Weather-Related Scales

Wind (knots) WMO classification Weather-Related Scale Appearance of wind effects ... 

Net uptake of heavy metals is due to the removal of heavy metals in crops or trees in the catchment and/or in aquatic plants and fish in lake. Weathering relates to the release of HM from primary minerals in the catchment. Sedimentation is the result of the setting of suspended particles in the lake. As a result of this process, the pollutant absorbed to the suspended particles is transported from the water compartment to the sediment compartment. Resuspension of sediment particles is the result of the turbulence at water-sediment interface. As a result of this process, the pollutant absorbed to the sediment particles is transported from the sediment compartment to the water compartment. The exchange processes at the sediment water interface include advection or infiltration, molecular diffusion, and bioturbation and bioirrigation (the latter are the transport of HM resulting from the ventilation of tubes and burrows in the sediments by benthic organisms). To scale these processes to the catchment, the sedimentation and resuspension rates are multiplied by the ratio of the lake area and the catchment (de Vries et al, 1998). 

Many important erosion-related phenomena are episodic and infrequent, such as flash floods, landslides, and glaciations, while others such as orogenesis and soil formation involve time scales that exceed those of major climate fluctuations. In either case, the time scale of human existence is too short to make adequate observations. Consequently, it is difficult to directly estimate the rates or characterize the effects of such phenomena on erosion products. The key to understanding weathering and erosion, on a continental scale, is to decipher the relationship between landforms, the processes that produce them, and the chemistry and discharge of river-borne materials. 

Soil-related data (HM and BC content in soil parent materials) were included in calculations to account the values of HM weathering. Also we considered the influence of soil types on forest biomass productivity. Runoff data (at scale 0.5 x 0.50 were directly used to get input data on drainage water fluxes, Qie. Forest-type-related data (wood biomass growth and HM content in wood biomass) inserted into our database were subdivided depending on either coniferous, deciduous or mixed forests. 

The case of liquids is simpler than weathering in that it is essentially a two agent situation, liquid and temperature. As described in Sections 4.12.3 and 6.6.1, the rate of attack may be governed by the rate of diffusion of the liquid into the material, which may be slow in relation to the time scale of an accelerated test. Also, it is necessary to consider that there may be physical change (swelling) of the polymer as well as chemical degradation. 

A publication summarises all the then available technical evidence related to the Seveso accident, and recommends operational criteria to ensure safety in commercial processes to produce trichlorophenol [4]. All the plant scale incidents were characterised [1] by the subsequent occurrence of chloracne arising from the extremely toxic and dermatitic compound 2,3,7,8-tetrachlorodibenzodioxin, formed during the thermal runaway reaction and dispersed in the ensuing explosion. It is also extremely resistant to normal chemical decontamination procedures, and after the 1968 explosion, further cases occurred after transient contact with plant which had been decontaminated and allowed to weather for 3 years, and which appeared free of dioxin [7,9]. The consequences at Seveso 447 cases of chemical burns (NaOH) and 179 of chloracne, only 34 with both [17],... 

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