Current regulatory environmental exposure assessments for decamethylcyclopentasiloxane (D5), used in a range of personal care products, are based on a number of erroneous assumptions. Using an estimated D5 flux to waste water of 11.6 mg cap−1 d−1, a 95.2% removal rate in Sewage Treatment Plants (STP) and a dilution factor of 10 results in modelled surface water concentrations that are up to an order of magnitude higher than concentrations observed downstream of STPs in two UK rivers. A GIS-based water quality model (LF2000-WQX) was used to predict concentrations of D5 in two UK rivers. Assuming the STP removal rate is reasonable, a waste water flux of 2.4 mg cap−1 d−1 is needed in order to obtain a reasonable match between predicted and observed in-river concentrations. This flux is consistent with measured effluent concentrations. The results highlight major uncertainties in estimating chemical emission rates for volatile chemicals used in personal care products and suggest that measured concentrations in waste water are needed to refine exposure assessments. 相似文献
Agricultural landscapes illustrate the impact of human actions on physical settings, and differential human pressures cause
these landscapes to change with time. Our study explored changes in the terraced landscapes of Nisyros Island, Greece, focusing
on the socioeconomic aspects during two time periods using field data, cadastral research, local documents, and published
literature, as well as surveys of the islanders. Population increases during the late 19th to early 20th centuries marked a significant escalation of terrace and dry stone wall construction, which facilitated cultivation on 58.4%
of the island. By the mid-20th century, the economic collapse of agricultural activities and consequent emigration caused the abandonment of cultivated
land and traditional management practices, dramatically reducing farm and field numbers. Terrace abandonment continued in
recent decades, with increased livestock grazing becoming the main land management tool; as a result, both farm and pasture
sizes increased. Neglect and changing land use has led to deterioration and destruction of many terraces on the island. We
discuss the socioeconomic and political backgrounds responsible for the land-use change before World War II (annexation of
Nisyros Island by the Ottoman Empire, Italy, and Greece; overseas migration opportunities; and world transportation changes)
and after the war (social changes in peasant societies; worldwide changes in agricultural production practices). The adverse
landscape changes documented for Nisyros Island appear to be inevitable for modern Mediterranean rural societies, including
those on other islands in this region. The island’s unique terraced landscapes may qualify Nisyros to become an archive or
repository of old agricultural management techniques to be used by future generations and a living resource for sustainable
management. 相似文献
Land taken by artificial surfaces has an impact on the quality of life and ecosystems. To reduce possible negative impacts of land take, the European Commission proposed setting a milestone objective for 2020 in terms of future rates of land take.
This paper describes a methodology to model the impacts of the 2020 land-take milestone proposed in the RERM in the European Union 27 MS. An integrated modelling framework was configured to assess the spatial impact of two land-take scenarios: a ‘Reference’ scenario, which is driven by demographic and economic trends, and a ‘Target 0’ scenario that follows the 2020 land-take milestone proposed in the RERM. We conclude that the implementation of the 2020 land-take milestone, by reducing future land take in Europe, will foster more efficient use of land (less land taken for the same activity levels) and minimise negative impacts on non-artificial land uses. 相似文献