Assessment of the importance of sorption for steroid estrogens removal during activated sludge treatment

Distribution coefficients (K(d)) between water and activated sludge particles (f(oc)=27.7+/-0.1%) were measured for the steroid estrogens (SE), estrone (E1), 17beta-estradiol (E2) and 17alpha-ethinylestradiol (EE2) in batch experiments. Experimental concentration levels ranged from environmentally realistic low ng/l to the high microg/l. In this range K(d)s were independent of their water concentration. The experimentally obtained K(d)s (with 95% confidence intervals) were 402+/-126 l/kg, 476+/-192 l/kg and 584+/-136 l/kg for E1, E2 and EE2, respectively. K(d)s were used to estimate the fraction of the total SE concentration that is expected to be sorbed in the activated sludge treatment tanks of a typical STP assuming equilibrium conditions. Assuming a suspended solids concentration of 4 g/l dissolved solids (ds), it was estimated that 61+/-9%, 66+/-13% and 70+/-6% of the total concentration of E1, E2 and EE2, respectively, would be sorbed during activated sludge treatment. The fraction of the SEs that was expected to be sorbed to suspended sludge particles in the effluents from a typical Danish STP was estimated to be only 0.20+/-0.06%, 0.24+/-0.10% and 0.29+/-0.07% of the total concentration of E1, E2 and EE2, respectively, at a suspended solids concentration of 5 mg/lds. For a typical STP the removal of steroid estrogens with excess sludge was estimated to be only 1.5-1.8% of the total loading if equilibrium conditions exists. Sorption is therefore not important for the fate of SEs in STPs compared to biodegradation.     

Patterns in species composition of rocky shore communities in sub-arctic fjords of eastern Iceland

Quantitative data on plants and animals from 20 transects of the eulittoral zone in 8 fjords of sub-arctic east Iceland were analysed by a number of classification and ordination techniques. Field work was carried out during two periods of spring tides in June and July 1987. The study was restricted to gently sloping stable bedrock, but transects were otherwise randomly chosen. Species composition was strongly influenced by the relative position of the transects along the length of the fjords. Species richness increased from heads towards mouths. Increased temperature fluctuations towards inner parts of fjords are suggested as an explanation for these patterns, while salinity is unlikely to be a critical factor. The analyses also indicate that degree of exposure, as measured both by a physically derived index and by a simple biological index, is an important factor in structuring these eulittoral communities, although affecting species richness only slightly, if at all. Classification of transects results in a number of community types which, however, are not well defined. A classification based on the presence/absence of three canopy-forming fucoids yields groups of transects differing in species composition and in degree of exposure. The rocky eulittoral communities of the fjords of eastern Iceland resemble those of northern Norway, but differ in that several key species of the latter communities are missing, probably largely due to the isolation of Iceland.     

Prey size selection,feeding rates and growth dynamics of heterotrophic dinoflagellates with special emphasis on Gyrodinium spirale

The relationship between size and growth rate in heterotrophic dinoflagellates (collected from the Kattegat, Denmark during 1989 and 1990) was studied. In addition, prey size selection, feeding rates and growth dynamics were studied for the naked heterotrophic dinoflagellate Gyrodinium spirale Bergh. Heterotrophic dinoflagellates have growth rates which are approximately three times lower than that of their potential competitors, the ciliates. G. spirale requires a relatively high prey concentration in order to grow. Ingestion rate at the maintenance level is about half of that of maximum ingestion rate. Consequently, yield is lower than typically found for planktonic protozoa. When exposed to low prey concentrations, the dinoflagellate is able to reduce its metabolism and thus prolong survival. The optimum prey particle size for G. spirale, which feeds by direct engulfment, corresponds to its own size. The ability to ingest relatively large prey may explain why these organisms are competitive in nature.     

Land use change around protected areas: management to balance human needs and ecological function.

Protected areas throughout the world are key for conserving biodiversity, and land use is key for providing food, fiber, and other ecosystem services essential for human sustenance. As land use change isolates protected areas from their surrounding landscapes, the challenge is to identify management opportunities that maintain ecological function while minimizing restrictions on human land use. Building on the case studies in this Invited Feature and on ecological principles, we identify opportunities for regional land management that maintain both ecological function in protected areas and human land use options, including preserving crucial habitats and migration corridors, and reducing dependence of local human populations on protected area resources. Identification of appropriate and effective management opportunities depends on clear definitions of: (1) the biodiversity attributes of concern; (2) landscape connections to delineate particular locations with strong ecological interactions between the protected area and its surrounding landscape; and (3) socioeconomic dynamics that determine current and future use of land resources in and around the protected area.     

可持续工商教育催生未来商业精英

本文为美国环保署副署长在世界资源研究所BELL会议上的讲话。这次会议召开于1997年，即8年前，但讲话内容并未“过时”。从中我们不仅可以了解贝迩项目的发展历史，而且还对一些环境管理制度有深入的理解。[编者按]     

Assessing Retrospective National Water Model Streamflow with Respect to Droughts and Low Flows in the Colorado River Basin

Streamflow monitoring in the Colorado River Basin (CRB) is essential to ensure diverse needs are met, especially during periods of drought or low flow. Existing stream gage networks, however, provide a limited record of past and current streamflow. Modeled streamflow products with more complete spatial and temporal coverage (including the National Water Model [NWM]), have primarily focused on flooding, rather than sustained drought or low flow conditions. Objectives of this study are to (1) evaluate historical performance of the NWM streamflow estimates (particularly with respect to droughts and seasonal low flows) and (2) identify characteristics relevant to model inputs and suitability for future applications. Comparisons of retrospective flows from the NWM to observed flows from the United States Geological Survey stream gage network over 22 years in the CRB reveal a tendency for underestimating low flow frequency, locations with low flows, and the number of years with low flows. We found model performance to be more accurate for the Upper CRB and at sites with higher precipitation, snow percent, baseflow index, and elevations. Underestimation of low flows and variable model performance has important implications for future applications: inaccurate evaluations of historical low flows and droughts, and less reliable performance outside of specific watershed/stream conditions. This highlights characteristics on which to focus future model development efforts.     

An Optimised Direct Lysis Method for Viral RNA Extraction and Detection of Foodborne Viruses on Fruits and Vegetables

Detection of norovirus (NoV) and hepatitis A virus (HAV) on fruits and vegetables using current standard methodologies can be inefficient. Method optimisat     

The continuous monitoring of field water samples with a novel multi-channel two-stage mini-bioreactor system

Toxicity monitoring of field water samples was performed using a novel multi-channel two-stage mini-bioreactor system and genetically engineered bioluminescent bacteria for the continuous monitoring and classification of the toxicity present in the samples. The toxicity of various samples spiked with known endocrine disrupting chemicals and phenol was also investigated for system characterization. The field samples used in this study were obtained from two different sites on a monthly basis--from a drinking water treatment plant, referred to as site N, and from a stream near a dam which is currently being constructed, referred to as site T. These samples were either pumped or injected into the second mini-bioreactors to initiate the toxicity test. Most of the samples did not show any specific toxicity. However, one sample showed to have, based upon the detection results, and was deemed toxic. The samples spiked with phenol showed possible responses in the DPD2540 and TV1061 channels, indicating the occurrence of both membrane and protein damage due to phenol. In the tests using an endocrine disrupting chemical, bisphenol A, DNA damage was detected in the DPD2794 channel with a concentration of 2 ppm. Finally, a simple but novel early warning protocol that can be used in a drinking water reservoir and a suspected place where effluents of toxic materials enter the water sourse was suggested with a schematic diagram. In conclusion, this system showed good feasibility for use as a toxicity monitoring system in the field and as an early warning system, indicating if effluents are toxic.