Leaching Behavior of Heavy Metals and Transformation of Their Speciation in Polluted Soil Receiving Simulated Acid Rain

Heavy metals that leach from contaminated soils under acid rain are of increasing concern. In this study, simulated acid rain (SAR) was pumped through columns of artificially contaminated purple soil. Column leaching tests and sequential extraction were conducted for the heavy metals Cu, Pb, Cd, and Zn to determine the extent of their leaching as well as to examine the transformation of their speciation in the artificially contaminated soil columns. Results showed that the maximum leachate concentrations of Cu, Pb, Cd, and Zn were less than those specified in the Chinese Quality Standards for Groundwater (Grade IV), thereby suggesting that the heavy metals that leached from the polluted purple soil receiving acid rain may not pose as risks to water quality. Most of the Pb and Cd leachate concentrations were below their detection limits. By contrast, higher Cu and Zn leachate concentrations were found because they were released by the soil in larger amounts as compared with those of Pb and Cd. The differences in the Cu and Zn leachate concentrations between the controls (SAR at pH 5.6) and the treatments (SAR at pH 3.0 and 4.5) were significant. Similar trends were observed in the total leached amounts of Cu and Zn. The proportions of Cu, Pb, Cd, and Zn in the EXC and OX fractions were generally increased after the leaching experiment at three pH levels, whereas those of the RES, OM, and CAR fractions were slightly decreased. Acid rain favors the leaching of heavy metals from the contaminated purple soil and makes the heavy metal fractions become more labile. Moreover, a pH decrease from 5.6 to 3.0 significantly enhanced such effects.     

小麦幼苗生长及其抗氧化酶活性对模拟酸雨与金属离子复合胁迫的响应

通过水培试验,研究了模拟酸雨(pH 3.5)与Al(3、30 mg/L)、Pb(25、250 mg/L)、Cd(0.11、mg/L)单独或复合胁迫对小麦幼苗生长及抗氧化酶活性的影响。结果表明,模拟酸雨与Al、Pb、Cd单独或复合处理12 d后,小麦幼苗根长降低54.01%~94.81%,苗高降低18.88%~77.95%,单粒萌根数降低21.87%~80.37%,其生长发育受到显著抑制,抑制效应随处理浓度增大和作用时间延长而增强,且复合处理组抑制效应更强;幼苗根部超氧化物歧化酶(SOD)活性在模拟酸雨与单一金属离子处理下显著升高,而在3种金属离子复合处理下显著降低,但酸性条件下无论金属离子单独及复合处理后,过氧化物酶(POD)活性均显著升高,过氧化氢酶(CAT)活性均明显下降。研究发现,酸性条件下3种金属离子对植物细胞均产生氧化胁迫作用,且它们复合胁迫的毒性效应大于其单独胁迫。     

Strength and Leaching Characteristics of Magnesium Phosphate Cement-Solidified Zinc- Contaminated Soil under the Effect of Acid Rain

Long-term static leaching experiments were conducted to investigate characteristics of magnesium phosphate cement (MPC) solidified/stabilized Zn-contaminated soil under impact of acid rain. Effects of initial pH values of acid rain, binder agent types and compositions, as well as curing age on strength and leaching characteristics of the sample were analyzed. Standard sand was used as raw material, with the content of cement at 15%. Our study used two types of MPC with MgO/KH₂PO₄(M/P) ratio of 3:1 and 6:1 (respectively referred to as M3 and M6), and also ordinary Portland cement with content at 15% (referred to as C15) as test control. Experimental results show that acid rain with pH = 2 has the greatest weakening effect on unconfined compressive strength (q_u) of the sample, while with pH = 4 and 7 such weakening effects on q_u are similar. Research findings also indicate that M6 is the most effective in immobilizing Zn-spiked soils, M3 is next and C15 is the least. The effect of Zn²⁺ on hydration of MPC is much lower than that of C15. Precuring method can improve q_u of the MPC-solidified samples and its resistance to acid rain. Compared with non-renewal, replacing acid rain leachant at designated intervals decreases q_u of the sample.     

模拟酸雨对3种果树的胁迫效应

以青梅(Prunus mume Sieb.&Zucc.)、龙眼(Dimocarpus longan Lour.)和杨桃(Averrvhoa carambola L.)3种南方果树为材料,研究不同pH值的模拟酸雨对其生理胁迫的效应.在酸雨胁迫下3种果树的叶片叶绿素含量均随pH值的降低有不同程度的下降,叶片伤害率、细胞质膜透性、脯氨酸及丙二醛(MDA)含量则随pH值的降低而上升.抗性较强的龙眼的生理生化指标的变幅最小,其次是杨桃,对酸雨胁迫反应较敏感的青梅变幅最大.     

模拟酸雨对茄科3种蔬菜种子萌发的影响

采用pH 2.0、3.0、4.0、5.0的模拟酸雨和pH 6.5的中性溶液(ck)处理番茄、茄子、辣椒3种蔬菜种子,研究酸雨胁迫强度对3种蔬菜种子萌发的影响。结果表明：从发芽率、发芽势、发芽指数3个萌发指标来看,番茄种子在pH 2.0～3.0的强酸雨胁迫下,萌发受到轻微抑制;茄子种子在pH 2.0～5.0的酸雨胁迫下,萌发一直受到抑制,尤其是在pH 2.0的强酸雨胁迫时表现出萌发几乎完全受到抑制,而辣椒种子在酸雨胁迫下,萌发几乎没有受到抑制。3个萌发指标均随着酸雨pH值的减小而减少。pH 2.0～5.0酸雨胁迫下,辣椒吸水值的变幅（13.75）﹤番茄（19.91）﹤茄子（20.58）,同等酸雨胁迫强度下,根长抑制指数、蛋白质含量降幅、丙二醛增幅辣椒﹤番茄﹤茄子。这表明抗酸雨胁迫能力：辣椒>番茄>茄子。     

Spatial Distribution,Potential Sources,and Risk Assessment of Trace Metals of Groundwater in the North China Plain

Diversion of water for irrigation from the Yellow River has impacted groundwater quality in the North China Plain (NCP). In this study, by using geochemical and isotope methods, groundwater origin, the spatial distribution of trace metals, pollution sources, and health risks were evaluated. Groundwater is recharged from surface water. The primary pollution components in surface water were B, Al, Se, Zn, Mn, and Ni—with concentrations exceeding standards by 100%, 84.4%, 64.4%, 31.1%, 20%, and 2.2%, respectively. In groundwater, exceeding standard rates for those elements were 100%, 100%, 61%, 25.7%, 39%, and 4.9%, respectively. The spatial distribution of polluted metals in surface water and groundwater was correlated, indicating an irrigation-influenced spatial distribution of trace metals in the groundwater. The trace metals were introduced via anthropogenic and geogenic activities. Zinc poses the most serious non-carcinogenic hazard for local residents. The ingestion pathway is much more likely to lead to zinc toxicity than the dermal absorption pathway. The carcinogenic Cd and Pb could result in an increased cancer risk for individuals exposed to the water. Non-carcinogenic hazard and carcinogenic risk attributable to groundwater is serious in the regions traversed by the rivers in the study area.     

Impacts of Yellow River Irrigation Practices on Trace Metals in Surface Water: A Case Study of the Henan-Liaocheng Irrigation Area,China

Large-scale irrigation practices may disturb local hydrologic cycles and distribute trace metals throughout the environment. Reported here is the spatial pattern of trace metals and associated health risks in an agricultural area of China, which has a long history of irrigation with water from the Yellow River. Multivariate statistical analyses and a risk-assessment model were employed to interpret the environmental data. It indicated that Zn, Se, B, Ba, Fe, Mn, Mo, Ni, V, Al, Li, Sr, Be, Cd, Cr, Cu, and Pb were all detected in the surface waters. Compared to drinking water guidelines, the primary trace metal pollution components (Al, Fe, Se, B, Mn, and Zn) exceeded drinking water standards by 40.7%, 14.8%, 29.6%, 25.9%, 11.1%, and 14.8%, respectively. Except for one site that exhibited anomalous metal concentrations, landscape features of trace metals identified a uniform distribution of trace metals for all sample sites. The calculated mean value of Hazard Quotients (HQs) exceeded the USEPA's recommendations by a factor of 2.9 times the threshold value. Primary sources of trace metals were associated with natural deposition, industrial and agrochemical processes, and a mixed source of both geogenic and anthropogenic origins.     

模拟酸雨对农作物种子萌发和幼苗生长的影响

研究模拟酸雨对3种农作物种子萌发年和幼苗生长的影响。结果表明：不同pH值(2．5,4．5,5．6)的模拟酸雨对水稻和小麦的种子萌发没有影响,但明显抑制了玉米种子萌发。模拟酸雨条件下,3种农作物幼苗的生长受到抑制,生物量减少,叶绿素和类胡萝卜素含量下降,而叶绿素a/b的变化却不明显。pH4．5和5．6的模拟酸雨对玉米Fv／Fm、光化学猝灭(qP)的影响较小,非光化学猝灭(NPQ)却明显下降,表明酸雨伤害了植物PSⅡ天线对激发能的非辐射耗散能力。     

模拟酸雨对大豆、花生生长和产量的影响

大豆(Glycine max)、花生(Arachis hy-pogaea)是我国主要油料作物,国内外均曾用大豆作为模拟酸雨的试验材料。本文对大豆作了较详细的观察。在大田中进行了花生试验,研究酸雨对其产量的影响。     

模拟酸雨和铝调控对茶叶主要化学品质与铝积累的影响

为研究模拟酸雨和铝(Al)对茶叶主要化学品质与Al积累的影响及其交互作用,采用3个酸度水平(pH 3.0、4.0、5.0)和4种Al浓度水平(0、10、20、30 mg L-1),用溶液培养法研究茶叶的主要化学指标和Al含量的异同.结果表明,在模拟酸雨下,茶叶的茶多酚和咖啡碱含量随酸度增加先增加后下降,氨基酸、儿茶素和...     

模拟酸雨对柚木幼苗生长、光合与水分利用的影响

模拟pH6.5(对照)、4.5和2.5三个酸雨梯度,研究其对1a生组培柚木(TectonagrandisL.f.)幼苗生长、光合与水分利用的影响。结果表明,尽管不同处理间的各项生理指标差异不明显,但模拟酸雨对柚木形态构件参数造成较严重的影响。pH4.5和pH2.5处理组柚木基径(D)和树高(H)增长明显下降,使得D2H下降更加显著;不同处理下柚木叶片净光合速率(Pn)和蒸腾速率(E)日变化趋于一致,气孔导度(gs)日变化与对应的叶片净光合速率日变化十分相似,同时,对照与两个处理的Pn与gs之间都表现正相关(p<0.01),且在pH4.5处理表现更为显著,但是对照和两个处理的E与gs的线性关系不显著;pH4.5和2.5处理的水分利用效率(WUE)日变化趋于一致;对照胞间CO2浓度与大气CO2浓度比(Ci/Ca)均值最低,表明对照柚木对CO2利用最有效。     

模拟酸雨-土壤酸化-杉木、木荷根系生长关系的研究

一、引言酸雨是当今世界重大的环境问题之一,它对生态环境的影响已引起各国政府及人们的极大关注。酸性降水对林木生长的影响目前有两种观点,即“由顶而下论”和“由底而上论”。持前一观点者认为,酸性降水淋洗树木叶子中的镁,伤害了树木的光合作用器官,影响树木的生长,导致森林的衰败。以西德学者     

稀土元素La对酸雨损伤蜡梅的影响

稀土元素Ｌａ对酸雨损伤蜡梅的影响周青黄晓华王冬燕邵爱华吴波（苏州铁道师范学院,２１５００９）ＥｆｅｃｔｏｆＲａｒｅＥａｒｔｈＬａｏｎｔｈｅＷｉｎｔｅｒｓｗｅｔＨａｒｍｅｄｂｙＳｉｍｕｌａｔｅｄＡｃｉｄＲａｉｎ．ＺｈｏｕＱｉｎｇ,ＨｕａｎｇＸｉａｏｈ...     

Wastewater as a Non-conventional Resource: Impact of Trace Metals and Bacteria on Soil,Plants, and Human Health

Abstract

In many arid and semi-arid regions, farmers are often obligated to informally use raw wastewater for irrigating their crops. The impacts of wastewater irrigation on soil, crops, and human health were investigated, regarding trace metals and bacteria. Cr, Cu, Fe, Ni, and Zn were detected in wastewater. Cr, Cu, and Zn accumulated in soil and crops in the order rocket?>?clover?>?cabbage. The Health Risk Index reported risk from Cr and Zn in rocket. Fecal coliforms in wastewater and crops were detected along with Escherichia coli, Staphylococcus aureus, and Pseudomonas aeruginosa. The frequency (%) was 86.7% (cabbage), 66.7% (rocket), and 43.3% (clover). The multiple antibiotic resistance index (0.503) rendered crops high risk source for contamination. The comprehensive pollution index classified wastewater severely polluted (≥2.01). Conclusions deduced crops alternative reservoirs for trace metals and human pathogens. Recommendations included implementation of low cost treatment methods, holding irrigation 5–15?days before harvest, assuming citric and acetic acids reducing solutions for trace metals, and suggested ofloxacin, amoxycillin/clavulanate, and amikacin antibiotics against reported bacteria.     

模拟酸雨对白筋叶片抗氧化酶活性及叶绿素荧光参数的影响

采用棚内盆栽方法, 设置pH值5.6 （对照）、4.0、3.0和2.0的模拟酸雨胁迫试验, 探讨其对白簕幼苗叶片MDA含量、保护酶活性、叶绿素含量、气体交换参数和叶绿素荧光参数的影响。结果表明, 随着模拟酸雨pH值的降低, MDA含量呈先降低后升高的趋势; SOD活性逐渐降低, POD活性逐渐升高, APX活性呈先升高后降低的变化。叶绿素a、叶绿素b、总叶绿素含量均比对照高, 在pH 4.0时达最大值。气孔限制值（Ls）、PSII实际光化学量子产量（ΦPSII）、光化学淬灭系数（qP）均随pH值的降低而下降, 净光速率（Pn）、气孔导度（Gs）、蒸腾速率（Tr）、水分利用效率（WUE）、PSII最大光化学效率（Fv/Fm）、PSII的潜在活性（Fv/Fo）、非光化学淬灭系数（qN）呈先升高后降低趋势, 且也都在pH 4.0时达最大值。由此推测, pH 4.0的酸雨处理有利于白簕幼苗的生长, 表明白簕幼苗可能喜欢生活在微酸环境中, 但是随着酸度加强, 反而起到抑制作用。     

模拟酸雨胁迫对茶树幼苗生长和光合生理的影响

茶是世界三大饮料之一,并且茶树在中国被广泛种植。酸雨是中国乃至全球面临的主要环境问题,本研究选用一年生茶树幼苗作为实验材料,品种为湘妃翠,采用盆栽的方法培养,通过模拟pH值2.5、pH值3.5、pH值4.5酸雨以及自来水(pH值6.5)作为对照对茶树进行全喷淋,探究模拟酸雨对茶树幼苗生长状况和光合生理的影响。结果表明pH值4.5模拟酸雨对茶树幼苗生长有一定促进作用,pH值2.5模拟酸雨对茶树幼苗生长具有抑制作用。茶树幼苗SPAD值(叶绿素相对含量)、以及叶绿素荧光参数Fv/Fm(PSⅡ最大光能转换率)、Fv/Fo(PSⅡ潜在活性)在pH值2.5酸雨胁迫下与对照组相比都显著降低,Fo(初始荧光产量)则显著增大。由此说明pH值2.5模拟酸雨对茶树幼苗具有较强的胁迫作用,pH值4.5模拟酸雨对茶树幼苗生长有促进作用。     

Trace Metal Bioaccumulation in Epibenthic Macroinvertebrates (EMI) from the San Pedro Shelf,California

Trace metal/metalloid (As, Ag, Cd, Cr, Cu, Hg, Ni, Pb, Se, Zn) bioaccumulation was measured over a period of ten years (1985–1995) in five species of epibenthic macroinvertebrates (EMI) from the San Pedro Shelf, California. Four of the species are numerical dominants in the Southern California Bight (SCB) and two species are commercially harvested. Among three echinoderms, a predatory sea star yielded highest tissue concentrations compared to a sea cucumber and a sea urchin, and concentrations measured in a mantid shrimp exceeded those from a prawn. Comparison of trace metal bioaccumulation from the study area, including the ocean outfall, and elsewhere indicated that bioaccumulation in local EMI was generally low. Measurements from an outfall station and two reference stations were used to evaluate the spatial and temporal relationship between trace metal bioaccumulation and the wastewater discharge. It was concluded that there was no spatial or temporal relationship between EMI trace metal bioaccumulation and the discharge.     

广州市流溪河降水离子浓度与电导率关系

通过对2006年7月～2008年5月在流溪河地区采集的106次降雨水样(雨量范围0.7～268.6 mm)进行化学测试,研究了降水中几类主要离子含量与电导率的关系。结果显示:(1)通过各化学离子含量计算的电导率与对应实测的电导率之间存在-2.94%的平均相对误差。(2)H⁺离子浓度与电导率之间的相关关系,在水样中pH<5.6时是正相关,在水样中pH≥5.6时呈现负相关规律。(3)电导率随离子总浓度的增加而增加,但当水样的总离子浓度相同或者H⁺和总离子浓度相同时,由于样品之间存在显著的其他化学组成差异,致使电导率的不一样。(4)将水样分成pH≥5.6和pH<5.6的两组后,每组中各离子浓度与电导率之间存在更好的回归关系,因此可以通过pH值、电导率的测定并利用回归方程来预测水中的其他化学成分含量。     

酸雨作用下的森林冠层盐基离子(Ca2+,Mg2+,K+)淋洗

在韶山针阔叶混交林中设立了10个30 m×30 m的样方,对1年中各个季节的森林截留沉降、降雨后树冠层总滤出量、盐基离子滤出量以及树冠层对H+和NH4+的摄入量进行了分析和估算.韶山森林湿沉降成分中以Ca2+为主,Mg2+,K+含量较低.树冠层盐基离子总滤出量中Ca2+最高,达到155.34 mmo1 m-2a-1,Mg2+最低,为30.74mmol m-2a-1,K+居中,为84.13 mmol m-2a-1.Ca2+的大量滤出表明它是树冠层缓冲降水酸度的主要介质,同时也表明酸雨对韶山森林的潜在危害,其在总滤出量中的比重的季节变化是夏(58.4%)＞春(54.1%)＞冬(51.4%)＞秋(32.5%).盐基离子的滤出量以冬→春→夏→秋依次递减,但是树冠层季节摄入NH4的量在30-100mmo1 m-2而对H+的摄入量则在30-180 mmol m-2.     

Role of Simulated Acid Rain on Acer negundo and Plant Nitrition

The short-term effects of simulated acid rain on Acer negundo L. have been investigated using photoacoustic spectroscopy and modulated fluorescence measurements. Three seeding groups of Acer negundo L. were treated with simulated acid rain at pH 3.0, 4.5 and 5.6 levels for three months. The results indicated the photosynthetic activity, expressed in terms of normalized oxygen evolution signal, photochemical energy storage, normalized variable fluorescence (Fv/Fm), photochemical and non-photochemical chlorophyll fluorescence quenching, ranges in the order pH 4.5 > pH 3.0 > pH 5.6. This stimulation effect has been confirmed by increased growth rate observed in relation with increased acidity levels. The nutritional aspects of this favorable effect of the acid rain on plant growth were discussed.