No abstract

No abstract

A sustainable management of nonrenewable metals calls for scienti®c-ecological understanding of the regional material household. The copper household in the USA between 1900 and 2100 was chosen to illustrate mathematical modelling of such systems. Relatively limited and inaccurate sets of data already allow a ®rst approximation of the metal management system. The copper¯uxes of the 20th century have contributed to the formation of two new ore deposits of the same order of magnitude as the currently still available reservoir (90 million tons), i.e. copper stock in consumption products (approx. 70 million tons) and in land®lls (approx. 40 million tons). Thè`l and®ll'', therefore, contains copper whose potential use is lost due to dilution. The long-term copper consumption stock is greater than the shortterm stock. Scenarios show that the current economically mineable Cu-stocks will be exhausted in 30 to 50 years if a change in the existing management system does not occur. In case of a reorientation, the use of copper as a``new resource'' in the consumption stocks appears to be the most promising strategy. The future waste management processes will have to increase their copper recycling rates.

No abstract

No abstract

No abstract

No abstract

Aquatic pesticide pollution from both agricultural and urban pest control is a concern in many parts of the world. Making an accurate assessment of pesticide exposure is the starting point to protecting aquatic ecosystems. This in turn requires the design of an effective monitoring program. Monitoring is also essential to evaluate the efficacy of mitigation measures aimed to curb pesticide pollution. However, empirical evidence for their efficacy can be confounded by additional influencing factors, most prominently variable weather conditions. This review summarizes the experiences gained from long-term (>5 years) pesticide monitoring studies for detecting trends and provides recommendations for their improvement. We reviewed articles published in the scientific literature, with a few complements from selected grey literature, for a total of 20 studies which fulfill our search criteria. Overall, temporal trends of pesticide use and hydrological conditions were the two most common factors influencing aquatic pesticide pollution. Eighteen studies demonstrated observable effects to surface water concentrations from changes in pesticide application rates (e.g., use restriction) and sixteen studies from interannual variability in hydrological conditions during the application period. Accounting for seasonal- and streamflow-related variability in trend analysis is important because the two factors can obscure trends caused by changes in pesticide use or management practices. Other mitigation measures (e.g., buffer strips) were only detectable in four studies where concentrations or loads were reduced by > 45%. Collecting additional agricultural (e.g., pesticide use, mitigation measures) and environmental (e.g., precipitation, stream flow) data, as well as establishing a baseline before the implementation of mitigation measures have been consistently reported as prerequisites to interpret water quality trends from long-term monitoring studies, but have rarely been implemented in the past.