Toxikologische Bewertung von Rüstungsaltlasten

A method was developed for the risk assessment of a military waste site. The method consists of two steps: 1. evaluation of the exposure through different pathways and 2. derivation of substance-specific tolerable intake levels. In this first part of the paper the quantitative exposure analysis will be discussed. Exposure depends on the conditions at the contaminated site (e.g. soil characteristics), the type of utilisation (residential area, industrial area etc.) and the substance properties. In a specific utilisation scenario, e.g. as residential area, different exposure pathways are contributing to the total contaminant uptake. Because of the properties of nitroaromatic compounds like 2,4,6-trinitrotoluene (good resorption through skin and accumulation in plants) exposure via dermal soil contact and via consumption of plants gains special importance. With these two exposure pathways as examples we explain the quantification of the exposure through different pathways by so-called exposure factors. By comparing the total exposure with tolerable intake levels for the compounds, waste site specific soil pollutant levels can be established (see second part of the paper in UWSF 6/94).     

Social and environmental trade-offs in tree species selection: a methodology for identifying niche incompatibilities in agroforestry

Natural resource degradation in highland regions is of increasing concern to the global community due to its role in aggravating poverty and the loss of environmental services to local and downstream users. The integration of trees into smallholder farming systems has been promoted as a means to enhance rural livelihoods while reversing the degradation of soil, water, biodiversity and related environmental services. Yet in addition to these benefits, negative impacts of trees on certain stakeholders or system components have also accompanied such efforts—suggesting that important trade-offs accompany afforestation. This paper presents a methodology for diagnosing problems stemming from cultivation of certain tree species in specific landscape niches. Data derived from the application of this methodology in two sites in the eastern African highlands are presented. Participatory diagnoses of landscape-level problems suggest that the negative impact of trees on water resource availability and crop yield are of critical concern to smallholder farmers. Ethnoecological data highlight the properties of different tree species that determine their suitability to specific farm and landscape niches. These data point to important opportunities for more socially- and environmentally-optimal integration of indigenous and exotic tree species into agricultural landscapes, and highlight the critical importance of local knowledge in forging solutions appropriate to contemporary realities.     

Prerequisite conditions for meaningful participation in brownfields redevelopment

Current research in environmental planning supports decision making based on collaborative planning mechanisms. While current research clearly details the limitations to and prerequisites for meaningful public participation in general and for select environmental issues, there is little focus on them in brownfields redevelopment. In practice, the general assumptions are that brownfields redevelopment is an ideally situated policy issue for participatory planning. However, as this paper will illustrate through case study research, there are several situational prerequisites that must be met before there can be meaningful citizen participation in brownfields redevelopment. By highlighting these prerequisites, the author's goal is to mobilize research and policy efforts to overcome those limitations and to foster widespread meaningful participation in the redevelopment of brownfields in residential neighborhoods.     

Occurrence and determination of organic oxidants in rivers and wastewaters

Two iodometric methods for the concentration and analysis of water samples containing organic oxidants were applied to rivers and wastewaters in Illinois, Delaware, and Pennsylvania. Oxidant concentrations detected were as high as 2.5 § 10⁻⁵ M; the methods were capable of detecting as little as 10⁻⁸ M. Compounds possibly responsible for the observed oxidizing activity include N-chloro compounds, organic peroxides, or quinones.