Investigation of Past and Present Multi-metal Input along Two Highways of British Columbia, Canada, Using Lead Isotopic Signatures

A multi-media monitoring field investigation, which included atmospheric, road sediment and soil samples, was carried out at two highway study sites to identify past and present Pb sources. Past Pb anthropogenic sources such as paint and leaded gasoline were linked to significant Pb accumulation in roadside soils at both sites through Pb isotopic analyses. This was achieved by identifying the distinct Pb isotopic composition in older versus newer Pb accumulation at different depths across the soil profile. Older Pb accumulations exhibited lower ²⁰⁶Pb/²⁰⁷Pb isotopic ratios, consistent with Canadian Pb-bearing ores, whereas newer Pb accumulations reflected a mixture of the ²⁰⁶Pb/²⁰⁷Pb ratios of road sediment samples, with the Pb isotopic signature of uncontaminated soil. Isotopic analyses were also helpful in identifying road sediment as an important current source of Pb in roadside soils, by comparing the isotopic signatures derived from road sediment and atmospheric dustfall. The known association of Pb with anthropogenic sources was used to indirectly relate other metals (Cu, Mn, Zn) to the same source by the Enrichment Ratio method. Significant positive correlations at the 90–95% confidence level were found between Cu, Zn and Pb Enrichment Ratios in roadside and dust deposition samples. Weaker correlations were found between Mn and Pb, at the highway study site with the least amount of traffic. However, correlations between these two metals were significant at the 90% confidence level for the busier highway site highlighting Mn potential anthropogenic source. An isotopic tracer study is suggested to further investigate the process of Mn redistribution in the environment due to exhaust fuel emissions. More research is needed regarding the potential impact from using a Mn-based fuel additive.     

Podzolization of soils under individual tree canopies in Southwestern British Columbia,Canada

On Burnaby Mountain in the coastal rainforest of British Columbia there are concentric, circular belts of podzolised soils around the stems of douglas fir and western hemlock trees. The most acid soils occur near each stem, and soils showing the greatest contrast in chroma between the eluvial and illuvial horizons occur beneath the periphery of the canopy of each tree. These circular belts of soils appear to be associated with limited flow of a very acid water from precipitation down a stem and much greater flow of less acid water from the periphery of the canopy.     

Water,Air, and Soil Pollution

Water, Air, & Soil Pollution -     

Concentric zonation of gleyed soils under individual tree canopies in southwestern British Columbia,Canada

A study was undertaken of concentric zoning of imperfectly and poorly drained, medium-textured soils around the stems of western hemlock and western red cedar in the coastal rainforest of British Columbia. The most acid profiles occur near each stem, and those having the greatest contrast in chroma between mottles and matrix occur beneath the periphery of the canopy of each tree. These circular belts of gleyed soils appear to be associated with, respectively, a limited flow of very acid water from precipitation down the stem and a much greater flow of less acid water from the periphery of the canopy.     

Viability of mountain caribou in British Columbia, Canada: Effects of habitat change and population density

Population viability analyses (PVA) are frequently employed to develop recovery plans and inform management of endangered species. Translating results from PVA into meaningful management recommendations often depends on an understanding of how population parameters change with environmental conditions as well as population density. The decline of mountain caribou (Rangifer tarandus caribou) in British Columbia, Canada, is believed to be caused by apparent competition with alternative prey species following changes to the forest age structure from timber harvest and wildfire. In addition, populations have been shown to decline at faster rates at low population density. To evaluate the potential effects of habitat change and population density on population persistence, we used stochastic projection models for 10 distinct populations varying in initial size from <10 to approximately 150 females. In an initial model, we used estimates of vital rates based on information sampled from >350 radiocollared caribou between 1984 and 2004. We then compared the results of the initial model to a set of models that evaluated the effects of habitat conditions and population density via their expected relationships to female adult survival. Assuming that vital rates remain constant over a 200-year time frame, only three populations have high probabilities (>0.95) of extinction. When models incorporate the declines in adult female survival know to occur with increasing proportions of young forest and declining population densities, all 10 populations are predicted to decline to extinction within <200 years. Based on our results, we suggest that PVA models that fail to incorporate the effects of changes in vital rates with habitat and population density may lead to overly optimistic assessments of the probability of population persistence in endangered species.     

Heavy Metal Contamination in Soils of Urban Highways Comparison Between Runoff and Soil Concentrations at Cincinnati,Ohio

Rainfall runoff from urban roadways oftencontains elevated amounts of heavy metals in both particulate anddissolved forms (Sansalone and Buchberger, 1997). Because metalsdo not degrade naturally, high concentrations of them in runoffcan result in accumulation in the roadside soil at levels thatare toxic to organisms in surrounding environments. This studyinvestigated the accumulation of metals in roadside soils at asite for which extensive runoff data were also available.For this study, 58 soil samples, collected from I-75 nearCincinnati, Ohio, were examined using X-ray fluorescence, C-Sanalyzer, inductively coupled plasma spectroscopy, atomicabsorption spectrometry and X-ray diffraction. The resultsdemonstrated that heavy metal contamination in the top 15 cm ofthe soil samples is very high compared to local backgroundlevels. The maximum measured amount for Pb is 1980 ppm (at 10–15 cm depth) and for Zn is 1430 ppm (at 0–1 cm depth). Metal content in the soil falls off rapidly with depth, and metalcontent decreases as organic C decreases. The correlation toorganic C is stronger than the correlation to depth. The resultsof sequential soil extraction, however, showed lower amounts ofPb and Zn associated with organic matter than was expected basedon the correlation of metals to % organic C in the whole soil.Measurement of organic C in the residues of the sequentialextraction steps revealed that much of the carbon was not removedand hence is of a more refractory nature than is usual inuncontaminated soils. Cluster analysis of the heavy metal datashowed that Pb, Zn and Cu are closely associated to one another,but that Ni and Cr do not show an association with each other orwith either organic C or depth. ICP spectroscopy of exchanged cations showed that only 4.5%of Pb, 8.3% of Zn, 6.9% of Cu and 3.7% of Cr in the soil isexchangeable. Combined with the small amounts of metals bound tosoluble organic matter, this result shows that it is unlikelythat these contaminants can be remobilized into water. At thissite, clays are not an important agent in holding the metals inplace because of low amounts of swelling clays. Instead, insoluble organic matter is more important. Mass balancecalculations for Pb in soil showed that most of the Pb came fromexhausts of vehicles when leaded gasoline was in use, and thatabout 40% of this Pb is retained in the soil.This study shows that, highway environments being a relativelyconstant source of anthropogenic organic matter as well as heavymetals, heavy metals will continue to remain bound to organicmatter in-situ unless they are re-mobilized mechanically. Removalof these heavy metals as wind-blown dust is the most likelymechanism. Another possibility is surface run-off carrying themetals into surface drainages, bypassing the soil. This studyalso shows that for those countries still using leaded gasoline,important reductions in Pb contamination of soils can be achievedby restricting the use of Pb additives.     

A study of canyon-dwelling mountain goats in relation to proposed hydroelectric development in northwestern British Columbia,Canada

Preliminary ecological relationships between a resident mountain goat Oreamnos americanus population and a proposed hydroelectric development were investigated in 1979 and 1980 along the Stikine river, in northwestern British Columbia. Population size was estimated at 316 animals, distributed along 54 km of the canyon. Steep canyon walls were utilized predominantly during summer. Adjacent forested areas became increasingly important during winter when icy conditions prevailed within the canyon. Spatial relationships of kidding and rutting areas, location of mineral licks, and utilization of plant life formations are also summarized. Localized goat mortality and possible temporary range abandonment observed in the proposed Site Z dam area may have resulted from 1978 and 1979 hydroelectric exploration activities. Proposed construction activities could similarly affect up to 56 goats. Proposed Tanzilla and Site Z reservoirs could reduce the 1979 study area population by about 17%, or 55 goats with the greatest flooding impact occurring in the Site Z reservoir. Major mitigation measures involve design and control of land and aerial access, and reduction of noise and related disturbances during critical biological periods. Examples are given for possible compensation measures including range enhancement, establishment of goast in vacant habitat, and development of viewing facilities. Resultant land and water access can provide long-term opportunities for increased hunter harvest and other non-consumptive uses of the animal resource, if properly regulated.     

Evidence of Elevated Ozone Concentrations on Forested Slopes of the Lower Fraser Valley, British Columbia, Canada

During the summers of 2001 and 2002, hourly average ozone concentrations were measured at three sites of differing elevation (188, 588, and 1221 m.a.s.l.) on the forested south-facing slopes of the Lower Fraser Valley (LFV), British Columbia. Sites experienced ozone concentrations ranging from 0 to 88 ppb in 2001, and 0 to 96 ppb in 2002. Daily patterns were in agreement with previous studies showing morning increases and late afternoon peaks. Reduced diurnal variation increased the exposure of higher-elevation forested sites. An upper-level ridge coinciding with a thermal coastal trough caused above-average ozone concentrations, and the ‘maximum acceptable’ 1-hour National Ambient Air Quality Objective (AQO) of 82 ppb to be exceeded. Maximum ozone concentrations and AQO exceedance frequency both increased with distance eastward in the valley. A preliminary survey of ozone-like injury symptoms on native shrubs suggested that the elevated ozone levels occurring in the LFV may cause injury to forest plants.     

Plant community functional shifts in response to livestock grazing in intermountain depressional wetlands in British Columbia, Canada

Wetlands are ecologically and economically important ecosystems with high conservation value. Although wetland vegetation is strongly determined by abiotic factors, grazing disturbance may also be an important influence on this community. We evaluated the effects of livestock grazing on wetland vegetation in marsh and wet meadow zones in intermountain depressional wetlands in the southern interior of British Columbia, Canada. We sampled marshes and wet meadows in 36 wetlands along a grazing intensity gradient ranging from fully fenced and ungrazed wetlands to unfenced wetlands heavily grazed by livestock. The amount of bare ground was used as a surrogate measure of the intensity of livestock grazing. Vegetation community structure and composition was strongly associated with grazing intensity. Increased livestock grazing favored shorter-lived and smaller plants; conversely, the frequency of tall and rhizomatous species, which constitute the dominant plant species in these systems, declined with higher livestock use. The effects of grazing were more pronounced in the marsh than in the wet meadow. Associations between species richness and grazing differed between zones: native and exotic species richness showed a unimodal response in the marsh while in the wet meadow exotic richness increased and native richness showed no response. The relationship between exotic frequency and grazing was also inconsistent between zones, with a negative association in the marsh and a positive but weak association in the wet meadow. Grazing-related changes in vegetation along the grazing intensity gradient were substantial and may affect the habitat value of these wetlands for dependent wildlife such as breeding waterfowl.     

高等级公路水土保持绿化工程方案探讨

以天水一谗口高等级公路工程为例,系统地介绍了可行性研究阶段水土保持方案中绿化工程设计的要求及内容。首先根据项目主体的要求,确定不同绿化功能和要求的地块的分布和面积,并划分不同的防治分区;其次分析和评价各类绿化地的立地条件,合理划分立地因子,提出不同防治分区各绿化地块拟采用的植物种及布局方案;最后,根据项目立体建设的要求,研究项目对绿化的特殊要求,提出可行的绿化方案,并进行典型设计。     

Distribution and Degradation of Fresh Water Plastic Particles Along the Beaches of Lake Huron, Canada

Resistivity of plastic litter to chemical weathering, mechanical erosion, and biological degradation poses a critical environmental threat. Plastic debris has increased in abundance over the past several decades along shorelines and at sea, where organisms mistake small particles including plastic pellets as a potential food supply. These pellets have been shown to adsorb persistent organic pollutants such as PCBs, which may endanger the organism and become ingested higher in the food chain. Although several studies have been conducted to determine the amount and effects of plastics pollution in marine environments, relatively little is known concerning fresh water plastics pollution. This study represents the first detailed examination of the distribution, types, and physical and chemical degradation processes of plastic particles in a fresh water setting. In conducting field surveys along the shoreline of Lake Huron, Canada, we were able to ascertain that the total number of pellets over multiple sampling localities comprise 94% of plastic debris. The majority of the pellets were found proximal to an industrial sector along the southeastern margin of the lake and their abundance steadily decreased northward, following the dominant lake current patterns. Laboratory analyses using Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy indicate predominant mechanical abrasion textures, including grooves, gauges, pits, and flakes, and less common chemical weathering features such as linear and crescentic fractures that developed from shrinkage during subaerial exposure. The predominant type of plastic, polyethylene, appears to be much more resistant to chemical weathering than polypropylene, as indicated by oxidation peaks on FTIR spectra suggesting that polypropylene degrades more readily under natural conditions on freshwater beaches.     

Water,Air, and Soil Pollution. Information for Authors

Water, Air, &; Soil Pollution -     

公路水土保持方案中临时占地的估算

针对公路建设项目在工程可行性研究阶段对临时占地的不确定性,提出了取土场区、弃渣场区、施工生产生活区、施工便道区、拆迁安置及专项设施改建区等各类临时占地面积的估算方法,并给出了工程应用实例。     

Model Assessment of Cattle and Climate Impacts on Stream Fecal Coliform Pollution in the Salmon River Watershed, British Columbia, Canada

A bacterial water quality model (BWQM) was developed and used to evaluate the impacts of cattle farming and climate change on the stream fecal coliform pollution in the Salmon River watershed in south-central British Columbia, Canada. The accuracy of the model simulation was evaluated using the Nash-Sutcliffe coefficient of efficiency (COE). The BWQM simulated the observed field data well, with the values of the COE ranging from 0.76 to 0.78 for the stream flow, from 0.55 to 0.60 for the fecal coliform (FC) concentration, and from 0.85 to 0.89 for the FC loading. The BWQM captured more than 79%, 66%, and 90% variation of the daily stream flow, FC concentration, and FC loading, respectively. The BWQM predicts that between 70% and 80% of the FC were transferred from the cattle farm to the Salmon River through the snowmelt-caused surface runoff during late winter and early spring, with the balance 20% to 30% coming from the soil-lateral flow and the groundwater return flow. The model also indicates that the stream FC concentration is sensitive to the distance of the cattle farm to the Salmon River. The model scenario analysis reveals that the climate change, at an assumed 1??C increment of daily air temperature, results in an increase in the stream FC concentration in the spring, fall, and winter, but there is also a decrease in the summer. The increased air temperature also changes the seasonal pattern of the stream FC concentration. Rainfall can reduce the stream FC concentration and mitigate the impact of the increased air temperature on the stream FC concentration as long as it does not result in a surface runoff or flooding event.     

金属矿水土流失特点探析

通过对收集到的55个水土保持方案和水土保持设施验收资料进行统计分析,总结归纳出了金属矿的水土流失特点,主要为造成水土流失面广量大、产生水土流失时间长和易诱发剧烈的水蚀、风蚀和重力侵蚀等,产生水土流失区域和防治重点区域为工业场地区、露天采场区、排土场区和尾矿库区。     

Biomonitoring of Trace Elements in Air and Soil Compartments Along the Major Motorway in France

The impact on the environment of Cd, Pb and Zn emissions from the A1 motorway, one of the busiest in France, was based on a simultaneous analysis of lichens, fungi and soil.The study was conducted in 12 rest areas located along a 55 kmstretch of the motorway. Cd, Pb and Zn concentrations in the top soil horizon (0–10 cm) largely exceeded their concentrations at the control site.The Cd-, Pb- and Zn levels in fruiting bodies of fungi Armillaria mellea, Coprinus comatus, Marasmius oreades and Paxillus involutus were highly variable between sites. The contamination degree of transplanted thalliof Parmelia caperata was well correlated to the cumulated traffic on the western side. On the eastern side, heavy metals originated from the traffic but also from neighbouring sources (urbanization and agricultural practices). Although lead levels are decreasing, leaded petrol is still on offer and lead remains an indicator of vehicle pollution.     

黄土高原地区西气东输工程沿线水土流失敏感性评价

西气东输管道的建设将直接破坏施工区范围内的地表植被,导致区域生态环境的恶化和水土流失的进一步加剧,加剧的水土流失反过来会对西气东输管道的安全运行形成较大的威胁,甚至在某些严重地区,由于崩塌、滑坡和泥石流的发生,可能会直接破坏管道,影响其安全运行.如何控制管道工程沿线地区的水土流失,加强区域友好环境的构建,不仅对于提高区域生态系统的功能具有重要意义,而且对于管道工程的安全运行具有重要的实际价值.本文在系统分析影响区域水土流失敏感性因子的基础上,在GIS的支持下,选取土壤、植被类型、坡度和坡向作为评价指标,采用图层权重-叠加模型和模糊分级模型,以专家经验打分法对各指标进行赋值,评价了黄土高原地区西气东输管道工程沿线10 km范围内水土流失的敏感性.根据研究结果将该区分为弱敏感、较敏感、敏感和高度敏感4类地区,并评价了水土流失敏感性的空间特征及其主要原因.在此基础上,从区域生态系统和管道工程的安全角度探讨了生态恢复和友好环境构建的基本措施.     

Mercury in soils of British Columbia,a mercuriferous region

Mercury concentrations in various horizons of British Columbia soils were determined to estimate natural background levels in soils from various geographical areas of the province. Highly enriched concentrations near the Pinchi Lake cinnibar deposit declined to background levels ranging from 10 to 310 ppb Hg in the district. In six other regions, concentrations in surface mineral horizons averaged 85 ppb and ranged to 490 ppb but surface horizons of peaty muck soils and those predominated by vegetative litter contained 164 ppb Hg on the average and as much as 741 ppb. Concentrations in subsurface horizons were lower than at the surface. A significant relationship between Hg concentration and organic matter content was observed. Comparison with soils from outside British Columbia indicated its location within a generalized mercuriferous belt accounted for the relatively high concentrations observed.     

公路水土保持技术理论研究进展

简要回顾了公路建设的水土流失影响,重点阐述了公路边坡水土保持的发展历程及其研究现状,指出亟待开展的4个主要研究方向:①开展不同侵蚀环境下公路建设新增水土流失规律与土壤侵蚀动力学机理研究;②建立不同区域公路建设水土保持监测技术体系,发展土壤侵蚀的预测预报理论技术;③加强公路建设水土流失防治体系与植被快速建植技术研究,构建水土保持标准化治理模式与技术标准;④推动公路建设水土保持损益分析及水土保持与经济社会可持续发展的关联研究。