氧化木糖无色杆菌(Achromobacte rxylosoxidans)LAX2对Cu、Pb和Cd复合污染土壤的生物矿化修复研究

我国土壤重金属复合污染较为突出,是目前亟待解决的土壤环境问题之一.本文研究了一株氧化木糖无色杆菌LAX2对Cu、Pb和Cd共存体系的生物矿化作用及其复合污染土壤的矿化修复作用.结果表明,菌株LAX2的发酵液、无菌发酵液和菌体细胞对3种重金属的去除能力大小顺序均为Pb~(2+)Cd~(2+)Cu~(2+).X-射线衍射、扫描电镜、红外光谱和能谱分析表明,3种重金属共存时菌株LAX2发酵液可诱导形成PbCO_3和CdCO_3晶体,而Cu不能单独成矿,混合矿物晶体呈长杆状.菌株LAX2发酵液能够明显降低黑钙土和白浆土中Cu、Pb和Cd的有效态含量,矿化修复30 d后,黑钙土中Cu、Pb、Cd的有效态含量分别降低了48.0%、71.4%、62.8%,白浆土中Cu、Pb、Cd的有效态含量分别降低了42.0%、63.2%、53.6%;碳酸盐结合态和铁锰氧化物结合态含量明显增加,可交换态和有机物结合态含量明显降低.矿化修复后的土壤中重金属的浸出毒性随修复时间的增长而降低,黑钙土中Cu、Pb、Cd浸出量分别降低了90.3%、93.2%、92.8%,白浆土中Cu、Pb、Cd浸出量分别降低了82.5%、86.1%、84.3%.以上结果说明,菌株LAX2可通过碳酸盐矿化作用固定土壤中的复合重金属,且在相同条件下对黑钙土的修复效果好于白浆土.     

Distribution of polychlorinated naphthalenes (PCNs) in the whole blood of typical meat animals

The concentrations and distribution of polychlorinated naphthalenes(PCNs) in the whole blood of eight typical terrestrial meat animals(chicken, duck, rabbit, pig, cattle, sheep,horse and donkey) consumed daily in our life were investigated. The total concentrations(on a liquid volume basis) of PCNs were in a range from 305 to 987 pg/L. Donkey blood contained the highest PCN concentrations. Mono-CNs were the dominant homolog group,accounting for 38%–71% PCNs. Apart from the mono-CNs and tri-CNs homolog groups, two hepta-CNs(mean: 9.5%) contributed most, followed by tetra-CNs(mean: 6.5%). The congeners CN1, 5/7, 24/14, 27/30, 52/60, 66/67, and 73 were the most abundant congeners or congener groups. The highest toxicity equivalencies(TEQs) were observed in cattle blood(117.4 fg TEQ/L) then chicken blood(117.1 fg TEQ/L). CN73 contributed 65% to total TEQs,followed by CN70(20%) and CN66/67(14%). The dietary intakes of PCNs were also estimated.Chicken meat, which forms the second largest component of meat product consumption in China, contributed most to the total TEQs(61%), followed by beef(27%) and pork(5.9%). The consumption of chicken might pose the highest risk from exposure to PCNs than other types of meat to populations who prefer to eat chicken meat.     

<Emphasis Type="Italic">Fusarium</Emphasis> head blight incidence and mycotoxin accumulation in three durum wheat cultivars in relation to sowing date and density

Durum wheat (Triticum turgidum var. durum) is an important crop in Europe, particularly in the Mediterranean countries. Fusarium head blight (FHB) is considered as one of the most damaging diseases, resulting in yield and quality reduction as well as contamination of grain with mycotoxins. Three winter durum wheat cultivars originating from Austria, Slovakia, and Poland were analyzed during 2012–2014 seasons for FHB incidence and Fusarium mycotoxin accumulation in harvested grain. Moreover, the effects of sowing density and delayed sowing date were evaluated in the climatic conditions of Southern Poland. Low disease severity was observed in 2011/2012 in all durum wheat cultivars analyzed, and high FHB occurrence was recorded in 2012/2013 and 2013/2014 seasons. Fusarium graminearum was the most abundant pathogen, followed by Fusarium avenaceum. Through all three seasons, cultivar Komnata was the most susceptible to FHB and to mycotoxin accumulation, while cultivars Auradur and IS Pentadur showed less symptoms. High susceptibility of cv. Komnata was reflected by the number of Fusarium isolates and elevated mycotoxin (deoxynivalenol, zearalenone, and moniliformin) content in the grain of this cultivar across all three seasons. Nivalenol was identified in the samples of cv. Komnata only. Genotype-dependent differences in FHB susceptibility were observed for the plants sown at optimal date but not at delayed sowing date. It can be hypothesized that cultivars bred in Austria and Slovakia show less susceptibility towards FHB than the cultivar from Poland because of the environmental conditions allowing for more efficient selection of breeding materials.     

Multicriteria ranking of workplaces regarding working conditions in a mining company

Ranking of workplaces with respect to working conditions is very significant for each company. It indicates the positions where employees are most exposed to adverse effects resulting from the working environment, which endangers their health. This article presents the results obtained for 12 different production workplaces in the copper mining and smelting complex RTB Bor – ‘Veliki Krivelj’ open pit, based on six parameters measured regularly which defined the following working environment conditions: air temperature, light, noise, dustiness, chemical hazards and vibrations. The ranking of workplaces has been performed by PROMETHEE/GAIA. Additional optimization of workplaces is done by PROMETHEE V with the given limits related to maximum permitted values for working environment parameters. The obtained results indicate that the most difficult workplace is on the excavation location (excavator operator). This method can be successfully used for solving similar kinds of problems, in order to improve working conditions.     

Algal uptake of dissolved organic nitrogen in wastewater treatment plants

The algal uptake of dissolved organic nitrogen(DON) in the anaerobic–anoxic–oxic(A_2O)process was investigated in this study. Anaerobic, aerobic and effluent DON samples from two wastewater treatment plants(WWTPs) were separated into hydrophilic and hydrophobic fractions using a DAX-8 resin coupled with an anion exchange resin and a nanofiltration(NF)pretreatment. Hydrophilic DON accounted for 66.66%–88.74% of the entire DON for the two plants evaluated. After a 15-day incubation, 16.95%–91.75% DON was bioavailable for algal growth, and untreated samples exhibited higher DON bioavailability, with 52.83% DON average uptake rates, compared with the hydrophilic and hydrophobic fractions(45.53% and 44.40%, respectively) because the pretreatment caused the inorganic salt to be resistant to algae. Anaerobic untreated samples, hydrophilic fractions and hydrophobic fractions showed higher DON reduction rates and higher biomass accumulation compared with the other DON fractions due to the decomposition of resistant organics by anaerobic and anoxic bacteria.DON in aerobic and effluent samples of plant A was more bioavailable than that of plant B with usages of 27.49%–55.26% DON. DON bioavailability in the anaerobic–anoxic–oxic process decreased in the following order: anaerobic effluent aerobic. The DON contents were reduced after anaerobic treatment in the two plants. The EEM-PARAFAC model identified three DON components, including two humic acid-like substances and one protein-like substance in plant A and two protein-like substances and one humic acid-like substance in plant B.     

我国典型陆地生态系统固碳重要区范围界定

全球变暖已成为当今最主要的全球性环境问题之一,建立固碳重要区也是应对全球气候变化的重要途径之一.根据我国陆地生态系统现状以及固碳相关的最新研究结果和政府文件,以森林、草地生态系统为主要研究对象,采用GIS空间叠置分析方法,界定我国典型陆地生态系统固碳重要区(注:涉及“全国”的各要素范围均未包含港澳台地区)的空间范围.研究结果:固碳重要区评价指标体系包括生态系统碳储量、碳汇和固碳潜力3个核心因子,界定过程包括界定范围选择、固碳高值区识别、固碳重要区范围确定和分区命名等步骤.在全国尺度界定了森林、草地两大类共计20个固碳重要区,总面积285.6×104 km2.其中,森林生态系统固碳重要区主要分布在我国东北部、西南部的深山区和东南部的山地丘陵,草地生态系统固碳重要区主要分布在内蒙古高原中东部、新疆西北部山地和青藏高原东南部.固碳重要区面积占全国国土总面积的29.8%,所提供的NPP(净初级生产力)量占全国NPP总量的40.7%,固碳能力是全国平均水平的1.37倍.固碳重要区范围界定结果符合“以较小面积获取较大服务”原则,适于作为我国实现碳减排目标的优先保护区域.      

基于PLFA法分析亚硝氮、硝氮和氨氮对厌氧微生物细菌群落的影响

利用磷脂脂肪酸(PLFA)技术研究了亚硝氮、硝氮和氨氮在不同浓度水平下对中温厌氧颗粒污泥中厌氧细菌群落结构的影响.结果表明,高浓度亚硝氮(360 mg·L-1,以N计)、硝氮(300 mg·L-1,以N计)和氨氮(3000 mg·L-1,以N计)使系统COD去除率分别下降至3.49%、10.85%和71.53%,并使污泥表面主要细菌由杆菌变为球状菌;亚硝氮和硝氮引起厌氧细菌和革兰氏阳性菌的含量下降,氨氮引起革兰氏阴性菌的含量下降;PLFA香农-威尔多样性指数随着亚硝氮和硝氮浓度的升高从1.12分别下降至0.96和1.03,氨氮对PLFA香农-威尔多样性指数无明显影响.     

A 1-Year Study on the Detection of Human Enteric Viruses in New Caledonia

Human enteric viruses occur in high concentrations in wastewater and can contaminate receiving environmental waters. Due to the lack of data on the prevalence of enteric viruses in New Caledonia, the presence and the concentrations of enteric viruses in wastewater and seawater were determined. Untreated wastewater and seawater samples were collected monthly for 1 year from a wastewater treatment plant (WWTP) and from the WWTP’s outlet, located directly on a popular recreational beach. Samples were tested for norovirus genogroups I and II (NoV GI and GII), astroviruses (AsV), sapoviruses (SaV), enteroviruses (EV), hepatitis A viruses (HAV), rotaviruses (RoV), human adenoviruses (HAdV) and human polyomaviruses (HPyV). To support these data, faecal samples from cases of gastroenteritis were tested for the first time for NoV and detected in the population. NoV GI, NoV GII, EV, SaV, HAdV and HPyV were detected in all wastewaters, RoV in 75 % and AsV in 67 %. HAV were not detected in wastewater. Overall, 92 % of seawater samples were positive for at least one virus. HPyV were detected most frequently in 92 % of samples and at concentrations up to 7.7 × 10³ genome copies/L. NoV GI, NoV GII, EV, SaV, RoV and HAdV were found in 33, 66, 41, 33, 16 and 66 % of seawater samples, respectively. AsV were not detected in seawater. This study reports for the first time the presence of NoV and other enteric viruses in New Caledonia and highlights the year-round presence of enteric viruses in the seawater of a popular beach.