Soil, lead transport

Lead is known to have a very low transport within plants. It is absorbed by the roots but effectively immobilized there (Adriano, 1986). In fact, plants such as Cistus ladanifer L. present low transfer coefficients, consequently the animals that eat these plants have a very low risk of ingesting significant amounts of lead. The bi-plot diagram of soil lead/aerial part lead... 

Salinization of soil results from a combination of evaporation, salt precipitation and dissolution, salt transport, and ion exchange (Shimojima et al., 1996). Excessive salinity in soil leads to toxicity in crops, reduction in soil fertility, reduction of... 

Relationship of Regional Road Traffic to Surface-Soil Lead Levels in Illinois, Argonne National Laboratory, Energy and Environmental Systems Division, Center for Transportation Research, Publication ANL/ES-1541987. 

Elevated lead contents were recorded in various species of plants from the vicinity of metal smelters, roadsides, soils heavily contaminated with lead, natural ore deposits, and lead recycling factories. Bioavailability of lead in soils to plants is limited, but is enhanced by reduced soil pH, reduced content of organic matter and inorganic colloids, reduced iron oxide and phosphorus content, and increased amounts of lead in soils. Lead, when available, becomes associated with plants by way of active transport through roots and by absorption of lead that adheres to foliage. Lead concentrations were always higher in the older parts of plants than in shoots or flowers. 

Essentially, acid is produced at the anode, and alkaline solution is produced at the cathode therefore, pH in the cathode is increased, while pH at the anode is decreased. The migration of H" firom the anode and OH from the cathode into the soil leads to dynamic changes in soil pH. H" is about twice as mobile as OH, so the protons dominate the system, and an acid front moves across the soil until it meets the hydroxyl fi ont in a zone near the cathode where the ions may recombine to generate water. Thus, the soil is divided in two zones with a sharp pH jump in between ahigh-pH zone close to the cathode and a low-pH zone on the anode side. The acmal soil pH values will depend on the extent of transport of H" and OH ions and the geochemical characteristics of the soil. 

EPA, 2006). Reentrainment of lead in particulate back into the atmosphere from dusts and soils after initial deposition of lead from the atmosphere also occurs due to atmospheric mobilization (Cowherd et al., 1985 U.S. EPA, 2006). The range of lead transport via the atmosphere can be many miles for the smallest size particles to as short as meters for reentrained dust particles at roadways for heavy traffic or for large lead paint particles, as occurs with weathering and flaking of lead-painted surfaces in older buildings where particles are mobilized to nearby soil surfaces, around the drip line."... 

The documented occurrence of pesticides in surface water is indicative that mnoff is an important pathway for transport of pesticide away from the site of appHcation. An estimated 160 t of atra2ine, 71 t of sima2ine, 56 t of metolachlor, and 18 t of alachlor enter the Gulf of Mexico from the Mississippi River annually as the result of mnoff (47). Field appHcation of pesticides inevitably leads to pesticide contamination of surface mnoff water unless mnoff does not occur while pesticide residues remain on the surface of the soil. The amount of pesticides transported in a field in mnoff varies from site to site. It is controUed by the timing of mnoff events, pesticide formulation, physical—chemical properties of the pesticide, and properties of the soil surface (48). Under worst-case conditions, 10% or more of the appHed pesticide can leave the edge of the field where it was appHed. 

The atmosphere may be an important transport medium for many other trace elements. Lead and other metals associated with industrial activity are found in remote ice caps and sediments. The transport of iron in wind-blown soil may provide this nutrient to remote marine areas. There may be phosphorus in the form of phosphine, PH3, although the detection of volatile phosphorus has not been convincingly or extensively reported to date. 

Johansson K, Bergback B, Tyler G. 2001. Impact of atmospheric long range transport of lead, mercury and cadmium on the Swedish forest environment. Water, Air Soil PoUut Focus 1 279-297. 

Evans RD, Rigler FH. 1985. Long distance transport of anthropogenic lead as measured by lake sediments. Water Air Soil Pollut 24 141-151. 

The temperature patterns follow a transition from the more oceanic western area (milder temperatures) to the central depression (high temperatures in summer and intense cold and fog in winter). The northwest-southeast cold and dry wind ( cierzo ) is characteristic of the central depression of the Ebro basin, especially in spring. The cierzo at the middle Ebro valley (around Zaragoza) can lead to soil erosion and salt transport [17]. The wind intensity at this area is highly correlated with evapotranspiration [18]. A mild warm wind is sometimes occurring (especially in summer) following the opposite direction (southeast-northwest). 

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