Biodegradation of wastewater of Najafgarh drain,Delhi using autochthonous microbial consortia : a laboratory study

There are seventeen drains, which discharge their untreated urban and industrial wastewaters into the Delhi segment of river Yamuna. The Najafgarh drain is the first and the largest drain, and it alone contributes 1667.84 mld i.e. 60% of the total wastewater discharge into the river Yamuna and as such add 81.36 tons of BOD load per day. As per the available data approximately 95% of the wastewater of this drain is biodegradable. In the present study, an attempt has been made to reduce the BOD load and COD levels of wastewater of Najafgarh drain using autochthonous microbial consortium. During this study the raw wastewater samples were treated for 6 h time interval with different concentration of consortium. It was observed that by increasing the existing microbial population in the wastewater sample by 150-200% there is a significant decrease in BOD and COD levels. Finally, BOD/COD ratios before and after biotreatment have been analyzed to assess the efficacy of the natural consortium.     

Temporal and spatial variation in the growth rates of Baltic herring (<Emphasis Type="Italic">Clupea harengus membras</Emphasis> L.) larvae during summer

It has been suggested that larval survival determines the year-class strength in most marine fish species. During their growth and development, the ability of the larvae to catch prey and avoid predation will increase. However, the factors affecting short-term changes in the growth of Baltic Sea herring have been little studied in the field. We collected Baltic herring (Clupea harengus membras L.) larvae from five different towing areas in the Archipelago Sea (SW Finland) during May and June 1989, right after the main spawning season. Twenty thousand two hundred and ten larvae were analysed and the area-specific growth rate (i.e. increase in standard length) was estimated by tracing the larval cohorts from the length-frequency data. This represents the first Baltic herring study with daily sampling during a long study period. The growth rate was related to environmental factors, such as temperature, number of zooplankters, and wind speed and direction. Large variation in larval growth rate occurred between areas: lowest and highest growth rates were 0.18 and 0.52 mm·day^-1. Temperature was an important variable controlling larval-fish growth rate. An increase of one 1°C in average water temperature corresponded to an increase in growth rate of 0.043 mm·day^-1. This may have been caused either by a direct temperature effect (changes in metabolic rate) or by the indirect effect of changes in food availability. We also found the densest herring populations in the areas with highest average water temperature. However, temperature and larval growth rate both increased towards the inner archipelago.     

Human health implications of clinically relevant bacteria in wastewater habitats

The objective of this review is to reflect on the multiple roles of bacteria in wastewater habitats with particular emphasis on their harmful potential for human health. Indigenous bacteria promote a series of biochemical and metabolic transformations indispensable to achieve wastewater treatment. Some of these bacteria may be pathogenic or harbour antibiotic resistance or virulence genes harmful for human health. Several chemical contaminants (heavy metals, disinfectants and antibiotics) may select these bacteria or their genes. Worldwide studies show that treated wastewater contain antibiotic resistant bacteria or genes encoding virulence or antimicrobial resistance, evidencing that treatment processes may fail to remove efficiently these bio-pollutants. The contamination of the surrounding environment, such as rivers or lakes receiving such effluents, is also documented in several studies. The current state of the art suggests that only some of antibiotic resistance and virulence potential in wastewater is known. Moreover, wastewater habitats may favour the evolution and dissemination of new resistance and virulence genes and the emergence of new pathogens. For these reasons, additional research is needed in order to obtain a more detailed assessment of the long-term effects of wastewater discharges. In particular, it is important to measure the human and environmental health risks associated with wastewater reuse.     

超声波对滇池蓝藻伪空胞和群体沉降性能的影响

为提高混凝沉淀藻水分离技术的分离效果,以滇池新鲜蓝藻为研究对象,研究不同超声波处理条件下,超声波对伪空胞、蓝藻群体沉降性能及水体水质的影响。结果表明:超声波对伪空胞的破坏效果满足准一级动力学规律,反应速率常数k随着超声波功率密度的增大而增大,并逐步趋于饱和;短时间低功率(5 s,5.0～16.7 W·L~(-1))的超声波能破坏伪空胞,改善蓝藻群体沉降性能,降低水体pH,且对水体DTN、DTP浓度的影响5%;在保证出水安全的前提下,综合考虑处理效果和经济成本,超声波功率密度16.7 W·L~(-1)、处理时间5 s为超声波处理滇池藻样的最佳条件,该条件下蓝藻伪空胞破坏率、沉降率分别为84%、80%。利用超声波对滇池蓝藻进行处理,确定了超声波对滇池蓝藻的伪空胞有破坏作用,可以改善蓝藻群体的沉降性能,达到大规模、无污染的藻水分离的目的,为蓝藻水华控制提供参考。     

Acetochlor as a soil pollutant

Acetochlor is a widely used herbicide all over the world. Similarly to other organic pollutants, the environmental fate of the acetochlor is strongly related to its adsorption properties. Static adsorption equilibrium measurements were carried out at 25 degrees C on different types of Hungarian soils characterized by varying amounts of organic matter and pH values. Isotherms obtained under different conditions, as well as on various soils, exhibit a similar shape, thus indicating a two-step adsorption process. The plots cannot be interpreted according to the classes of isotherms suggested by Giles. The adsorption coefficients (K) were estimated from the initial slope of the curves. These values were determined not only by the type of the soil, but also by the composition of the aqueous media. The organic matter adsorption coefficients (Kom) were also calculated and they were approximately identical for soils of high organic matter. Due to the low value of the adsorption coefficients, the acetochlor is a rather mobile pollutant of the soil posing a potential danger to the aquatic environment. For soils with high organic content, the Kom values are similar to each other and, due to the significant coverage of the inorganic surfaces, the adsorption is controlled by the solute-organic substance interactions. The adsorption of weakly polar compounds, however, is remarkable even on those soils where the organic content is low. In this case, the binding is governed by the solute-inorganic surface interactions. This conclusion is nicely proved by the adsorption of the acetochlor on quartz. According to our hypothesis, the second part of the adsorption step is controlled by the solute-adsorbed solute interactions. The role of the organic matter in this region of the isotherm is probably negligible. As the organic matter content of the soils plays an important role in the acetochlor adsorption, humic substances must have a strong influence upon the transport of this compound. Experiments to obtain adsorption isotherms of further pesticides and the development of a quantitative model are in progress.     

The use of a lacertid lizard as a model for reptile ecotoxicology studies--part 1 field demographics and morphology

At the European level, lacertid lizards have been proposed as potential model species for reptile ecotoxicology. We studied demographic and morphological aspects of natural field subpopulations of Podarcis bocagei inhabiting similar agricultural habitats which were either regularly exposed to pesticides, or not. Parameters examined in this study included population size and density, sex ratio, adult body size, fluctuating asymmetry in femoral pores and parasite prevalence. In general, we detected few statistically significant differences between the exposed and reference subpopulations. Although field situations are ecologically complex and factors other than pesticides may be acting, the absence of observable effects on field subpopulations is probably indicative that lizards are coping or compensating for this level of exposure.     

模拟农田低污染水中不同基质对海菜花生长的影响

采用海菜花湿地中试装置研究砾石、砂土、红壤土、紫土及稻田土5种基质对海菜花种子萌发、幼苗生长、花茎产量和模拟低污染水水质的影响。结果表明:种植在红壤土和稻田土中的海菜花种子萌发率(74.25%和73.68%)高于砂土和紫土;从生长状况分析,稻田土和紫土比另外3种基质更有利于海菜花幼苗的生长;从花茎累计产量分析,5种基质中海菜花在紫土中的总开花数(22朵)、花茎数(32根/m ²)及花茎总质量(145.10 g)最高,花茎总质量其次为稻田土(117.60 g);从N、P的去除效果分析,5种基质条件下海菜花中试湿地对氨氮(N$H_{4}^{+}$-N)、硝氮(N$O_{3}^{-}$-N)和总氮(TN)去除效果较好,红壤土对总磷(TP)去除效果较好,稻田土较差。     

Testing environment Kuznets curve (EKC) hypothesis in different regions

Environmental Science and Pollution Research - This study examines the association between air pollution and economic growth based on the idea of environment Kuznets curve (EKC) hypothesis which...