Accretion of Pollutants in Snow Exposed to Urban Traffic and Winter Storm Maintenance Activities. I

Urban snow is impacted by traffic activities and winter maintenance practices that result in significant accretion of dissolved, colloidal, and suspended solids in a complex heterogeneous snow matrix that includes heavy metals, inorganic, and organic compounds. Extended residence times of snow as a roadway snowbank exposed to these pollutant-generating activities lead to significant pollutant accretion and partitioning in the snow matrix. This study analyzed four highway sites in urban Cincinnati with respect to specific water quality indices for the residence time of roadway snow. Chloride levels in roadway snow illustrate a direct correlation to application of de-icing salts. While accretion of total dissolved solids (TDS) was initially rapid with a decrease late in the event, total suspended solids (TSS) accretion demonstrated a more gradually increasing trend for the duration of roadway snow, approaching 105?mg/L. Temporal trends towards increasing total chemical oxygen demand (CODt) exerted by roadway snow are similar to TSS, with CODt values approaching 105?mg/L. Applications of 2.2×105?kg of de-icing salt containing cyanide as an anticaking agent, along a 27-km section of interstate, resulted in approximately 6 kg of cyanide discharged along this major north-south interstate in the study area. Results indicate that traffic activities and winter storm management practices can have a significant impact on pollutant accretion in urban snow.     

Automated GIS-Based System for Speed Estimation and Highway Safety Evaluation

Although geographic information systems (GISs) have been applied in different areas of transportation, full use of their potential in speed profile analysis and highway design consistency studies has yet to be made. The possibilities that GISs offer for analysis and the increasing number of highway inventories supported by such systems, including traffic data and crash rates, suggest that the implementation of a highway design consistency analysis module within a GIS will facilitate and improve road safety studies. It is with this aim that a GIS-based computer system that builds vehicle speed profiles and analyzes highway design consistency has been developed, in which an operating speed prediction model, acceleration/deceleration rates, and other features can be configured by the engineering user in order to obtain an analysis that is more representative of drivers and local conditions. Application of this system to the study of the design consistency of highways is described, using three examples.     

Lagoon Effluent Treatment Using Grass Filtration

The Western Treatment Plant (WTP) is one of the largest treatment plants in Australia treating more than 500 ML of sewage per day, discharging treated effluent to Port Phillip Bay in Victoria, Australia. The Port Phillip Bay Environmental Study (1992–1996) concluded that there was a need to reduce nitrogen loads from WTP to lower the risk of eutrophication, especially during winter when grass filtration was in operation. Therefore, in 1997, Melbourne Water initiated a pilot study to investigate the effectiveness of grass filtration for polishing wastewater that had received prior lagoon treatment. The study involved field monitoring of seven trial grass filtration bays at the WTP for hydraulic and water quality data from mid-May to early-October 1997. The results of the pilot study revealed that the removal rates of these nutrients were higher during the first half of the trials than during the second half. The results also showed that the removal rates of nutrients were inversely proportional to the hydraulic loading rates of the bays. A hydraulic loading rate of 40 mm/d was found to be optimal in this pilot study for achieving a balance between wastewater throughput and nutrient removal.     

Impact of Rainfall on the Productivity of Highway Construction

Heavy rainfall often leads to complete suspension of highway construction due to saturated and unworkable soil conditions. Therefore, quantifying the impact of rainfall on the productivity of highway construction is essential in preparing realistic schedules and cost estimates for the preconstruction stage and in analyzing weather-related claims for the postconstruction stage. This paper presents a decision support system for quantifying the impact of rainfall on productivity and duration of common highway construction operations, namely: earthmoving, construction of base courses, construction of drainage layers, and paving operations. The system incorporates a knowledgebase and a database. The knowledgebase includes if∕then type rules, acquired from experts in highway construction operations, and the database contains hourly records of weather parameters from the closest weather station to the construction site. The system, named WEATHER, is a software system that provides user-friendly interface, including menus, dialog boxes, and graphical capabilities to facilitate data input and output.     

Characterization and Pollutant Loading Estimation for Highway Runoff

Three highway segments typical of urban, semiurban, and rural settings in the Piedmont region of North Carolina were monitored to characterize the respective runoff constituent concentrations and pollutant discharge or export loadings. Runoff from the impervious bridge deck (Site I) carried total suspended solids (TSSs) concentrations and loadings that are relatively higher than typical urban highways, whereas nitrogen and phosphorus loadings are similar to agricultural runoff. Site II included a pervious roadside shoulder with traffic volume equal to that of Site I. Site III was a nonurban highway having lower traffic counts and imperviousness due to the presence of a roadside median. The existing roadside shoulder and median appeared to attain at least 10–20% hydrologic attenuation of peak runoff discharges, more than 60% reduction of event mean concentration of TSSs, and attenuation of the first-flush concentrations for most pollutant constituents. Bulk precipitation data collected at the bridge deck site indicated that 20% of TSS loadings, 70–90% of nitrogen loadings, and 10–50% of other constituent exports from the roadway corridors might have originated from atmospheric deposition during dry and wet weather conditions. The long-term highway pollutant loadings have been derived to provide a basis for comparing highway runoff with other categories of nonpoint sources (NPSs).     

Evaluating Urban Pollutant Buildup/Wash-Off Models Using a Madison, Wisconsin Catchment

Buildup/wash-off (BUWO) models are widely used to estimate pollutant export from urban and suburban watersheds. Here, we propose that the mass of washed-off particulate during a storm event is insensitive to the time between storm events (the traditional predictor of particulate accumulation in BUWO models). Our analysis employed USGS data of total suspended solids and discharge data for nonsnow events in a 9.4-km2 suburban catchment in Madison, Wis. Kinetic energy of rainfall was calculated using National Weather Service NEXRAD radar reflectivity. A regression analysis found that storm event runoff volume and rainfall kinetic energy explained 81% of the variability in event particulate load; volume alone explained 69% of the variability in event loads. Time between storm events was not significant. Additionally, we simulated storm event particulate loads using a BUWO model and a model assuming a constant mass available for wash-off. Both models produced very similar predictions over a range of parameterizations, suggesting that buildup models could perhaps be simplified under many circumstances.     

Determining Primary Productivity of Lake Roosevelt with 14C

During two sampling trips in 1997, primary productivity was measured at 11 stations in Lake Roosevelt using a radioactive carbon tracer capable of determining subtle changes in water quality. Both spatial and temporal variations in productivity were observed. For the August 1997 field trip, productivities on the mainstem reservoir ranged from 485 to 1,243 mgC∕m2∕d, with an average value of 783 mgC∕m2∕d. Temporal differences between the August and October trips varied by as much as 880 mgC∕m2∕d. The data are compared to measurements taken over a four-year period to determine subtle, long-term changes in the water quality. Productivity at Lake Roosevelt is heavily influenced by tributary inflow, and generally increased in the reservoir reaches below the mouths of the tributaries. Mainstem sites between the tributaries had lower productivities than the upstream and downstream tributary sites, indicating that nutrients may be rapidly utilized in the immediate vicinity of the inflows. However, productivities in the tributary arms were consistently low, despite the fact that their physicochemical properties stimulated growth in the reservoir. The productivity data illustrate the difficulty in characterizing a large water body as a homogeneous quantity in terms of assessing loading impacts. The results also demonstrate that long-term changes in water quality can be masked by short-term events. The long-term trend is that Lake Roosevelt, a eutrophic/mesotrophic lake, is becoming an oligotrophic lake, but seasonal rainfall events influence the lake's specific characterization.     

Surface Runoff from Full-Scale Coal Combustion Product Pavements during Accelerated Loading

In this study, the release of metals and metalloids from full-scale portland cement concrete pavements containing coal combustion products (CCPs) was evaluated by laboratory leaching tests and accelerated loading of full-scale pavement sections under well-controlled conditions. An equivalent of 20 years of highway traffic loading was simulated at the OSU/OU Accelerated Pavement Load Facility (APLF). Three types of portland cement concrete driving surface layers were tested, including a control section [i.e., ordinary portland cement (PC) concrete] containing no fly ash and two sections in which fly ash was substituted for a fraction of the cement; i.e., 30% fly ash (FA30) and 50% fly ash (FA50). In general, the concentrations of minor and trace elements were higher in the toxicity characteristic leaching procedure (TCLP) leachates than in the leachates obtained from synthetic precipitation leaching procedure and ASTM leaching procedures. Importantly, none of the leachate concentrations exceeded the TCLP limits or primary drinking water standards. Surface runoff monitoring results showed the highest release rates of inorganic elements from the FA50 concrete pavement, whereas there were little differences in release rates between PC and FA30 concretes. The release of elements generally decreased with increasing pavement loading. Except for Cr, elements were released as particulates (>0.45?μm) rather than dissolved constituents. The incorporation of fly ash in the PC cement concrete pavements examined in this study resulted in little or no deleterious environmental impact from the leaching of inorganic elements over the lifetime of the pavement system.     

Crash risks of older drivers: a panel data analysis

Considerable progress has been made on understanding older drivers' safety issues. None the less, findings from previous research have been rather inconclusive. Differences in data and research methodology have been suggested as factors that contribute to the discrepancies in previous findings. One of the methodological limitations is the lack of considering temporal order between events (i.e. the time between onset of medical condition, symptom and crash). Without time-series data, a 'snap-shot' of medical conditions and driving patterns were often linked to more than 1 year--of crash data, hoping to accumulate enough data on crashes. The interpretation of the results from these studies is difficult in that one cannot explicitly attribute the increase in highway crash rates to medical conditions and/or physical limitations. This paper uses a panel data analysis to identify factors that place older drivers at greater crash risk. Our results show that factors that place female drivers at greater crash risk are different from those influencing male drivers. More risk factors were found to be significant in affecting older men's involvement in crashes than older women. When the analysis controlled for the amount of driving, women who live alone or who experience back pain were found to have a higher crash risk. Similarly, men who are employed, score low on word-recall tests, have a history of glaucoma, or use antidepressant drugs were found to have a higher crash risk. The most influential risk factors in men were the number of miles driven, and use of antidepressants.     

Alcohol intake and severity of injuries on highways in Mexico: a comparative analysis

AIMS: To analyze the association between alcohol intake and the severity of injuries sustained from traffic accidents on a Mexican highway. DESIGN: An observational unit evaluated drivers involved in auto accidents. SETTING: Mexico-Cuernavaca Highway, Mexico. A 60 km-long road with many altitude variations and sharp curves. PARTICIPANTS: Three hundred and eighty-six drivers involved in traffic accidents between March and September, 1994. MEASUREMENTS: A questionnaire was applied to the driver, an occupant or witness at the site of the accident to collect information about the driver, vehicle characteristics, type of accident, day-night occurrence, road section (Mexico-Cuernavaca or Cuernavaca-Mexico) and weather conditions. A physical examination was carried out to determine the presence and severity of injuries. FINDINGS: There were 177 injured people, including 12 deaths, with rates of 67.5 injuries and 4.58 deaths per 10,000 km driven. Variables associated with alcohol intake (p < 0.05) included: severity of injuries, non-use of seat belt, vehicle size and occurrence at night. Risk factors for severe injuries were: alcohol intake (adjusted OR 6.1 CI 95% 1.6-24.0); non-use of seat belt (OR 4.9 CI 2.2-10.8), age < 25 years (OR 3.6 CI 1.0-12.7), age > 54 years (OR 6.0 CI 1.4-25.0), speed > 90 km/h (OR 2.6 CI 1.1-6.3) and occurrence at night (OR 2.6 CI 1.3-5.3). CONCLUSIONS: Alcohol intake is a major risk factor for severe injuries from highway traffic accidents. Its association with other risk factors such as non-use of seat belt and excessive speed suggests the importance of designing interventions aimed at reducing alcohol intake among automobile drivers.     

Transport and Distribution of Particulate Matter Phosphorus Fractions in Rainfall-Runoff from Roadway Source Areas

During runoff transport, phosphorus (P) partitions between dissolved and particulate matter (PM) phases. PM-based P distributes across the particle-size distribution (PSD). This study investigates the transport and distribution for P and PM in runoff from a fully paved highway watershed in Baton Rouge, La. Eight events with discrete manual runoff sampling are studied. PSDs are modeled with a cumulative gamma distribution and PM-based P distributions are modeled with a Freundlich-type power law. P and PM fractions examined are dissolved, suspended, settleable, and sediment. Measured mass transport of these fractions is modeled based on flow-limited (zero-order) or mass-limited (first-order) delivery. Results demonstrate that transport of each fraction can be represented by these limiting categories, but fractions illustrate differing elution rates during the same event. Event-based signatures for PM or P are controlled by the fraction that dominates the transported mass. Even for small source area catchments such as roadways without complex flow patterns, where first-order transport should dominate, transport of P and PM fractions is not consistently first-order; exceptions are mainly dissolved and suspended fractions. A water quality volume (WQV) for 25 mm of runoff resulted in 100% capture for all fractions of seven events and significant bypass for all fractions of a single event with a 1-year return frequency. By contrast, a WQV of 5 mm of runoff resulted in significant bypass for most fractions for seven events and 100% capture for the single event of the lowest runoff volume.     

Early participation in an HIV cohort study slows disease progression and improves survival. The Swiss HIV Cohort Study

Unprecedented mortality occurred in bald eagles (Haliaeetus leucocephalus) at DeGray Lake, Arkansas, during the winters of 1994-1995 and 1996-1997. The first eagles were found dead during November, soon after arrival from fall migration, and deaths continued into January during both episodes. In total, 29 eagles died at or near DeGray Lake in the winter of 1994-1995 and 26 died in the winter of 1996-1997; no eagle mortality was noted during the same months of the intervening winter or in the earlier history of the lake. During the mortality events, sick eagles were observed overflying perches or colliding with rock walls. Signs of incoordination and limb paresis were also observed in American coots (Fulica americana) during the episodes of eagle mortality, but mortality in coots was minimal. No consistent abnormalities were seen on gross necropsy of either species. No microscopic findings in organs other than the central nervous system (CNS) could explain the cause of death. By light microscopy, all 26 eagles examined and 62/77 (81%) coots had striking, diffuse, spongy degeneration of the white matter of the CNS. Vacuolation occurred in all myelinated CNS tissue, including the cerebellar folia and medulla oblongata, but was most prominent in the optic tectum. In the spinal cord, vacuoles were concentrated near the gray matter, and occasional swollen axons were seen. Vacuoles were uniformly present in optic nerves but were not evident in the retina or peripheral or autonomic nerves. Cellular inflammatory response to the lesion was distinctly lacking. Vacuoles were 8-50 microns in diameter and occurred individually, in clusters, or in rows. In sections stained by luxol fast blue/periodic acid-Schiff stain, the vacuoles were delimited and transected by myelin strands. Transmission electron microscopy revealed intramyelinic vacuoles formed in the myelin sheaths by splitting of one or more myelin lamellae at the intraperiodic line. This lesion is characteristic of toxicity from hexachlorophene, triethyltin, bromethalin, isonicotinic acid hydrazide, and certain exotic plant toxins; however, despite exhaustive testing, no etiology was determined for the DeGray Lake mortality events. This is the first report of vacuolar myelinopathy associated with spontaneous mortality in wild birds.     

Performance Evaluation of Aerated Lagoon in Summer and Winter Conditions

A 1-year study evaluated the performance of a full-scale aerated lagoon, located in a midwest community in the United States. The objective of this study was to evaluate the performance of the lagoon under varied temperature conditions. The main parameters for evaluation were 5-day biochemical oxygen demand, total suspended solids, and ammonia-N. In addition, phosphorus and bacteriological qualities of the effluent were investigated. In general, the facility met 5-day biochemical oxygen demand and suspended solids limits required by the National Pollutant Discharge Elimination System. The lagoon reduced the ammonia-N concentration efficiently during late spring, summer, and fall, with values ranging from 0.3 to 4.2 mg∕L. In the winter period the activities of the nitrifying bacteria diminished, resulting in a reduced nitrification rate. The ammonia-N during winter ranged from 8.8 to 23 mg∕L. During the spring months (March to May) the nitrification rate slowly increased with the rise in temperature. This reflects the time period and environment necessary to reach an effective nitrification population in the system. The adjustment period was reversed in the fall months with a declining population of nitrifiers and decreased nitrification rates. The effluent total phosphate levels ranged from 0.6 to 4.9 mg∕L. Effluent fecal coliform values ranged from 10 to 1,110∕100 mL.     

Snow Characterization at a City Snow Storage Facility

A field investigation involving snow coring, surveying, and melt water collection was undertaken at a city snow storage facility to characterize the snow and melt water in Edmonton, Alberta, Canada. The investigation revealed a high content of both salts and sediment within the snow, a pile volume of 500,000?m3, a snow density of 0.63–0.83?g/cm3, and an average road salt content of 1.2 g/L within the melted snow. The salt within the Poundmaker snow pile, one of Edmonton’s five snow storage sites, represented approximately 1.5–2.0% of the total amount of salt that was used on the city roads during the 2006/2007 winter. Melt water fractionation took place on-site during the spring melt and salt concentrations in the March melt water (early spring) were often more than 10 times the concentration of the bulk snow. Some of the factors affecting the snow and melt water composition included the snow retention time on streets, snow source, weather/climate, sampling technique, and snow site characteristics/operations.     

Pipe Heating System with Underground Water Tank for Snow Thawing and Ice Prevention on Roads and Bridge Decks

In order to prevent traffic accidents on snow-covered bridge decks, the writers developed a new pipe heating system that uses only groundwater stored in a large underground tank. The underground tank provides geothermal energy, i.e., groundwater of constant temperature, through heating pipes embedded in concrete pavements with no electric heater or fuel boiler. The pipe heating system was constructed at approximately 50% of the cost of comparable systems. In addition, there is a reduction of 10% in operating costs compared with the previous system. The present paper outlines its design and construction and provides fundamental data for the developed system. The piped heating system has kept the road conditions safe during the winter season by always removing the snow and ice from the heated road and bridge sections earlier than the surrounding roads. According to long-term temperature measurements, this system has prevented the road temperature from decreasing below 0°C, even through nighttime and morning periods. This report presents the system as an economical and effective solution for snow thawing and ice prevention.     

Accretion and Partitioning of Heavy Metals Associated with Snow Exposed to Urban Traffic and Winter Storm Maintenance Activities. II

Compared to storm water runoff, urban roadway snow exposed to traffic and winter maintenance practices has a much greater capacity to accumulate and retrain heavy metals and other anthropogenic constituents. Heavy metals once released in the environment are not degraded and partition between the dissolved and particulate-bound fractions. Residence time, solid loadings, alkalinity, hardness, and pH influence partitioning. Accretion and partitioning of Pb, Cu, Cd, Zn, Al, Ca, Na, Mg, and Fe from a series of urban highway sites in Cincinnati, Ohio, are compared to temporal accretion trends at a control site removed from the highway environment. Results from partitioning analysis indicate that Pb, Cu, Cd, Zn, Al, Mg, and Fe were all highly particulate bound, while Na and Ca were mainly dissolved for all highway sites. Partition coefficients for most heavy metals in snowmelt ranged from 103 to 106?L/kg. Concentrations for Pb, Cu, Cd, Zn, and cyanide were orders of magnitude higher than at the control site and exceeded storm water runoff concentrations by one to two orders of magnitude. For residuals analyses, the specific surface area generally increased with decreasing particle size while the predominance of total surface area (SA) was associated with the medium to coarser size fractions. Heavy metal mass trends followed similar general trends to that of the SA. Characterization of accretion and partitioning of these metals is a necessary first step toward development of management and treatment strategies designed to address urban snow pollution.     

Impact of Annual Average Daily Traffic on Highway Runoff Pollutant Concentrations

The objective of this study was to evaluate correlations between annual average daily traffic (AADT) and storm water runoff pollutant concentrations generated from California Department of Transportation (Caltrans) highway sites. Analyses of data collected from the Caltrans four-year (1997–2001) highway runoff characterization program revealed that, in general, pollutant concentrations from urban highways were higher than those found from nonurban highways. For a limited number of pollutants, however, the concentrations from nonurban highways were found to be higher than the concentrations from urban highways. No direct linear correlation was found between highway runoff pollutant event mean concentrations and AADT. However, through multiple regression analyses, it was shown that AADT has an influence on most highway runoff constituent concentrations, in conjunction with factors associated with watershed characteristics and pollutant build-up and wash off. The other noticeable factors shown to influence the accumulation of pollutants on highways were antecedent dry period, drainage area, maximum rain intensity, and land use.     

Mortality during the 1996/7 winter

There was a sharp peak in mortality during the 1996/7 winter, resulting in an estimated 49 thousand excess deaths. This article describes the timing of the winter peak, the population affected and the main causes of death. The relationship between excess winter mortality, temperature and influenza is also explored. The peak in the number of deaths in December 1996 and January 1997 coincided with a peak in the number of deaths attributed to influenza and with low temperatures. However, the excess winter mortality was higher than expected, based on the experience of previous winters.     

Physiologic responses of preparturient and postparturient Holstein-Friesian cows to summer heat stress in Arizona

A group of 18 Holstein-Friesian cows were studied in central Arizona to evaluate seasonal heat stress factor in preparturient and postparturient dairy cows. Physiologic measurements were made within 2 weeks before calving and within 1 week after calving. The studies were conducted during the cool winter months of December and Janurary and during the hot summer months of July, August, and September. Comparisons were made of rectal temperatures, vaginal temperatures, skin temperatures, respiratory rates, and heart rates between the 2 groups of preparturient and postparturient cows and between the 2 seasons of the year. Rectal temperatures, vaginal temperatures, skin temperatures, and respiratory rates of both preparturient and postparturient cows were significantly higher during the hot weather season than during the cool weather season. Heart rate was not significantly affected by hot weather. The respiratory rates, heart rates, and rectal temperatures of preparturient cows were significantly higher than in postparturient cows during cool weather; however, this relationship was masked by hot weather.