垃圾堆填区渗出液对干旱季节树苗生长的影响

本试验于１９９４年７月至１月在香港望后石垃圾堆填区进行,研究了垃圾堆填区渗出液浇灌对几种亚热带树种生长及其生理学过程的影响．结果表明,在高温低湿、植物遭受水分亏缺的条件下,应用适当浓度的垃圾堆填区渗出液浇灌同水灌和肥水灌溉类似,可显著地提高树苗的移栽成活率,促进树苗的生长,尤其对耐干旱能力低的树种,其效果更为显著．与对照相比,用适当浓度的渗出液或水浇灌显著地改善植株的水分关系,降低叶片的脱落酸（ＡＢＡ）含量,促进气孔的开放．另外,处理植株叶片的光合特性也得到了不同程度的改善．根据以上结果,作者认为,在干旱季节植物遭受严重水分亏缺的条件下,应用适当浓度的垃圾堆填区渗出液浇灌可显著地缓解干旱对树苗生长的影响,为综合治理垃圾堆填区渗出液提供了一条经济、实用和可行的途径．     

Concentrations and bioaccessibilities of metals in exterior urban paints

Paint fragments have been collected from a variety of structures (e.g. walls, lamp posts, doors, railings) from the urban environment of Plymouth, UK, and concentrations of metals determined following acid digestion. Concentrations of most metals were highly variable and spanned several orders of magnitude among the samples (e.g. Pb = 4.5 to 36 900 μg g⁻¹; Cr = 1.9 to 775 μg g⁻¹; Zn = 39 to 23 500 μg g⁻¹). The bioaccessibilities of the metals were evaluated using a physiologically based extraction test that simulates the chemical conditions of the human stomach and intestine. The bioaccessibility of a given metal was highly variable among the samples and was greater in the stomach than the intestine in some cases (e.g. Cd, Pb) and greater in the intestine in others (e.g. Co, Cr). Based on total and bioaccessible concentrations in urban paints, Pb remains the metal of greatest concern from a human health perspective.