The concentrations, distribution and sources of PAHs in agricultural soils and vegetables from Shunde, Guangdong, China

The concentrations, distribution and sources of 16 polycyclic aromatic hydrocarbons (PAHs) were determined in 30 agricultural soil and 16 vegetable samples collected from subtropical Shunde area, an important manufacturing center in China. The total PAHs ranged from 33.7 to 350 μg/kg in soils, and 82 to 1,258 μg/kg in vegetables. The most abundant individual PAHs are phenanthrene, fluoranthene, chrysene, pyrene and benzo(b)fluoranthene for soil samples, and anthracene, naphthalene, phenanthrene, pyrene and chrysene for vegetable samples. Average vegetable–soil ratios of total PAHs were 2.20 for leafy vegetables and 1.27 for fruity vegetables. Total PAHs in vegetable samples are not significantly correlated to those in corresponding soil samples. Principal component analyses were conducted to distinguish samples on basis of their distribution in each town, soil type and vegetable specie. Relatively abundant soil PAHs were found in town Jun’an, Beijiao, Chencun, Lecong and Ronggui, while abundant vegetable PAHs were observed in town Jun’an, Lecong, Xingtan, Daliang and Chenchun. The highest level of total PAHs were found in vegetable soil, followed by pond sediment and “stacked soil” on pond banks. The PAHs contents in leafy vegetables are higher than those in fruity vegetables. Some PAH compound ratios suggest the PAHs derived from incomplete combustion of petroleum, coal and refuse from power generation and ceramic manufacturing, and paint spraying on furniture, as well as sewage irrigation from textile industries. Soil PAHs contents have significant logarithmic correlation with total organic carbon, which demonstrates the importance of soil organic matter as sorbent to prevent losses of PAHs.     

原子荧光光谱法同时测定环境水体中痕量锡和锌

采用原子荧光光谱法同时测定环境水样中痕量锡和锌,优化了试验条件。锡在1.00μg/L～10.0μg/L、锌在20.0μg/L～200μg/L范围内线性良好,方法检出限锡为0.13μg/L,锌为1.76μg/L,锡和锌标准溶液测定的相对标准偏差分别为2.9%和4.0%,环境水样加标回收率锡为96.4%～106%,锌为92.0%～111%。     

Biohydrogen production through fermentation using liquid swine manure as substrate

In this paper, continuous production of hydrogen through fermentation with liquid swine manure as substrate was researched using a semi-continuously fed fermenter (8 L in total volume and 4 L in working volume). The pH and temperature for the fermenter were controlled at 5.3 +/- 0.1 and 35 +/- 1 degrees C, respectively, throughout the experiment. Three hydraulic retention times (16, 20, and 24 h) were investigated for their impact on the efficiency and performance of the fermenter in terms of hydrogen yields. The results indicate that hydraulic retention time (HRT) has a strong influence on the fermenter performance. An increasing HRT would increase the variation in hydrogen concentration in the offgas. To produce hydrogen with a fairly consistent concentration, the HRT of the fermenter should not exceed 16 h, which, however, did not appear to be short enough to control methanogenesis because the offgas still contained about 5% methane. When methane content in the offgas exceeded 2%, an inverse linear relationship between hydrogen and methane was observed with a correlation coefficient of 0.9699. To increase hydrogen content in the offgas, methane production has to be limited to below 2%. Also, keeping oxygen content in the fermenter below 1.5% would increase the hydrogen concentration to over 15%. The product to substrate ratio was found to be around 50% for the fermenter system studied, evidenced by the observation that for every 6 liters of manure fermented, 3 liters of pure hydrogen were produced, which was significant and encouraging.     

某造桥厂噪声影响分析与控制

对某桥梁制造厂进行噪声监测,得到该厂设备噪声影响情况,找到主要噪声源,提出具有针对性的噪声控制对策,为项目的整改提供了科学依据.     

劳动防护服号型设置的研究

本文对劳动防护服的号型设置进行了分析与研究。《劳动防护服号型》是各类劳动防护服制作中广泛使用的基础性国家标准,依据当前劳动者人体尺寸的统计分析和企业劳动防护服生产供应实际情况,科学合理设置服装号型,以符合国家标准的科学性、实用性以及增强劳动防护服的舒适性功能。     

Effect of manganese ion on the mineralization of 2,4-dichlorophenol by ozone

Mineralization of 2,4-dichlorophenol (DCP) was studied by ozone with Mn(2+) as an ozonation catalyst. Laboratory scale semi-batch ozonation experiments were conducted at room temperature. The results showed that trace amount of Mn(2+) accelerated the mineralization of DCP. Total organic carbon removal rate was independent on Mn(2+) dosage at its range of 0.1-0.5 mgL(-1). Dissolved ozone concentration in the solution remained low level in the catalytic ozonation process, which indicated that Mn(2+) catalyzed decomposition of ozone. DCP mineralization was inhibited in catalytic ozonation by the addition of carbonate. Electron spin resonance/spin-trapping technique was used to determine hydroxyl radicals, and the results showed that larger amounts of hydroxyl radicals were produced in catalytic ozonation system than those of single ozonation. Intermediates mainly including aliphatic carboxylic acids were determined qualitatively and semi-quantitatively by GC-MS. And, a general pathway for mineralization of DCP was proposed.     

我国生物质废物污染现状与资源化发展趋势

我国的生物质废物具有产生量大、可降解有机物含量高的特点,如果能对其进行有效的利用,不但能减少污染,还将会有助于缓解我国能源短缺的现状。介绍了我国生物质废物的污染现状及生物质废物资源化的主要途径,指出我国生物质废物资源化中存在的问题,并提出今后的发展方向及发展对策。     

高密度电阻率法延时性勘探在地质灾害监控预警中的应用

将高密度电阻率法延时性技术应用于地质灾害（堤坝渗漏及岩土体稳定性）监控与预警中是一种创新。结果表明,高密度电阻率法的延时性勘探能有效地划分可能发生地质灾害的地段及位置;同时,还能为灾害治理提供区域性和地下结构方面的基础资料。     

滑坡勘查中的高密度电阻率法异常特征

以某滑坡区为例,使用高密度电阻率法对滑坡区的异常特征进行了研究,并对获取的视电阻率断面进行了地形校正.结果表明,对于沉积岩地区滑坡,滑坡体与滑床间存在明显的电性差异,根据经过地形改正的滑坡区视电阻率异常特征和断面,更清晰和直观显示了滑坡体的纵横向展布、主滑动面的位置与埋深,进而可圈定滑坡体的规模,从而为滑坡治理提供可靠的地球物理依据.