The occurrence of aristolochic acids in neotropical troidine swallowtails (Lepidoptera: Papilionidae)

Summary. Analysis of individuals of 17 troidine species demonstrated the presence of aristolochic acids in these butterflies in varying concentrations. Although aristolochic acids do not occur in Aristolochia galeata leaves, they were present in Battus polydamas larvae reared on these leaves, and thus may be synthesized by the larvae from chemical precursors in the plant. Received 17 August 1999; accepted 20 January 2000     

Physical–chemical processes of sustainable materials’ production from hazardous toner waste,galvanic glass waste and spent foundry sand

Journal of Material Cycles and Waste Management - Several sustainable white ceramic composites were prepared from 3 to 7 wt.% of hazardous toner waste, 30–40% of spent foundry sand,...     

Hazardous bauxite red mud and ferrous slag management to produce sustainable construction materials

Journal of Material Cycles and Waste Management - This paper reports the development and characterization of new ceramics from hazardous bauxite red mud (50...     

Hydrophobicity of soil colloids and heavy metal mobilization: effects of drying

Drying of soil may increase the hydrophobicity of soil and affect the mobilization of colloids after re-wetting. Results of previous research suggest that colloid hydrophobicity is an important parameter in controlling the retention of colloids and colloid-associated substances in soils. We tested the hypothesis that air-drying of soil samples increases the hydrophobicity of water-dispersible colloids and whether air-drying affects the mobilization of colloid-associated heavy metals. We performed batch experiments with field-moist and air-dried (25 degrees C) soils from a former sewage farm (sandy loam), a municipal park (loamy sand), and a shooting range site (loamy sand with 25% C(org)). The filtered suspensions (<1.2 microm) were analyzed for concentrations of dissolved and colloidal organic C and heavy metals (Cu, Cd, Pb, Zn), average colloid size, zeta potential, and turbidity. The hydrophobicity of colloids was determined by their partitioning between a hydrophobic solid and a hydrophilic aqueous phase. Drying increased hydrophobicity of the solid phase but did not affect the hydrophobicity of the dispersed colloids. Drying decreased the amount of mobilized mineral and (organo-)mineral colloids in the sewage farm soils but increased the mobilization of organic colloids in the C-rich shooting range soil. Dried samples released less colloid-bound Cd and Zn than field-moist samples. Drying-induced mobilization of dissolved organic C caused a redistribution of Cu from the colloidal to the dissolved phase. We conclude that drying-induced colloid mobilization is not caused by a change in the physicochemical properties of the colloids. Therefore, it is likely that the mobilization of colloids in the field is caused by increasing shear forces or the disintegration of aggregates.