Determination of nitroarenes in precipitation collected in Kanazawa, Japan

Occurrence, partition behavior, source and ecological risk assessment of nitro-PAHs in the sediment and water of Taige Canal, China

Nitrated polycyclic aromatic hydrocarbons (NPAHs) are widespread organic pollutants that possess carcinogenic and mutagenic properties, so they may pose a risk to the environment and human health. In this study, the concentrations of 15 NPAHs and 16 polycyclic aromatic hydrocarbons (PAHs) in 30 surface water samples and 26 sediment samples were measured in 2018 from the Taige Canal, one of the main rivers flowing into Taihu Lake, China. The total NPAH concentrations in water and sediment ranged from 14.7 to 235 ng/L and 22.9 to 96.5 ng/g dw, respectively. 9-nitrophenanthrene (nd-76.3 ng/L) was the dominant compound in surface water, while 2+3-nitrofluoranthene (1.73-18.1 ng/g dw) dominated in sediment. Among PAHs, concentration ranging from 1,097 to 2,981 ng/L and 1,089 to 4,489 ng/g dw in surface water and sediment, respectively. There was a strong positive correlation between the log octanol-water partition coefficient (K_ow) and log sediment-water partition coefficient due to hydrophobic interaction. The fugacity fraction value increased with the decrease of log K_ow, and chrysene was transferred from water into sediment. The residual NPAHs in surface water and sediment of the Taige Canal have partial correlation. Diesel engine and coal combustion emissions were probably the principal sources of NPAHs in surface water and sediment. The results of ecological risk assessment showed that some NPAHs in water (e.g, 1-nitropyrene and 6-nitrochrysene) and sediment (e.g., 2-nitrobiphenyl, 5-nitroacenaphthene, 9-nitrophenanthrene and 2+3-nitrofluoranthene) had moderate ecological risks, which should be of concern.

Nitrated- and oxygenated-polycyclic aromatic hydrocarbon in urban soil from Nepal: Source assessment, air-soil exchange, and soil-air partitioning

In contrast to more frequently investigated priority pollutants, such as polycyclic aromatic hydrocarbons (PAHs), only little is known about the fate and distribution of nitrated- and oxygenated-PAHs (NPAHs and OPAHs) in urban soils, particularly in Indian sub-continent. Moreover, experimental data on air-soil exchange and soil-air partitioning are also lacking, which is critical in assessing the partitioning, fugacity coefficient, and secondary emission of PAH-derivatives. Hence, this article provides an insight into the fate, sources, air-soil exchange, and soil-air partitioning of PAH-derivatives on a molecular basis. Prospective health risk due to their exposure has also been discussed. The result showed that PAH-derivatives had significantly polluted all four Nepalese cities. Ʃ₁₅NPAHs and Ʃ₂OPAHs in soil were 4 and 20 times lower than their parent-PAHs, and ranged 396-2530 ng/g (median 458 ng/g) and 91.9-199 ng/g (median 94.9 ng/g), respectively. Ʃ₁₅NPAHs was higher than a few global studies, while Ʃ₂OPAHs was lower than some of the less urbanized/remote areas worldwide. The 6-Nitobenzo[a]pyrene (6-NBaP) was most abundant in soil, and accounted for 10-12% of Ʃ₁₅NPAHs, while Benzanthrone (BZONE) exceeded among OPAHs, and represented 71-76% of Ʃ₂OPAHs, respectively. Source identification study indicated that direct emissions from domestic/residential cooking and heating and secondary formations are the essential sources of derivative chemicals in soil. Fugacity fraction ratio (f_ratio) indicated volatilization from the soil. The soil-air partitioning study showed sorption by soil organic matter/black carbon has little role in soil-air partitioning of PAH-derivatives in Nepal's urban soil. The toxicity equivalency quotients (TEQs) of NPAHs (314 ± 102 ng/g) was estimated slightly higher than their parent-PAHs (294 ± 121 ng/g) suggesting a relatively higher risk of soil toxicity in Nepal.

Maternal 1-nitropyrene exposure during pregnancy increases susceptibility of allergic asthma in adolescent offspring

1-nitropyrene (1-NP) is widespread in the environment, as a typical nitrated polycyclic aromatic hydrocarbon. The purpose of this research was to explore the effects of gestational 1-NP exposure on susceptibility of allergic asthma in offspring. Maternal mice were exposed to 1-NP (100 μg kg^-1) by gavage throughout the whole pregnancy. Pups were sensitized by injecting with ovalbumin (OVA) on postnatal day (PND)23, 29, and 36, respectively. At 7 days following the last injection, sensitized mice were exposed to aerosol OVA. As expected, there were quite a few inflammatory cells in the lungs of OVA-sensitized pups, accompanied by bronchial wall thickening and hyperemia. Elevated goblet cells and overproduced mucus were observed in the airways of OVA-sensitized pups. Interestingly, gestational 1-NP exposure aggravated infiltration of inflammatory cells, mainly eosinophils, in OVA-sensitized offspring. Although it had little effect on airway smooth muscle layer thickening and basement membrane fibrosis, gestational 1-NP exposure aggravated goblet cell hyperplasia, Muc5ac mRNA upregulation, and mucus secretion in the airways of OVA-sensitized and challenged offspring. Mechanistically, gestational 1-NP exposure aggravated elevation of pulmonary IL-5 in OVA-sensitized pups. These findings suggest that gestational 1-NP exposure increases susceptibility of allergic asthma in offspring.

The presence of nitroarenes formed by secondary atmospheric processes in the Japanese freshwater environment

In this study, the concentrations and distributions of nitrated polycyclic aromatic hydrocarbons (NPAHs) were characterized in the freshwater environment of a Japanese city. While the NPAHs were few in number, they were found in pg/L concentrations and the specific isomers suggested the deposition of NPAHs formed via the atmospheric transformation of PAHs. The absence of NPAHs formed via primary combustion processes such as automobile exhaust, suggests that improvements in emission standards are being reflected in the environment, though the NPAHs formed by secondary atmospheric processes are still a significant ecotoxicological threat. The stability of the NPAHs was also examined in spiked freshwater matrices. There was a significant decrease in spiked NPAHs over this period, suggesting that they were either being sorbed or transformed and are therefore not long lived in the freshwater environment. This indicates that the NPAHs found in freshwater samples are from recent deposition.

Oxidative stress and genotoxicity biomarker responses in tilapia (Oreochromis niloticus) exposed to environmental concentration of 1-nitropyrene

The present study aimed to assess whether environmental 1-nitropyrene (1-NP) concentration will induce genotoxicity and oxidative damages in tilapia, lives in estuarine and brackish water. Tilapia were exposed to waterborne 1-NP. Cellular antioxidant enzyme activity of glutathione peroxidase and oxidative damage, i.e., lipid peroxidation, protein and DNA oxidation were used as biomarkers of oxidative stress, while the micronucleus test was used for evaluation of chromosomal damage and was used as an indication of genotoxicity. Results showed that all biomarkers for oxidative stress positively responded, and micronucleus and other nuclear abnormalities frequencies significantly increased (p<0.001). This study showed that environmentally relevant 1-NP concentration in test water (0.15ng/L) and in fish (3ng/kg) induced genotoxicity and oxidative stress. Micronuclei and other nuclear abnormalities were probably formed as a result of oxidative stress. In conclusion, exposure to lower waterborne 1-NP concentration can pose a risk to freshwater and estuarine organisms through accumulation.

Distributions of nitrated polycyclic aromatic hydrocarbons in the sediment of Osaka Bay, Japan

The distributions of 15 nitrated polycyclic aromatic hydrocarbons (NPAHs) in sediments collected at 44 sites throughout Osaka Bay, Japan were examined. The highest total NPAHs, with a concentration of 1949ng/kg dry weight, were detected near the city of Amagasaki. Some sites near the cities of Osaka, Kishiwada, sand Sakai registered ng/kg levels of NPAHs, but individual NPAH concentrations were relatively lower than those in previous studies. The sources were estimated using principal component analysis, and NPAHs were derived from exhaust gases of automobiles and industries at some sites. However, our results suggest that it is difficult to estimate the source, especially in coastal areas near big cities and large industrial areas, because the generation pathways between parent polycyclic aromatic hydrocarbons (PAHs) and nitrated PAHs are slightly different, and the ratio of PAHs and NPAHs could not be accurately reflect the characters of sources in sediments especially at coastal areas with large-scale industrial zones.

Atmospheric deposition of polycyclic aromatic compounds and associated sources in an urban and a rural area of Chongqing, China

Monthly bulk (dry + wet) deposition samples were collected at an urban and a rural site in Chongqing, southwestern China during May 2014 to April 2015 for analyzing the contents of parent polycyclic aromatic hydrocarbons (PPAHs) and three types of substituted PAHs (SPAHs) including oxygenated PAHs (OPAHs), nitrated PAHs (NPAHs) and methyl PAHs (MPAHs). Annual average (±standard deviation) deposition fluxes of ΣPPAHs, ΣOPAHs, and ΣMPAHs were 536 ± 216; 221 ± 118, and 131 ± 41.9 ng/m²/d, respectively, in the urban area, and 347 ± 185, 160 ± 112, and 85.2 ± 32.0 ng/m²/d, respectively in the rural area. Deposition of ΣNPAHs (6.01 ± 3.93 and 3.91 ± 4.84 ng/m²/d) were about two orders of magnitude lower than those of ΣPPAHs. In the urban area, temporal variations of PPAHs and MPAHs fluxes were positively correlated with particle deposition, while the trends of OPAHs and NPAHs were probably controlled by secondary formation. In the rural area, SPAHs and PPAHs deposition fluxes had similar temporal trends but differed from particle deposition. High relative humidity in Chongqing likely played an important role in facilitating the partitioning of OPAHs to atmospheric aerosols and resulting in the relatively high OPAHs level in winter. Principle component analysis identified secondary formation (21.7%) and combustion emission (52.7%) as two important contributors to polycyclic aromatic compounds (PACs) deposition fluxes in urban area.

Use of low density polyethylene membranes for assessment of genotoxicity of PAHs in the Seine River

The genotoxicity of river water dissolved contaminants is usually estimated after grab sampling of river water. Water contamination can now be obtained with passive samplers that allow a time-integrated sampling of contaminants. Since it was verified that low density polyethylene membranes (LDPE) accumulate labile hydrophobic compounds, their use was proposed as a passive sampler. This study was designed to test the applicability of passive sampling for combined chemical and genotoxicity measurements. The LDPE extracts were tested with the umu test (TA1535/pSK1002 ± S9) and the Ames assay (TA98, TA100 and YG1041 ± S9). We describe here this new protocol and its application in two field studies on four sites of the Seine River. Field LDPE extracts were negative with the YG1041 and TA100 and weakly positive with the TA98 + S9 and Umu test. Concentrations of labile mutagenic PAHs were higher upstream of Paris than downstream of Paris. Improvement of the method is needed to determine the genotoxicity of low concentrations of labile dissolved organic contaminants.

Nitrated polycyclic aromatic hydrocarbons (nitro-PAHs) in the environment - A review

Nitrated polycyclic aromatic hydrocarbons (nitro-PAHs) are derivatives of PAHs with at least one nitro-functional group (-NO₂) on the aromatic ring. The toxic effects of several nitro-PAHs are more pronounced than those of PAHs. Some nitro-PAHs are classified as possible or probable human carcinogens by the International Agency for Research on Cancer. Nitro-PAHs are released into the environment from combustion of carbonaceous materials (e.g. fossil fuels, biomass, waste) and post-emission transformation of PAHs. Most studies on nitro-PAHs are about air (gas-phase and particulate matter), therefore less is known about the occurrence, concentrations, transport and fate of nitro-PAHs in soils, aquatic environment and biota. Studies on partition and exchange of nitro-PAHs between adjacent environmental compartments are also sparse. The concentrations of nitro-PAHs cannot easily be predicted from the intensity of anthropogenic activity or easily related to those of PAHs. This is because anthropogenic source strengths of nitro-PAHs are different from those of PAHs, and also nitro-PAHs have additional sources (formed by photochemical conversion of PAHs). The fate and transport of nitro-PAHs could be considerably different from their related PAHs because of their higher molecular weights and considerably different sorption mechanisms. Hence, specific knowledge on nitro-PAHs is required. Regulations on nitro-PAHs are also lacking. We present an extensive review of published literature on the sources, formation, physico-chemical properties, methods of determination, occurrence, concentration, transport, fate, (eco)toxicological and adverse health effects of nitro-PAHs. We also make suggestions and recommendations about data needs, and future research directions on nitro-PAHs. It is expected that this review will stimulate scientific discussion and provide the basis for further research and regulations on nitro-PAHs.

Photo-induced toxicity and oxidative stress responses in Tigriopus japonicus exposed to nitro-polycyclic aromatic hydrocarbons and artificial light

Photo-induced toxicity is an important phenomenon in ecotoxicology because sunlight reaches many organisms in their natural habitats. To elucidate whether sunlight enhances the toxicity of nitro-polycyclic aromatic hydrocarbons (nitro-PAHs), the acute toxicities of 10 nitro-PAHs and the related compound 1-nitropyrene (1-NP) to Tigriopus japonicus were assessed in darkness or under light conditions. In addition, the relationships among the toxicity of 1-NP to T. japonicus, lighting condition, and the concentration of reactive oxygen species (ROS) formed were investigated in the presence or absence of the ROS scavenger ascorbic acid in the test solutions. Light irradiation increased the toxicity of all tested nitro-PAHs except 1,5-dinitronaphthalene. Among the compounds tested, 1-NP was the most phototoxic: it was more than 1000 times more toxic under the light conditions than in darkness. In contrast, at the same light levels, pyrene was not phototoxic. Light irradiation induced the generation of ROS in the 1-NP exposure groups, and the immobilization rate of T. japonicus increased with the amount of ROS produced. The addition of ascorbic acid to the test solutions suppressed both the generation of ROS and the light-induced immobilization of T. japonicus. To accurately assess the ecotoxicologic risk of nitro-PAHs, their overall photo-induced toxicity must be considered.

Evaluation of genotoxic effects of surface waters using a battery of bioassays indicating different mode of action

With the burgeoning contamination of surface waters threatening human health, the genotoxic effects of surface waters have received much attention. Because mutagenic and carcinogenic compounds in water cause tumors by different mechanisms, a battery of bioassays that each indicate a different mode of action (MOA) is required to evaluate the genotoxic effects of contaminants in water samples. In this study, 15 water samples from two source water reservoirs and surrounding rivers in Shijiazhuang city of China were evaluated for genotoxic effects. Target chemical analyses of 14 genotoxic pollutants were performed according to the Environmental quality standards for surface water of China. Then, the in vitro cytokinesis-block micronucleus (CBMN) assay, based on a high-content screening technique, was used to detect the effect of chromosome damage. The SOS/umu test using strain TA1535/pSK1002 was used to detect effects on SOS repair of gene expression. Additionally, two other strains, NM2009 and NM3009, which are highly sensitive to aromatic amines and nitroarenes, respectively, were used in the SOS/umu test to avoid false negative results. In the water samples, only two of the genotoxic chemicals listed in the water standards were detected in a few samples, with concentrations that were below water quality standards. However, positive results for the CBMN assay were observed in two river samples, and positive results for the induction of umuC gene expression in TA1535/pSK1002 were observed in seven river samples. Moreover, positive results were observed for NM2009 with S9 and NM3009 without S9 in some samples that had negative results using the strain TA1535/pSK1002. Based on the results with NM2009 and NM3009, some unknown or undetected aromatic amines and nitroarenes were likely in the source water reservoirs and the surrounding rivers. Furthermore, these compounds were most likely the causative pollutants for the genotoxic effect of these water samples. Therefore, to identify causative pollutants with harmful biological effects, chemical analyses for the pollutants listed in water quality standards is not sufficient, and single-endpoint bioassays may underestimate adverse effects. Thus, a battery of bioassays based on different MOAs is required for the comprehensive detection of harmful biological effects. In conclusion, for genotoxicity screening of surface waters, the SOS/umu test system by using different strains combined with the CBMN assay was a useful approach.

Differences in the ability of two marine annelid species, Thalassodrilides sp. and Perinereis nuntia, to detoxify 1-nitronaphthalene

Bioremediation is a promising method for remediating environmentally polluted water. We investigated the abilities of two benthic annelid species to biotransform 1-nitronaphthalene, a nitrated polycyclic aromatic hydrocarbon. We used an oligochaete, Thalassodrilides sp. (Naididae), collected from the sediment beneath a fish farm and a polychaete, Perinereis nuntia, which was obtained from a commercial source. Populations of both organisms were exposed to 1400 μg L(-1) of 1-nitronaphthalene in seawater for 3 days in the dark at 20 °C. The concentration of the pollutant decreased to 12 μg L(-1) in the seawater containing the Thalassodrilides sp. and to 560 μg L(-1) in the seawater containing P. nuntia. The 1-nitronaphthalene concentration in the bodies of the animals increased from 12 to 94 μg kg(-1) in Thalassodrilides sp. and from 0.90 μg kg(-1) to 38,000 μg kg(-1) in P. nuntia. After 3 days, 99% and 40% of the 1-nitronaphthalene had been biotransformed in the Thalassodrilides sp. and P. nuntia experimental groups, respectively. We then tested the acute toxicity of residual 1-nitronaphthalene from the same water using mummichog (fish) larvae. After the larvae had been exposed for 96 h, the percentage of apparently unaffected larvae remaining was 83.3% in Thalassodrilides sp. group but only 16.7% in the P. nuntia group. Clearly, of the two species we studied, Thalassodrilides sp. had a superior ability to convert 1-nitronaphthalene into substances that were nontoxic to mummichog larvae. Therefore, we recommend the use of this species for bioremediation of chemically polluted sediments.

Reproductive toxicity of 1-nitronaphthalene and 1-nitropyrene exposure in the mummichog, Fundulus heteroclitus

After pregnant mummichog were implanted with 1-nitronaphthalene or 1-nitropyrene via cholesterol pellet, we investigated the effects of the chemicals on embryo normality, hatchability and days to hatch of normal embryos, and growth and survival of hatched larvae from normal embryos of the implanted mummichog. Hatchability was the parameter most sensitive to the effects of both 1-nitronaphthalene and 1-nitropyrene. The 4-week lowest-observed-effect concentration (LOEC) of 1-nitronaphthalene, based on the actual concentrations in the eggs in the test, was 447 ng g(-1) wet wt.; and the LOEC and no-observed-effect concentration (NOEC) of 1-nitropyrene were 958 and 344 ng g(-1) wet wt., respectively. The 4-week LOEC of 1-nitronaphthalene, based on the concentration in the water, was estimated at 4.8 µg L(-1) by using the reported bioconcentration factor; and the LOEC and NOEC of 1-nitropyrene, based on the concentration in the water, were estimated at 3.1 and 8.6 µg L(-1), respectively. The reported environmental concentrations of 1-nitropyrene and 1-nitronaphthalene are over three magnitudes lower than the toxicity values we obtained. Therefore, the effects of environmental levels of 1-nitropyrene and 1-nitronaphthalene on fish reproduction, not including genomic effects on embryos, appear to be almost negligible. However, DNA damage has been detected in marine organisms exposed to 1-nitropyrene. Further studies of the genotoxicity of nitrated polycyclic aromatic hydrocarbons at environmental levels are therefore needed to evaluate their ecotoxicological risks.

The molecular properties of nitrobenzanthrone isomers and their mutagenic activities

The mutagenic activity of five mono-substituted nitrobenzanthrones (NBA) has been determined in the Ames assay (Takamura-Enya et al., 2006). In the present study, a theoretical investigation of the electronic properties of all mono-substituted NBA isomers and their relation to mutagenic activity are presented. Equilibrium geometries, vertical ionization potentials (VIP), vertical electron affinities (VEA), relative energies, dipole moments and electronic dipole polarizabilities, and the IR and Raman spectra of NBA isomers calculated by Density Functional Theory (DFT) methods are presented. The position of the nitro group affects the spectral features of the IR and Raman spectra of the NBA isomers. The results show that a good linear relationship exists between the summation of Raman activities (∑ARaman) over all the 3N-6 vibrational modes and the mutagenic activity of the NBA isomers in Salmonella typhimurium strains. The spectroscopic results suggest that the unknown mutagenic activities of 4-NBA, 5-NBA, 6-NBA, 8-NBA and 10-NBA are predicted to follow the order 4-NBA>10-NBA>5-NBA>8-NBA>6-NBA.

Phototransformations of dinitropyrene isomers on models of the atmospheric particulate matter

The 1,6 and 1,8-dinitropyrenes (DNP) isomers are strong mutagens and carcinogens encountered in diesel exhaust and airborne particles. Relative photodegradation rates were determined and some products were characterized when these isomers were irradiated adsorbed onto models of the atmospheric matter. These are compared to their photochemical behavior in a polar nonprotic solvent. The 1,8-DNP isomer is three times more reactive than the 1,6-DNP when irradiated adsorbed onto silica gel surfaces, while the reverse order is observed in solution, demonstrating the influence of structural differences and environmental effects on the photoreactivity. Oxygen is a key factor in the formation of pyrenediones from 1,8-DNP in solution and on silica gel which is not the case for 1,6-DNP. The average pore diameter (2.5 versus 6.0 nm) of the silica surfaces induces a significant change in the product distribution and relative yields of 1,8-DNP because pyrenediones or 8-hydroxy-1-nitropyrene are not produced in the smaller pore silica. A 6-hydroxy-1-nitropyrene product is observed both in acidic alumina and silica (6.0 nm) surfaces. On acidic alumina the rates of phototransformation of the isomers are equal, a significant increase in the relative yield of the hydroxynitropyrene product is observed compared to the silica and unidentified products in which the absence of NO₂ and pyrene absorption bands were observed, demonstrating the surface effect on the photodegradation. Overall, the presence of some products indicates the occurrence of a nitro-nitrite rearrangement on the surface with the participation of a pyrenoxy radical as their precursor.

Bioaccumulation of nitroarenes in bivalves at Osaka Bay, Japan

This paper reports for the first time the detection and occurrence of nitroarenes (NPAHs) in marine organisms. Mussels and oysters collected from Osaka Bay, Japan, had total NPAHs concentrations that ranged from 2380 to 24,688 pg/g dry and 2672 to 25,961 pg/g dry, respectively. Relatively higher concentrations were detected in sampling sites located near the central district and suburbs of Osaka City implying that the most probable sources of NPAHs in the two bivalves are exhaust gases and smokes emitted by automobiles and industrial plants. Bivalves had relatively higher residues of 1-nitronaphthalene, 2-nitronaphthalene, 3-nitrophenanthrene, and 9-nitrophenanthrenes. Residues of 2-nitrofluorene, 1-nitropyrene, 4-nitropyrenes, and 6-nitrochrysene were much lower compared to nitronaphthalenes and nitrophenanthrenes. Inter-species differences was only observed for 2-nitronaphthalene with oysters exhibiting significantly higher residues than mussels.

Retrospective analyses of atmospheric polycyclic and nitropolycyclic aromatic hydrocarbons in an industrial area of a western site of Japan

Thirteen polycyclic aromatic hydrocarbons (PAHs) and four nitropolycyclic aromatic hydrocarbons (NPAHs) on the surfaces of airborne particulates, which were collected at an industrial area of a western site of Japan during periods from 1976 to 1998, were retrospectively analyzed. PAHs and NPAHs were extracted from airborne particulates using hexane with ultrasonication, and then analyzed by HPLC systems with fluorescence detection and chemiluminescence detection, respectively. The total concentrations (mean +/- SD, n = 34) were 15.54 +/- 21.24 ng/m3 for PAHs and 5.85 +/- 8.16 pg/m3 for NPAHs. The concentrations of PAHs and NPAHs were found to be highest during the period between 1979 and 1982, and then reduced. The annual concentrations of PAHs and NPAHs were highly correlated with those of air pollutants from motor vehicle origin, such as carbon monoxide, suspended particulates and non-methane hydrocarbons. The results suggested that motor vehicle emissions were one of the predominant sources of atmospheric PAHs and NPAHs.

Nitrated Polycyclic Aromatic Hydrocarbons in the Environment: Formation, Occurrences and Analysis

A review is presented on the formation and occurrence in the atmosphere of nitrated polycyclic aromatic hydrocarbons. Some analytical methodologies (covering various matrices) are also considered.

Determination of atmospheric nitrobenzanthrones by high-performance liquid chromatography with chemiluminescence detection

A method using high-performance liquid chromatography with chemiluminescence detection was developed for analyzing mutagenic nitrobenzanthrone (NBA) isomers in airborne particulates. The method was a modification of our previously described method for analyzing nitropolycyclic aromatic hydrocarbons (NPAHs). The pretreatment and reducing conditions for 1-, 2-, 3- and 10-NBAs were the same as those for NPAHs. In order to separate these NBA isomers, we used a polymeric-type ODS column (Cosmosil 5C-18MS); a mixture of 40% acetonitrile and 60% 10 mM imidazole-HClO4 buffer was employed as the mobile phase at a flow rate of 1 mL/min. The isomers of 1-, 2-, 3- and 10-NBA were determined in chemiluminescence with linear calibration graphs from 0.1 to 4 pmol, from 200 to 4000 pmol, from 1 to 50 pmol and from 10 to 400 pmol, respectively. The detection limits (S/N = 3) of 1-, 2-, 3- and 10-NBA isomers were 0.02 pmol, 35 pmol, 0.3 pmol and 3 pmol, respectively. The method was used to analyze airborne particulates at a heavy traffic site in Kanazawa. 2- and 3-NBAs were detected in the extracts of the particulates, while 1-NBA and 10-NBA were not detected. The atmospheric concentrations of 2- and 3-NBAs were 1.83 pmol/m3 and 24.7 fmol/m3, respectively.

Determination of 3-nitrobenzanthrone in surface soil by normal-phase high-performance liquid chromatography with fluorescence detection

A sensitive method for determining 3-nitrobenzanthrone in surface soil was developed. 3-Nitrobenzanthrone was reduced to 3-aminobenzanthrone by refluxing at 60 degrees C with hydrazine and Raney nickel for 20 min, and 3-aminobenzanthrone was determined by normal-phase high-performance liquid chromatography (HPLC) with fluorescence detection. We used a cyanopropyl stationary phase and an n-hexane-ethyl acetate (3:1, v/v) mobile phase, since 3-aminobenzanthrone exhibits fluorescence in a low-polarity solvent such as n-hexane or ethyl acetate, but not in a polar solvent such as water or methanol. The calibration graph showed good linearity (r2>0.9999) in the range of 0.002-2 ng, and the detection limit was 0.002 ng (S/N=3). 3-Nitrobenzanthrone in extracts from surface soil collected in the Chubu area (central area) of Japan was determined after clean-up using silica gel chromatography and high-performance liquid chromatography on a pyrenylethyl stationary phase. The concentration of 3-nitrobenzanthrone in surface soil was determined in the range of 1.2-1020 pg/g soil.

Seasonal fluctuation of the mutagenicity of river water in Fukui, Japan, and the contribution of 2-phenylbenzotriazole-type mutagens

To clarify their mutagenic potential, samples of water from the Mawatari, Asuwa and Kitsune rivers, which flow through the central area of Fukui, Japan, were seasonally collected at six sites using blue rayon from July 1998 to August 2000. Forty-five of 52 (87%) of the water samples exhibited mutagenicity toward Salmonella typhimurium YG1024 and YG1029 with and without S9 mix, and the highest potencies were observed in YG1024 with S9 mix. The samples collected in summer and autumn tended to be more mutagenic than those collected in winter and spring. Fractionation using high-performance liquid chromatography (HPLC) suggests that several compounds are responsible for the mutagenicity of river water samples, and some of the major mutagens seem to be common among the samples. Three 2-phenylbenzotriazole (PBTA)-type mutagens, 2-[2-(acetylamino)-4-[(2-hydroxyethyl)amino]-5-methoxyphenyl]-5-amino-7-bromo-4-chloro-2H-benzotriazole (PBTA-3), 2-[2-(acetylamino)-4-amino-5-methoxyphenyl]-5-amino-7-bromo-4-chloro-2H-benzotriazole (PBTA-4) and 2-[2-(acetylamino)-4-[bis(2-hydroxyethyl)amino]-5-methoxyphenyl]-5-amino-7-bromo-4-chloro-2H-benzotriazole (PBTA-6), were quantified in samples collected between July 1998 and April 1999. At least one of these PBTA-type mutagens was detected in 23/24 (96%) of the samples. The amounts of PBTA-3, -4 and -6 were <0.08-58.7, <0.1-15.0 and <0.07-467.9 ng/g of blue rayon, respectively, and high levels of PBTA congeners were detected in the samples collected from each river in July and November 1998. The contributions of these PBTA congeners to the mutagenicity of water samples were also high in July and November 1998. The highest total contribution was observed for samples from the Asuwa river (67.6%). These findings suggest that these three rivers were continually and heavily contaminated with mutagens, and PBTA congeners were some of the major mutagens in these rivers.