Heavy Metals in Urban Soils of East St. Louis,IL, Part I: Total Concentration of Heavy Metals in Soils

ABSTRACT

The city of East St. Louis, IL, has a history of abundant industrial activities including smelters of ferrous and non-ferrous metals, a coal-fired power plant, companies that produce organic and inorganic chemicals, and petroleum refineries. A protocol for soil analysis was developed to produce sufficient information on the extent of heavy metal contamination in East St. Louis soils. Soil cores representing every borough of East St. Louis were analyzed for heavy metals—As, Cd, Cu, Cr, Hg, Ni, Pb, Sb, Sn, and Zn. The topsoil contained heavy metal concentrations as high as 12.5 ppm Cd, 14,400 ppm Cu, ppm quantities of Hg, 1860 ppm Pb, 40 ppm Sb, 1130 ppm Sn, and 10,360 ppm Zn. Concentrations of Sb, Cu, and Cd were well correlated with Zn concentrations, suggesting a similar primary industrial source. In a sandy loam soil from a vacated rail depot near the bank of the Mississippi River, the metals were evenly distributed down to a 38-cm depth. The clay soils within a half-mile downwind of the Zn smelter and Cu products company contained elevated Cd (81 ppm), Cu (340 ppm), Pb (700 ppm), and Zn (6000 ppm) and displayed a systematic drop in concentration of these metals with depth. This study demonstrates the often high concentration of heavy metals heterogeneously distributed in the soil and provides baseline data for continuing studies of heavy metal soil leachability.     

Heavy metals in urban soils of East St. Louis, IL. Part II: Leaching characteristics and modeling

The city of East St. Louis, IL, has a history of abundant industrial activities including smelters of ferrous and non-ferrous metals, a coal-fired power plant, companies that produced organic and inorganic chemicals, and petroleum refineries. Following a gross assessment of heavy metals in the community soils (see Part I of this two-part series), leaching tests were performed on specific soils to elucidate heavy metal-associated mineral fractions and general leachability. Leaching experiments, including the Toxicity Characteristic Leaching Procedure (TLCP) and column tests, and sequential extractions, illustrated the low leachability of metals in East St. Louis soils. The column leachate results were modeled using a formulation developed for fly ash leaching. The importance of instantaneous dissolution was evident from the model. By incorporating desorption/adsorption terms into the source term, the model was adapted very well to the time-dependent heavy metal leachate concentrations. The results demonstrate the utility of a simple model to describe heavy metal leaching from contaminated soils.     

Heavy metals in urban soils of East St. Louis, IL, Part I: Total concentration of heavy metals in soils

The city of East St. Louis, IL, has a history of abundant industrial activities including smelters of ferrous and non-ferrous metals, a coal-fired power plant, companies that produce organic and inorganic chemicals, and petroleum refineries. A protocol for soil analysis was developed to produce sufficient information on the extent of heavy metal contamination in East St. Louis soils. Soil cores representing every borough of East St. Louis were analyzed for heavy metals--As, Cd, Cu, Cr, Hg, Ni, Pb, Sb, Sn, and Zn. The topsoil contained heavy metal concentrations as high as 12.5 ppm Cd, 14,400 ppm Cu, ppm quantities of Hg, 1860 ppm Pb, 40 ppm Sb, 1130 ppm Sn, and 10,360 ppm Zn. Concentrations of Sb, Cu, and Cd were well correlated with Zn concentrations, suggesting a similar primary industrial source. In a sandy loam soil from a vacated rail depot near the bank of the Mississippi River, the metals were evenly distributed down to a 38-cm depth. The clay soils within a half-mile downwind of the Zn smelter and Cu products company contained elevated Cd (81 ppm), Cu (340 ppm), Pb (700 ppm), and Zn (6000 ppm) and displayed a systematic drop in concentration of these metals with depth. This study demonstrates the often high concentration of heavy metals heterogeneously distributed in the soil and provides baseline data for continuing studies of heavy metal soil leachability.     

Characteristics of regional nucleation events in urban East St. Louis

Continuous measurements of aerosol size distributions (3 nm–2 μm) were carried out over a 26 month period (1 April 2001–31 May 2003; 650 days with valid data) in urban East St. Louis, IL, as a part of the US Environmental Protection Agency's Supersite program. This paper analyzes data for the 155 days on which “regional nucleation events” were observed during this study. Such events were observed during every month of the study except January 2003. We observed some differences, however, between events in the summer (defined here as April–September) and winter (December–February). Regional nucleation events were observed more frequently in summer months (36±13% of days) than in winter (8±7%), and nucleated particles grew faster in the summer (6.7±4.8 nm h⁻¹) than in winter (1.8±1.9 nm h⁻¹). The daily maximum in the number concentration of nanoparticles formed by nucleation (4.8±3.5×10⁴ cm⁻³) was highly variable and showed no clear seasonal dependence. Particle formation increased particle concentrations by an average factor of 3.1±2.8. Maximum daily rates of 3 nm particle production (17±20 cm⁻³ s⁻¹) were also highly variable and without a clear seasonal dependence. During these events, particle formation rates were typically near their maxima at 08:00–09:00 a.m., but particle production sometimes persisted at diminishing rates until late in the afternoon (15:00–16:00 p.m.).     

The Evolution of Visibility Deterioration and Aerosol Spectra in the St. Louis Urban Plume

Under the auspices of Project METROMEX, studies of visibility de-teoration downwind of St. Louis were conducted during July-August 1974-1975. Estimates of horizontal visual range, standard meteorological data, and aerosol characteristics within the mixing layer were acquired upwind, over, and downwind of the metropolitan area by means of airborne transects. Aerosol number, surface, and volume distributions for particles between 0.025-2.5 µm were generated from the airborne measurement of Aitken nucleus concentrations, cloud condensation nuclei, and aerosols detected in situ with optical probes. Visibility reduction amounting to 50% of prevailing regional upwind visibilities consistently occurs at a distance corresponding to 2-3 hours travel time downwind for an air parcel moving with the mean transport wind. The regions of visibility minimum do not coincide with locations of maximum Aitken nucleus concentrations, but rather correspond in space and time to increased values of cloud condensation nuclei and increased numbers of particles in the 0.1-2.5 µm diameter range. Comparisons of observed aerosol evolution with similar laboratory studies suggest that most of the light scattering aerosols are of secondary origin.     

Gaseous Pollutants in St. Louis and Other Cities

During the fall of 1972, a study was undertaken to characterize gaseous air pollutants in the St. Louis metropolitan area. Information obtained in this study will be used in planning air pollution modeling studies to be carried out over the next 4 or 5 years under the Regional Air Pollution Study (RAPS) of the Environmental Protection Agency. From analyses of roadway samples, it was found that certain compounds in automotive emissions such as acetylene, carbon monoxide, o-xylene, ethylene, and 2-methylpentane occur in consistent proportions to other compounds. The concentrations of these indicator compounds in atmospheric samples were used to estimate the amounts of other hydrocarbons present that are attributable to automotive related emissions. Methane, ethane, and propane were found to originate principally from nonautomotive sources, both at St. Louis University and the St. Louis CAMP station. Similar concentrations were found in urban and non-urban areas. A comparison of ethylene-CO and propyl-ene-CO ratios in urban and non-urban areas indicates that CO can serve as an indicator of transport of urban pollutants. Sunlight irradiations of captured air samples showed increasing ozone production with increasing initial concentrations of hydrocarbons and nitrogen oxides. Substantial ozone and peroxyacetyl nitrate were formed from a total non-methane hydrocarbon concentration of only ¹/₄ ppm C.     

Public Awareness and Concern with Air Pollution in the St. Louis Metropolitan Area

The public attitudes survey involving St. Louis City, St. Louis County, and Madison and St. Clair Counties, Illinois, was completed and published in the fall of 1964. A total of 1002 respondents gave needed information for the development of an acceptable abatement program. Substantial proportions from the study area expressed the view that they have had some negative reaction to the quality of the air. These respondents indicated that air pollution meant, primarily, odor and smoke with residents of some localities indicating other significant elements. The interviewed persons felt that factories and businesses were the prime causal agents in the existence of air pollution. Over 90 percent of all respondents felt that some governmental agency should do something about air pollution in the St. Louis area, with some bi-state metropolitan agency being the principal choice. The residents also expressed a willingness to pay minimal tax support for such a program. Indications as to the significance of air pollution in a general problems context, difference in attitudes between sub-sections of the study area, and more detailed analysis of the problem, its causes, and possible cures are contained in the study r     

Day of the week variations of photochemical pollutants in the St. Louis area

As part of the Environmental Protection Agency's Regional Air Pollution Study (RAPS) a network of 25 stations continuously recorded aeromatic data in the Greater St. Louis area. Various photochemical pollutants (O₃, NO, NO₂ and total hydrocarbons) and some selected meteorological variables (wind speed, temperature, and solar radiation) were analyzed with respect to the day of the week using 11 months of data collected during the warm months of the year — periods during which high ozone concentrations were common in St. Louis. The results reveal that the sign (±) of the workday to Sunday differences in the concentration of ozone depends to a large extent on the distance of the measurement from the major emission area of the metropolitan area of St. Louis. The data suggest that this is due to the impact of nitric oxide on the ambient ozone concentrations. This appears to offer at least a partial explanation for some of the contrasting results reported by various investigators regarding the differences in ozone concentrations between weekends and weekdays.     

Sediment processes and mercury transport in a frozen freshwater fluvial lake (Lake St. Louis, QC, Canada)

An open-bottom and a closed-bottom mesocosm were developed to investigate the release of mercury from sediments to the water column in a frozen freshwater lake. The mesoscosms were deployed in a hole in the ice and particulate mercury (Hg_P) and total dissolved mercury (TDHg) were measured in sediments and in water column vertical profiles. In addition, dissolved gaseous mercury (DGM) in water and mercury water/airflux were quantified. Concentrations of TDHg, DGM, and mercury flux were all higher in the open-bottom mesocosm than in the closed-bottom mesocosm. In this paper we focus on the molecular diffusion of mercury from the sediment in comparison with the TDHg accumulation in the water column. We conclude that the molecular diffusion and sediment resuspension play a minor role in mercury release from sediments suggesting that solute release during ebullition is an important transport process for mercury in the lake.     

Radiative heating rates and some optical properties of the St. Louis aerosol,as inferred from Aircraft measurements

Radiative heating rates were determined from measurements made aboard an aircraft flying within and above the St. Louis boundary layer during the Regional Air Pollution Study (RAPS; 1975–1976). In the mean, heating rates tor both solar and infrared radiation were found to diminish steadily from a maximum near the surface to nearly zero above the mixing layer. Similarly, there was a mean decrease in large particle aerosol concentrations and in extinction coefficient with height to insignificant values above the mixing layer. Over the entire mixing depth, there was an average net solar warming and an average net longwave cooling due to the presence of aerosol. When normalized for a 24 h period the solar warming was found to be very slightly less than the magnitude of the long-wave cooling, although the former somewhat exceeded the latter during midday. Derived values of the asymmetry parameter and single scattered albedo were large, the value for each averaging close to 0.9. The ratio of backscatter to absorption for the aerosol was approximately unity.Thus the arosol was not a strongly absorbing material and. consequently, the aerosol healing or cooling rates were not very large within the St. Louis mixing layer and the total (solar + IR) effect of the temperature changes on the atmospheric motions were likely to have been insignificant.     

Relationships between direction of wind flow and ozone inflow concentrations at rural locations outside of St. Louis,MO

The relationships between the monthly and seasonal averages of the daily 1200–1500 h O₃ inflow concentrations and wind flow direction have been evaluated. The O₃ measurements used are those during inflow of air parcels from upwind to rural monitoring stations outside of St. Louis, MO. The results obtained are consistent with the O₃ measurements reported from other monitoring studies at rural locations both to the west and east of St. Louis. Although there is a stratospheric component to these ground level rural O₃ concentrations, it is likely that most of the O₃ measured during the warmer months of the year is associated with photochemical O₃ formation in the planetary boundary layer and in the free troposphere. A substantial part of the increments in rural O₃ concentrations which occur from west to east of St. Louis during the warmer months of the year appear best to be accounted for as a result of photochemical formation O₃ precursors from anthropogenic emission sources to the east of St. Louis. Differences in the values of meteorological parameters with wind flow direction account for only a small part of the differences in O₃ concentration observed.     

A chemical model for urban plumes: Test for ozone and particulate sulfur formation in St. Louis urban plume

A chemical model with anthropogenic sources of nitrogen oxides and hydrocarbons is applied to simulate the chemical behaviour of pollutants in the St. Louis urban plume. It is suggested that a substantial increase in peroxy radical concentrations (HO₂,RO₂) in the polluted air mass outside its source region leads to an effective formation of secondary pollutants like ozone and sulfate particles. The model indicates characteristic time for ozone generation in the plume of a few hours. Maximum ozone mixing ratio of 115 ppb is predicted after 4 h transport time outside the source region. Conversion rates of SO₂ to H₂SO₄ through gas phase reactions with hydroxyl and peroxy radicals are estimated to be 1–5%h⁻¹. This leads to an approx 25% conversion of SO₂ to paniculate sulfur in the plume during the day. Agreement with measured ozone concentrations and flow rates of ozone and participate sulfur in the St. Louis plume on 18 July 1975 can be taken as strong indications that ozone and sulfate particle formation in the plume proceeds through the suggested mechanisms.     

Relationships involving fine particle mass,fine particle sulfur and ozone during episodic periods at sites in and around St. Louis,Mo

The measurements during episodic periods in the St. Louis area in 1975 and 1976 of fine particle sulfur, fine particle mass and ozone are related. Such episodes are concentrated into time periods in the late spring and summer months. During such episodes, particle sulfur is the major constituent of the fine particle mass. The sum of the non-sulfur species in the fine particle mass do not show similar episodic patterns as the fine particle sulfur.Elevated concentrations of fine particle sulfur and of ozone usually occur together within the same episodic time periods. However, the day to day variations in fine particle sulfur and of ozone do differ somewhat within these time periods.Both fine particle sulfur and ozone show the influence of regional scale and local scale atmospheric photochemical processes on their formation during episodic time periods. Regional scale boundary layer processes frequently appear to contribute more to fine particle sulfur concentrations than to ozone formation. Local scale primary emissions also contribute to the ambient fine particle sulfur concentrations at core urban locations.     

Effects of Soil Amendments at a Heavy Loading Rate Associated with Cover Crops as Green Manures on the Leaching of Nutrients and Heavy Metals from a Calcareous Soil

The potential risk of groundwater contamination by the excessive leaching of N, P and heavy metals from soils amended at heavy loading rates of biosolids, coal ash, N‐viro soil (1:1 mixture of coal ash and biosolids), yard waste compost and co‐compost (3:7 mixture of biosolids to yard wastes), and by soil incorporation of green manures of sunn hemp (Crotalaria juncea) and sorghum sudangrass (Sorghum bicolor × S. bicolor var. sudanense) was studied by collecting and analyzing leachates from pots of Krome very gravelly loam soil subjected to these treatments. The control consisted of Krome soil without any amendment. The loading rate was 205 g pot^? 1 for each amendment (equivalent to 50 t ha^? 1 of the dry weight), and the amounts of the cover crops incorporated into the soil in the pot were those that had been grown in it. A subtropical vegetable crop, okra (Abelmoschus esculentus L.), was grown after the soil amendments or cover crops had been incorporated into the soil. The results showed that the concentration of NO₃‐N in leachate from biosolids was significantly higher than in leachate from other treatments. The levels of heavy metals found in the leachates from all amended soils were so low, as to suggest these amendments may be used without risk of leaching dangerous amounts of these toxic elements. Nevertheless the level of heavy metals in leachate from coal ash amended soil was substantially greater than in leachates from the other treatments. The leguminous cover crop, sunn hemp, returned into the soil, increased the leachate NO₃‐N and inorganic P concentration significantly compared with the non‐legume, sorghum sudangrass. The results suggest that at heavy loading rates of soil amendments, leaching of NO₃ ^? could be a significant concern by application of biosolids. Leaching of inorganic P can be increased significantly by both co‐compost and biosolids, but decreased by coal ash and N‐viro soil by virtue of improved adsorption. The leguminous cover crop, sunn hemp, when incorporated into the soil, can cause the concentration of NO₃‐N to increase by about 7 fold, and that of inorganic P by about 23% over the non‐legume. Regarding the metals, biosolids, N‐viro soil and coal ash significantly increased Ca and Mg concentrations in leachates. Copper concentration in leachate was increased by application of biosolids, while Fe concentration in leachates was increased by biosolids, coal ash and co‐compost. The concentrations of Zn, Mo and Co in leachate were increased by application of coal ash. The concentrations of heavy metals in leachates were very low and unlikely to be harmful, although they were increased significantly by coal ash application.     

Long-range transport of acidifying substances in East Asia—Part II: Source–receptor relationships

Region-to-grid source–receptor (S/R) relationships are established for sulfur and reactive nitrogen deposition in East Asia, using the Eulerian-type Community Multiscale Air Quality (CMAQ) model with emission and meteorology data for 2001. We proposed a source region attribution methodology by analyzing the non-linear responses of the CMAQ model to emission changes. Sensitivity simulations were conducted where emissions of SO₂, NO_x, and primary particles from a source region were reduced by 25%. The difference between the base and sensitivity simulations was multiplied by a factor of four, and then defined as the contribution from that source region. The transboundary influence exhibits strong seasonal variation and generally peaks during the dry seasons. Long-range transport from eastern China contributes a significant percentage (>20%) of anthropogenic reactive nitrogen as well as sulfur deposition in East Asia. At the same time, northwestern China receives approximately 35% of its sulfur load and 45% of its nitrogen load from foreign emissions. Sulfur emissions from Miyakejima and other volcanoes contribute approximately 50% of the sulfur load in Japan in 2001. Sulfur inflows from regions outside the study domain, which is attributed by using boundary conditions derived from the MOZART global atmospheric chemistry model, are pronounced (10–40%) over most parts of Asia. Compared with previous studies using simple Lagrangian models, our results indicate higher influence from long-range transport. The estimated S/R relationships are believed to be more realistic since they include global influence as well as internal interactions among different parts of China.     

Relationships between direction of wind flow and fine particle sulfur concentrations within and upwind of St Louis,MO

The relationships are considered between monthly and quarterly means of the fine particle sulfur (S) concentrations and wind flow direction, period of day and season of the year. The measurements used are those obtained at selected urban and at rural monitoring stations in the St Louis area during the Regional Air Pollution Study in 1975, 1976 and 1977. Higher mean fine particle S concentrations are observed with wind flows from the E compared to the W and from the NE and SE quadrants compared to the NW quadrant. Substantially higher fine particle S concentrations are obtained with wind flows from the E compared to the W even when conditions are selected so that the values of temperature, solar radiation intensity and wind speed are within the same restricted ranges. A consistent increase in the fine particle S concentrations occurs through the late morning and afternoon with decrease in the evening and especially in the early morning during spring and summer months with wind flows from the E.The contributions are estimated for local scale and regional scale processes to the observed fine particle S concentrations. Local scale processes include those involving atmospheric formation and primary emissions each contribute 0.6−1.0 and 0.6 μg m⁻³ of the fine particle S. Regional scale processes account for the greater part of the observed concentrations especially when the wind flows are from the SE or SW. Regional scale episodes involving passage of warm high pressure systems to the E of St Louis with accumulation of precursors made especially significant contributions to formation of fine particle S.The atmospheric gas phase and liquid phase chemical reactions contributing to the formation of fine particle S are discussed. Emphasis is placed on the effects of chemistry on the seasonal variations in concentrations of fine particle S.