Lead within ecosystems on metalliferous mine tailings in Wales and Ireland

A comparative study of the concentrations of lead in ecosystems developed on metalliferous mine tailings was undertaken. Mine soils, vegetation, ground-dwelling invertebrates and Apodemus sylvaticus from nine abandoned mines in Wales and a modern Irish mine site were sampled in order to evaluate and compare exposure risks to wildlife. The mine sites had a wide range of relatively high concentrations of total lead in their tailings (from 1058 to 46,630 mg kg(-1)) but the extractable lead fractions were extremely variable and not clearly related or proportional to the total values. The high soil concentrations were reflected in vegetation collected from most of the sites with the exception of the modern mine, but there was no statistical relationship, on a site basis, between available soil lead and that in plant leaf samples. The highest plant concentrations were found in litter, which in all but one of the Welsh sites exceeded the threshold guideline value of 150 mg kg(-1). Food-chain transfer was shown by high concentrations of lead in invertebrates and A. sylvaticus from the abandoned Welsh mines. A highly significant relationship existed between lead in grass and the grasshopper, Chorthippus brunneus. Adverse effects on soil invertebrates, essential to the decomposition processes and cycling of essential nutrients, were identified as probably the major obstacle to natural ecosystem development on the abandoned Welsh sites. Toxicological risk of lead to the small mammals from the Welsh sites, but not the modern Irish tailings, is indicated given the high lead concentrations in dietary items and the resultant residues in kidney with some evidence of renal oedema in animals from two sites. The absence of a significant relationship between the estimated dietary lead concentration. calculated on a site basis, and the total body concentration in A. sylvaticus, was attributed, in part, to the large size of the home range and the partial feeding of individual animals off the contaminated mine site.     

Linear alkylbenzene sulfonates (LAS) in the terrestrial environment

The occurrence of linear alkylbenzene sulfonates (LAS) in a series of soil samples originating from the municipality of Roskilde has been studied. The study includes soil samples from eight different locations with different histories: a preserved natural area that has not been cultured for 50-100 years, a soil that has been ecologically cultured for 40 years, a soil sustainably manured in ecologically culture for 5 years (formerly conventionally cultured) and a soil that has been conventionally cultured using artificial fertilizer. In addition, a soil was studied that had been sludge amended by applying medium amounts of sludge as well as a soil that has been amended with high amounts of sludge for a 25-year period. In the latter case, the sludge amendment was abandoned 6 years before the first sampling, followed by the application of artificial fertilizers. Finally, a meadow in the run-off zone from a sludge storage area was included in the investigations. In addition to the soil samples, selected samples of the applied sludge and other fertilizers were analyzed for their possible content of LAS. Apart from the location where the soil had been heavily sludge-amended and the location situated in the run-off zone of the sludge storage, concentrations of LAS in all soil samples were found to be below approximately 1 mg/kg, which is well below the proposed preliminary soil quality criteria for LAS of 5 mg/kg. On the other hand, the study unambiguously disclosed that in the case of heavy sludge amendment, the proposed soil quality criteria might well be exceeded.     

Poly-chlorinated biphenyls,poly-chlorinated naphthalenes and polynuclear aromatic hydrocarbons in severn estuary (U.K.) sediments

Sediments taken from the upper part of the Severn Estuary have been extracted by cyclic steam distillation into hexane. Analysis of the extract revealed a variety of organic pollutants including alkanes and several poly-nuclear aromatic hydrocarbons (PNA's). A PCB residue was detected and quantified using the technique of carbon-skeleton gas chromatography employing a 3% palladium catalyst and 2% RbCl salt column. The level of PCB in the sediments was found to be of the order of 1 ppm. No significant levels of poly-chlorinated napthalene (PCN) or DDT and related species were found.Organic contamination of one sediment (Arlingham) was found to be associated with the coal particles present in the sample. Levels of contamination at Arlingham were thus shown to be a function of sample composition rather than of the geographical location of the site.     

The relation between heavy metals and particle size fractions within the severn estuary (U.K.) inter-tidal sediments

Samples of Severn Estuary (U.K.) inter-tidal sediments were fractionated into a range of particle sizes. The heavy metal concentrations in the non-residual portion (acid leach) of the sediment increased with decreasing particle size. However, the general trend was upset by a large proportion of coal particles from the adjacent S. Wales coalfield, within one specific fraction causing an enhanced heavy metal concentration. There were significant (99% confidence level) correlations between the amount of less than 20 μm material in the sediment and the concentration of Fe, Pb, Cu and Mn; lower, but still significant correlations (95% confidence level) were found for Zn, Cd, Ni and Cr. No significant correlation was found for Co. The ratio of heavy metal associated with the less than 20-μm fraction of the sediment to the metal associated with the unfractionated sediment increased for Cu, Pb, Cd and Zn in the lower part of the estuary.     

Fate and effects of linear alkylbenzene sulphonates (LAS) in the terrestrial environment

Linear alkylbenzene sulphonates (LAS) are a group of anionic surfactants, characterised by having both a hydrophobic and a hydrophilic group. LAS is one of the major ingredients of synthetic detergents and surfactants and is used world-wide for both domestic and industrial applications. LAS is relatively rapidly aerobically degraded, but only very slowly or not at all degraded under anaerobic conditions. Therefore, LAS can be found in very high concentrations in most sewage sludge and enter the soil compartment as a result of sludge application. LAS can be found in elevated concentrations in soil immediately after sludge amendment, but a half-life of approximately 1-3 weeks will generally prevent accumulation in soil and biota. The concentration in soils that have not received sewage sludge recently, is generally less than 1 mg kg-1 and not more than 5 mg LAS kg-1. This is below the lowest concentration of LAS where effects have been observed in the laboratory. The laboratory data is in accordance with field studies using aqueous solutions of the sodium salt of LAS. However, observations of the ecological impact of sewage sludge applications or application of LAS spiked into sludge indicates a lower toxicity of LAS when applied in sludge. On the basis of the information reviewed in this paper, it is concluded that LAS can be found in high concentrations in sewage sludge, but that the relatively rapid aerobic degradation and the reduced bioavailability when applied via sludge, most likely will prevent LAS from posing a threat to terrestrial ecosystems on a long term basis.     

An investigation of the relation between ten per cent fines load and crushing value tests of aggregates (U.K.)

Ten per cent fines load and ACV tests are two well accepted tests for assessing the mechanical properties of aggregates. While the load producing ten per cent fines is determined in the former test, the amount of fines produced under 40 ton load is given as ACV in the latter test. Both tests are standardised in the U.K. and carried out in the same way, on the approximately same amount of aggregate. Shergold and Hosking (1959) showed for a number of materials including two rock types that the fines versus load relation in the aggregate crushing test gave a non-linear relation. They also suggested that there was a linear relation between 7.5 to 12.5% fines range, passing through the coordinates (0.–4) in the fines versus load diagram, irrespective of rock types. Based on this assumption, they proposed a means of estimating the ten per cent fines load of aggregate from the crushing test. This method was also accepted by the British Standards (BS 812-1975). The analysis of experimental and published aggregate test results indicate that the fines versus load relation of aggregates is linear and has a varying intercept and slope in the fines versus load diagram. Based on this concept, a diagram was produced to determine the ACV of aggregates from the ten per cent fines load, or vice versa. In general, an acceptable fit was obtained between the best fitting line to the test results and the proposed relation except for the ACV greater than 30. The proposed relation is not only very simple to apply, but also enables the determination of any per cent of fines load from a minimum number of experiments. Additionally, the proposed relation between the ten per cent fines load and the ACV of aggregates increased the applicability of the specifications which are often given in terms of one of the aggregate test results or determination of an aggregate property from other known properties.     

Lead and zinc in a contaminated pasture at minera,North Wales,and their impact on productivity and organic matter breakdown

Pb and Zn levels were determined in upper and lower soil horizons and vegetation at 14 sites along a 75 m transect in a pasture adjacent to an abandoned Pb/Zn mine spoil in North Wales, and in an uncontaminated control site 500 m from the transect.Water-soluble, 0.1 M calcium chloride, 0.5 M acetic acid, and nitric/perchloric acid extractable levels of soil Zn and Pb were estimated. Depth of accumulated litter and loss on ignition were also measured and estimates of soil humus content were obtained for all transect sites. Dry matter productivity was assessed during Summer 1978 in an exclosure adjacent to the transect.Loosely bound soil Zn and Pb levels increased in upper and lower horizons in soils up to 6 and 8 m respectively from the mine spoil. There was little or no water-extractable lead. Amounts of the more tightly bound forms of both metals declined exponentially from the mine spoil at the transect origin, a pattern of distribution suggesting that erosion by wind is almost exclusively the cause of pollution of adjacent pasture sites.With the exception of water-soluble metals, vegetation Pb and Zn levels were markedly lower than zinc levels. Apart from water-soluble Pb, metal levels in vegetation declined exponentially with distance along the transect.Productivity was very low on the toxic soils adjacent to the spoil but rose to ca. 5000 kg ha^?1 y^?1 10 m from the spoil and remained fairly constant thereafter. Litter was absent on the most and the least toxic soils, reached a peak of 3 cm depth at 6 m and declined steadily thereafter, none being recorded beyond 40 m. Loss on ignition and soil humic matter in upper soil horizons peaked at 387 and 230 mg g^?1 air dried soil 16 m along the transect. Lower soil horizons had maximum values of 224 (loss on ignition) and 100 mg g^?1 air dried soil (soil humic matter) 8 m from the spoil. In both horizons both declined steadily with increasing distance from the spoil, but greater amounts were recorded in all transect soils than in the control site.Sensitivity to metal contamination increased in the sequence; productivity < litter accumulation < soil organic matter breakdown < soil humus decomposition.     

The feasibility of using disused water treatment filter beds for rearing carp (Cyprinus Carpio L.) in the U.K.

The feasibility of rearing carp (Cyprinus carpio) at a disused water treatment works in East London (U.K.) was investigated. The 10 ha of filter beds represented an atypical site for carp culture; in order to assess whether in-house aquaculture would enable a Water Authority to gain advantage in cost, availability and disease-free status of stock, a series of trials was undertaken. These enabled comparison of the weight of carp produced in relation to: extensive cultivation, artificial feeding, a range of stock densities and a range of ages and sizes. The filter beds were unsuitable for natural spawning, early fry production and the rearing of first year fish (0⁺ age group). However, growing-on of subsequent stages (i.e. 0⁺ − 1⁺ or 1⁺ − 2⁺) gave good survival (60–80%) and growth rates. Fish stocked at 20 g in April/May reached 200–400 g by September and 1 kg plus, 1 yr later. Production levels of 300–350 kg ha⁻¹ yr⁻¹ without artificial foods (i.e. extensive cultivation) and up to 2.2 tonnes ha⁻¹ yr⁻¹ with supplementary feeding were comparable with mainland European fish farms. These high values reflect the eutrophic nature of this site and successful exploitation of the available secondary production. It was possible to harvest 15,000–20,000 carp yr⁻¹ for restocking. Carp rearing integrated with existing operations and activities on site (e.g. pipe and equipment stores) and represents a novel, alternative use of a semi-redundant site. Cost benefit assessment showed that fish production was economically viable returning nominal profit margins of between £1.10 and £2.06 kg⁻¹ of carp harvested. The resultant cost/benefit ratios per kilogram harvested were 1:1.9 for extensive production (without feeding) and 1:1.34–1.43 when intensive cultivation employing artificial foods was used.     

英美对公共交通型自动扶梯的技术要求

GB16899-2011《自动扶梯和自动人行道的制造与安装安全规范》对公共交通型自动扶梯或自动人行道的定义是：“适用于下列情况之一的自动扶梯或自动人行道：a）是公共交通系统包括出口和入口处的组成部分;b）高强度的使用,即每周运行时间约140h,且在任何3h的间隔内,其载荷达100％制动载荷的持续时间不少于0．5h．”     

Man,animal and the environment,more especially in Wales

The environmental problems of Wales are discussed, with special reference to the appearance of the countryside, water, lead and other pollutants, agriculture and animal husbandry. Reference is made to steps being taken to control pollution and land spoilage, and to the remarkable recovery of the River Rheidol, despite slightly raised blood levels of Aberystwyth residents.     

Mercury contamination in the vicinity of a derelict chlor-alkali plant Part II: contamination of the aquatic and terrestrial food chain and potential risks to the local population

This study investigated the environmental impact and level of risk associated with mercury (Hg) contamination near a derelict chlor-alkali plant in Pavlodar, Northern Kazakhstan. Several species of fish were sampled from the highly polluted Lake Balkyldak and the nearby river Irtysh, to assess the extent of Hg bioaccumulation in the aquatic food chain and potential human health risks. A small number of bovine tissue samples, water samples, soil and plant samples from a nearby village were also investigated in order to make a preliminary assessment of potential impacts on the terrestrial food chain. Mercury levels in fish caught from Lake Balkyldak ranged from 0.16 to 2.2 mg kg(-1) and the majority of fish exceeded current human health criteria for Hg. Interspecies comparisons indicated that Hg is accumulated in the order dace>carp>tench. Site-specific bioaccumulation factors (BAF) were calculated for THg, and were estimated for MeHg. Fish from the river Irtysh and floodplain oxbow lakes contained between 0.075 and 0.159 mg kg(-1) of Hg and can be regarded as uncontaminated. Soils were found to be impacted by past atmospheric emissions of Hg. Cattle grazing in the surroundings of the factory are exposed to Hg from contaminated soils, plants and surface water, but the consumption of contaminated fish from the lake appears to be the main route of exposure for humans.     

In-vivo estimates for the uptake of caesium-137 by cattle grazing contaminated pasture around the Esk and Irt estuaries,Cumbria, U.K.

Sea water contaminated with diluted radioactive effluent from the Windscale nuclear complex in Cumbria periodically floods low-lying grazing pasture around the estuaries of the rivers Esk, Irt and Mite near Ravenglass. During 1979, an experiment was carried out to measure the transfer of caesium-137 from grass to muscle in cows grazing these pastures. Grass samples were taken and in vivo external gamma-ray measurements were made on cattle. A very low transfer coefficient was found, less than 9 × 10^?4 days kg^?1 with a best estimate of 4 × 10^?4 days kg^?1, compared with a more usual value of around 3 × 10^?2 days kg^?1. The low transfer seems to occur because the bulk of the caesium-137 on the grass is bound to resuspended estuarine surface sediment deposited during flooding. In this form, the caesium-137 is only poorly absorbed across the gut of the grazing cattle.     

Gamma-emitting natural and anthropogenic radionuclides in the terrestrial environment of Kongsfjord,Svalbard

This paper presents results obtained from a radiometric survey, conducted by the Norwegian Radiation Protection Authority, into the levels of gamma-emitting radionuclides, both anthropogenic and natural, in the terrestrial environment of Kongsfjorden, which lies on the North-Western Coast of Spitsbergen in the Arctic archipelago of Svalbard (79 degrees N, 12 degrees E). Samples of terrestrial matrices were taken during field campaigns conducted between 2000 and 2002 and analysed for a range of gamma-emitting radionuclides. The objectives of this study included an assessment of the levels of gamma-emitting radionuclides in the terrestrial environment of the region, identification of processes and activities that influence the accumulation and redistribution of such nuclides within the region and elucidation of the behaviour of such radionuclides within a high arctic environment. Results indicate a quite homogenous spatial distribution of such radionuclides within the study area and highlight the relatively low levels of contamination by the anthropogenic radionuclide, 137Cs, on Svalbard. Average values and ranges of the radionuclides activities in surface soils (0-3 cm) were: 238U 42 Bq/kg (17-134), 226Ra 43 Bq/kg (12-137), 232Th 21 Bq/kg (4-52), 40K 283 Bq/kg (31-564), 137Cs 35 Bq/kg (1-146). Average levels of these nuclides in avian faecal materials were 238U 63 Bq/kg, 226Ra 54 Bq/kg, 232Th 19 Bq/kg, 40K 365 Bq/kg, 137Cs 78 Bq/kg. Enrichment of radionuclides is apparent in soils taken from locations close to bird colonies in the locale, maximum levels of the radionuclides being found in samples associated with such colonies. The results indicate that this is due to concentration of such radionuclides within the faecal material of the birds and subsequent enrichment of the nearby soils either via direct incorporation of the faeces into the soil or by leaching processes. The results indicate that this process may result in contamination of non-related species, such as Svalbard reindeer (Rangifer tarandus playrhynchus), via pathways other than the traditionally accepted route of atmospheric deposition-vegetation-reindeer.     

英国郊野公园的特点和设计要则

随着城市化进程的飞速发展,在城市建设问题日益突出的今天,郊野公园已终成为战略上保存重要的绿色空间和为城区居民提供休闲娱乐的重要载体.通过对英国郊野公园典型案例分析,以城市发展方向和市民需求为出发点,着重阐述郊野公园功能特征和设计要则,旨在探讨郊野公园的景观定位以及对我国建设郊野公园的借鉴意义.     

城市规划管理的司法监督——基于美英日三国的制度比较

在西方民主国家制度的基本建构中,司法作为保障公民基本权利、维护社会公正公平的最后屏障,发挥着监督和制约立法与行政两大公权机构的重要作用。本文从司法与立法、司法与行政的关系的角度,对美英日三国城市规划管理的司法监督机制及其运行特征进行分析．总结其成功的经验及失败的教训。     

城市规划管理的司法监督——基于美英日三国的制度比较

在西方民主国家制度的基本建构中,司法作为保障公民基本权利、维护社会公正公平的最后屏障,发挥着监督和制约立法与行政两大公权机构的重要作用.本文从司法与立法、司法与行政的关系的角度,对美英日三国城市规划管理的司法监督机制及其运行特征进行分析,总结其成功的经验及失败的教训.     

Uptake and release of zinc by aquatic bryophytes (Fontinalis antipyretica L. ex. Hedw.)

The zinc uptake and posterior release by an aquatic bryophyte—Fontinalis antipyretica L. Ex Hedw.—was experimentally studied in laboratory exposing the plants to different zinc concentrations in the range, 1.0–5.0 mg l⁻¹, for a 144 h contamination period, and then exposed to metal-free water for a 120 h decontamination period. The experiments were carried out in perfectly mixed contactors at controlled illumination, using mosses picked out in February 1997, with a background initial zinc concentration of 263 mg g⁻¹ (dry wt.). A first-order mass transfer kinetic model was fitted to the experimental data to determine the uptake and release constants, k₁ and k₂, the zinc concentration in mosses at the end of the uptake period, C_mu, and at the equilibrium, for the contamination and decontamination stages, C_me and C_mr, respectively. A bioconcentration factor, BCF=k₁/k₂ (zinc concentration in the plant, dry wt./zinc concentration in the water) was determined. A biological elimination factor defined as BEF=1−C_mr/C_mu was also calculated. BCF decreases from about 4500 to 2950 as Zn concentration in water increases from 1.05 to 3.80 mg l⁻¹. BEF is approximately constant and equal to 0.80. Comparing Zn and Cu accumulation by Fontinalis antipyretica, it was concluded that the uptake rate for Zn (145 h⁻¹) is much lower than for Cu (628 h⁻¹) and the amount retained by the plant decreased by a factor of about seven.     

融合传统与创新理念的英国城市桥梁建设

本文系统地介绍了笔者考察英国期间,对伦敦、诺丁汉、考文垂和利兹等城市的城市桥梁建设的总体印象和分类考察的情况,以及获得的相关启示,并提出了一些建议,希望为国内同行提供有借鉴意义的资料,以期促进我国城市桥梁建设的健康发展。