Author
P.A. Cross
Bio: P.A. Cross is an academic researcher. The author has an hindex of 1, co-authored 1 publications receiving 1064 citations.
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1,064 citations
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TL;DR: In this paper, a synthesis of the use of selected trace elements as proxies for reconstruction of paleoproductivity and paleoredox conditions is presented, and the combined used of U, V and Mo enrichments may allow suboxic environments to be distinguished from anoxic-euxinic ones.
2,708 citations
TL;DR: In this paper, the long-term behavior of landfills with respect to changes in oxidation-reduction status is discussed based on theory and model simulations, and it seems that the somewhere postulated enhanced release of accumulated heavy metals would not take place within the time frames of thousands of years.
Abstract: The major potential environmental impacts related to landfill leachate are pollution of groundwater and surface waters. Landfill leachate contains pollutants that can be categorized into four groups (dissolved organic matter, inorganic macrocomponents, heavy metals, and xenobiotic organic compounds). Existing data show high leachate concentrations of all components in the early acid phase due to strong decomposition and leaching. In the long methanogenic phase a more stable leachate, with lower concentrations and a low BOD/COD-ratio, is observed. Generally, very low concentrations of heavy metals are observed. In contrast, the concentration of ammonia does not decrease, and often constitutes a major long-term pollutant in leachate. A broad range of xenobiotic organic compounds is observed in landfill leachate. The long-term behavior of landfills with respect to changes in oxidation-reduction status is discussed based on theory and model simulations. It seems that the somewhere postulated enhanced release of accumulated heavy metals would not take place within the time frames of thousands of years. This is supported by a few laboratory investigations. The existing data and model evaluations indicate that the xenobiotic organic compounds in most cases do not constitute a major long-term problem. This may suggest that ammonia will be of most concern in the long run.
2,122 citations
TL;DR: In this paper, a two-equation turbulence model (one equation for turbulence kinetic energy and a second for a generic turbulence length-scale quantity) is implemented in a three-dimensional oceanographic model (Regional Oceanographic Modeling System; ROMS v2.0).
641 citations
TL;DR: In this article, the use of optical and microwave remote sensing data for soil and terrain mapping with emphasis on applications at regional and coarser scales is reviewed. But, most studies so far have been performed on a local scale and only few on regional or smaller map scale.
635 citations
TL;DR: In this article, the authors introduce the concept of landform impediments, termed buffers, barriers and blankets, that impede sediment conveyance by limiting the connectivity between landscape compartments, which operate as a series of switches which turn on/off processes of sediment delivery, determining the effective catchment area at any given time.
Abstract: Catchment configuration and the nature of connectivity within and between landscape compartments affect the operation of sediment cascades and geomorphic responses to disturbance events of differing magnitude and frequency. This paper introduces the concept of landform impediments, termed buffers, barriers and blankets, that impede sediment conveyance by limiting the connectivity between landscape compartments. Buffers restrict sediment delivery to channels, barriers inhibit sediment movement along channels, and blankets drape channel or floodplain surfaces affecting the accessibility of sediment to entrainment. These features operate as a series of switches which turn on/off processes of sediment delivery, determining the effective catchment area at any given time. Using previously documented examples, the role of these features in affecting the operation of sediment cascades in a low relief, passive landscape setting such as the Australian landmass is contrasted to examples from high relief, uplifting settings in New Zealand. The Australian examples are further explored by examining how changes to landscape connectivity brought about by human disturbance since European settlement have impacted upon landscape sensitivity and prospects for river recovery. This approach to analysis of impediments to sediment conveyance is generic and can be applied in any environmental setting.
511 citations