Soil contamination issues: past, present and future, a personal perspective

Hidróxidos Duplos Laminares Para Remoção De Poluentes Aquosos

“…5,16±4,2 4,96±2,7 4,90±4,2 (1) 10,0 mg L -1 Nitrite (mg L -1 ) 0,010±0,003 0,014±0,01 0,014±0,01 (1) (2) 5,0 mg L -1 (min) Table 3. Results of the physicochemical analyses carried out in the three sample sites during the period evaluted (1) Standard established by the Decree 2.914 of December 12 th , 2011. (2) Standard established by Resolution 357 of 2005.…”

“…Os estudos de cinética de adsorção das soluções galvânicas de Cu 2+ (aq) em biosorvente foram realizados em duplicata para o período de 120 min. O procedimento envolveu frascos de vidro contendo 25 mL do adsorvato e 0,2g de biosorvente, enquanto as coletas foram realizadas nos tempos 1,2,3,4,5,10,20,30,40,50, 60 e 120 min. A alíquota coletada, foi agitada, filtrada, posteriormente diluída, acidificada e analisada por EAA (VARIAN AA240FS).…”

Remediating polluted soils

“…Many important organic pollutants are non-polar and hydrophobic with very large octanol:water partition (K ow ) coefficients; these also have a high affinity for organic matter and can become occluded within the soil humus fraction. Partitioning between solid and liquid phases will also vary with contaminant concentration (Tiller 1996) and factors that show marked temporal and spatial variation such as pH, competitive adsorption and inputs of organic compounds (Staunton 2004). These soil-specific factors can have a major influence on pollutant impact; Khan and Scullion (2000), for example, demonstrated significant effects of biosolid metals in some soils but no effect in others.…”

“…In the case of metals, there is a scarcity of information about the kinetics of metal reactions in soils (Helmke and Naidu 1996), of desorption reactions for ingested soil in the human digestive system (Tiller 1996), and uncertainty about the bioavailability of metal complexes (Slaveykova and Wilkinson 2005). Sparks (2000) considered that the use of molecular scale in situ analytical techniques had significantly advanced the determination of speciation and sorption-release mechanisms of metals and oxyanions in soils.…”

“…In principle, the effectiveness of this process should decline as the total concentration of pollutants falls. Also, the rate at which water can be effectively circulated depends on the kinetics of desorption; as noted previously, information on these kinetics is limited for many pollutants (Tiller 1996). Where cycles of soil flushing are too rapid to allow desorption to re-establish phase equilibria concentrations, pollutant concentrations in groundwater can increase once treatment ceases (Aksoy and Culver 2000).…”