Dissipation of atrazine, enrofloxacin, and sulfamethazine in wood chip bioreactors and impact on denitrification

Wood chip bioreactors are receiving increasing attention as a means of reducing nitrate in subsurface tile drainage systems. Agrochemicals in tile drainage water entering wood chip bioreactors can be retained or degraded and may affect denitrification. The degradation of 5 mg L atrazine, enrofloxacin, and sulfamethazine under denitrifying conditions in wood chips from an in situ reactor was determined. The impact of these chemicals on denitrifying microorganisms was assessed using the denitrification potential assay, most probable number (MPN), and quantitative polymerase chain reaction targeting the gene of the denitrifiers. Initial half-lives for these chemicals in the aqueous phase were 0.98 d for atrazine, 0.17 d for enrofloxacin, and 6.2 d for sulfamethazine. Similar rates of disappearance in autoclaved and nonautoclaved wood chip solutions during the first 48 h suggested sorption was the dominant mechanism. The presence of atrazine did not impair denitrification potential, the MPN, or the copy number. The denitrifier MPN and copy number in sulfamethazine- and enrofloxacin-treated microcosms were less than the control within the first 5 d after chemical addition, whereas the denitrification potentials were not affected. However, after 45 d the denitrification rate, MPN and gene copy numbers for sulfamethazine and enrofloxacin were similar to that of the no-chemical control, indicating that acclimation of the denitrifier population to the antibiotic or reduced bioavailability over time allowed recovery of the denitrifier population.     

Influence of the local spring warming on the breeding phenology in blackcap (Sylvia atricapilla) in Croatia

Recent papers have shown that climate change affects many species, including birds. Several papers from different areas have devoted attention to the negative correlation between the dates of breeding and year, and also negative correlation between the dates of breeding and air spring temperatures. Recent work give some firm evidence for postulating causal relationship between spring temperature and laying dates. We used 31 years (1979-2009) of data from blackcap Sylvia atricapilla in Mokrice area, Northwestern Croatia to assess whether there has been any systematic change in breeding phenology through time.Among environmental factors possibly affecting the breeding date, consideration was given to mean monthly air temperatures (April-May). Over the past three decades, the breeding date of blackcap in our study population has changed significantly: They started breeding progressively earlier (11.77 days). Two regression analysis with laying date as criterion variable showed that spring temperatures can significantly predict variation of laying date and that there are also some other unknown factors which significantly explain variation of laying date. We conclude that blackcaps across Northwestern Croatia are breeding earlier and that mean air spring temperatures is probably the most important factor causing it, among other factors.     

一株产酸性α-淀粉酶菌株的筛选、纯化及酶学性质

从南宁酒厂附近土壤中筛选到一株产淀粉酶的野生菌株GXBA-4,经革兰氏染色、芽孢染色以及16SrDNA鉴定,初步确定为解淀粉芽孢杆菌(Bacillus amyloliquefacien).将该菌株发酵液经过硫酸铵沉淀和凝胶过滤纯化出一种α-淀粉酶,该酶相对分子质量约为57×103;反应最适温度为40~45℃,适应温度范围广,30℃时仍具有80%以上的相对活力;最适pH为5.0,为低温酸性淀粉酶.该酶水解可溶性淀粉的产物,经HPLC检测主要是以葡萄糖,麦芽糖以及麦芽三糖为主的低聚糖,分别以α-环糊精、β-环糊精、可溶性淀粉、玉米生淀粉为底物,还原糖产物比为0:0:99:3.4,表明该酶为典型的α-淀粉酶.     

Distribution and ecotoxicological significance of trace element contamination in a ~150 yr record of sediments in Lake Chaohu, Eastern China

This paper presents the concentrations, vertical profiles and possible sources of selected major and trace elements in a sediment core covering ～150 years of sedimentation in Lake Chaohu, eastern China. Element concentrations were measured by portable X-ray Fluorescence Spectroscopy (XRF) and were used to evaluate possible environmental consequences of the recent industrialization in China. Statistical analyses identify four groups: (1) organic carbon (OC), total nitrogen (TN), Pb, Zn, and As associated with the use of chemical fertilizers and pesticides; (2) Mn, Cr, Ni and Cu from industrial and mining activities; (3) Fe, Rb, K, Co, Ti and Ca influenced by post-depositional processes and land exploitation; and (4) Zr and Sr from the soil. The vertical profiles of elements placed in the first two groups show distinct increases in concentrations above depths of 20 cm (~1978), coincident with the timing of industrialization in China, and the anthropogenic-derived fluxes are higher than the lithogenic-derived fluxes over the last three decades. With the exception of Zr and Sr, association of the measured metals with organic carbon and nitrogen suggests that organic matter may act as a carrier phase. The geoaccumulation index (I(geo)) reveals increased contamination from elements in the first two groups in recent years. Element concentrations, compared with the Effects Range-Low (ERL) and Effects Range-Median (ERM) levels set by NOAA, suggest that adverse biological effects from Ni contamination are very likely.     

Inactivation, reactivation and regrowth of indigenous bacteria in reclaimed water after chlorine disinfection of a municipal wastewater treatment plant

Disinfection of reclaimed water prior to reuse is important to prevent the transmission of pathogens. Chlorine is a widely utilized disinfectant and as such is a leading contender for disinfection of reclaimed water. To understand the risks of chlorination resulting from the potential selection of pathogenic bacteria, the inactivation, reactivation and regrowth rates of indigenous bacteria were investigated in reclaimed water after chlorine disinfection. Inactivation of total coliforms, Enterococcus and Salmonella showed linear correlations, with constants of 0.1384, 0.1624 and 0.057 L/(mg·min) and R² of 0.7617, 0.8316 and 0.845, respectively. However, inactivation of total viable cells by measurement of metabolic activity typically showed a linear correlation at lower chlorine dose (0-22 (mg·min)/L), and a trailing region with chlorine dose increasing from 22 to 69 (mg·min)/L. Reactivation and regrowth of bacteria were most likely to occur after exposure to lower chlorine doses, and extents of reactivation decreased gradually with increasing chlorine dose. In contrast to total coliforms and Enterococcus, Salmonella had a high level of regrowth and reactivation, and still had 2% regrowth even after chlorination of 69 (mg·min)/L and 24 hr storage. The bacterial compositions were also significantly altered by chlorination and storage of reclaimed water, and the ratio of Salmonella was significantly increased from 0.001% to 0.045% after chlorination of 69 (mg·min)/L and 24 hr storage. These trends indicated that chlorination contributes to the selection of chlorine-resistant pathogenic bacteria, and regrowth of pathogenic bacteria after chlorination in reclaimed water with a long retention time could threaten public health security during wastewater reuse.     

液桥凝聚用于办公废纸脱墨的研究

研究了混合办公废纸脱墨的选择性凝聚技术，在废纸浆中添加分散在水中并不与水相溶的长链烷作凝聚剂，这些凝聚剂选择性地将印刷墨粉通过液桥连结在一起，且形成大颗粒的球形聚团，再分选脱除。研究表明只需要加入占纸重量4％的廉价长链烷，即可获得95％以上的脱墨率。因此在混合办公废纸脱墨时加入凝聚剂进行液桥凝聚，可降低脱墨浆中的尘埃度并增加产品的白度。     

Chemical aspects of mass spawning in corals. II. (-)-Epi-thunbergol,the sperm attractant in the eggs of the soft coral Lobophytum crassum (Cnidaria: Octocorallia)

Sea turtles migrate between feeding and nesting areas that are often geographically separated by hundreds or thousands of kilometers. Observations of their aggregations at sea and at nesting beaches have led to the hypothesis that sea turtles migrate in socially structured groups. While this migratory strategy is common to many marine vertebrates, socially facilitated behavior is not well documented in testudines. In 1990 and 1991, we attached satellite transmitters to olive ridleys (Lepidochelys olivacea Eschscholtz) found ovipositing together during a mass nesting at Nancite Beach, Costa Rica, to determine whether they migrate independently or in groups after they leave the nesting beach. Results showed that the turtles were not spatially associated during the internesting period, were capable of re-establishing themselves as a group during a subsequent nesting emergence, and were not spatially associated during their postnesting migrations to oceanic feeding areas. We suggested that what appear to be socially structured groups of L. olivacea are in fact individual turtles simultaneously using the same habitat.     

Appearance of excessive lipids in amniotic fluid as a sign of fetal hyperlipidaemia

The appearance of excessive lipids in amniotic fluid during Caesarean section raised the suspicion of a hyperlipidaemic fetus. The amniotic fluid had elevated cholesterol (53 mg/dl) and triglycerides (81 mg/dl). At the age of 2 months, the infant was hyperlipidaemic (cholesterol of 161 mg/dl and triglycerides of 84 mg/dl). The case suggests the possibility of prenatal diagnosis of hyperlipidaemia, a major risk factor for atherosclerosis.     

Ecological Consequences of Atmospheric Ozone Depletion in Northern Regions (Arkhangelsk Oblast)

Data on skin cancer morbidity and the total ozone concentration in the atmosphere over Arkhangelsk were processed using a standard method. The results showed that ozone depletion contributes to the increase of morbidity accounted for by this nosological form.