In recent years, benzotriazoles (BTs) and UV filters have received an increasing attention as emerging contaminants due to their wide presence in environment. BTs and UV filters were commonly used industrial and household chemicals, adding into industrial products and personal care products. Because of their incomplete removal in wastewater treatment plants (WWTPs), BTs and UV filters could enter the environment either via direct discharge during various activities or via indirect discharge of effluent of WWTPs. Moreover, BTs and UV filters could strongly absorb in sludge, so that they would enter the environment with the biosolid application in agricultural land, which might lead to the occurrence and accumulation in soil and plant. Therefore, it is necessary to develop an extraction and analytical method for simultaneous analyisis of BTs and UV filters in different environment mediums. The analytical method could be used to determine the occourrence and dissipation of BTs and UV filters in water, sediments and biosolid-amended soil. This study selected 4 typal BTs and 10 UV filters as the objects, and developed an extraction and analytical method for simultaneous analyisis of the target compounds in different environment mediums. Solid phase extraction (SPE) and accelerated solvent extration (ASE) were applied as pretreatment methods for water and solid samples, respectively. BTs were determined by LC-MS/MS, while UV filters were determined by GC-MS. The developed methods were proved sensitive and simple. The extraction recoveries of most target compounds were range from 70% to 120%. Meanwile, method detection limits and quantification limits of target compounds can meet the analysis requirements in different environment mediums. Sampling was carried out at 21 sampling sites of 4 rivers (Shima River, Danshui River, Xizhijiang River and Dongjiang River) in in Dongjiang River Basin to determine the occurrence of BTs and UV filters in water and sediments. The results showed that the major contaminants in water samples were BTs, meanwhile BT had the highest concentration (6211±1309 ng/L), followed by 5-TT with the concentration of 296±12.4 ng/L. UV-329 was the only detected UV filter in water samples due to the hydrophobicity of UV filters. BT was the major BTs detected in sediments at the concentration between 0.9±0.1 ng/g and 336±29.8 ng/g. UV-329 was the major UV filters detected in sediments at the concentration between 0.5±0.1 ng/g and 396±74.7 ng/g. Moreover, the concentrations of UV filters had seasonal variation. The usage of UV filters in summer was larger than that in winter, which lead to higher concentrations in sediments for wet season than dry season. Field trials of biosolid application on agricultural land were carried out at 3 sites (Zhejiang, Hunan and Shandong). The trials included 3 treatments: control (without application of biosolid), T1 (a single application of biosolid), and T2 (repeated application of biosolid). Most of the target compounds were detected in the sludge at the concentrations ranged from 28.3±1.2 ng/g to 389±13.7 ng/g. The concentrations of target compounds in biosolid-amended soil for T1 and T2 were < LOD - 10.3±3.1 ng/g and < LOD - 33.3±7.3 ng/g, respectively. Meanwhile, the concentrations of contaminants for T2 were significantly higher than which for T1. The results showed that biosolid application would lead the accumulation of contaminants in soils. Soil types and farming methods would influence the dissipation of contaminants in biosolid-amended soils, particularly for BTs. Significant linear correlations between between the concentrations of benzotriazole ultraviolet stabilizers (BUVSs) (UV-326, UV-327, UV-328, UV-329 and UV-P) and soil organic carbon were showed in biosolid-amended soils. The field dissipation of 2 BTs (BT and 5-TT) and 5 BUVSs (UV-326, UV-327, UV-328, UV-329 and UV-P) was observed in 1-yr monitoring of Shandong site. The field trials contained several treatm
To prevent UV damage, UV filters are added to various personal care products. It is frequently detected in the water environment due to its large usage. Including 4-methylbenzylidene camphor (4-MBC), 2-ethylhexyl-4-methoxycinnamic acid (EHMC) and octocreline (OC), three kinds of organic UV filters, and they both have lipophilicity and high octanol-water partition coefficients can accumulate in organisms and present potential environmental hazards. Therefore, in this study, 4-MBC, EHMC, and OC were used as research objects to develop the toxic and toxicological effects on aquatic vertebrate fish.The following results have been obtained:The short-term reproduction experiments of fish (Japanese medaka) with three UV absorbers significantly decreased fish fertility, among which 4-MBC caused a decrease in fertilization rate; histological results confirmed that three UV filters promoted the development of F0 female ovaries, 4-MBC and OC significantly inhibited spermatogenesis in the male testis, whereas EHMC induced maturation of mature sperm in the testis; 4-MBC induced significant up-regulation of VTG and E2 levels in the F0 female oocytes of the F0 generation. EHMC and OC induced both female and male of VTG, E2, and 11-KT levels were significantly upregulated in plasma, while 4-MBC significantly reduced 11-KT levels in plasma of males; three UV filters significantly altered the transcriptional expression of HPG axis-associated genes; three UV filters both had significant effects on the hatching rate, hatching time, deformity rate, juvenile length and accumulative mortality of the F1 generation. This indicates that the three UV filters not only have reproductive and developmental toxicity but also have endocrine disrupting effects on the medaka.Toxicological mechanism test results show that three types of UV filters mainly affect fish PPAR signaling pathway and CYP450 signaling pathway. Validation trials showed that 4-MBC, EHMC, and OC significantly increased the levels
2, 7-dimethyl-3, 6-diazacyclohepta-1, 6-diene perchlorate (dye 1) and 1-chloro-2, 7-dimethyl-3, 6-diazacyclohepta-1, 6-diene perchlorate (dye 2) used for solar blind detection in the previous literature were synthesized. A new dye, 3, 6-diazacyclohepta-1, 6-diene perchlorate (dye 3) was synthesized based on fundamental principles of Ultraviolet (UV) absorption spectroscopy and the requirements of UV filter. These dyes were characterized and compared by Elemental analysis, FT-IR spectroscopy, UV spectroscopy and thermogravimetric analysis (TGA). The solution filter and dye-doped PVA film with different dyes were prepared. UV spectroscopy measurements were carried out to investigate the absorption properties of these filters in the UV region. The photostability and temperature stability experiments of these filters were also studied. The results showed that these filters had high blocking levels in UV region while maintaining good transmittance in the solar blind range. The dye-doped PVA film exhibited better photostability and temperature stability than solution filter. Besides, dye-doped PVA film also had good thermal stability. Solar blind detection system was constructed by combining a solar blind UV intensified charge coupled device (ICCD)camera with UV filters (solution or film), potassium nickel sulfate hexahydrate crystal (KNSH) and colored glasses. The solar blind detection system containing dye 2 or dye 3 solar blind UV filter could successfully image the corona discharge. The experiment results showed that the dye 2 and dye 3 had met the requirements of solar blind detection.
UV filters, a group of Ultra-violet absorbent, are widely used as sunscreen in personal care products such as, cosmetics, beauty creams and skin lotions, lipsticks, hair sprays, hair dyes, shampoos, etc. After application, these compounds enter aquatic system mainly through two pathways, one is from the recreational activities, such as swimming and bathing in lakes and rivers (direct inputs), and another way is via wastewater treatment plants (WWTPs) after showering, washing, etc (indirect inputs).Concerns about the occurrence and distribution of UV filters in the environments increased in recent years, because their continuous input into the environments and causing their extensive distribution in wastewater, sludge, surface water, sediment, biota samples, and their bioaccumulative ability as well as their hormonal activity to aquatic organism and human.Until recently, little is known about the occurrence and distribution of UV filters in China. The aims of this paper are,1) to establish a rapid, sensitive analytical method for determination of 7 widely used UV filters in sludge and sediment, including Benzophenone (BP), Benzophenone-3 (BP-3), 4-Methylbenzylidene camphor (4-MBC), Ethylhexyl dimethylp-aminobenzoate (ODPABA), Ethylhexyl methoxycinnamate (EHMC), Octocrylene (OC) and Butyl methoxydiben-zoylmethane (BMDBM); 2) the occurrence and distribution of UV filters in sludge collected in 19 municipal wastewater treatment plants (WWTPs) in Guangdong Province; 3) the occurrence and distribution of UV filters in 28 sediments collected in/around the potable water sources in Taihu Lake.Firstly, an analytical method has been developed, based on Soxhlet-extraction, clean-up bysilica gel or/and neutral alumina, and determination using GC-EI-MS. The results indicated that the recoveries of UV filters in spiked samples varied from 71.72% to 128.88%, with the relative standard deviations （RSD） less than 14.53 %.The occurrence and distribution of 5 UV filters was investigated in 19 sludge samples, the results indicated that OC, EHMC and BP were the mainly detected compounds in these sludge samples, with concentrations ranging from 22.69 to 3664.49 ng/g，1.48 to 2055.82 ng/g and 17.15 to 774.35 ng/g, respectively. 4-MBC was detected in all sludge samples at LOD, except in KFQD (3.75 ng/g) and SZNS (56.56 ng/g). ODPABA was detected in 11 samples out of 19 sludges with concentration ranging between 6.42-469.47 ng/g. Meanwhile two main sources of these chemicals were indentified as domastic sewage and industrial wastewater, e.g, from cosmetic plants.The levels and distribution of 7 UV filters were studied from sediment samples from Taihu Lake. BP, BP-3 and EHMC were detected in all 28 samples with concentration ranging between 1.39-14.89 ng/g，0.18-5.24 ng/g and 0.09-2.00 ng/g, respectively. OC was detected in all sediment samples, which was at LOD level in 13 samples, while varied from 0.16 to 0.86 ng/g in the other samples. ODPABA was found in XK-3 at 0.64 ng/g. And 4-MBC was not detected in any of the sediments. The results indicated that the heavily polluted region in Taihu Lake was Meiliang Bay, followed by Gonghu District.Two synthetic musks, 1,3,4,6,7,8-hexahydro-4,6,6,7,8,8-hexamethyl-yclopenta- γ]-2-benzopyran （HHCB） and 7-acetyl-1,1,3,4,4,6-hexamethyl-1,2,3,4- tetrahydronapthalene （AHTN）, often were used as biomarkers indicating pollution from domestic waster to surface water. In this study the correlation between HHCB/AHTN and BP, disclosed pollution from domestic water discharged from inhabitants to Taihu Lake.
Organic ultraviolet absorbents (UVAs), including ultraviolet (UV) filters and ultraviolet (UV) stabilizers, are a group of widely used chemicals that are able to absorb UVB (290nm~320nm) and UVA (320nm~400nm) and return to ground state rapidly through emitting the absorbed energy as thermal energy or other safe ways. UV filters are commonly used in in personal care products, such as sunscreens, to reduce harmful effects on skin caused by solar radiation. UV stabilizers are also applied in a variety of industrial products such as plastics, coating and building materials to prevent degradation of the products due to absorb UV radiations. UVAs could enter the environment via human activities, such as swimming, or through discharge of industrial waste water. UVAs have been found in a variety of environmental media, e.g, drinking water, surface water, and sediments. However, researvh involving bioaccumulation and biomagnification of UVAs, such as 2-ethylhexyl-2-cyano-3, 3-diphenylacrylate (OCR) and 2-ethylhexyl-4-methoxy cinnamate (EHMC), have been proved to exhibt endocrine and developmental toxicity. UVAs may pose threat to the the environment and ecosystems. Therefor, it is of significance to conduct the studies on UVAs bioaccumulation via food chains. In addition, these studies can also provide data support for the environmental risk evaluatuion of the investigated UVAs.In this study, we chose seven classes (covering thirteen kinds) of UVAs, which are commonly used in China as the target compounds. These investigated compounds included. 2-hydroxyl-4-methoxy benzophenone (BP-3), 2-hydroxy-4-(octyloxy) benzophenone (UV-531), avobenzone (AVO), 3-(4-methylbenzylidene) camphor (4-MBC), 2-ethylhexyl-2-cyano-3, 3-diphenylacrylate (OCR), 2-ethylhexyl 4- (dimethylamino) benzoate (ODPABA), 2-ethylhexyl-4-methoxy cinnamate (EHMC) and benzotriazole UV stabilizers including UV-P, UV-329, UV-326, UV-234, UV-328 and UV-327. Marine aquatic organisms including wild and farmed were collected form the Pearl River Estuary, South China. Preliminary investigation of the pollution level, bioaccumulation and biomagnification in wildlife and farmed organisms was performed. The main results of this study listed as follows: （1）Thirteen UVAs were detected in the marine wildlife organisms expect ODPABA. Total concentration of UVAs ranged from 48 to 596 ng/g lw. The concentration ratios of UVSs to UVAs were within the range from 70% to 95%. BP-3, 4-MBC, OCR, UV-531, UV-P, UV-329, UV-234, UV-328 and UV-327 were frequently detected (detectable rate ≥70%) with the concentration level of 0 to 50 ng/g lw, expect UV-531. UV-531 presented the highest concentration and its median and maximum concentrations were 202.53 ng/g lwand 294.63 ng/g lw, respective. The level of biota-sediment accumulation factors (BSAFs) for wildlife benthic organisms is within the range of 0-1.5, and only UV-531 exceeded 1. This indicted that UVAs could accumulate in organisms, on the other hand UVAs might be more prone to be adsorbed by sedmiments or metabolized in organisms which lead to the low BSAF numbers.（2）In this study, 24 species belong to three classes of osteichthyes, cephalopods and malacostraca were investigates. The total concentrations of UVAs in three classes were in the following order: osteichthyes (fish and eel) (141.59-596.31 ng/g lipid wt), cephalopodas (squid and cuttlefish) (108.98–113.23 ng/g lw lipid wt), crabs (48.09-259.63ng/g lipid wt) and shrimps (46.85- 205 ng/g lw lipid wt). Other than UV-531 and 4-MBC, concentrations of UVAs were generally higher in the detritus-feeded osteichthyes than in the non- detritus-feeded. The concentrations of UVAs were higher in carnivorous mantis shrimp (205ng/g lipid wt) than those in omnivorous sword prawn and kuruma prawn(46-52 ng/g lw), implying that feeding habit could contribute to UVAs accumulation in shrimps. On the other hand, habitat habits of the organisms did not lead to significant differences of the UVAs concentrati
Organic ultraviolet absorbents are compounds or substances that are able to absorb ultraviolet radiation and rapidly return to ground state by thermally emitting the energy through a series of vibrational transitions. They are widely used in cosmetic products and personal care products to reduce harmful effects on skin caused by solar radiation. In addition, UV stabilizers are also applied in a variety of polymer materials such as plastics and coating material to prevent yellowing and degradation of the products. As a result, they have been found widely in environment. Presence of organic UV absorbents in the environment has drawn increasing concerns due to their ecological potential, such as endocrine disrupting properties. Many organic UV absorbents have potential for bioaccumulation and through trophic web given their strong lipophilicity. However, compared to other hydrophobic organic contaminants, environmental occurrence, fate, and ecological impacts of organic UV absorbents are far from well-studied. This work aimed to develop a method for simultaneous determination of 13 most commonly applied UV filters and stabilizers in aquatic organism tissues. The target compounds including six classes UV absorbents, i.e. avobenzone(BM-DBM), 2-hydroxy-4-methoxybenzophenone (BP-3), 2-ethylhexyl-4-methoxycinnamate (OMC), 3-(4-methylbenzylidene)camphor (4-MBC), 2-ethylhexyl 4-(dimethylamino)benzoate (EHDAB), 2-ethylhexyl-2-cyano-3,3-diphenylacrylate (OCR) and benzotriazole UV stabilizers 2-(2-hydroxy-5-methylphenyl)benzotriazole (UV-P), 2-tert-butyl-6-(5-chloro-2H-benzotriazol-2-yl)-4-methylphenol (UV-326),2,4-di-tert-butyl-6-(5-chloro-2H-benzotriazol-2-yl)phenol (UV-327), 2-hydroxy-4-(octyloxy)benzophenone (UV-531), 2-(2H-benzotriazol-2-yl)-4,6-bis(1-methyl-l-phenylethyl)phenol (UV-234), 2-(2H-benzotriazol-2-yl)-4,6-di-tert-pentylphenol(UV-328), 2-(2H-benzotriazol-2-yl)-4-(1,1,3,3-tetramethylbutyl)phenol (UV-329). The method was validated and applied to detect the UV absorbents in aquatic organism collected from the Pearl River Delta and Estuary, South China. The results include: 1) A sensitive and reliable method was developed for simultaneous determination of 13 UV filters in aquatic organism tissues by optimizing ultrasonic-assisted extraction, gel permeation chromatography (GPC), and high performance liquid chromatography coupled with tandem mass spectrometry (HPLC-MS/MS) condition. The recoveries of the target analytes in the fortified samples ranged from 65.6% to 108.4%. The method limits of detection and quantification were in the range of 0.1-2.7 ng g-1 dw and 0.2-4.8 ng g-1 dw, respectively. 2) Bioaccumulation of organic ultraviolet absorbents in wild aquatic organism from Xiangzhou Bay, Daya Bay and Liuxihe Reservoir, Guangzhou was investgated. BP-3, 4-MBC and UV-329 were detected in the wild aquatic organism with the concentration at 0.68-8.15 ng g-1 lw (lipid weight), 0.34-23.46 ng g-1 lw, 1.27-26.12 ng g-1 lw and 21.3-41.44 ng g-1 lw. Which may suggested the target compounds have the potential for bioaccumulation in wild aquatic organisms. None of organic ultraviolet absorbents was detected in all samples. Bioaccumulation of organic ultraviolet absorbents in farmed fish from Yangjiang Bay was investgated. OCR, UV-234, UV-327 and UV-328 were detected in the fish belly with the concentration at 248.8-250.6 ng g-1 lw, 2.9–3.9 ng g-1 lw, 4.3-8.0 ng g-1 lw and 46.0 ng g-1 lw. The frequency of organic ultraviolet absorbents detected in farmed fishes was lower than wild ones.
Benzotriazoles (BTs) and UV filters have been regarded as emerging contaminants due to their wide presence in the environment and possible adverse impacts. Benzotriazoles (BTs) are high production volume chemicals that find broad application in various industrial processes as well as in households, e.g. as a corrosion inhibitor in dishwasher detergents and de-icing/anti-icing fluids, an ultraviolet light stabilizer in plastics, and an antifogging agent in photography and airport. Ultraviolet (UV) filters have been commonly used in cosmetic formulation such as sunscreens and skin care products in order to reduce the risk of skin cancer due to overexposure to two types of harmful UV irradiation classified as UV-A and UV-B (280-400 nm wavelength ranges) by blocking UV radiation from 200 to 400 nm wavelengths. BTs and UV filters especially for BT has been detected in treated sewage effluents, surface water and ground water due to its high usage, relatively high mobility and persistence. Currently, some studies have been conducted in the occurrence and distribution of BTs and UV filters in the environment. However, there is very little information in the literature regarding the occurrence and removal, photo-transformation mechanisms biodegradation mechanisms for BTs and UV filters and their potential photoproducts as well as possible environmental conditions and factors that could influence photolysis and biodegradation.The investigation scope of this thesis is listed as follows: Firstly, develop and validate an analytical method for simultaneous determination of four BTs and six UV filters by using gas chromatography-tandem mass spectrometry (GC-MS/MS) technique, after sample pretreatment with soild phase extraction (SPE) for ground water, influent and effluent samples and pressurized liquid extraction (PLE) for sludge samples. Secondly, examine the occurrence and removal of four BTs and six UV filters in a full scale municipal wastewater treatment plant (WWTP) (Bolivar, Adelaide, South Australia), with effluent reclamation for irrigation and aquifer recharge. A mass balance analysis was applied to establish mass flux in the plant and removal mechanisms of these compounds inside the treatment units. Thirdly, investigate UV photolysis of BT, 5-TTri and CBT in aqueous solutions and the effect of pH, metal ions, HA, a UV filter BP-3 and in aqueous solutions induced by four Fe(III)-carboxylate complexes (oxalate, tartrate, succinate and citrate). The possible photolytic pathways of target compounds have also been proposed based on the identified photoproducts. Fourthly, investigate the biodegradation efficiency of three BTs (BT, 5-TTri and CBT) and one representative UV filter, BP-3, in the laboratory under aerobic and anaerobic conditions (nitrate-reducing, sulfate reducing and Fe (III) reducing conditions). Fresh activated sludge and anaerobic digested sludge were used as inoculums for aerobic and anaerobic microcosms, respectively, in order to understand the fate of the three selected BTs and one UV filter in the WWTPs and environment. Finally, investigate the biodegradation efficiency of BT, 5-TTri and CBT in the laboratory batch studies using fresh groundwater and aquifer materials under aerobic and anaerobic conditions in order to understand the fate of three selected BTs in the native aquifer.A new method using GC-MS/MS was developed for the determination of four benzotriazoles i.e. benzotriazole (BT), 5-methylbenzotriazole (5-TTri), 5-chlorobenzotriazole (CBT), 5,6-dimethylbenzotriazole (XTri)), and six UV filters i.e. benzophenone-3 (BP-3), 3-(4-methylbenzylidene)camphor (4-MBC), octyl 4-methoxycinnamate (OMC), 2-(3-t-butyl-2-hydroxy-5-methylphenyl)-5-chloro benzotriazole (UV-326), 2-(2'-Hydroxy-5'-octylphenyl)-benzotriazole (UV-329), octocrylene (OC) in ground water, influent, effluent and sludge samples. SPE and PLE were applied as the preconcentration method for water samples (ground water, influent and effluent) and sludge samples, respectively. The optimized method allowed us to quantify all target compounds with the method detection limits ranging from 0.29 to 11.02 ng/L, 0.50 to 16.3 ng/L, 0.50 to 14.1 ng/L and 0.33 to 8.23 ng/g in ground water, influent, effluent and sludge samples, respectively. The recoveries of the target analytes in ground water, influent, effluent and sludge samples were 70 -150%, 75-121%, 82-127% and 81-133%, respectively. The developed analytical method was applied in the determination of these target compounds in ground water, influent, effluent and sludge samples collected from Bolivar WWTP in Adelaide, South Australia.Occurrence and removal of four BTs and six UV filters in different treatment stages in a full scale municipal wastewater treatment plant (Bolivar WWTP, Adelaide, South Australia), with the final effluent reclaimed for irrigation and aquifer recharge was investigated. BT, 5-TTri and BP-3 were found as the dominant compounds detected in the wastewater samples with average concentrations up to 5706±928 ng/L, 6758±1438 ng/L and 2086±1027 ng/L in influent, and up to 2439±233 ng/L, 610±237 ng/L and 153±121 ng/L in effluent, respectively. In the biosolid, 4-MBC and OC were found with the highest concentrations of 962±135 ng/g and 465±65 ng/g, respectively. Concentrations in the aqueous phase decreased significantly for most target compounds. According to the mass balance results in the entire water line, the losses of influent mass load were 53% to 59% for BT, 54% to 96% for 5-TTri, CBT and XTri, 91% to 97% for BP-3, OMC and UV-329, and only 8% to 46% for 4-MBC, UV-326 and OC in the two sampling campaigns. Sorption onto sludge played a dominant role in the removal for UV filters, especially for 4-MBC, UV-326 and OC, which accounted for 54%-92% of influent loads, while degradation played a significant role for the other compounds. Degradation of 4-MBC and OC in sludge was also observed in sludge stabilization lagoon.Photolysis of BT, 5-TTri and CBT in aqueous solutions under UV radiation at 254 nm and the impact of pH, salinity, metal species and dissolved organic matter on the photo-transformation processes have been investigated. Three selected BTs were all found to undergo rapid transformation to form several photoproducts. The half-lives for the photolysis of BT, 5-TTri and CBT ranged from 2.8 h to 14.3 h, 7.1 h to 24.3 h and 5.1 h to 20.5 h, respectively, in various aqueous solutions containing metal ions and dissolved organic matter. Photolysis rates decreased with increasing solution pH. Metal species Cu2+ and Fe3+, and especially humic acid had inhibitory effects on the photolysis of all three BTs under UV light irradiation at 254 nm. We propose the formation of three major photoproducts via instantaneous polymerization of small intermediates generated during the photolysis of BT including (A) 2, 6-diethylaniline, (B) phenazine and (C) 1, 6-dihydroxyphenazine, formation of two photoproducts (4-methylaniline and N, N-diethylaniline- p-toluidine) and three photoproducts (4-chloroaniline, Aniline and 2,6-diethylaniline) via N-N and N-NH bond scission and dechlorination process during the photolysis of 5-TTri and CBT, respectively. The effects of Fe (III)-carboxylate complexes on photodegradation of three benzotriazoles, BT, 5-TTri and CBT in aqueous solutions were investigated under the exposure to UV irradiation at 254 nm in the presence of Fe (III) and four carboxylate ions (oxalate, tartrate, succinate and citrate). The results showed that the presence of Fe (III)-carboxylate complexes significantly enhanced the photodegradation rates of all three selected BTs. The photodegradation of BT, 5-TTri and CBT followed the first-order reaction kinetics with their half-lives ranged from 0.57 to 3.98 h for BT, 6.08 to 8.25 h for 5-TTri, and 2.63 to 5.50 h for CBT in the four systems of Fe (III)-carboxylate complexes. While the half-lives ranged between 3.40 and 4.82 h for BT, between 6.42 and 11.55 h for 5-TTri, and between 4.13 and 6.08 h for CBT in the systems with three BTs alone, only Fe (III) or carboxylate. The degradation rates of these BTs were dependent on the pH values, carboxylates and Fe (III)/carboxylate ratios. Both BT and CBT showed the highest photodegradation rates with the shortest half-life of 0.57 h and 2.63 h, respectively, at the initial Fe (III)/oxalate ratio of 10/200 µmol/L in aqueous solutions at pH 3, while 5-TTri had the highest photodegradation rate with the shortest half life of 6.42 h at the initial Fe (III)/succinate ratio of 10/10 µmol/L. The presence of co-solutes (e.g. UV filters) can potentially influence the environmental fate of micropollutants. The photolysis of BT and BP-3 (a UV filter), as well as their interactions in aqueous solutions under UV and artificial solar light with or without added humic acid (HA) and metal ions (Cu2+ and Fe3+), has been investigated. BT was found to be photosensitive under UV irradiation, but photostable under solar light. The half-lives for the photolysis of BT were 2.8 h in pure aqueous solution increasing to 4.5 h in the presence of BP-3 (1.0 mg/L). BP-3 was photostable under both UV and artificial solar light. Solar radiation exposure of 50 days resulted in a relatively small loss of BP-3 (8 %) in pure aqueous solutions, while resulted in a greater loss of BP-3 (up to 31 %) at HA 50 mg/L. UV irradiation of the BT solutions containing BP-3 led to formation of five photoproducts, formed mainly by N–N and N–NH bond scission, polymerisation and hydroxylation. In the case of BP-3, one major photoproduct was isolated and tentatively identified as 2,4-dimethylanisole, formed by the loss of hydroxy and benzoyl groups.Biodegradability of three benzotriazoles BT, 5-TTri, CBT and a UV filters BP-3 was investigated in the laboratory in order to understand its behaviour and fate under aerobic and anaerobic (nitrate, sulfate and Fe (III) reducing) conditions. Biodegradation experiments were conducted in microcosms with 10% of activated sludge and digested sludge under aerobic and anaerobic conditions, respectively. All four target compounds were degraded by microorganisms under aerobic and anaerobic conditions. Both the biodegradation efficiency and biodegradation products were dependent on the predominant terminal electron-accepting condition. Among the redox conditions studied, the shortest biodegradation half lives for BT and 5-TTri were 114 days and 14 days, respectively, under aerobic condition. The shortest half-life for CBT and BP-3 were 26 days and 4.2 days, respectively, under Fe (III) reducing condition and anaerobic control condition, respectively. The longest biodegradation half lives for BT and CBT were 315 days and 96 days, respectively, under sulfate reducing condition, that of 5-TTri was 128 days under nitrate reducing condition, while that of BP-3 was 10.7 days under aerobic condition. These results suggest that aerobic biodegradation is the dominant natural attenuation mechanism for BT and 5-TTri, while the most favorable process for CBT and BP-3 was anaerobic biodegradation. Biodegradation of BP-3 produced two products (4-cresol and 2,4-dihydroxybenzophenone) under aerobic and anaerobic conditions. Biotransformation of BP-3 to 2,4-dihydroxybenzophenone via demethylation of the methoxy substituent (O-demethylation) occurred in cultures under each redox condition. This study demonstrated that different predominant terminal electron-acceptors present in natural environment play a key role on the biodegradation of BT, 5-TTri, CBT and BP-3, leading to specific biodegradability. This could have significant implications on in-situ biodegradation of the selected benzotriazoles and UV filters in aerobic and anaerobic waters, soils and sediments.Biodegradation of three selected BTs, BT, 5-TTri and CBT in aquifer was investigated. Biodegradation experiments were conducted in microcosms with 5 mL fresh groundwater and 5 g aquifer materials under aerobic and anaerobic (nitrate, sulfate, and Fe (III) reducing) conditions. All three BTs were positively degraded by microorganisms in aquifer materials under aerobic and anaerobic conditions. Under aerobic conditions, BT and 5-TTri were found to be degraded fastest with their half-lives of 43 days and 31 days, respectively, among the redox conditions used. Under anaerobic conditions, CBT was found to be degraded better with its half-life of 21 days under nitrate reducing conditions than under aerobic conditions with its half-life of 47 days. Aerobic conditions are more favorable for the biodegradation of BT and 5-TTri, while anaerobic conditions are the most favorable for CBT. The two BT derivatives 5-TTri and CBT could be biotransformed into BT via demethylation and dechlorination reactions, respectively.
The solar blind UV image detection technology has been applied in a variety of areas, such as corona detection, fire alarm and missile approach warning, regarding its imperviousness to solar clutter and low false alarm rate. The research on this technology starts late in China, and the strict confidentiality of the related research results in the deficiency of this technology comparing to the top in the world. To improve this technology, the development of the UV detection core devices and the quantitative analysis of UV detection are especially important. At present, there are three major difficulties in the parametric test and the radiometric calibration of solar blind UV core devices, which impedes the improvement of solar blind UV image detection technology. First, the standard detectors used in UV radiometric calibration cannot achieve high sensitivity and low calibration uncertainty simultaneously. Secondly, for the completely packaged solar blind UV ICCD, some key parameters such as spectral responsivity can only be inferred from other parameters like gray value or photon numbers. This unavailability of the absolute measurement results in the reduction of test accuracy. Thirdly, the lack of in-depth study on weak UV radiometric calibration limits the application of solar blind UV image detection technology in many areas such as corona detection.Hence, this thesis studies the parametric test and radiometric calibration of the solar blind UV image intensifier and ICCD.A new type of standard detector used in solar blind UV radiometric calibration is established by using the cavity pyroelectric detection system as standard, which achieves high sensitivity and low calibration uncertainty simultaneously. The pyroelectric detector is selected as the core device of the detection system and the main factors that affect its performance are theoretically analyzed. High sensitivity and low calibration uncertainty are achieved by optimizing the structure of the pyroelectric detection system. In addition, the modified function of absolute spectral responsivity of the detection system is derived and the main performance parameters are evaluated. The results demonstrate that the detection system satisfies the requirements of the project. Based on this, the absolute spectral responsivity calibration is achieved, and the relative spectral responsivity gauge for the system and the solar blind UV radiometric calibration standard with a low uncertainty of<1.2% are establishedThe parametric test and the radiometric calibration for the solar blind UV ICCD and image intensifier are performed. The uncertainties of the parametric test and the calibration of the core devices are effectively reduced in this UV spectral. Based on the established low uncertainty standard detector, the parametric test and radiometric calibration for the solar blind image intensifier, ICCD and the associated filters are performed. First, the absolute spectral responsivity calibration and integral responsivity test of the image intensifier are achieved, which has an uncertainty of < 1.6% and < 2.1% respectively. Secondly, the relative spectral responsivity of the ICCD is tested. The reasons for the differences between the test results of the ICCD and the image intensifier are discussed. In addition, the out-off-band cutoff depths for the matching filters of ICCD is tested, whose uncertainty is < 1.1%.To improve the solar blind UV detection technology in the extremely weak UV radiometric calibration of photon counting, the weak solar blind UV radiometric calibration is studied. This may be helpful to solve the problem of the incapability of accurately quantifying the radiation of the target source in corona detection and many others areas. The single photon detector is chosen as a standard for the weak solar blind UV radiometric calibration. The reasons for choosing single photon detector and its working principle are discussed. Moreover, a method for calibr