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491.
492.
The Aquatic Macrophyte Community Index (AMCI) is a multipurpose tool developed to assess the biological quality of aquatic
plant communities in lakes. It can be used to specifically analyze aquatic plant communities or as part of a multimetric system
to assess overall lake quality for regulatory, planning, management, educational, or research purposes. The components of
the index are maximum depth of plant growth; percentage of the littoral zone vegetated; Simpson's diversity index; the relative
frequencies of submersed, sensitive, and exotic species; and taxa number. Each parameter was scaled based on data distributions
from a statewide database, and scaled values were totaled for the AMCI value. AMCI values were grouped and tested by ecoregion
and lake type (natural lakes and impoundments) to define quality on a regional basis. This analysis suggested that aquatic
plant communities are divided into four groups: (1) Northern Lakes and Forests lakes and impoundments, (2) North-Central Hardwood
Forests lakes and impoundments, (3) Southeastern Wisconsin Till Plains lakes, and (4) Southeastern Wisconsin Till Plains impoundments,
Driftless Area Lakes, and Mississippi River Backwater lakes. AMCI values decline from group 1 to group 4 and reflect general
water quality and human use trends in Wisconsin. The upper quartile of AMCI values in any region are the highest quality or
benchmark plant communities. The interquartile range consists of normally impacted communities for the region and the lower
quartile contains severely impacted or degraded plant communities. When AMCI values were applied to case studies, the values
reflected known impacts to the lakes. However, quality criteria cannot be used uncritically, especially in lakes that initially
have low nutrient levels. 相似文献
493.
Bisphenol A: emissions from point sources 总被引:14,自引:0,他引:14
Bisphenol A is widely used for the production of epoxy resins and polycarbonate plastics. Special in vitro test systems and animal experiments showed a weak estrogenic activity for Bisphenol A. Based on in vitro receptor interaction studies, the activity was estimated to be 2 x 10(-3) lower than that of estradiol. Especially aquatic wildlife could be endangered by waste water discharges. To manage possible risks arising from Bisphenol A contamination, the major fluxes need to be obtained and the contributors to the contamination of municipal treatment plants need to be determined. In this study, industrial emitters and communal waste waters were monitored simultaneously. Mixed samples were taken over periods of one week at nine sample sites. The results showed that the concentrations and fluxes were variable. The paper industry was the major Bisphenol A contributor to the influent of the waste water treatment plant. All the other fluxes measured, including two household areas, were considerably low. About 90% of the total load was removed during the waste water treatment. 相似文献
494.
Germany seems to be one of the leading nations in solid waste management, especially in the case of packaging waste; success
stories about the ongoing increase in recycling strengthen this impression. However, enormous costs and questionable ecological
benefits are the result of Germany's packaging ordinance and the formation of the recycling organization Duales System Deutschland
(DSD). This article shows that similar progress in the reduction and recycling of packaging could have been realized without
the packaging ordinance and dual system, with lower costs. This regulatory impact analysis of the German packaging ordinance
covers all the effects on the different life-cycle stages of packaging, from production to recycling or disposal. The conclusion
is that a fragmentary solid waste management approach – one that is based, like the German packaging ordinance, more on ideology
than on facts – leads to enormous costs and questionable ecological benefits. To improve this situation, there is a need for
an integrated solid waste management approach, based on evaluation of the economic, environmental, and social effects of different
waste management options for the materials involved.
Received: February 4, 1999 / Accepted: April 30, 1999 相似文献
495.
Remodeling the clock: coactivators and signal transduction in the circadian clockworks 总被引:1,自引:0,他引:1
Frank Weber 《Die Naturwissenschaften》2009,96(3):321-337