the UV light power promoted the photodecomposition of P1 under the experimental condition. In addition, this study evaluated the change in absorbable organic halogens (AOX) and three kinds of toxicity changes in the BP-4 solution after chlorination and the UV/chlorine process, including the acute toxicity of luminescent bacteria, endocrine disrupting effect and cytotoxicity. The UV/chlorine process exhibited lower ecotoxicity than chlorination in water treatment.

Effect of elevated benzophenone-4 (BP4) concentration on Chlorella vulgaris growth and cellular metabolisms.

Benzophenone-4 (BP4), as the raw material of common sunscreen products, usually shows strong eco-toxicity and endocrine-disrupting activity in aquatic animals. However, the potential adverse effect of BP4 on aquatic vegetation is still unclear. In order to evaluate the inhibitory effect of BP4 on phytoplankton, wild and acclimated Chlorella vulgaris was used as representative aquatic plant cells and experimental studies were conducted on the characteristics of its growth and cellular metabolisms upon exposure to elevated BP4 concentrations (1, 5, 10, 20, 50, and 100 mg L-1). C. vulgaris basically appeared low sensitivity to BP4 exposure because the 96-h EC50 was measured as 65.16 mg L-1 for its wild type. The 96-h EC50 of the acclimated type, which was pre-exposed to 10 mg L-1 of BP4 and transferred twice, was 140.76 mg L-1. By cellular response tests regarding non-enzymatic antioxidants carotenoid content, malondialdehyde (MDA), enzyme antioxidant superoxide dismutase (SOD) activity, and the photosynthetic efficiency, it was clarified that increasing exposure concentration elevated the hindrance to cellular metabolism. However, the rate of BP4 utilization as substrates for C. vulgaris growth showed a trend of decreasing with increasing BP4 concentration. The higher 96-h EC50 value of the acclimated C. vulgaris to BP4 inhibition than the wild C. vulgaris showed the enhanced tolerance capability; however, the continuous stress response of acclimated type should be taken into account when using microalgae species for toxicity assessment.

Chlorination and chloramination of benzophenone-3 and benzophenone-4 UV filters.

The objective of this research was to explore the fundamental reactions between chlorine/chloramine and 2-hydroxyl-4-methoxyl benzophenone (BP3)/2-hydroxyl-4-methoxyl benzophenone-sulfonic acid (BP4), which were the most common reactions in benzophenone-type UV filters during drinking water treatment processes. Both BP3 and BP4 could react with free chlorine and chloramine, with reactions following pseudo-first-order kinetics in excess of chlorine (HClO) and chloramine (NH2Cl). Generally, chlorination was more rapid than chloramination. BP4 was less reactive than BP3 toward both chlorine and chloramine, due to the presence of an electron-accepting sulfonate group. Therefore, BP3 had a significantly higher disinfection by-products (DBP) formation potential than BP4. Chlorination of BP3 and BP4 generated remarkably higher levels of DBPs than chloramination, with high pH conditions facilitating the formation of chloroform but inhibiting the formation of haloacetic acid (HAAs). Comparison of the reaction behavior of two different BP-type UV filters, i.e., BP3 and BP4, revealed that certain functional groups significantly affected the reactivity of BP-type UV filters in chlorination and chloramination processes. This contribution may provide new insights into the reaction behavior of UV filters during drinking water disinfection process using chlorine and/or chloramine as disinfectant, and provide guidelines for drinking water safety management.

Maternal exposure to UV filters: associations with maternal thyroid hormones, IGF-I/IGFBP3 and birth outcomes.

BACKGROUND: Several chemical UV filters/absorbers ('UV filters' hereafter) have endocrine-disrupting properties in vitro and in vivo. Exposure to these chemicals, especially during prenatal development, is of concern. OBJECTIVES: To examine maternal exposure to UV filters, associations with maternal thyroid hormone, with growth factor concentrations as well as to birth outcomes. METHODS: Prospective study of 183 pregnant women with 2nd trimester serum and urine samples available. Maternal concentrations of the chemical UV filters benzophenone-1 (BP-1) and benzophenone-3 (BP-3) in urine and 4-hydroxy-benzophenone (4-HBP) in serum were measured by liquid chromatography-tandem mass spectrometry (LC-MS/MS). The relationships between 2nd trimester maternal concentrations of the three chemical UV filters and maternal serum concentrations of thyroid hormones and growth factors, as well as birth outcomes (weight, height, and head and abdominal circumferences) were examined. RESULTS: Positive associations between maternal serum concentrations of 4-HBP and triiodothyronine (T3), thyroxine (T4), insulin-like growth factor I (IGF-I) and its binding protein IGFBP3 were observed in mothers carrying male fetuses. Male infants of mothers in the middle 4-HBP exposure group had statistically significantly lower weight and shorter head and abdominal circumferences at birth compared to the low exposure group. CONCLUSIONS: Widespread exposure of pregnant women to chemical UV filters and the possible impact on maternal thyroid hormones and growth factors, and on fetal growth, calls for further studies on possible long-term consequences of the exposure to UV filters on fetal development and children's health.

Development of photoprotective, antiphototoxic, and antiphotogenotoxic formulations of ocular drugs with fluoroquinolones.

The development of innovative solutions in photosafety of photolabile pharmaceutical products may help to reduce the adverse effects of these products, caused by light exposure. Providing new data in this area of study is particularly important in case of drugs applied topically on sensitive organs such as eyes. The main goal of this research is to investigate whether two potential excipients, namely: p-coumaric acid and benzophenone-4, affect the photodegradation, phototoxicity and photogenotoxicity of water solutions of four fluoroquinolones: ciprofloxacin, lomefloxacin, fleroxacin and clinafloxacin. We conducted a set of bioassays combined with the application of high-performance liquid chromatography and mass spectrometry techniques. The significant reduction of phototoxic and photogenotoxic abilities was evaluated in mixtures with ciprofloxacin and p-coumaric acid by using the umu test with Salmonella typhimurium TA1535/pSK1002, the methylthiazol tetrazolium reduction assay, and the micronucleus assay with the V79 cell line. In the bacterial assay the opposite effect was observed for the formulation with lomefloxacin and p-coumaric acid. This may be explained by the significant differences in the profile of the lomefloxacin photodegradation products. Further, the photoprotective and antiphotomutagenic abilities of ciprofloxacin mixed with benzophenone-4 were assessed. Promising results obtained in compositions with ciprofloxacin may be a basis for further research. Nevertheless, the increase in the DNA damage potential in mixtures with p-coumaric acid and two other antibiotics shows the importance of the safety evaluation of such innovative combinations.

Presence of benzophenones commonly used as UV filters and absorbers in paired maternal and fetal samples.

BACKGROUND: Previous studies have demonstrated widespread exposure of humans to certain benzophenones commonly used as UV filters or UV absorbers; some of which have been demonstrated to have endocrine disrupting abilities. OBJECTIVES: To examine whether benzophenones present in pregnant women pass through the placental barrier to amniotic fluid and further to the fetal blood circulation. METHODS: A prospective study of 200 pregnant women with simultaneously collected paired samples of amniotic fluid and maternal serum and urine. In addition, unique samples of human fetal blood (n=4) obtained during cordocentesis: and cord blood (n=23) obtained at delivery, both with paired maternal samples of serum and urine collected simultaneously, were used. All biological samples were analyzed by TurboFlow-liquid chromatography - tandem mass spectrometry for seven different benzophenones. RESULTS: Benzophenone-1 (BP-1), benzophenone-3 (BP-3), 4-methyl-benzophenone (4-MBP), and 4-hydroxy-benzophenone (4-HBP) were all detectable in amniotic fluid and cord blood samples and except 4-HBP also in fetal blood; albeit at a low frequency. BP-1 and BP-3 were measured at ~10-times lower concentrations in fetal and cord blood compared to maternal serum and 1000-times lower concentration compared to maternal urine levels. Therefore BP-1 and BP-3 were only detectable in the fetal circulation in cases of high maternal exposure indicating some protection by the placental barrier. 4-MBP seems to pass into fetal and cord blood more freely with a median 1:3 ratio between cord blood and maternal serum levels. Only for BP-3, which the women seemed to be most exposed to, did the measured concentrations in maternal urine and serum correlate to concentrations measured in amniotic fluid. Thus, for BP-3, but not for the other tested benzophenones, maternal urinary levels seem to be a valid proxy for fetal exposure. CONCLUSIONS: Detectable levels of several of the investigated benzophenones in human amniotic fluid as well as in fetal and cord blood calls for further investigations of the toxicokinetic and potential endocrine disrupting properties of these compounds in order for better assessment of the risk to the developing fetus.

Acute Toxicity and Ecological Risk Assessment of Benzophenone-3 (BP-3) and Benzophenone-4 (BP-4) in Ultraviolet (UV)-Filters.

Ultraviolet (UV)-absorbing chemicals (UV filters) are used in personal care products for the protection of human skin and hair from damage by UV radiation. Although these substances are released into the environment in the production and consumption processes, little is known about their ecotoxicology effects. The acute toxicity and potential ecological risk of UV filters benzophenone-3 (BP-3) and benzophenone-4 (BP-4) on Chlorella vulgaris, Daphnia magna, and Brachydanio rerio were analyzed in the present study. The EC50 values (96 h) of BP-3 and BP-4 on C. vulgaris were 2.98 and 201.00 mg/L, respectively. The 48 h-LC50 of BP-3 and BP-4 on D. magna were 1.09 and 47.47 mg/L, respectively. The 96 h-LC50 of BP-3 and BP-4 on B. rerio were 3.89 and 633.00 mg/L, respectively. The toxicity of a mixture of BP-3 and BP-4 on C. vulgaris, D. magna, and B. rerio all showed antagonistic effects. The induced predicted no-effect concentrations of BP-3 and BP-4 by the assessment factor method were 1.80 × 10-3 and 0.47 mg/L, respectively, by assessment factor (AF) method, which were both lower than the concentrations detected in the environment at present, verifying that BP-3 and BP-4 remain low-risk chemicals to the aquatic ecosystem.

Transformation and toxicity assessment of two UV filters using UV/H2O2 process.

The treatment of two typical UV filters benzophenone-4 (BP4) and benzophenone-9 (BP9) was evaluated in aqueous solutions by UV/H2O2 process. High-resolution accurate mass spectrometry (HRMS) was used to identify the degradation intermediates. A total of 12 BP4 degradation products and 17 BP9 degradation products were identified. A series of OH-initiated reactions, including hydroxylation, dihydroxylation, decarboxylation, demethylation, and ring breaking, lead to the final mineralization of BP4 and BP9. The degradation mechanisms of BP4 and BP9 are also proposed, separately. Toxicity prediction and assessment indicate that the bio-toxicity of the intermediates is higher, even if the parent compounds are completely transformed. It is necessary to further assess the environmental risk of BP4, BP9 and their intermediates in engineered systems and ambient aquatic environments.

Exposure to UV filters during summer and winter in Danish kindergarten children.

BACKGROUND: Ultra violet (UV) filters with known or suspected endocrine disrupting properties are widely used in sunscreens and other personal care products, clothing, food packaging and many other consumer products. Danish kindergarten children have sunscreens applied daily during summer to prevent skin burns. OBJECTIVES: To estimate the assumed contribution of sunscreens to the total exposure to UV filters, we measured the urinary excretion of UV filters during summer and winter in kindergarten children. METHODS: Spot- and first morning urines were collected during a summer and a winter day in 2013. A total of 266 urine samples were collected from 55 children and were analysed for content of benzophenone (BP), benzophenone-1 (BP-1), benzophenone-2 (BP-2), benzophenone-3 (BP-3), 5-chloro-2-hydroxybenzophenone (BP-7), 4-methyl-benzophenone (4-MBP), 4-hydroxybenzophenone (4-HBP), 3-(4-methylbenzylidene)-camphor (4-MBC), and 3-benzylidene camphor (3-BC) by LC-MS/MS. RESULTS: Of the analysed UV filters, the children excreted predominantly BP-1, BP-3 and 4-HBP. The urine levels were significantly higher in summer samples compared to winter samples, however exposure during winter was still evident. Furthermore, children with the highest concentrations of UV filters in summer urines also tended to be among those with the highest winter levels. CONCLUSION: Exposures to UV filters during summertime can partly be explained by the intended use of UV filters in sunscreens, which is considered to be beneficial for children during outdoor activities. However, exposure to UV filters all year round together with large inter-individual variation indicate that children's exposure to UV filters also comes from other consumer items, presumably highly influenced by the general lifestyle of an individual child: this is completely unintended, without benefit, and potentially harmful.

Ecological risk assessment associated to the removal of endocrine-disrupting parabens and benzophenone-4 in wastewater treatment.

The occurrence of four widely used and endocrine disrupting parabens (PBs) (methylparaben, propylparaben, butylparaben and benzylparaben) and a polar UV filter (benzophenone-4) were determined in influent and effluent wastewater from the 19 major wastewater treatment plants (WWTPs) of Catalonia, Spain. For their analysis an on-line solid-phase extraction-liquid chromatography-tandem mass spectrometry (SPE-HPLC-MS/MS) method was developed and validated. Laboratory analysis revealed high levels for both PBs and BP4, with maximum concentrations of 5700ngL(-1) and 1806ngL(-1), respectively, in influent samples, and 137ngL(-1) and 1080ngL(-1), respectively in effluent wastewaters. Removal rates (RE%) for the target compounds in each WWTPs were calculated. RE% for parabens were almost 100%, whereas for BP4 values where in the range 5-91%. The half-life time (t1/2), hydraulic retention time (HRT), and annual mass load (ML) for each facility was estimated. Results indicated that there was no clear influence of HRT on the RE% of BP4. MLs for BP4 were in the range 0.9-110.1kgy(-1), with the highest values in the most populated areas. Finally, a risk assessment, estimated in terms of hazard quotients (HQs), was carried out for aquatic biota. HQs for the target compounds in effluent wastewaters indicated a negligible effect, whereas for some influent wastewaters' HQs pointed out that some species are at risk.

Ozonation of the UV filter benzophenone-4 in aquatic environments: Intermediates and pathways.

The occurrence of benzophenone-4 (BP-4) in water environments may pose a serious public health hazard due to its potential endocrine disrupting effects. In this work, the intermediates, probable degradation pathways and toxicity changes during ozonation of BP-4 in aqueous solution were systematically investigated. Results revealed that alkaline conditions favored the oxidation of BP-4. However, inorganic anions (Cl(-), NO3(-), SO4(2-)), cations (K(+), Ca(2+), Mg(2+)) and humic acid had no remarkable effect on BP-4 removal within the tested concentrations. Ozonation was also effective for the fast removal of BP-4 in real waters. The TOC suggested a low mineralization rate, even after the complete BP-4 removal. Meanwhile, the treated mixtures exhibited an obvious inhibition to the bioluminescent bacteria Photobacterium phosphoreum, indicating the formation of transformation products with higher toxicities. Furthermore, fourteen products were identified by means of liquid chromatography-mass spectrometry. Notably, seven of them have not been reported previously. The quenching test indicated that the degradation processes probably were dominated by OH. Next, possible degradation pathways were proposed and further justified by theoretical calculations of frontier electron densities. This investigation will contribute to the systematic elucidation of the ozonation process of UV filters in aquatic environments.

Photochemical processes involving the UV absorber benzophenone-4 (2-hydroxy-4-methoxybenzophenone-5-sulphonic acid) in aqueous solution: reaction pathways and implications for surface waters.

The sunlight filter benzophenone-4 (BP-4) is present in surface waters as two prevailing forms, the singly deprotonated (HA-) and the doubly deprotonated one (A(2-)), with pKa2 = 7.30 ± 0.14 (µ ± σ, by dissociation of the phenolic group). In freshwater environments, BP-4 would mainly undergo degradation by reaction with ·OH and direct photolysis. The form HA(-) has a second-order reaction rate constant with ·OH (k(·OH)) of (1.87 ± 0.31)·10(10) M(-1) s(-1) and direct photolysis quantum yield Φ equal to (3.2 ± 0.6)·10(-5). The form A(2-) has (8.46 ± 0.24)·10(9) M(-1) s(-1) as the reaction rate constant with ·OH and (7.0 ± 1.3)·10(-5) as the photolysis quantum yield. The direct photolysis of HA(-) likely proceeds via homolytic breaking of the O-H bond of the phenolic group to give the corresponding phenoxy radical, as suggested by laser flash photolysis experiments. Photochemical modelling shows that because of more efficient direct photolysis (due to both higher sunlight absorption and higher photolysis quantum yield), the A(2-) form can be degraded up to 3 times faster than HA(-) in surface waters. An exception is represented by low-DOC (dissolved organic carbon) conditions, where the ·OH reaction dominates degradation and the transformation kinetics of HA(-) is faster compared to A(2-). The half-life time of BP-4 in mid-latitude summertime would be in the range of days to weeks, depending on the environmental conditions. BP-4 also reacts with Br2(·-), and a rate constant k(Br2(·-),BP-4) = (8.05 ± 1.33)·10(8) M(-1) s(-1) was measured at pH 7.5. Model results show that reaction with Br2(·-) could be a potentially important transformation pathway of BP-4 in bromide-rich (e.g. seawater) and DOM-rich environments.

Presence of UV filters in surface water and the effects of phenylbenzimidazole sulfonic acid on rainbow trout (Oncorhynchus mykiss) following a chronic toxicity test.

UV filters belong to a group of compounds that are used by humans and are present in municipal waste-waters, effluents from sewage treatment plants and surface waters. Current information regarding UV filters and their effects on fish is limited. In this study, the occurrence of three commonly used UV filters - 2-phenylbenzimidazole-5-sulfonic acid (PBSA), 2-hydroxy-4-methoxybenzophenone (benzophenone-3, BP-3) and 5-benzoyl-4-hydroxy-2-methoxy-benzenesulfonic acid (benzophenone-4, BP-4) - in South Bohemia (Czech Republic) surface waters is presented. PBSA concentrations (up to 13µgL(-1)) were significantly greater than BP-3 or BP-4 concentrations (up to 620 and 390ngL(-1), respectively). On the basis of these results, PBSA was selected for use in a toxicity test utilizing the common model organism rainbow trout (Oncorhynchus mykiss). Fish were exposed to three concentrations of PBSA (1, 10 and 1000µgL(-1)) for 21 and 42 days. The PBSA concentrations in the fish plasma, liver and kidneys were elevated after 21 and 42 days of exposure. PBSA increased activity of certain P450 cytochromes. Exposure to PBSA also changed various biochemical parameters and enzyme activities in the fish plasma. However, no pathological changes were obvious in the liver or gonads.