Runoff constituent

Two synthetic pyrethroid insecticides, bifenthrin and permethrin (3-phenoxybenzyl (lR5)-cis-fra s-3-(2,2-dichlorovinyl)-2,2-dimcthylcyclopropane-carboxylate), are the major runoff constituents considered in our monitoring and evaluation studies. Bifenthrin has a solubility of <1 ppb, and a Koc of240,000 ml g. Permedirin has a solubility of 6 ppb in water, and a Ka- of 100,000 ml g (5). The stroi adsorption on soil suggests that a large fiaction of the pesticide is associated wifii die suspended solids in nursery runoff. This determines that the downstream distribution of these pesticides is closely related to distribution of sediments, and that practices aiming to remove suspended solids from runoff will also be effective in reducing the level of these pesticides. 

The harmful liquid that collects at the bottom of a landfill is known as leachate. The generation of leachate is a result of uncontrolled runoff, and percolation of precipitation and irrigation water into the landfill. Leachate can also include the moisture content initially contained in the waste, as well as infiltrating groundwater. Leachate contains a variety of chemical constituents derived from the solubilization of the materials deposited in the landfill and from the products of the chemical and biochemical reactions occurring within the landfill under the anaerobic conditions. 

These values are significantly different from those that have been earlier calculated by RAIN-ASIA model (World Bank, 1994). These differences might be related to the much more detailed and comprehensive national data sets on geological, soil, climate (precipitation, temperature, evapotranspiration, runoff, etc.) and vegetation mapping, physico-chemical properties of soils and geological rocks. This allows the authors to calculate more precise values of all constituents used for maximum sulfur critical load calculation and mapping. 

Source Constituent in paraffin fraction of petroleum. Dodecane may be present in stormwater runoff from asphalted roadways and general use of petroleum oils and tars (quoted, Verschueren). 

Various plant lipid constituents contain cresols (Fiege and Bayer 1987). Runoff from terrestrial sources may contribute cresols to surface waters in addition to endogenous sources such as aquatic plants, animals, and microbes. 

Nickel is a natural constituent of soil and is transported into streams and waterways in runoff either Ifom natural weathering or Ifom disturbed soil. Much of this nickel is associated with particulate matter. Nickel also enters bodies of water through atmospheric deposition. 

The concept of constancy of the chemical composition of sea water, i.e., that the ratios of the major dissolved constituents of sea water do not vary geographically or vertically in the oceans except in regions of runoff from the land or in semienclosed basins, was firsr proposed indirectly in 1819 by Marcet and expanded later by Forchammer and Dittmar. The concept... 

Waste Treatment. Environmental concerns have increased the need to treat liquid discharges from all types of industrial processes, as well as runoffs where toxic substances appear as a result of leaks or following solubilization (see Wastes, industrial). One method of treatment consists of an ion-exchange system to remove the objectionable components only. Another involves complete or partial elimination of liquid discharges by recycling streams within the plant. This method is unacceptable unless a cyclic increase in the impurities is eliminated by removing all constituents prior to recycling. 

The mixture of organic constituents in the marine environment is extremely complex. Their origin is partly terrigenuous many compounds are produced in the marine environment itself. The different sources and their relative importance for the complexation of trace metals in estuaries, coastal seas and open ocean are riverine input, runoff from the coastal zone, resuspension, import of water mases, atmospheric input and in situ biological production. 

Evangelou, V. P, B. J. Barfield, and R. I. Bamhisel. 1987. Modeling release of chemical constituents in surface mine runoff and in coal mine sedimentation ponds. Trans. Am. Soc. Agric. Eng. 30 82-89. 

Although most of the volatile components are released to the atmosphere, a small fraction is dissolved and/or carried away with the water in the soil matrix. Leached waters are carried with the water as it percolates through the underlying soil strata. Most of the organic constituents contained in the leachate receive additional treatment as they pass through the soil column. Leached wastes can also be lost in surface runoff. 

Constituent Urban runoff (stormwater) Agricultural runoff ... 

The rate of sedimentation is controlled largely by the rate at which an element is converted (uptake by organisms, precipitation, coprecipitation, ion exchange) into an insoluble, setdeable form. Hence the reactivity of the elements influences the time that elements spend, on the average, as constituents of the seawater. For most elements residence times have been determined on the basis of estimates of the input by runoff from the land or from calculations of sedimentation times. Remarkably similar results are obtained by these two... 

Runoff Losses Due to Hydrogen Ion Loading. Runoff losses from zinc, and presumably galvanized steel, are dependent upon hydrogen ion load in 3- and 12-month exposure. Such an effect is not apparent in 1-month exposures. Hydrogen ion dissolves zinc carbonate, perhaps the major constituent of the corrosion film, by the reaction... 

The species Si02(aq) may be taken as a measure of dissolution and weathering of silicate minerals in the surficial zone of the continental crust, but the same does not apply to other dissolved constituents of continental runoff. All the major cations (Ca2 +, Mg2+, Na +, and K + ) originate from different rock types and in... 

Sediment concentration and silica concentration show a consistent inverse relation during periods of storm runoff, and silica minima commonly tend to precede peak discharge by 2-4 hours, depending on how fast a rise occurs. Sediment concentration varies much more than does any of the dissolved constituents. 

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