Determination of sulphite in mineral soils

Summary Two methods were evaluated to determine the concentration of sulphite in sandy loam soils. Use of p-rosaniline-formaldehyde reagent and sodium tetrachloromercurate as extractant proved effective only if a wide soil to extractant ratio was employed. Use of Ellman's reagent in conjunction with this extractant was however, unsatisfactory. Soils exposed to heavy atmospheric pollution differed in sulphite concentration only marginally compared with relatively unpolluted soils. The effect of soil water content on the stability of sulphite in soil was also determined.     

Hybrid aspens responses to alkalisation of soil: growth, leaf structure, photosynthetic rate and carbohydrates

Interactions between photosynthetic rate, transpiration, content of soluble carbohydrates, leaf dimensions and structural parameters and growth of hybrid aspen (Populus tremula?×?P. tremuloides Michx.) were studied in relation to soil pH and chemical composition. The investigations were conducted in two plantations on former agricultural lands in North Estonia. One plantation was established on a territory influenced for a long time by alkaline cement dust pollution before plantation establishment and the other on an unpolluted territory. At pH 7.4 and higher concentrations of Ca, K, Mg, N and P in soil on the polluted area inhibition of height growth and diameter at breast height, leaf area and dry mass was observed compared to the unpolluted plantation with an optimum soil pH of 6.7. Differences in hybrid aspen leaves in the two plantations were related to the lower net photosynthetic and transpiration rates and higher starch and sucrose contents in the polluted plantation. Leaves from alkaline soil had a thicker palisade mesophyll layer and lower number of stomata at abaxial epidermis. The relatively low N concentration in leaves in the polluted area was associated with the low height and diameter at breast height of trees.     

工矿区不同类型生物结皮对大气降尘重金属的富集规律及其影响因子

大气降尘是矿区土壤重金属的主要来源,而生物结皮对大气降尘重金属有显著的富集作用。为探究不同类型生物结皮对大气降尘重金属的富集规律及其影响因子,选取宁东典型火电厂周边生物结皮广布区作为试验样地,3类生物结皮作为研究对象,并以临近裸土作为对照,对比分析了生物结皮富集大气降尘过程中土壤理化性质、酶活性及重金属含量的变化,采用相关分析、冗余分析和方差分解方法探讨了不同类型生物结皮的结皮层(A层)和层下土壤(B层)重金属含量与其土壤物理、化学性质及酶活性之间的关系。结果表明：燃煤烟尘是矿区大气降尘重金属污染的主要来源,涉及重金属元素包括Cd、Cr、Hg、Pb、Zn、As。生物结皮对源自大气降尘的重金属元素均具有显著的富集作用,且在不同演替阶段生物结皮间的富集规律完全一致：藓结皮>混生结皮>藻结皮;重金属综合污染指数评价结果显示：生物结皮对重金属具有表层富集效应,表现为A层污染程度高于B层。不同类型生物结皮A、B层综合污染指数存在显著差异,排序为：藓结皮>混生结皮>藻结皮;和对照相比,三类生物结皮均能通过富集大气降尘增加其A、B层养分和细颗粒物含量并改善土壤质地。方差分解结...     

玉米在重金属污染条件下的生态分化与品种退化

通过易地栽种实验,研究了经历不同重金属污染时期的玉米种群在正常条件下的平均相对生长率、不同时间的开花百分率及其整株重、株高、穗重、５０ 粒种子重、有效穗长和无效穗长等数量性状在不同玉米种群间的差异．结果表明,经历较长时期重金属污染适应的玉米种群在正常条件下栽种,具有较低的平均相对生长率,生活史缩短,植株矮化,产量降低．可以看出,玉米对重金属污染的适应导致了生态分化和品种退化,并讨论了玉米对重金属污染适应的耐性代价．     

Paleolimnological reconstruction of the effects of atmospheric deposition of acids and heavy metals on the chemistry and biology of lakes in New England and Norway

Sediment cores from nine lakes in southern Norway (N) and six in northern New England (NE) were dated by ¹³⁷Cs, ²¹⁰Pb and in NE also by pollen, and were analyzed geochemically and for diatoms. Cores from two N and three NE lakes were analyzed for cladocerans. ¹³⁷Cs dating is unreliable in these lakes, probably due to mobility of Cs in the sediment. In Holmvatn sediment, an up-core increase in Fe, starting ca. 1900, correlates with geochemical indications of decreasing mechanical erosion of soils. Diatoms indicate a lake acidification starting in the 1920's. We propose that soil Fe was mobilized and runoff acidified by acidic precipitation and/or by soil acidification resulting from vegetational succession following reduced grazing. Even minor land use changes or disturbances in lake watersheds introduce ambiguity to the sedimentary evidence relating to atmospheric influences. Diatom counts from surface sediments in 36 N and 31 NE lakes were regressed against contemporary water pH to obtain coefficients for computing past pH from subsurface counts. Computed decreases of 0.3–0.8 pH units start between I890 and I930 in N lakes already acidic (pH 5.0–5.5) before the decrease. These and lesser decreases in other lakes start decades to over a century after the first sedimentary indications of atmospheric heavy metal pollution. It is proposed that the acidification of precipitation accompanied the metal pollution. The delays in lake acidification may be due to buffering by the lakes and watersheds. The magnitude of acidification and heavy metal loading of the lakes parallels air pollution gradients. Shift in cladoceran remains are contemporary with acidification, preceding elimination of fishes.     

重金属污染影响植食性昆虫的研究进展

重金属污染是世界各国面临的最为棘手的问题之一,对生态系统和食品安全构成了严重威胁。作为生态系统中食物链和食物网的重要环节,植食性昆虫是环境中重金属迁移、积累的重要媒介,其因重金属污染而受到的影响引起了大家的关注。本文综述了从2007至2018年重金属污染对植食性昆虫影响的研究进展。昆虫受重金属胁迫的研究途径有人工饲料添加、野外田间暴露、“土壤-植物-昆虫”食物链传递以及体外注射等。积累在植食性昆虫体内的过量重金属可导致其存活率、繁殖力和种群增长率降低,生长发育迟缓。重金属污染对植食性昆虫的生理生化毒性包括细胞超微结构破坏和DNA损伤,体内能量物质含量降低,酶活性、基因表达改变等。植食性昆虫会通过重金属硫蛋白、解毒酶活性的诱导等机制抵御重金属的毒害,从而对低浓度、长期重金属暴露产生生态适应性,甚至提高对其他逆境(如农药等)的耐受性。     

Human health risks from consuming cabbage (Brassica oleracea L. var. capitata) grown on wastewater irrigated soil

The present study investigated the impact of cumulative irrigation with wastewater on the soil properties and, its health hazards on the consumers of cabbage plants at south Cairo Province, Egypt. Irrigation water, soil and cabbage plants were sample d from two polluted and other two unpolluted farms. The physicochemical properties of water and soil were analyzed and the growth parameters, as well as nutrients and heavy metals concentration in cabbage were investigated. In addition, the daily intake of metals (DIM) and health risk index (HRI) were estimated. Wastewater posed a decrease in the availability of N, P and K, but increases heavy metals in the soil solution. Cabbage stem and root lengths as well as the number of leaves and biomass were greatly reduced in the polluted farms. In addition, the photosynthetic pigments, carbohydrates and proteins were decreased under pollution stress. The concentration of most investigated metals in the leaves and roots were increased with translocation factor greater than one for Pb, Cd, As, Cr, Ni, Fe, and Co. The study revealed that the HRI exceeded one for Pb and Cd in polluted and unpolluted plants; and Fe in polluted ones. Irrigation with wastewater is not suitable for cabbage as it has health risks on humans due to accumulation of heavy metals. It worth noting that, the high ability of cabbage plants to accumulate Pb and Cd from both polluted and unpolluted soils should be taken into consideration when consuming this plant.     

火电厂周边不同生物结皮细菌群落特征差异及其影响因素

为探究大气降尘重金属污染对矿区周边不同类型生物结皮细菌群落结构的影响,利用高通量测序技术分析位于宁东能源化工基地典型火电厂周边的3类生物结皮(藻结皮ZB、混生结皮HB、苔藓结皮TB)和对照(CK,裸土)的细菌丰度和群落结构,并探讨了影响细菌群落结构的环境因子。结果表明: 不同类型生物结皮的理化性质和重金属含量存在差异,且由于生物结皮对大气降尘重金属的富集作用造成各类结皮均达重度污染级别。在相对丰度排名前10的优势细菌门中,芽单胞菌门、蓝细菌门在不同类型生物结皮之间差异显著。细菌群落α多样性由高到低排序依次为CK>TB>HB>ZB。非度量多维排序(NMDS)结果显示,裸土细菌群落与其他3种生物结皮存在明显差异。相关性分析表明,生物结皮演替对细菌群落组成具有显著影响,细菌多样性和组成与pH、养分、重金属含量等密切相关。放线菌门、绿弯菌门相对丰度与pH值呈显著正相关关系,而与全氮(TN)、全磷(TP)、Pb、Zn、Cd均呈显著负相关关系;冗余分析结果表明,TN、pH、TP、有机碳(SOC)是影响3种生物结皮细菌群落α多样性以及一些优势菌群相对丰度的主要土壤环境因子,而重金属Pb、Zn、Cd是影响细菌群落结构的主要重金属元素,对细菌群落数量和多样性有抑制或刺激作用。说明pH、重金属和养分是影响结皮细菌群落组成的关键因子。总体而言,长期的重金属富集作用会对生物结皮的细菌多样性和群落组成产生影响。     

Activity and heavy metal resistance of non-specific esterases in leaf beetle Chrysomela lapponica from polluted and unpolluted habitats

We compared the general activity and heavy metal resistance of non-specific esterases in two populations of the leaf beetle Chrysomela lapponica from habitats severely contaminated by heavy metals (mostly Ni and Cu) and two populations from unpolluted habitats. Concentrations of Ni and Cu in adult beetles from the most polluted site were 7.7 and 3.6 times higher that in beetles from unpolluted habitats. Larval esterases showed higher activity and lower susceptibility to heavy metals than esterases of adults. Larval esterase activity did not differ between populations from polluted and unpolluted sites, but adult beetles from polluted localities had lower esterase activity than beetles from unpolluted habitats. Both Cu and Ni sulfates in millimolar concentrations in vitro suppressed esterase activity of larvae from unpolluted habitats, but caused no negative effect on esterases of larvae from polluted sites. Similarly, inhibition of adult esterase activity by Ni was stronger in beetles from unpolluted localities than in beetles from polluted localities. This indicates that resistance of non-specific esterases to heavy metals is higher in leaf beetle populations from contaminated environment.     

土壤砷植物暴露途径的土壤因子模拟

确定土壤中重金属生物有效性是评价土壤重金属污染生态风险的关键,然而在生态风险评价实际应用中,测定土壤重金属生物有效性耗时且高成本,限制了生物有效性评价法的应用。通过对模式植物的文献搜集,总结了影响植物富集土壤砷的7个土壤因子,揭示了土壤砷植物暴露的影响机制。运用SPSS 18.0对文献数据集各个土壤因子进行了回归分析、相关性分析和共线性分析。单因子回归分析表明营养盐类对植物富集砷影响很小,可以忽略不计;相关性分析和共线性分析结果表明土壤因子之间存在多元共线性;主成分分析结果表明,植物富集砷浓度主要受土壤质地的物理综合指标以及土壤总砷含量和土壤酸碱度等化学综合指标影响。其中植物富集浓度受土壤中总砷浓度影响最大,受土壤质地中砂粒含量影响其次;土壤粉粒、粘粒、有机质含量和阳离子交换量对富集也有一定影响;而土壤酸碱度对植物富集浓度的影响相对较小。最终通过数学模型解释植物富集砷浓度随土壤性质变化的规律,建立了土壤性质与土壤砷植物暴露的相关关系,为土壤重金属生物有效性风险评价法提供理论依据。     

Ecological and radiological hazards due to natural radioactivity and heavy metals in soils of some selected mining sites in Nigeria

Abstract

In this study, the radiological and pollution risks associated with mining of minerals in Nigeria were assessed. Soil samples were collected from a total of 30 illegal mining sites, 10 each from gold, coal and tin mining sites. Thirty soil samples were also collected from unpolluted sites around the mine works. The activity concentrations of the natural radionuclides in the samples were determined using a well calibrated Sodium Iodide Na(Tl) detector. The concentration of Pb, Zn, Cu, Mn, Cr, Cd, Ni and As were determined using an energy dispersive X-ray fluorescence (EDXRF) analyses. The results showed elevated levels of the radionuclides and heavy metals in the mining sites compared to the unpolluted soils. The average outdoor annual effective dose (OAED) obtained were lower than the International Commission on Radiological Protection (ICRP) recommended limit of 1 mSv/y. The results of the geo-accumulation index however showed that the soils of the study areas were strongly contaminated with Pb, Cd and As.     

Abundance,Composition and Activity of Ammonia Oxidizer and Denitrifier Communities in Metal Polluted Rice Paddies from South China

While microbial nitrogen transformations in soils had been known to be affected by heavy metal pollution, changes in abundance and community structure of the mediating microbial populations had been not yet well characterized in polluted rice soils. Here, by using the prevailing molecular fingerprinting and enzyme activity assays and comparisons to adjacent non-polluted soils, we examined changes in the abundance and activity of ammonia oxidizing and denitrifying communities of rice paddies in two sites with different metal accumulation situation under long-term pollution from metal mining and smelter activities. Potential nitrifying activity was significantly reduced in polluted paddies in both sites while potential denitrifying activity reduced only in the soils with high Cu accumulation up to 1300 mg kg⁻¹. Copy numbers of amoA (AOA and AOB genes) were lower in both polluted paddies, following the trend with the enzyme assays, whereas that of nirK was not significantly affected. Analysis of the DGGE profiles revealed a shift in the community structure of AOA, and to a lesser extent, differences in the community structure of AOB and denitrifier between soils from the two sites with different pollution intensity and metal composition. All of the retrieved AOB sequences belonged to the genus Nitrosospira, among which species Cluster 4 appeared more sensitive to metal pollution. In contrast, nirK genes were widely distributed among different bacterial genera that were represented differentially between the polluted and unpolluted paddies. This could suggest either a possible non-specific target of the primers conventionally used in soil study or complex interactions between soil properties and metal contents on the observed community and activity changes, and thus on the N transformation in the polluted rice soils.     

Influence of acid rain and ozone on soil heavy metals under loblolly pine trees: A field study

A field growth chamber study was conducted to determine the effects of ozone and simulated acid rain (SAR) on soil heavy metals. Loblolly pine (Pinus taeda L.), grown in open-top chambers, was exposed to three concentrations of ozone (charcoal filtered air with 0.026 µL O₃ L^-1, and two non-filtered treatments in which ozone concentrations were 0.074 µL L^-1 and 0.147 µL L^-1, respectively) and two levels of SAR (pH 3.5 and 5.2). Ozone was applied for 12 h d^-1 for 9 months and acid rain deposition was 125 mm event^-1. After 9 months exposure, soil pH, organic matter and DTPA-extractable heavy metals (Cd, Pb, Zn, Mn, Fe, Cu) were determined on soil samples collected from exposed chambers at two depths (0–15 cm and 15–30 cm). Simulated acid rain decreased the original soil pH. The concentrations of Cd, Pb and Mn at SAR pH 3.5 were significantly higher than at SAR pH 5.2. Ozone did not affect Zn, Fe and Cu, but a significant interaction between pH and O₃ on Mn, Pb and Cd was observed. Due to the poor drainage capacity of this soil, leaching of heavy metals was not observed.     

Concentration and ecological risk of heavy metal in street dusts of Eslamshahr,Iran

This study was done to evaluate heavy metal concentrations in street dust samples, to compare measured concentrations in samples to background concentrations in order to make evaluations for pollution indices, and to describe the quality of street dust in the studied area in relation to pollution. A total of 30 cumulative samples were collected from the streets of Eslamshahr City. Concentrations of heavy metals were determined using an Inductively Coupled Plasma-Optical Emission Spectrometry (ICP-OES). Results determined mean concentrations (mg/kg) of the heavy metals Cd, Cr, Cu, Ni, Pb, and Zn, in collected samples of street dust as 0.34, 35.1, 239, 42.4, 71.3, and 573, respectively. I_geo values for Cd and Cr, Cu, Ni, Pb, and Zn showed level of moderately polluted, unpolluted, moderately to strongly polluted, unpolluted, moderately polluted and moderately to strongly polluted, respectively. The pattern of total metal concentrations in the studied area was ranked as follows: Zn and Cu>Pb>Cd>Ni>Cr. The highest values for the monomial potential ecological risk (E_r) were observed for Cd (114). The mean level of RI for the studied soil samples was 192 (91.3–244), which is classed as presenting a strong potential ecological risk.     

Survey of atmospheric heavy metal deposition in Suqian using moss contamination

Abstract

Heavy metal pollution in the atmosphere is a major environmental problem, which has important impacts on ecosystems and human health. In this study, the atmospheric deposition of cadmium (Cd), chromium (Cr), copper (Cu), nickel (Ni), lead (Pb), vanadium (V), and zinc (Zn) in Suqian, China, was investigated by using the moss Haplocladium microphyllum as a bioindicator. The survey was carried out during the summer of 2017 at 40 homogenously distributed sampling sites. Cr, Cu, Ni, Pb, V, and Zn were analyzed by inductively coupled plasma atomic emission spectrometry, and Cd was analyzed by inductively coupled plasma mass spectrometry. Wide variations in heavy metals (Cd, Pb, and Zn) indicated that the concentrations of elements are influenced by local emission sources. Spatial distribution maps of the elements were constructed using geographic information system technology. The pollution load index showed that the study area was moderately polluted to unpolluted. Significant positive correlations (p?<?.01) and weak positive correlations (p?<?.05) were identified among some of the elements, indicating that they originated from common sources. A principal component analysis classified the heavy metals into natural and anthropogenic sources, and identified four primary sources: nature soil dust, industry activities, traffic emission, and agricultural activities.     

Cadmium effects on growth and physiology ofUlva lactuca

The chlorophyceanUlva lactuca L. was grown in the laboratory in unialgal culture to sufficient size so that up to 70 discs, 24 mm in diameter, could be punched out of a single plant. Using such discs,U. lactuca was then tested with various concentrations of Cd under continuous-flow conditions. A concentration of 4.5 ppm Cd was lethal toU. lactuca within 6 days. Control discs in unpolluted water increased in diameter at a rate of 8 to 13 % day⁻¹ over a 6-day period. At sublethal concentrations of Cd a sharp reduction in growth rate was observed at increasing concentrations up to approximately 0.3 ppm Cd, whereas from 0.3 ppm Cd to the lethal concentration the reduction of the growth rate was significantly less. Reduction in photosynthetic performance corresponded closely to the reduction in growth rate. At ambient concentrations of 0.8 ppm Cd, the plants concentrated Cd by a factor of approximately 50 in 6 days. Much higher concentration factors were attained in lower ambient concentrations. After removal from Cd-polluted water into flow-through culture in unpolluted water, a subsequent loss of Cd was indicated and the plants recovered rapidly. Plants exposed up to 3 d to 0.7 ppm Cd recovered sufficiently to produce viable gametes 7 days after removal from Cd. Because it has a relatively short life span and apparently loses Cd subsequent to exposure to Cd-polluted water,Ulva lactuca is not recommended as an alga for monitoring in-situ environmental pollution.     

Effects of organic and heavy metal pollution on chironomids within a pristine upland catchment

Several studies, particularly in the Northern Hemisphere, have demonstrated that chironomids are responsive to pollution (e.g., heavy metals, organic). In Australia, there is limited evidence that chironomid species have differential sensitivities to water pollution, with several studies reporting high tolerance of heavy metal pollution. We investigated the impact of both zinc-rich mine waste and organic effluent on chironomids within an effectively pristine background using the Chironomid Pupal Exuviae Technique (CPET). Chironomid species assemblages were strongly influenced by both mine drainage and organic pollution. Community composition differed between unpolluted streams and locations downstream of the pollution sources, and between the two different sources of pollution. Thirty seven of the most abundant species exhibited strong responses to water pollution varying from greatly increased abundance to complete absence. Ten species had higher abundance at one of the polluted sites compared to unpolluted sites; six in the presence of zinc pollution and five in the presence of organic pollution. One species responded positively to both pollution types. Our results indicate that contrary to the mixed reports of Australian chironomids for being insensitive to pollution, we found that they displayed a strong pollution response to both organic and heavy metal contamination.     

Biological Responses in the Earthworm Eisenia fetida Exposed to Soils near a Typical Lead Acid Battery Plant

There are increasing concerns over the environmental implications involved in battery plant due to the elevated metal concentrations in the surrounding soils. Earthworms are regarded as a model organism for evaluation of terrestrial environmental pollution. The biochemical responses in the earthworms, Eisenia fetida, exposed to polluted soils were investigated. Soil samples at 0, 50, 100, 200, 500 and 1000 m from a battery plant were collected and used to assess the relationship between sampling distance and biochemical responses in E. fetida. Biochemical alterations were carried out on 1, 3, 7 and 14 d of exposure. The metallothionein (MT), malondialdehyde (MDA) and antioxidant enzymes (superoxide dismutase (SOD), catalase (CAT) and peroxidase (POD)) were measured. The results demonstrated that concentrations of heavy metals, especially Pb, decreased sharply with increase in distance, which may be due to the leaching and accumulation of Pb in soil during production processes. The concentrations of MT and MDA increased with exposure (dosage and time), indicating that E. fetida presented dose and time dependence after heavy metal exposure. The activities of SOD and CAT increased after heavy metal induction, while the activity of POD was lower than that of the control group. The SOD, CAT and POD present a cooperative effect for the protection of lipids and enzymes due to the pollution. The soils around the battery plant were polluted with metals giving rise to adverse biological effects.     

Resistance and resilience of Cu-polluted soil after Cu perturbation, tested by a wide range of soil microbial parameters

Copper (Cu)-polluted and unpolluted soils were used to study the effect of initial pollution on soil biological resistance and resilience by measuring the responses to perturbation using different parameters. Microbial biomass carbon, substrate-induced respiration and copy numbers of 16S rRNA gene were grouped as general parameters, while potential ammonia oxidation rate and copy numbers of amo A gene were grouped as specific functions. In addition, to illustrate how initial pollution affects soil biological resistance and resilience following secondary perturbation, the microbial community structure, together with free Cu²⁺ activities ([Cu²⁺]) in soil pore water and soil pH were also measured after secondary perturbation. Results showed that general parameters were more stable than specific ones. High [Cu²⁺] and low pH in soil pore water induced by Cu addition may lead to apparently low resistance and resilience, whereas the formation of a tolerant community after Cu pollution, secondary perturbation and Cu aging may contribute to resistance and resilience. Analysis of the phospholipid fatty acids profile showed that microbial community structure shifted along with the [Cu²⁺] gradient. The microbial community structure of the control soil was both resistant and resilient to 400 mg kg⁻¹ Cu perturbation, whereas other treatments were neither resistant nor resilient.     

不同重金属污染水平下生物结皮及下层土壤细菌群落的差异性分析

为了探究生物结皮及下层土壤细菌群落多样性及结构在不同重金属污染水平下的差异及其影响因素,以宁夏东部工矿区和封育草地内广泛分布的两类生物结皮为研究对象,采用高通量测序技术,分析结皮层(A层)和结皮下层(B层)土壤细菌群落结构和多样性差异。采用相关分析、冗余分析探讨两个生境生物结皮各层次细菌群落与土壤环境因子的关系。结果表明：(1)相较于封育区,工矿区2类生物结皮对源自大气降尘的重金属元素具有更显著的表层富集作用,并表现出显著的种间差异：苔藓结皮>藻结皮。污染负荷指数评价结果显示：工矿区生物结皮各层次重金属污染程度更高,且均表现为A层污染程度高于B层。(2)两个生境的优势细菌门组成基本一致,均为放线菌门、变形菌门、酸杆菌门。受生物结皮类型、重金属污染程度的影响,细菌群落结构差异显著,主要表现为：工矿区藻结皮A、B层的α多样性指数均大于封育区,而苔藓结皮A、B层的细菌多样性指数高于封育区,丰富度指数低于封育区。主坐标分析结果显示,不同生境的生物结皮细菌群落结构差异明显,而同一生境的生物结皮细菌群落结构相似。重金属As、Pb、土壤黏粒含量和pH是影响生物结皮细菌群落结构的主要土壤环境因子...