黄磷尾气生产甲酸中尾气净化试验研究

通过综合研究试验筛选,研发专门适用以黄磷生产中外排废尾气为原料,匹配当今较先进的甲酸甲酯水解法(改进工艺)生产具有广泛用途和良好市场前景的环保型有机强酸———甲酸,完全满足优级甲酸生产的气体净化、提纯、提浓工艺技术,且安全可靠,经济合理。     

Historical trends in the anthropogenic heavy metal levels in the tidal flat sediments of Lianyungang, China

The sedimentation of metals can preserve the historical record of contaminant input from local and regional sources and provide information on the historical changes in regional water and sediment quality. We report the ²¹⁰Pb activities and the heavy metal (Cd, Cr, Cu, Mn, Pb and Zn) depth profiles from sediment cores retrieved in 2010. The mean sedimentation rates of 0.85-1.5 cm/yr are determined by ²¹⁰Pb dating. The sediments in the tidal flat have recorded heavy metal deposition and thus allow the establishment of a connection between the temporal evolution of the heavy metal pollution and the historical changes in the economic development of Lianyungang. The enrichment factors (EF) are calculated to estimate the level of contamination stored in these sediments. The results show that in the studied sites, Cr and Cu display low EF values and are mainly from lithogenic origin. For the other studied trace metals, a great variability in the sedimentary record is observed. Significant anthropogenic enrichment over the last 50 years is revealed at the tidal flat that receives fluvial inputs. Zinc is the element with the highest EF values, followed by the order of Pb > Cd > Mn > Cu and Cr. The temporal variations of the heavy metals peak during the late 1980s to the early 2000s and show a decreasing trend afterward. The pollution intensity of the tidal flat is determined by using EF and the geo-accumulation index (I_geo), which show that, based on the I_geo scale, the tidal flat of Haizhou Bay is unpolluted to moderately polluted.     

Influence of Chironomid Larvae on oxygen and nitrogen fluxes across the sediment-water interface (Lake Taihu, China)

The microscale distribution of oxygen,the nitrogen flux and the denitrification rates in sediment inhabited by chironomid larvae(Tanypus chinensis) were measured in eutrophic Lake Taihu,China.The presence of the chironomids in the sediment increased the oxygen diffusional flux from 10.4 ± 1.4 to 12.7 ± 2.5 mmol O 2 /(m 2 ·day).The burrows of the larvae represented "hot spots" and strongly influenced the nitrogen cycles and diagenetic activity in the sediment.The results indicate that the bioturbation effects of Tanypus chinensis chironomid larvae increased the capacity of the sediment as a sink for nitrate and a source for ammonium.Nitrate influx and ammonium outflux were increased 8.8 and 1.7 times,respectively.Under bioturbation,the amount of nitrate consumed was greater than the amount of ammonium released.The total denitrification rate was also enhanced from 0.76 ± 0.34 to 5.50 ± 1.30 mmol N/(m 2 ·day).The net effect was that the bioturbated sediments acted as a net sink for inorganic nitrogen under direct and indirect bioturbation effects compared to the control.     

Speciation of organic phosphorus in a sediment profile of Lake Taihu I: Chemical forms and their transformation

Organic phosphorus(nonreactive P,NRP)is a major component of P in sediments,but information about its chemical forms and dynamic transformation is limited.The chemical forms and dynamic behaviors of NRP in a sediment profile from Lake Taihu,a freshwater and eutrophic lake in China,were investigated.Five forms of NRP in the sediments were extracted based on a chemical fractionation technique,including easily labile NRP(NaHCO3-NRP),reactive metal oxide-bound NRP(HCl-NRP),humic acid-associated NRP(NaOH-NRPHA),fulvic acid-associated NRP(NaOH-NRPFA)and residual NRP(Res-TP).There were notable transformations with increasing sediment depth from the labile NaHCO3-NRP and NaOH-NRP pools to the recalcitrant HCl-NRP and Res-TP pools,which caused the NRP to become increasingly recalcitrant as the early diagenetic processes proceeded.Further analyses showed that the relative changes in contents of organic matter and reactive Fe oxides in the sediment profile triggered a competition for binding NRP fractions and led to the transformation of NRP.The results highlighted the importance of abiotic processes in regulating the diagenesis of organic P and its stability in sediments.     

无线电干扰系统电磁辐射安全限值的研究

在严格遵循国家有关部门电磁辐射防护规定中的相关标准情况下,进行无线电干扰系统的实验和操作中,发现当系统长时间使用时,按照电磁辐射相关安全标准设置安全间距仍会对人体健康产生不利影响。文章根据实验数据,对电磁辐射相关安全标准进行了深入研究和探讨,在对国家安全标准探讨的基础上提出考虑电磁辐射危害时不能仅仅将人体作为点来考虑,应充分认识到人体作为等效天线的特征以及吸收功率的问题。     

一种钢渣中氯离子的测定方法

利用蒸馏装置蒸出钢渣中的氯离子,使用硝酸汞滴定方法进行滴定,选用两种钢渣,在不同实验室分别进行了分析测定的比较和验证。结果表明:该方法简便易操作,重现性和准确性都比较高,作为钢渣中氯离子的测定是可行的。     

Response of anaerobes to methyl fluoride, 2-bromoethanesulfonate and hydrogen during acetate degradation

To use the selective inhibition method for quantitative analysis of acetate metabolism in methanogenic systems,the responses of microbial communities and metabolic activities,which were involved in anaerobic degradation of acetate,to the addition of methyl fluoride(CH3F),2-bromoethanesulfonate(BES)and hydrogen were investigated in a thermophilic batch experiment.Both the methanogenic inhibitors,i.e.,CH3F and BES,showed their effectiveness on inhibiting CH4 production,whereas acetate metabolism other than acetoclastic methanogenesis was stimulated by BES,as reflected by the fluctuated acetate concentration.Syntrophic acetate oxidation was thermodynamically blocked by hydrogen(H2),while H2-utilizing reactions as hydrogenotrophic methanogenesis and homoacetogenesis were correspondingly promoted.Results of PCR-DGGE fingerprinting showed that,CH3F did not influence the microbial populations significantly.However,the BES and hydrogen notably altered the bacterial community structures and increased the diversity.BES gradually changed the methanogenic community structure by affecting the existence of different populations to different levels,whilst H2 greatly changed the abundance of different methanogenic populations,and induced growth of new species.     

液化石油气汽车尾气减排的研究与试验

为了减少机动车的尾气污染物排放,中国大、中城市大力推广使用燃气公共汽车和出租车,燃气汽车尾气污染物排放对城市环境影响,如何减少燃气汽车的尾气排放是目前面临的一个新课题。采用在燃气汽车燃料中加注适量的CPG-4型增效剂的方法进行对比实验研究,通过改善其燃烧特性,达到燃气汽车节能减排的目的。试验表明,在燃气汽车燃料中加注适量的CPG-4型增效剂能节约燃气消耗6%左右,大幅减少HC和PM的排放。     

基于GIS的贵州省茶园生态适宜性研究

通过利用GIS技术,在土地利用现状以及喀斯特空间分布的基础上初步划分茶叶种植适宜地和不适宜地。选择对茶叶生长密切相关的地形地貌(海拔、坡度、坡向)、气候条件(光、热、降水条件及空气相对湿度)及土壤条件(土壤pH值)等8个生态评价因子,通过专家打分确定各因子权重,应用GIS空间叠加分析模块实现贵州茶园生态适宜性评价。结果表明:贵州省适宜茶叶种植的面积为32417.00km2,占国土面积的18.40%,其中非常适宜种植茶叶的区域面积为10618.00km2,占国土面积的6.03%;适宜种植茶叶的区域面积为11554.00km2,占国土面积的6.56%;比较适宜种植茶叶的区域面积为10245.00km2,占国土面积的5.81%;不适宜种植茶叶的区域面积为143735.45km2,占国土面积的81.60%。以上评价结果将为贵州茶产业的大力发展提供科学依据和技术基础。     

Effects of fenvalerate concentrations and its chiral isomers on bacterial community structure in the sediment environment of aquaculture ponds

To investigate the effect of chiral pesticide fenvalerate (FV) on the micro-ecological environment of aquaculture pond sediment, we used an indoor static experiment to observe the effects of FV added at different concentrations with different chiral isomers on the changes in the sediment bacterial community. The 16S rDNA high-throughput sequencing technique was used to conduct sequencing and analysis of the bacterial community structure as well as changes in aquaculture pond sediments after 4 weeks of cultivation. The results showed that the microbial alpha diversity indices (Sobs and Shannon indices) of the treated groups were significantly lower than those of the control group after 4 weeks (P < 0.05), and the values in the high-concentration group were significantly lower than those of the low-concentration group (P < 0.05). In terms of bacterial group composition, the proportion of abundance of Proteobacteria and Acidobacteria in the treated groups were greater than in the control group after 4 weeks, while the proportion of abundance of Bacteroidetes and Verrucomicrobia were lower. In the high-concentration FV treatment group, the proportion of abundance of Bacteroidetes, Acidobacteria, Chloroflexi, Nitrospinae, unclassified_k_norank, Ignavibacteriae, and Nitrospirae were significantly different from those of the other groups (P < 0.05). Principal coordinate analysis (PCoA) and ANONISIM/Adonis analysis showed that the cis-enantiomer had a stronger effect on the bacterial community as the concentration of FV increased. In addition, the linear discriminant analysis effect size (LEfSe) and linear discriminant analysis (LDA) results revealed differences in the level of enrichment of bacterial groups caused by FV at different concentrations and isomer levels. Collectively, this study showed that FV residue has a pronounced effect on bacterial communities in sediment, which becomes more significant with increasing exposure concentration. The effects of the cis- and trans-enantiomers of FV on the sediment environment are different; the cis-enantiomer has a stronger effect on the bacterial community.