Degradation of benzo[a]pyrene in soil with arbuscular mycorrhizal alfalfa

Mycorrhizal and non-mycorrhizal alfalfa (Medicago sativa) was grown in pots containing soil artificially contaminated with various levels of benzo[a]pyrene (B[a]P) (0, 1, 10 and 100 mg kg(-1)). Soil and plants were sampled after 30, 40, 50, 60 and 90 days and compared with unlanted pots. The percentage of mycorrhizal root length colonized by Glomus caledoniun was not significantly affected by the addition of B[a]P up to 10 mg kg(-1) but was significantly lower at 100 mg kg(-1)B[a]P compared with low concentrations (p < 0.05). There was no difference in soil polyphenol oxidase and dehydrogenase activity among the controls and applications of 1 and 10 mg kg(-1) of B[a]P. However, enzyme activities were significantly higher at 100 mg kg(-1) B[a]P compared with the other three treatments, and there was no mycorrhizal effect. Over a period of 90 days the concentration of B[a]P in soil in which alfalfa was grown was significantly lower than in unplanted soil (p < 0.05). Degradation rates of B[a]P added at 1, 10 and 100 mg kg(-1) without G. caledonium were 76, 78 and 53%, and with mycorrhizal inoculation were 86, 87 and 57%. The degradation rate in unplanted soil was significantly lower than in planted soil, and was significantly higher in medium- and low-B[a]P treatments than in the high B[a]P concentration tested. There is a possibility of enhancement phytoremediation of PAHs in rhizosphere soil with arbuscular mycorrhizal fungi.     

Genotoxic assessment of anthracene and benzo [a] pyrene to milkfish Chanos chanos

Mutagenic and genotoxic effects of polycyclic aromatic hydrocarbons, anthracene and benzo [a] pyrene (BaP), in milkfish Chanos chanos were determined using micronucleus (MN) test and comet assay (CA). Distinct mean frequencies of nuclear abnormalities such as MNs; binucleated micronuclei, nuclear bud, and fragmented apoptotic cells were measured. Significant increase in DNA damage with five classes of damage level was observed and expressed in terms of arbitrary unit (AU). Mean frequencies of total nuclear abnormalities were 0.5?±?0.25 cells in control; 0.67?±?0.33 cells in solvent control; 70?±?9.60 cells in 0.176?mg?L^?1 anthracene, and 91.83?±?6.25 cells in 0.031?mg?L^?1 BaP. The greatest DNA damage of 170AU was observed in 0.176?mg?L^?1 anthracene-exposed group and 182AU was observed in 0.031?mg?L^?1 BaP-treated fish. This study confirmed that the CA and MN assays are useful tools in determining potential genotoxicity of water pollutants and might be appropriate as a part of monitoring program.     

Accumulation and phytoavailability of benzo[a]pyrene in an acid sandy soil

Effects of benzo[a]pyrene (B[a]P) on ryegrass (Lolium perenne L.) growth, plant accumulation and dissipiation of B[a]P in a red sandy soil (Hapli-Udic Argosol) were studied in a pot experiment. The plants were grown for 61 days in soil spiked with B[a]P at 0, 12.5, 25 and 50 mg kg⁻¹. Control pots without plants were also set up. Soil extractable B[a]P, plant shoot and root biomass, and concentrations of B[a]P in plant shoots and roots were determined. Ryegrass biomass was increased by addition of B[a]P and root B[a]P concentrations were significantly correlated with B[a]P application rate, but no such correlation was found for shoot B[a]P concentrations. This indicates that B[a]P enhanced the growth of the ryegrass. The extractable B[a]P concentration in the planted soil was significantly lower than that in the unplanted control soil at the rate of 50 mg B[a]P kg⁻¹. This indicates that ryegrass may help to dissipate B[a]P in soil at concentrations over 50 mg kg⁻¹ soil although the mechanism for this is not understood.     

兰州地区苯并(a)芘的环境多介质迁移和归趋模拟

利用Level Ⅲ逸度模型模拟计算了稳态假设下苯并(a)芘在兰州地区大气、水体、土壤和沉积物中的相间迁移通量、浓度分布.结果表明:大气的平流输入和化石燃料燃烧是该区域苯并(a)芘的主要来源,土壤是其最大的储库,占总残留量的99.6%;在大气、水体、土壤和沉积物中的浓度分别为1.61×10-10 mol·m-3、9.39×10-7 mol·m-3、7.13×10-4 mol·m-3和9.17×10-5mol·m-3,模型计算浓度与同期实测浓度吻合较好,验证了模型的可靠性,并通过灵敏度分析,确定了模型的关键参数.     

苯并[a]芘对马氏珠母贝血淋巴细胞DNA损伤的研究

通过单细胞凝胶电泳技术（彗星试验）研究了苯并[a]芘（B[a]P）对马氏珠母贝（Pinctada martensi）血淋巴细胞DNA的损伤。结果显示,在相同暴露时间内,不同质量浓度的B[a]P均能引起马氏珠母贝血淋巴细胞DNA损伤。4μg.L-1 B[a]P处理组DNA含量、彗尾长度和Olive尾矩均最大,分别为34.39%、281.73和60.31μm。随着暴露时间的延长,彗星尾长明显增加,表现出明显的时间-效应关系,而DNA含量和Olive尾矩没有呈现出规律性变化。此外,在不同的染毒时间内,对照组和各处理组之间均存在显著差异（P〈0.05）,3个指标具有很好的一致性。研究表明,彗星试验是检测B[a]P对马氏珠母贝血淋巴细胞DNA损伤的一种有效手段,马氏珠母贝血淋巴细胞DNA损伤可作为指示B[a]P污染的一种有效生物标志物用于早期预警监测。     

苯并[a]芘对马氏珠母贝血淋巴细胞DNA损伤的研究

通过单细胞凝胶电泳技术(彗星试验)研究了苯并[a]芘(B[a]P)对马氏珠母贝(Pinctada martensi)血淋巴细胞DNA的损伤。结果显示,在相同暴露时间内,不同质量浓度的B[a]P均能引起马氏珠母贝血淋巴细胞DNA损伤。4μg.L-1 B[a]P处理组DNA含量、彗尾长度和Olive尾矩均最大,分别为34.39%、281.73和60.31μm。随着暴露时间的延长,彗星尾长明显增加,表现出明显的时间-效应关系,而DNA含量和Olive尾矩没有呈现出规律性变化。此外,在不同的染毒时间内,对照组和各处理组之间均存在显著差异(P<0.05),3个指标具有很好的一致性。研究表明,彗星试验是检测B[a]P对马氏珠母贝血淋巴细胞DNA损伤的一种有效手段,马氏珠母贝血淋巴细胞DNA损伤可作为指示B[a]P污染的一种有效生物标志物用于早期预警监测。     

固定化微生物对土壤中苯并芘的降解

研究了3株细菌与3株真菌对土壤中苯并芘（BaP）的降解动态,从中筛选出1株细菌（Bacillus sp.）和1株真菌（Mucor sp.）,并采用吸附法将混合菌固定在改性后蛭石上,研究了固定化混合菌对土壤中BaP的降解效果。结果表明：细菌中芽孢杆菌（Bacillus sp.,SB02）降解率最高,42 d对B[a]P的降解率为33.0%,降解速率也最快,1周可降解12.6%的BaP;真菌中毛霉（Mucor sp.,SF06）降解率最高,42 d对B[a]P的降解率为69.7%;以改性后蛭石为载体用吸附法制得的固定化混合菌,传质性能好,对BaP的降解率42 d可达95.32%,高于游离菌20个百分点。     

Modification of mutagenic activity of benzo[a]pyrene by trace elements in the Ames assay

Benzo[a]pyrene (BaP) is one of the most ubiquitous environmental contaminants and exerts potent carcinogenicity and mutagenicity. In the presence of rat liver S9 mix, four trace elements, germanium (Ge), iron (Fe), zinc (Zn), and molybdenium (Mo), were included in the Ames Salmonella microsome/mutagenic assay to test their inhibitory effects on BaP-induced mutations. All trace elements were found to exert an inhibitory effect in tester TA98 and TA100 strains; Fe was the most potent among the elements tested, whereas Zn was weakly inhibitory to prevent mutations. The present findings demonstrate that the antimutagenic potential of trace elements, notably Fe, may be attributed to its modulatory effect on the bioactivation and detoxification processes of BaP.     

An efficient fluorescent polymer sensing material for detection of traces of benzo[a]pyrene in environmental samples

A selective sensing polymer for detecting the air pollution marker benzo[a]pyrene (B[a]P) was prepared by molecular imprinting. When the B[a]P adsorb onto the polymer at an excited wavelength 266?nm, it emits a characteristic signal at 432?nm. The intensity of fluorescence signal corresponds to the concentration of B[a]P adsorbed onto the polymer. The cross-selectivity of the sensing polymer using other 5 PAHs was proven by comparing fluorescence intensities, and the effect of matrix in terms of total dissolved solids on sensing property of the polymer was evaluated. Using this polymeric sensor, it is possible to detect 1 part per trillion (ppt) concentration of B[a]P in environmental samples without laborious solvent extraction procedure generally used in gas chromatograph analysis.     

Distribution of benzo[a]pyrene in discrete regions of rat brain tissue using light microscopic autoradiography and gamma counting

In order to study the distribution of benzo[a]pyrene (B[a]P) in rat brain, Sprague-Dawley male rats, 21-day-old, weighted 40–50 g were given a single intravenous (iv) injection of 3.7 × 10⁵ Bq kg^?1 of ¹⁴C-B[a]P. Rats were sacrificed at 1, 6, 12, 24, or 48 h after the administration of radiolabeled B[a]P. Light microscopic autoradiography and gamma counting were used. Gamma counting and light microscopic autoradiography showed that ¹⁴C-B[a]P localized in hippocampus at 1 h, in cerebral cortex at 6 h, and corpus striatum at 24 h after treatment. After B[a]P administration, silver grains rose with time reaching a peak at 24 h and sharp decrease at 48 h. The silver grains distribution was higher in neurons than in gliocytes. Thus, B[a]P penetrated the blood-brain barrier and distributed in various regions of rat brain.     

Degradation of benzo[a]pyrene in an experimentally contaminated paddy soil by vetiver grass (Vetiveria zizanioides)

A pot experiment was conducted to study the effect of growing vetiver grass on the biodegradation of benzo[a]pyrene (B[a]P) under glasshouse conditions. Plant biomass, microbial biomass C and degradation of B[a]P were determined. B[a]P disappeared faster in the plant treatments than in unplanted controls. Disappearance of B[a]P was accompanied by an increase in soil microbial biomass C. Vetiver grass may promote the biodegradation of B[a]P under flooded conditions by plant roots by stimulating the microbial biomass. Microbial biomass was the main factor affecting dissipation of B[a]P under flooded conditions.     

Evaluation of 3-hydroxy-benzo[a]pyrene levels in Nile tilapia (Oreochromis niloticus) after waterborne exposure to Benzo[a]pyrene

3-Hydroxy-benzo[a]pyrene (3-OH-BaP), a toxic compound with the ability to covalently bind with the macromolecules (proteins and DNA), is one of the major phenolic metabolites of benzo[a]pyrene (BaP). The purpose of this study was to evaluate the presence of 3-OH-BaP in the bile and plasma of Nile tilapia by HPLC with fluorescence detection, after waterborne exposure to BaP (10 and 100?µg?L^?1). Metabolites were detected in bile and plasma, and conjugates of 3-OH-BaP (glucuronide and/or sulphate conjugates) were the majority forms in both biological fluids, glucuronide 3-OH-BaP being the main metabolite in bile. Our data suggest that extrahepatic tissues as intestine or gill are important in BaP metabolism and need to be the considered sources of metabolites released into the blood. Although, low levels of 3-OH-BaP in toxic form (free form) were detected in plasma, one cannot exclude the possibility of circulating the levels leading to adverse effects.     

Benzo [a] pyrene concentrations in topsoils of North Bahrain

A comprehensive field study was conducted to determine the background concentrations of benzo [a] pyrene (B[a]P) in soil samples collected at different points on a grid covering most of the northern and middle parts of the Kingdom of Bahrain. The average B[a]P concentration was 108.4?ng?g^?1 in winter and 73.0?ng?g^?1 in summer. The capital city, Manama, and the industrial areas of the country showed the highest levels of B[a]P.     

苯并[a]芘和菲对缢蛏血细胞DNA损伤的研究

为研究苯并[a]芘和菲对缢蛏的毒性效应,将缢蛏(Sinonovacula constricta)分别暴露于浓度为0.45 mg·L-1、0.15 mg·L-1、0.05 mg·L-1苯并[a]芘溶液和0.45 mg·L-1、0.15 mg·L-1、0.05 mg·L-1菲的溶液中,采用单细胞凝胶电泳实验(彗星实验)技术检测不同暴露时间缢蛏血淋巴细胞的DNA损伤程度,对照组为清洁海水。结果显示,高浓度(0.45 mg·L-1)苯并[a]芘溶液和(0.45 mg·L-1)菲溶液在短期(7 d)内即可导致缢蛏血细胞显著的DNA损伤,并且随苯并芘[a]和菲浓度的增大和暴露时间的延长,DNA损伤程度增加。21 d恢复实验后,各浓度组DNA损伤又均有不同程度的恢复,但中高浓度组(0.45 mg·L-1和0.15 mg·L-1)与对照组仍显著性差异。两种多环芳烃物质对缢蛏血细胞的DNA损伤作用均存在较显著时间-剂量-效应关系。其中,苯并芘[a]对缢蛏血细胞的DNA损伤作用要高于菲。     

The toxic effect of CuO of different dispersion degrees on the structure and ultrastructure of spring barley cells (Hordeum sativum distichum)

Environmental Geochemistry and Health - Nowadays, nanotechnology is one of the most dynamically developing and most promising technologies. However, the safety issues of using metal nanoparticles,...     

Effects of benzo(a)pyrene on blood components,tumor markers,and oxidative status in mice

This study was carried out to investigate the effect of long-term exposure to benzo(a)pyrene (B(a)P) in mice. Hemogram, tumor markers, oxidative status, and B(a)P residues in liver tissue were evaluated. Sixty albino Swiss mice were randomly distributed equally into three groups; the control was given 0.1?mL corn oil once a week for 8 weeks. The other two groups were given 20 and 40?mg B(a)P per kg body weight once a week orally for the same period. B(a)P-treated mice suffered from depression and ascites, and macrocytic normochromic anemia was recorded at the 16th and 30th week. There was marked leukocytosis with lymphocytosis at the early stage of the experiment, followed by leukopenia, lymphopenia, and neutropenia at the end of the experiment. Monocytes and arginase activity were elevated throughout the experiment. Alpha feto-protein was detected only in the experimental groups in the 30th week of the experiment. A marked increase in lipid peroxides associated with a decrease in reduced glutathione and glutathione-S-transferase (GST) activity was observed in liver homogenate of the B(a)P-exposed animals. Residues of B(a)P were detected in liver tissue with a concentration parallel to the B(a)P dose level. In conclusion, B(a)P caused abnormal changes in the hemogram, evidence of tumor formation through B(a)P-induced oxidative stress, and it was accumulated in the liver tissue of mice.     

微生物对水-沉积物中苯并[a]芘-镉复合污染修复的研究

从广东汕头贵屿镇的沉积物中分离得到1株对PAHs有较好降解能力且有较强重金属耐受性的菌株（简称B4）,菌种鉴定表明该菌为氧化节杆菌属。以土著微生物、处理方式、沉积物、修复时间等为不同的影响因子对该菌修复水体/沉积物中苯并[a]芘（BaP）-镉（Cd）复合污染进行了初步研究。结果表明：该菌同时具有降解BaP和吸附Cd的性能;土著微生物对BaP有一定的降解能力,并能显著促进B4降解BaP,当体系中BaP质量浓度为1.00 mg.L-1时,降解率达到了68.3%;Cd的吸附却因土著微生物的存在发生一定程度的解吸。振荡培养对BaP的降解效果略优于静止培养修复,而静止修复却更有利于Cd的去除。沉积物促进体系Cd的吸附,却减弱了菌种对BaP的降解。在静止培养修复中,BaP的降解主要发生在7 d以前,降解率保持在35%左右,此时Cd的去除效果亦较好。     

铅-苯并[a]芘复合污染在土壤-植物体系的归宿规律研究

通过室内盆栽试验研究了中、低浓度铅（Pb）和苯并[a]芘（B[a]p）复合污染在土壤-植物系统中的归宿规律和相互影响,以考查Pb-B[a]p复合污染的相互作用.采用4因素6水平均匀设计试验方案,w（Pb）范围为0～1 120 mg·kg^-1,w（B[a]p）范围为0～6.4 mg·kg^-1.结果表明,在非根际环境中,Pb的不同结合态未受到B[a]p的影响,而土壤中B[a]p的自然降解过程也未受到Pb的影响;在黑麦草根际环境中,Pb的可交换态和碳酸盐结合态以及Fe/Mn氧化物结合态含量与非根际土壤相比明显降低,有机物和硫化物结合态含量明显升高,这与黑麦草根际分泌物和植物根际的吸收作用有关;玉米和黑麦草地上部和根部Pb含量均与土壤中Pb总量之间呈显著正相关关系,与B[a]p含量间不存在显著相关性;在玉米和黑麦草根际环境中,B[a]p的降解速率比非根际土壤有明显提高,其中黑麦草的促降解作用强于玉米;Pb对玉米和黑麦草根际土壤中B[a]p的降解过程具有一定的抑制作用,这与根际环境对Pb的活化作用进而增加Pb对微生物有效性有关;Pb对植物根部吸附B[a]p的过程也有一定影响.总体而言,在根际和非根际条件下B[a]p与Pb的共存均未影响Pb的归宿,在非根际环境中Pb也未影响B[a]p的归宿,但在根际环境中Pb抑制了B[a]p在土壤中的降解及植物根部对B[a]p的吸收.     

高铁酸钾降解荧蒽和苯并[a]芘的偏振荧光光谱研究

考察了高铁酸钾对荧蒽和苯并[a]芘两种PAHs(多环芳烃)的降解反应过程,并应用偏振荧光光谱技术研究了荧蒽和苯并[a]芘两种PAHsr降解体系反应过程及其差别的识别,着重探讨了两种PAHs降解体系反应过程中的多种荧光波长模式与偏振度、三维荧光(EEM)与偏振三维荧光(PEEM)变化规律,最后由时间扫描荧光模式直接获得反应动力学拟合方程式.实验结果表明,各荧光识别模式一致地显示出高铁酸钾对荧蒽和苯并[a]芘的显著性降解作用及其对应的各荧光强度变化规律,即反应时间大于40 s后,两种PAHs(多环芳烃)的降解反应均不明显,且降解过程中均无新的荧光发色团结构生成.在高铁酸钾与荧蒽/苯并[a]芘摩尔比为1∶1、1∶4、4∶1的各降解体系的反应过程均符合一级反应动力学规律.荧蒽降解曲线的线性关系更高,苯并芘降解速率更快,多种荧光光谱相结合能够实现对PAHs的降解过程的便捷而有效的追踪,其揭示的结果与分子机理一致,即苯并[a]芘分子较荧蒽分子具有更大的π电子密度,因而在Fe(Ⅵ)夺电子过程中,更易于失去电子而被Fe(Ⅵ)氧化降解.