In situ phytoremediation of arsenic- and metal-polluted pyrite waste with field crops: effects of soil management

Sunflower, alfalfa, fodder radish and Italian ryegrass were cultivated in severely As-Cd-Co-Cu-Pb-Zn-contaminated pyrite waste discharged in the past and capped with 0.15 m of unpolluted soil at Torviscosa (Italy). Plant growth and trace element uptake were compared under ploughing and subsoiling tillages (0.3 m depth), the former yielding higher contamination (∼30%) in top soil.Tillage choice was not critical for phytoextraction, but subsoiling enhanced above-ground productivity, whereas ploughing increased trace element concentrations in plants. Fodder radish and sunflower had the greatest aerial biomass, and fodder radish the best trace element uptake, perhaps due to its lower root sensitivity to pollution. Above-ground removals were generally poor (maximum of 33 mg m⁻² of various trace elements), with Zn (62%) and Cu (18%) as main harvested contaminants. The most significant finding was of fine roots proliferation in shallow layers that represented a huge sink for trace element phytostabilisation.It is concluded that phytoextraction is generally far from being an efficient management option in pyrite waste. Sustainable remediation requires significant improvements of the vegetation cover to stabilise the site mechanically and chemically, and provide precise quantification of root turnover.     

Planting woody crops on dredged contaminated sediment provides both positive and negative effects in terms of remediation

There is currently a requirement for studies focusing on the long-term sustainability of phytoremediation technologies. Trace element uptake by Salix, Populus and Alnus species planted in dredged contaminated canal sediment and concentrations in sediment and pore waters were investigated, eight years after a phytoremediation trial was initiated in NW England. Soil biological activity was also measured using invertebrate and microbial assays to determine soil quality improvements. Zinc was the dominant trace metal in foliage and woody stems, and the most mobile trace element in sediment pore water (∼14 mg l⁻¹). Biological activity had improved; earthworm numbers had increased from 5 to 24, and the QBS index (an index of microarthropod groups in soil) had increased from 70 to 88. It is concluded that biological conditions had improved and natural processes appear to be enhancing soil quality, but there remains a potential risk of trace element transfer to the wider environment.     

Human health risk from Heavy metal via food crops consumption with wastewater irrigation practices in Pakistan

The current study was designed to investigate the potential human health risks associated with consumption of food crops contaminated with toxic heavy metals. Cadmium (Cd) concentration in surface soils; Cd, lead (Pb) and chromium (Cr) in the irrigation water and food crops were above permissible limits. The accumulation factor (AF) was >1 for manganese (Mn) and Pb in different food crops. The Health Risk Index (HRI) was >1 for Pb in all food crops irrigated with wastewater and tube well water. HRI >1 was also recorded for Cd in all selected vegetables; and for Mn in Spinacia oleracea irrigated with wastewater. All wastewater irrigated samples (soil and food crops) exhibited high relative contamination level as compared to samples irrigated with tube well water. Our results emphasized the need for pretreatment of wastewater and routine monitoring in order to avoid contamination of food crops from the wastewater irrigation system.     

典型喀斯特地区土壤-作物系统镉的富集特征与污染评价

为了研究喀斯特地区Cd在表层土壤和农作物中的富集特征及影响因素,为土地安全利用提供理论依据,选择在重庆市黔江区中部采集表层土壤样品360件、深层土壤样品7件、85件水稻样品和73件玉米样品(配套采集根系土样),分析了土壤及农作物中Cd的含量、土壤中TFe2O3、Mn、有机质(Corg)、Se等含量和土壤pH.基于地统计...     

Effects of simulated acid rain on the injury and physiological responses of crops

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试论黄淮海地区的自然资源及国家级作物商品基地的建设

根据中国主要农业区——黄淮海地区的自然和社会经济条件,分析了该区小麦、玉米、大豆、棉花等在气候-土壤生态适应性的基础上,采用逐级生产力估算方法,计算出四大作物的商品量,论证了该地区建设为全国性四大作物商品基地的可能性。     

黄土高原主要农作物水分盈亏与雨养农业问题

黄土高原在气候上属亚湿润向半干旱的过渡地区。水分缺乏是农业生产的重要限制因素。本文围绕降水和蒸发,主要作物的需水和降水间的相互关系,农田干湿状况和水分盈亏额进行了分析讨论。认为,发展雨养农业应该是黄土高原农业生产的一条基本方针;在雨养农业作物的选择上,除谷子可以在全区种植外,其他作物受地区局限性很大;发挥雨养农业生产潜力的基本途径应该是增加土壤水分含量和提高土壤有效水分的利用系数,为达到这一目的宜采用平整土地、增施肥料等一系列农业措施。     

农作物种植结构与农民收入及其对环境影响的分析

农民增收问题是三农问题的重要环节。本文以湖南省张家界市慈利县零溪镇大庄村第五、八、十六组为研究对象,分析了自1980年实行土地包产到户以来农作物种植结构的变化及农民收入之间的关系,认为在本地以柑橘为主的单一类型农作物规模化经营最有利于降低农民劳动强度、提高农民收入,对环境既有正面影响也有负面影响,并对其带来的环境影响提出了思考和建议。     

骨炭粉对Cd污染农田的修复效果与稳定性评价

为了探明骨炭粉对Cd污染土壤的修复效果及稳定性,以潮土与红壤Cd污染农田土壤为对象,基于土壤Cd有效态、作物降Cd率（DR,%）及降Cd失活率（IR,%）等指标,研究田间条件下施用3种浓度（0.25%、0.50%及1.0%）骨炭粉对Cd污染土壤的修复效果及120,360d后修复效果的稳定性.结果表明：骨炭粉处理均能有效促进潮土与红壤中作物生长,增加作物产量.施用骨炭粉能不同程度提高土壤中pH值、阳离子交换量（CEC）、全磷及有效磷含量;其中,0.5%和1.0%骨炭粉处理均显著（P<0.05）提高土壤pH值、土壤全磷及有效磷含量.与对照相比,不同骨炭粉处理120d后潮土和红壤中有效态Cd含量分别降低32.1%~48.4%、32.8%~56.2%,360d后土壤中有效态Cd仍然显著低于对照,降幅为26.9%~37.8%、25.8%~39.5%.对修复后三季作物Cd吸收测定结果表明,与对照相比,不同浓度（0.25%~1.0%）骨炭粉处理的第一季作物降Cd率（DR_-Cd）分别达36.0%~60.4%、33.9%~58.2%,作物降Cd率随骨炭粉施用量增加而增加.基于降Cd失活率（IR_-Cd）对骨炭粉修复效果的稳定性测定结果表明,潮土与红壤施用骨炭粉360d后,第三季作物降Cd失活率IR_-Cd为21.2%~34.7%和6.2%~21.6%,表明在酸性红壤中修复效果的稳定性大于潮土.综上骨炭粉对Cd污染土壤的修复效果及其稳定性结果表明,骨炭粉在Cd污染农田土壤修复中具有较大应用价值.     

秸秆等纤维作物的综合利用进展

本文综述了近年来国内外综合利用麦秆、棉秆、玉米秆、甘蔗渣等纤维作物技术以及有关研究的进展情况,以期有助于环境保护和自然资源的充分利用。