公路路面径流水污染与控制技术探讨

结合国内外研究成果 ,对公路路面径流中主要污染物及其来源、路面径流水质特征、影响路面径流污染的因素 ,及常用路面径流污染控制措施进行了综合分析。认为公路路面径流水质变化很大 ,污染强度较高 ,主要污染物为 SS和 COD,其平均浓度超过污水排放限值 ,在对水质有较高要求的水域路段 ,应通过非工程措施和工程措施的综合实施来实现污染控制。非工程措施主要包括加强公路运输管理、路面清扫、限制除冰剂的使用等 ;工程措施包括植被控制、湿式滞留池、渗滤系统及人工湿地系统等 ,在实际工程应用中 ,可将几种方法组合使用。     

城市雨水径流的污染及控制措施研究

指出城市雨水径流污染已经成为非点源污染的主要组成部分,通过对城市雨水径流污染物来源及成分分析,系统地整理了有关国内外城市雨水径流污染研究的资料,为我国的城市雨水污染控制和利用提出了一些建议和意见。     

Sources of heavy metals and polycyclic aromatic hydrocarbons in urban stormwater runoff

Polycyclic aromatic hydrocarbons (PAHs) and heavy metals were measured in road debris collecting in urban areas and in the suspended sediment (SS) component of runoff from two stormwater catchments in Dunedin, New Zealand. Levels in the road debris ranged from 119-527 microg/g for lead, 50-464 microg/g for copper, 241-1 325 microg/g for zinc and 1.20-11.6 microg/g for sigma16PAH. The SS from the largely rural catchment (20% urban) had similar concentrations to the road debris, indicating that this urban material was the main source of the contaminants measured in the stormwater. Similar PAH fingerprint profiles and isomer ratios indicative of dominant pyrogenic (combustion) sources were also found in these two groups of materials. The SS from the 100% urban catchment contained 2- to 6-fold higher concentrations of metals and 10-fold greater levels of sigma16PAH. The higher levels of lead and copper were probably a result of industrial land uses in this catchment, while the additional zinc was linked to an abundance of zinc-galvanised roofing iron in the catchment's residential suburbs. The PAH profiles and isomer ratios were different for this urban catchment and suggested that a disused gasworks was contributing PAHs to the stormwater runoff.     

Size fractionation of metals in runoff from residential and highway storm sewers

Stormwater sampling for particulate, colloidal, and dissolved metals was conducted for several storms at six outfalls in Monmouth County, NJ. Samples were initially sequentially filtered through 5 microm, 0.45 microm, and 10 kDa filters. Of the heavy metals, Cu and Zn were mostly either dissolved (<10 kDa) (20-100%) or in the particulate size fractions >5 microm (0->70%). Pb and Cr were associated exclusively with particles >5 microm in size. Fe, Al, and Si were found mostly in larger size fractions (>70%), with smaller amounts 0.45-5 microm in size. Preliminary data from a small set of samples passed through coarser filters suggested that metals may actually be largely associated with particles larger than 20 microm. Variable and sometimes large dissolved fractions of Cu and Zn can contribute to erratic metals removal by structural best management practices (e.g., wet ponds, detention basins). The size fractionation of stormwater constituents has implications for the design and performance of stormwater control structures and the aquatic toxicity risks posed by the metals. The results demonstrate the importance of obtaining particle size data when planning stormwater treatment.     

沈阳城区雨水径流中重金属的空间分布规律研究

为了探究沈阳市地表雨水中的重金属含量的空间分布特征以及雨水中重金属的来源,选取沈阳市8个具有代表性的地点作为采样点,对地面雨水径流中的铁、锰、铜、锌、铅、镉、砷等重金属元素含量进行测定,并运用主成分分析方法对测试结果进行了分析。结果表明,铁、锰、铜、锌、铅为主要成分,其中铁的含量占7种重金属含量的68.686 2%,锰含量占18.463 0%,铜含量占8.877 3%,锌含量占3.484 9%,铅含量占0.483 3%。运用模糊聚类分析方法对地表雨水径流中的重金属含量进行了空间分布规律的研究,其中火车站与中街地表雨水径流中重金属含量高,三好街、制药厂、热电厂及立交桥四者地表雨水径流中重金属含量较高,公园与小区地表雨水径流中重金属含量较低,通过分析可以推断出地表雨水径流中的重金属可能来源于土壤灰尘和交通车辆。     

Lead,iron, chromium and zinc in road runoff at Pullman,Washington

The inputs of iron, lead, chromium and zinc to a 0.6 acre road surface were investigated. The selection of a viaduct in Pullman, Washington as a study area permitted the exclusion of metal input from non-road surfaces. Dust and precipitation metal deposition rates were measured at the viaduct as well as at a control location. It was found that the primary source of metals at the road surface was the operation of motor vehicles. For three separate storm events, runoff samples were collected, flow was measured and runoff samples were analyzed for total solids, total metals and dissolved-colloidal metals. Less than 5 percent of each metal in the runoff samples existed in the dissolved-colloidal fraction. Mean concentrations of total metals in road runoff were 1.86, 89, 0.139 and 19.1 mg/l for Pb, Fe, Cr, and Zn, respectively. A mathematical model was developed allowing the estimation of metal loadings for a storm event typical of the area, given the total runoff volume for the particular storm event. It was also found that a residual amount of metals remains on the road surface after each storm.     

我国城市道路径流水质及污染物控制研究现状

根据我国城市道路径流水质以及污染物控制的研究现状,建议今后应结合现有雨水利用手段,针对不同城市、不同区域、不同路面形式、不同季节、不同降雨类型对雨水径流水质进行系统研究,并利用各种方式对雨水污染物加以控制,以利于更好地开展雨水水质研究工作。     

Rain water leachates of heavy metals in road surface sediments

Samples of street surface and roadside gutter sediments within a separately sewered catchment in N.W. London have been analysed for heavy metal contamination. Particle size distributions are presented and the removal efficiency of metal species demonstrated for various street cleaning procedures. Laboratory sorption and desorption studies are described and solution concentrations are obtained for Pb, Cd and Mn.Solubility curves are typically variable with time with Mn showing the strongest tendency to attain equilibrium. No obvious dependence of metal concentrations on grain size is readily apparent although Cd tends to desorb more rapidly from size fractions greater than 250 μm.     

Multiple evaluations of the removal of pollutants in road runoff by soil infiltration

Groundwater replenishment by infiltration of road runoff is expected to be a promising option for ensuring a sustainable urban water cycle. In this study, we performed a soil infiltration column test using artificial road runoff equivalent to approximately 11-12 years of rainfall to evaluate the removal of pollutants by using various chemical analyses and bioassay tests. These results indicated that soil infiltration treatment works effectively to remove most of the pollutants such as organic matter (chemical oxygen demand (CODMn) and dissolved organic carbon (DOC)), P species, polycyclic aromatic hydrocarbons (PAHs), numerous heavy metals and oestrogenic activities. Bioassay tests, including algal growth inhibition test, Microtox and mutagen formation potential (MFP) test, also revealed effective removal of toxicities by the soils. However, limited amounts of NO3, Mn, Ni, alkaline earth metals, perfluorooctane sulphonate (PFOS) and perfluorooctane sulphonamide (FOSA) were removed by the soils and they possibly reach the groundwater and cause contamination.     

Impacts of rainfall events on runoff water quality in an agricultural environment in temperate areas

Since a rise in dissolved organic carbon (DOC) concentrations has been observed for surface waters at least over the last two decades, a change in weather conditions (temperature and precipitations) has been proposed to partly explain this increase. While the majority of DOC delivery from soils to stream occurs during rainfall events, a better understanding of the rainfall influence on DOC release is needed. This study has been conducted in Brittany, western France, on agricultural experimental plots receiving either cattle manure (CM) or pig slurry (PS) as fertilizers in accordance with local practices. Each plot was instrumented with a flow meter and an auto sampler for runoff measurements. The results show that export of DOC during high intensity events is higher than during lower intensity rainfalls. Fertilization has a noticeable impact on total organic carbon (TOC) fluxes with an increase of five to seven folds for PS and CM respectively. If TOC shock load occurs shortly after the rainfall peak, DOC maximum appears with the first flush of the event. Organic carbon (OC) is mainly under colloidal (41.2%) and soluble (23.9%) forms during the first stage of a rainfall event and a control of rainfall intensity on OC colloidal transport is suggested. These findings highlight the potential risk of receiving water quality degradation due to the increase of heavier rainfall events with climate change in temperate areas.     

Transport of polycyclic aromatic hydrocarbons and pesticides during snowmelt within an urban watershed

During snowmelt events in urban watersheds large amounts of organic contaminants are mobilized, potentially affecting the quality of surface and groundwater resources. The transport of polycyclic aromatic hydrocarbons (PAHs) and two pesticides in the highly urbanized Highland Creek watershed within the city of Toronto, Canada, was investigated by sampling river water during two snowmelt periods. The dissolved and the particulate fractions were separately extracted and analyzed. While during normal flow conditions levels of the sum of nine PAHs including phenanthrene, anthracene, fluoranthene, pyrene, benzo(b)fluoranthene, benzo(k)fluoranthene, benzo(a)pyrene, indeno(1,2,3-c,d)pyrene, and benzo(ghi)perylene ranged between 18 and 45 ng/L, concentrations at the onset of melting varied from 550 to 4500 ng/L. Considering enhanced stream discharge rates during snowmelt the contaminant flux in the river increased by three orders of magnitude. The intensity of the melt event largely determined the extent of the PAH concentration increase in the river. The relatively water soluble pesticides chlorothalonil and lindane (γ-HCH) also tended to appear early during melting. Their enrichment in river water may be influenced by the thickness of the snow pack at the onset of melting, and the mode of melt water ablation from the snow pack to the stream, i.e. whether it occurs by overland or sub-surface flow.     

Estimation of source contribution to nitrate loading in road runoff using stable isotope analysis

The nitrogen load was determined in road runoff during rainfall events. Moreover, nitrate isotopes analysis was conducted to determine the contribution of nitrates from atmospheric deposition and leaching from road dust. The concentrations of NO₃-N in road runoff were higher than those in atmospheric deposits for each rainfall event, except one event with a long antecedent dry weather period. The δ¹⁸O-NO₃ in road runoff was lower than in atmospheric deposits and higher than in leachate from road dust; however, no difference in δ¹⁵N-NO₃ was observed. By using δ¹⁸O-NO₃ as an indicator for evaluating NO₃-N sources in road runoff, contribution ratios of NO₃-N from road dust were estimated to be 14–22%, 23–25%, and 22–34% for Event 1 to Event 3, respectively. These results indicated that the NO₃-N from the atmosphere accounts for more than half of the NO₃-N in road runoff.     

Toxicity evaluation of road dust in the runoff process using a benthic ostracod Heterocypris incongruens

Road dust is considered an important source of sediment contamination; however, there are few studies on the toxicity of road dust on benthic organisms. This study evaluates the toxicity of road dust on the benthic ostracod, Heterocypris incongruens, through a 6-day direct exposure experiment. All six road dust samples collected in heavy traffic areas caused high mortality of the ostracod, whereas the road dust collected in a residential area did not show toxicity to the ostracod. After maintaining the mixture of road dust and water for 24 h, the toxicity of the road dust decreased significantly for three of the six samples in the heavy traffic areas, suggesting these road dust samples become less toxic in the surface runoff process. In addition, we conducted the same toxicity test on manipulated road dust using different solid/liquid ratios and holding times to evaluate the change in toxicity caused by the runoff process. Wet road dust that had been separated from a dust-water mixture after a holding time of 1 h or 24 h did not show lethal toxicity, while the water-soluble fraction of the mixture caused high mortality of the ostracod at a solid/liquid ratio of 1:2 and 1:4. However, after a 7-day holding time of the dust-water mixture, the wet road dust and the water-soluble fraction showed lethal toxicity to the ostracod. These results suggest that toxicants of road dust seemed to exist mainly in water soluble fraction eluted off by rain water; however, particle-bound fraction again showed lethal toxicity after 7 days of incubation.     

Roadside PM10 and associated metals in Constantine,Algeria

Samples of particulate matter less than or equal to 10 μm (PM10) were collected every other day using an Airmetrics MiniVol portable air sampler in Constantine, the third largest and most densely populated city of Algeria with a population of 600,000. The main objective of this study was to assess the concentrations of particulate matter (PM) with an aerodynamic diameter ≤10 μm (PM10), and dust-laden trace metals in a residential area with heavy traffic during two months, from 25 March 2010 to 24 May 2010. Furthermore, the present work examines the daily levels of metallic elements Fe, Zn and Cu. The PM10 concentrations ranged from 7.6 to 159.4 μg/m³ during the study period. WHO’s daily PM10 average guide value of 50 μg/m³ was exceeded 10 times over 31 samples. HYSPLIT back trajectories were used to identify the source locations of the pollutants. Rain scavenging of atmospheric particulate matter led to a substantial decrease in PM10 concentrations. During the study period, Zn was detected in one sample at a concentration of 0.78 μg/m³. It is believed that air masses originating from Iceland’s Eyjafjöll volcano may have transported clouds of ashes rich in Zn to the sampling site on that occasion. A maximum of 2.92 μg/m³ of Cu was observed when the volcanic cloud reached the sampling site four times during the corresponding 24-h sampling period.     

道路施工过程中的路基路面质量控制分析

在众多学者的基础上进行归纳与总结,对道路施工过程中的路基路面的质量进行分析,并对路基路面管理方面、路基质量控制方面以及路面控制方面提出了建设性的意见,以期为我国交通事业的发展做出贡献。     

Contribution of trace metals from atmospheric deposition to stormwater runoff in a small impervious urban catchment

The contribution of atmospheric deposition to emissions of trace metals in stormwater runoff was investigated by quantifying wet and dry deposition fluxes and stormwater discharges within a small, highly impervious urban catchment in Los Angeles. At the beginning of the dry season in spring 2003, dry deposition measurements of chromium, copper, lead, nickel, and zinc were made monthly for 1 year. Stormwater runoff and wet deposition samples also were collected, and loading estimates of total annual deposition (wet+dry) were compared with annual stormwater loads. Wet deposition contributed 1-10% of the total deposition inside the catchment, indicating the dominance of dry deposition in semi-arid regions such as Los Angeles. Based on the ratio of total deposition to stormwater, atmospheric deposition potentially accounted for as much as 57-100% of the total trace metal loads in stormwater within the study area. Despite potential bias attributable to processes that were not quantified in this study (e.g., resuspension out of the catchment or sequestration within the catchment), these results demonstrate atmospheric deposition represents an important source of trace metals in stormwater to waterbodies near urban centers.     

在新林区建设中大力发展林区道路的必要性

通过对林区道路现状的分析,阐述了在新林区建设中大力发展林区道路的必要性,并对今后林区道路建设及养护管理提出了可行的建议及对策,对于促进山区林业经济发展、方便林区群众生产生活具有重要的意义。     

Partitioning and granulometric distribution of metal leachate from urban traffic dry deposition particulate matter subject to acidic rainfall and runoff retention

Vehicular transportation coupled with urban hydrology is a significant source as well as vector of particulate matter (PM) and particulate-bound metal inventories in urban systems. This study examines the granulometric distribution of metals from dry deposition PM generated from 17 dryfall periods and equilibrium metal partitioning with runoff PM distribution from eight rainfall-runoff events at an urban inter-state watershed in Baton Rouge, LA. Dry deposition PM is a coarse non-uniform gradation with a d(50m)=304mum and a peak surface area at 106mum. Results indicate acid rain is not a significant metal contributor to runoff but is capable of leaching metals from PM to runoff. Retained runoff partitioning resulted in particulate-bound predominance for As, Cd, Cr, Cu, Pb, and Zn while Ca and Mg remained predominately dissolved. The finer PM fraction (<75mum) generates the highest metal concentrations and the highest metal mass is associated with the coarser fraction (>75mum). This coarse fraction is also the most labile when exposed to acidic rainfall; generating up to 90% of the total metal mass leached from the entire PM gradation. Comparing dry deposition and runoff PM of equal mass and size gradation, retained runoff PM is enriched with metals (except Pb). Results indicate the labile coarse fraction of dry deposition PM can be a significant source of metal leaching while runoff PM (mobilized dry deposition PM) stored in a BMP can be metal-enriched with the potential for re-leaching or scour.     

Nutrients transport in the bare urban redeveloped soil system during runoff process

Stormwater pollution in redeveloped soils mixed with construction wastes imposes a serious impact to receiving waters. The transport and distribution of rainfall water and nutrients in the surface-flow and subsurface-flow (including side-flow and down-flow) of bare redeveloped soil runoff system were determined. Results indicated that the flow patterns and pollutants transport of surface-flow were different from those in subsurface-flow. The flowrate of surface-flow increased at the beginning and reached to a stable state, and then disappeared immediately after the rainfall stopped. While the flow rate of subsurface-flow was persisted and decreased gradually artery the rainfall. Most of the pollutants were carried in the surface-flow, which directly results in polluting the surface-receiving waters. And the pollutants distribution percent in side-flow was higher than that in down-flow. Results obtained in this study will provide information for the management of stormwater pollution in the bare redeveloped soil mixed with construction wastes.