Testing for such contamination was conducted by the Department of Nuclear Engineering at the University of Illinois. Samples were taken from a site near a lead smelter plant in St. Louis with the intent that similar studies on sites in East St. Louis would follow. Possible neurological damage is one of many environmental health hazards associated with lead exposure. Wavelength Dispersive X-Ray Flourescence (WDXRF) was used to determine the prescence of lead and other heavy metals from the smelter samples. (Esguerra and Landsberger, 1994)
Through cooperative efforts between the East St. Louis Horticultural Council, and the University of Illinois, the sites for some existing and proposed gardens, located throughout the city, have been tested for soil productivity and presence of contaminants. This report discusses the results of those experiments and their implications for city-wide horticultural production.
Consequences for likely soil conditions
Because of the type of metal industry developed in the area, lead, zinc and cadmium are the trace elements most probable to be found as surface contaminants, deposited from smokestacks at the surrounding plants.
Twelve different sites within the city of East St. Louis were sampled to determine
heavy metal content of urban soils. Sample locations were taken from overlaying a
regular mile-square grid over the city and sampling at each intersection on the grid,
on-site personnel making final choices on the basis of choosing adjacent open land
sites when the point of intersection was paved or otherwise unsuitable.
The sites occur in areas zoned for a variety of uses Five soil samples taken to a depth of 4 inches
with a garden trowel were obtained at each site. The five samples for each site were
combined then the composite samples were air-dried and sent to the Department of
Nuclear Engineering, University of Illinois at Urbana-Champaign. The
determination of heavy metals was performed utilizing Wavelength Dispersive X-
Ray Fluorescence (Esguerrra and Landsberger, Department of Nuclear Engineering,
The principal metals determined in this study are: Lead (Pb), Zinc (Zn), and
Cadmium (Cd). These elements were selected due to their association with the type
of metal industry developed in the area and their potential hazard for humans.
Other elements also evaluated were: Cu, Sn, V, Cr, Sr, Zr, Rb, and Ba. The results of
these analysis (Figure 1) were compared with the range of proposed maximum acceptable concentrations of trace elements in soils for
agricultural activities (Figure 2) (Kabat-Pendias, 1991).
The results indicate that there is considerable variability in the content of Pb, Zn and
Cd in the 12 sampled sites. Nevertheless, the level of these heavy metals in the soil
in many cases is close to or above the limits considered acceptable for agricultural
Consequences of soil texture and organic content for heavy metal take-up
The mobility of heavy metals in soils, and consequently their bioavailability, is
associated with soil characteristics as CEC (Cation Exchangeable Capacity) and
percentage Organic Matter in the mineral soil. The CEC is highly correlated with the
clay content and clay type in the soil (Sillanpa, 1972). For these reasons these two
parameters (texture and organic matter) were determine for the 12 samples analyzed
for heavy metal content. The results of the texture and Organic Matter
determination are presented in Table 5. The soil texture in the 12 sites varies from
48 to 79% sand and the organic matter from 2 % to 6%.
Amelioration and remediation of polluted soils
Although intensive research has been done on heavy metal contaminated soil
remediation, there are aspects of the problem that remain not completely
understood. Moreover, while observed values of trace elements may be quite high,
each trace element has its own response to specific soil-plant conditions, making it
difficult to establish satisfactory generalizations (Sauerberk, 1991). Nevertheless,
some recommendation can be made for sites contaminated by heavy metals.
Some measures to reduce Cadmium (Cd) soil pollution that have been summarized
by Alloway (1990) are also valid for Lead (Pb) and Zinc (Zn) contamination:
1. Removing the polluted soil or covering it with a thick layer of unpolluted
material, can ensure that roots do not reach the underlying polluted soil and that
capillarity and/or evaporation does not bring soluble metals such as Cd into the
2. Adding agricultural lime to achieve ph 7 can reduce bioavailability of metals
and is the most widely used remedial treatment.
3. Increasing the adsorptive capacity of the soil by adding organic matter. The
effectivenes of this practice is highly related to the specific trace element in excess.
The addition of organic matter does not reduce mobility for all metals. It has been
shown that some metals (e.g., Cd and Cu) are mobile as organic chelates. (Sillanpaa,
1972, Lo et.al, 1992)
4. Growing non-food crops , or in cases of slight contamination growing species
or cultivars with a low potential to accumulate Cd.
5. Recently heap leaching has began to be investigated a a tehnique for
remediation of heavy metal contaminated soils (Hanson et al., 1992)
Implications of observed soil conditions in East St. Louis
1. The area analyzed has shown variable but generally high values of Pb, and Cd. In general these values were close to or above the admissible limits for agricultural production. The variability in the type of predominant trace element ant soil characteristics indicate that each site may deserve a different consideration. 2. One important aspect related to the remediation of soils is their situation with respect to sewage flooding -- a common problem in East St. Louis where storm sewers are in a state of decay. Besides all the usual undesirable aspects of this problem, sewage can contain high concentration of heavy metals. Therefore the successful recuperation of a site will be highly dependent on its potential for flooding. The most outstanding characteristic of the East St. Louis soil samples is their variability. However, given that that variability is unavoidable, the concommitant lack of generalization of soil recuperation measures has led to statements such that "the literature does not reveal any generally adequate method for rapid reclamation of soils heavily contaminated by trace metals. The effects of each treatment will depend upon soil properties, mainly on CEC and on plant response. Therefore, the reclamation or improvement of arable land polluted with trace elements needs to be designed to a specific plant-soil system" (Kabata-Pendias, 1990).
LA 437/465 Studio Work Fall94: testing and observation
Soil Texture Triangle
As part of the work for the Urban Land Potential Studio, samples from selected locations around the city were chosen for testing. The intent was to get a feel for the general quality of soils in the area for gardening or other uses. This fall, the class took samples from an additional four sites chosen by Rufus Williams of the USDA Soil Conservation Service as potentially valuable sites for community gardens.
Five samples per site were taken using a common garden trowel to remove 4-6" of topsoil. The five samples on each site were taken one from each of four corners, and one in the center. This was done to account for any variability within a site. The samples were labeled and bagged for future testing. In addition to these four sites, samples from other sites previously sampledwere added, for a total of 26 sites in East St. Louis. Testing for productivity and heavy level metal levels was performed by the Dept. of Nuclear Engineering. Click here to return to that section In addition, the studio performed two separate soil texture tests in order to gain a better understanding of the soil conditions in East St. Louis. The first was a field test which can easily be done by a homeowner. The second method requires lab equipment and is more accurate.
Finally, a rough calculation of organic content was made for each sample using the United States Soil Conservation Service's soil color guide to organic matter content. A chart of painted squares of varying shades of brown were used to compare each sample's color to determine a rough % of organic matter. The results of the grit, ribbon and organic matter field tests were used to get a general idea of the soil properites of the samples. A more accurate lab test was conducted afterwards with the help of University of Illinois Soils Professor John Hassett.
NOTE: samples should be dry before proceeding
1) measure out as close to a 50g. sample as possible on the scales (do not
include rocks, pebbles, clinkers, or large organic material) Note: weight
of cup should be subtracted from the reading either electronically or by
2) record the weight of the sample
3) add 20mg of calgon to the sample of soil in the cup
4) add de-ionized water to get the level in the cup about 1/2 full (about 350ml)
5) mix in mixer for 10 minutes to break up loose particles
6) pour mixed sample into measuring cylinder - wash out the cup with de-ionized water and pour into beaker- add enough de-ionized water to get the sample level even with the 1000ml measuring line on the beaker.
7) put stopper on measuring cylinder and shake 4-5 times (about 20 or so seconds)
8) put in hydrometer and get intitial reading for reference (use a few drops of ethyl alcohol to eliminate any foam on top of sample). The graduated hydrometer will indicate the number of grams of material suspended per liter of water.
9) take reading at 40 seconds after allowing the cylinder to stand. Since this is the time required for heavier sandparticles to drop out of suspension, the hydrometer measure of suspended material will equal the grams of silt and clay still suspended in the solution after the sand has dropped out.
10) subtract this reading from the original sample weight to get the grams of sand.
11) take another reading in 2 hours (this is time required for silt to drop out of suspension). At this time the only particles left in suspension are clay, so the hydrometer reading will equal the remaining grams of clay.
12) add the clay and sand weights together and subtract their sum from the total sample weight to get the grams of silt.
13) by dividing the grams of each particle by the total sample weight, percentages of each particle size can be attained.
The results of the studio's soil testing was informative. The majority of the soil samples seemed to have a high percentage of sand, some approaching 80% or more. Relatively few samples appeared to have been "ideal" garden soils of 40%sand, 40%silt, and 20% clay. A few soils represented a high clay component of 20-30 %. The conclusion is that these reflect an extreme variability of soil condition in East St. Louis. Not only were the percentages of particle size variable, the frequency of non-soil particles in the samples was disturbing. Aside from rocks and grass roots, the most abundant of these non-soil particles were "clinkers". "Clinkers" are rock-like particles that have formed from the residue of coal-fired furnaces used throughout East St. Louis in the past. Such particles were present in over half of the samples.
The presence of clinkers, the high variability in texture results, and the high possiblity of contamination, all indicate the need for a comprehensive soils testing program for the city of East St. Louis. Although this variability is to be expected from a river flood plain, with a history of intense human and industrial use, it suggests that there are no simple rules of thumb that can be used for reliable site selection for growing either for home or industrial-scale food production. All projects, whether they be small-scale gardens or large scale agricultural production, rely on the quality of the soil. The city, therefore, should concentrate effort on a soils initiative in order to identify areas of contamination, areas of poor soil, and areas of productive soil.
1. Alloway, B. J. ed. 1990. Heavy Metals in Soils. Blackie and Son Ltd., London, 339 p.
2. Colten, C. E. 1988. Historical Assesment of Hazardous Waste Management in Madison and St. Clair Counties, Illinois, 1890-1980. HWRIC RR-030.
3. Editor Basics. Fine Gardening. April, 1994.
4. Esguerra,L and Landsberger, S. 1994. Report on Determination of lead and heavy metals in soil samples around a Lead Smelter Plant and Environs in East S. Louis by Wavelenght Dispersive X-Ray Fluorescence.
5. Hanson, A., Samani, Z., Dwyer, B., Jacquez, R. 1992. Heap leaching as a solvent- extraction technique for remediation of metal-contaminated soils. ACS-sym-ser (American Chemical Society) 491 pp 108-121.
6. Hassett, John. Interview, Professor of Soils. University of Illinois. November 1994.
7. Kabat-Pendias, A. and Pendias, H., 1992. Trace Elements in Soils and Plants. CRC Press, Boca Raton, FL, 2nd. ed.,365 pp.
8. Lo, K.S.L., Yang, W.F., Lin, Y. C. 1992. Effect of organic matter on the specific absorption of heavy metals by soil. Pp 139-153 in: Toxicol. Environ. Chem. V 34 (2/4) Gordon and Breach Publishers.
9. Sauerbeck, D. R. 1991. Plant, element and soil properties governing uptake and availability of heavy metals derived from sewage sludge. Water, Air, and Soil Pollution 57-58: 227-237.
10. Sillanpaa, M. 1972. Trace elements in soils and agriculture. FAO Soils Bulletin 17.
Document author(s) : LA 437/465 Fall 1995
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Citizens, Gardens, and Soil
East St. Louis Action Research Project