Nachweis von Natural Attenuation mittels Isotopenuntersuchungen an einem ehemaligen Kokereistandort

Natural attenuation of mono- (BTEX) and polycyclic aromatic hydrocarbons (PAHs) was studied in groundwater at a former gas plant site over a distance of about 500 m. The contamination source was located within a 4–6 m thick succession of interbedded silt and sand (K _f =1,4?10^?7 m/s) at a depth of about 5–6 m below the surface. Groundwater flow times between source and the receiving surface waters were determined on the order of a few hundred years. The main contaminants were found to be benzene and naphthalene with concentrations up to 200,000 and 8,500 μg/l, respectively. Over the past 9 years, concentrations within the contaminant plume have decreased and degradation of benzene was proven by compound specific carbon isotope analyses. In addition, sulphur isotope studies revealed that sulphate reduction has played a significant role. This was supported by ambient sulphate concentrations of 300–1,800 μg/l at the site that are sufficient to sustain a long-term perspective for this process. In agreement with these physico-chemical conditions, no transfer of BTEX or PAHs from the plume into the nearby river has been observed.     

Sulfat-dominierter BTEX-Abbau im Grundwasser eines ehemaligen Gaswerksstandortes

In the area of a former gas-works in Düsseldorf (Germany) a soil and groundwater contamination with up to 100 mg/l BTEX (benzene, toluene, ethylbenzene and xylenes) was investigated. Benzene is the dominant aromatic hydrocarbon in the groundwater. The investigations show a natural biodegradation of BTEX by oxygen, manganese oxides, nitrate, ferric hydroxide and sulfate in the sand and gravel aquifer. Sulfate reduction is the most important degradation process in the contamined groundwater. As a product of sulfate reducion, sufids were formed in the sediments of the aquifer. A balance of oxidants is presented as a tool to quantify BTEX degradation and to differ this from sorption and dilution processes. In the contaminated area the degradation of aromatic hydrocarbons leads to the release of carbon dioxide. The highest free CO ₂ -concentration was found in the region of the groundwater table. Outgassing of CO ₂ is important and was verified by deep-specific soil-gas sampling. The knowledge of these processes in the subsoil is a requirement for making predictions for in-situ remediation effects.     

Microcosms-experiments to assess the potential for natural attenuation of contaminated groundwater

Groundwater samples from six wells of a former gas plant site were characterised using chemical, microbial and ecotoxicological methods. Degradation studies were performed in batch-culture under aerobic conditions with the groundwater samples containing their autochthonous microflora and original contaminant mixture. The highest O2-consumption (3 mmol 100 ml-1), combined with BTEX (8.3 mg l-1) and naphthalene (171.3 mg l-1) degradation, as well as formation of organic acids was found after N- and P-supplementation with the highest contaminated groundwater sample. The other highly polluted groundwater sample showed no activity obviously because of the toxicity of some compounds. The major part of the PAHs and BTEX was eliminated in the assays with the low contaminated groundwater samples. The results indicate that the microbial degradation capacity and thereby the natural attenuation capacity in each groundwater differ and cannot be assessed simply by chemical, microbial and toxicological data. Additionally activity tests with authentic groundwater samples with and without nutrient supplementation are recommended.     

Abbau aromatischer Kohlenwasserstoffe und Metabolitenbildung im Grundwasserleiter eines ehemaligen Gaswerkstandorts

Hydrochemical investigations were performed at a contaminated site in the area of a former gasplant at Düsseldorf, Germany, between October, 1995 and November, 1996. The changes of the biodegradation processes in the aquifer during the remediation of groundwater and soil were monitored. The organic contaminants present in the groundwater were mainly BTEX (benzene, toluene, ethylbenzene, xylenes) and low moleuclar weight PAH (plycyclic aromatic hydrocarbons). At the beginning of the remediation activities, natural degradation of the contaminants occurred with sulfate reduction as the prevailing terminal electron accepting process. Due to oxygen input into the aquifer during soil removal the biodegradation process was disturbed and the concentrations of aromatic hydroarbons and sulfate rose significantly. The aromatic acids occuring as metabolites of the aromatic hydrocarbons reacted specifically to the changes in the degradation processes.     

The influence of nitrate leaching through unsaturated soil on groundwater pollution in an agricultural area of the Basque country: a case study

The average nitrate concentration in the groundwater of the Vitoria-Gasteiz (Basque Country) quaternary aquifer rose from 50 mg NO3-/l during 1986 to over 200 mg/l in 1995, which represents an increase of some 20 mg NO3-/l per year. From 1995 to 2002, the nitrate concentration of the groundwater slightly decreased. Nitrate groundwater pollution during the period 1986-1993 was the result of the abusive use of fertilizers and of the modification in the recharge patterns of the aquifer from surface water sources. From 1993 onwards, apart from a possible rationalization in fertilizer use, the change in the origin of water for irrigation and wetland restoration (water is taken now from artificial pools outside the quaternary aquifer) must be explained in order to account for the observed decrease in nitrate concentration in the groundwater. The water of the aquifer and of the unsaturated zone were studied in two experimental plots (one of them cultivated and the other uncultivated) for 18 months (January 1993-June 1994), during the period of maximum contamination, to evaluate the effect of fertilizers on soil water and on the water in the saturated zone. The soil water was sampled using soil lysimeters at various depths. The volumetric water content of the soil was measured at the same depths using time domain reflectrometry (TDR) probes. Samples of groundwater were taken from a network of wells on the aquifer scale, two located close to the two experimental plots. The temporal evolution of nitrate concentrations in soil solutions depends on the addition of fertilizers and on soil nitrate leaching by rain. During episodes of intense rain (>50 mm in a day), the groundwater deposits are recharged with water coming from the leaching of interstitial soil solutions, causing an increase in the groundwater nitrate concentrations. The mass of nitrate leached from the cultivated zone is five times higher than that of the nitrate leached from the uncultivated zone (1147 kg NO3-/ha in the cultivated sector as against 211 kg NO3-/ha in the uncultivated sector), although part of the nitrate leached into the soil had been previously deposited by the rise of the water table. If we consider that the level of groundwater input is similar in both plots, we may conclude that 964 kg NO3-/ha circulated towards the groundwater in the cultivated zone during the period under study, representing 87% of the nitrate applied to the soil in the form of fertilizer during that period.     

Impact of irrigating rice paddies with groundwater containing arsenic in Bangladesh

Soil and soil-water As profiles were obtained from 4 rice paddies in Bangladesh during the wet growing season (May-November), when surface water with little arsenic is used for irrigation, or during the dry season (January-May), when groundwater elevated in arsenic is used instead. In the upper 5 cm of paddy soil, accumulation of 13+/-12 mg/kg acid-leachable As (n=11) was observed in soil from 3 sites irrigated with groundwater containing 80-180 microg/L As, whereas only 3+/-2 mg/kg acid-leachable As (n=8) was measured at a control site. Dissolved As concentrations averaged 370+/-340 microg/L (n=7) in the upper 5 cm of the soil at the 3 sites irrigated with groundwater containing 80-180 microg/L As, contrasting with soil water As concentrations of only 18+/-7 microg/L (n=4) over the same depth interval at the control site. Despite the accumulation of As in soil and in soil water attributable to irrigation with groundwater containing elevated As levels, there is no evidence of a proportional transfer to rice grains collected from the same sites. Digestion and analysis of individual grains of boro winter rice from the 2 sites irrigated with groundwater containing 150 and 180 microg/L As yielded concentrations of 0.28+/-0.13 mg/kg (n=12) and 0.44+/-0.25 mg/kg (n=12), respectively. The As content of winter rice from the control site was not significantly different though less variable (0.30+/-0.07; n=12). The observations suggest that exposure of the Bangladesh population to As contained in rice is less of an immediate concern than the continued use of groundwater containing elevated As levels for drinking or cooking, or other potential consequences of As accumulation in soil and soil-water.     

Spatial variation of boron in groundwater in South Iraq

The research investigated boron variability in space and time, using 450 groundwater samples from 75 representative wells in the Safwan–Zubair area of Basra district, South Iraq, collected monthly from January to June 2000, with also 75 soil samples from selected farms in the same area. Minimum and maximum values of boron concentrations range from 1.49 to 9.49 ppm respectively. Boron concentration in groundwater spatially occurs in 90% in frequency between 2 and 4 ppm, while 5% below 2 ppm and 5% is more than 4.0 ppm to more than 9.0 ppm, where the soluble boron concentrations of soil samples range from 0.60 to 7.02 ppm. Soil boron concentration spatially occurs 95% below 6.0 ppm and 5% more than 6.0 ppm. The results show that the variability of boron concentration in groundwater and in soil mostly depends upon irrigation water, cyclic differences of the sediment facies horizontally and vertically, and also the period of precipitation (rainfall); i.e. wetting and drying processes. The results indicate that there will always be available boron in the soil at the end of the irrigation period (May–June) ready to be leached again by the first percolated rainfall (effective rainfall) to join the groundwater at higher concentration. The results show that the variability of boron concentration in groundwater and in soil mostly depends upon irrigation water, cyclic differences of the sediment facies horizontally and vertically, and also the period of precipitation (rainfall); i.e. wetting and drying processes. The results indicate that there will always be available boron in the soil at the end of the irrigation period (May–June) ready to be leached again by the first percolated rainfall (effective rainfall) to join the groundwater at higher concentration.     

Biological reduction of uranium in groundwater and subsurface soil

Biological reduction of uranium is one of the techniques currently studied for in situ remediation of groundwater and subsurface soil. We investigated U(VI) reduction in groundwaters and soils of different origin to verify the presence of bacteria capable of U(VI) reduction. The groundwaters originated from mill tailings sites with U concentrations as high as 50 mg/l, and from other sites where uranium is not a contaminant, but was added in the laboratory to reach concentrations up to 11 mg/l. All waters contained nitrate and sulfate. After oxygen and nitrate reduction, U(VI) was reduced by sulfate-reducing bacteria, whose growth was stimulated by ethanol and trimetaphosphate. Uranium precipitated as hydrated uraninite (UO2 x xH2O). In the course of reduction of U(VI), Mn(IV) and Fe(III) from the soil were reduced as well. During uraninite precipitation a comparatively large mass of iron sulfides formed and served as a redox buffer. If the excess of iron sulfide is large enough, uraninite will not be oxidized by oxygenated groundwater. We show that bacteria capable of reducing U(VI) to U(IV) are ubiquitous in nature. The uranium reducers are primarily sulfate reducers and are stimulated by adding nutrients to the groundwater.     

Risk assessment of exposure to volatile organic compounds in groundwater in Taiwan

The purpose of this study is to assess the risks from exposure to 14 volatile organic compounds (VOCs) in selected groundwater sites in Taiwan. The study employs the multimedia environment pollutant assessment system (MEPAS) model to calculate the specific non-cancer and cancer risks at an exposure level of 1 μg/L of each VOC for a variety of exposure pathways. The results show that the highest specific non-cancer risk is associated with water ingestion of vinyl chloride (VC) and that the highest specific cancer risk is associated with indoor breathing of VC. The three most important exposure pathways for risk assessment for both non-cancer and cancer risks are identified as water ingestion, dermal absorption when showering, and indoor breathing. Excess tetrachloroethylene (PCE), trichloroethylene (TCE), dichloroethylene (DCE), and VC are detected in the groundwater aquifers of one dump site and one factory. However, the study suggests that the pollutants in the contaminated groundwater aquifers do not travel extensively with groundwater flow and that the resulting VOC concentrations are below detectable levels for most of the sampled drinking-water treatment plants. Nevertheless, the non-cancer and cancer risks resulting from use of the contaminated groundwater are found to be hundred times higher than the general risk guidance values. To ensure safe groundwater utilisation, remediation initiatives for soil and groundwater are required. Finally, the study suggests that the current criteria for VOCs in drinking water might not be capable of ensuring public safety when groundwater is used as the primary water supply; more stringent quality criteria for drinking water are proposed for selected VOCs.     

Effect of ethanol on BTEX biodegradation kinetics: aerobic continuous culture experiments

The use of ethanol as an automotive fuel oxygenate represents potential economic and air-quality benefits. However, little is known about how ethanol may affect the natural attenuation of petroleum product releases. Chemostat experiments were conducted with four pure cultures (representing archetypes of the known aerobic toluene degradation pathways) to determine how ethanol affects benzene, toluene, ethylbenzene, and xylene (BTEX) biodegradation kinetics. In all cases, the presence of ethanol decreased the metabolic flux of toluene (measured as the rate of toluene degradation per cell). This negative effect was counteracted by an ethanol-supported increase in biomass, which is conducive to faster degradation rates. When the influent total organic carbon (TOC) of the toluene-ethanol mixture was kept constant, the metabolic flux of toluene was proportional to its relative contribution to the influent TOC. This empirical relationship was used to derive a mathematical model that simulated effluent benzene concentrations as a function of the influent mixed-substrate composition, the dilution rate, and Monod kinetic coefficients. Under carbon-limiting conditions (1 mg/L influent benzene), the data and model simulations showed an increase in benzene removal efficiency when ethanol was fed at low concentrations (ca. 1 mg/L) because its positive effect on cell growth outweighed its negative effect on the metabolic flux of benzene. High ethanol concentrations, however, had a negative effect, causing oxygen limitation and increasing effluent benzene concentrations to higher levels than when benzene was fed alone. The slower BTEX degradation rates expected at sites with high ethanol concentrations (e.g., at gasohol-contaminated sites) could result in longer BTEX plumes and a greater risk of exposure.     

Grundwasser- und Bodenluftuntersuchungen im Testfeld Süd

Within the framework of a current DFG (German Research Foundation) program natural attenuation processes of BTEX have been investigated in a Quaternary porous aquifer below a manufactured gas plant in Southwest Germany. Seasonal and regional variations of the BTEX plume have been registered since 1996 by detailed hydrochemical monitoring and frequent soil gas investigations. Taking into account that degradation of organic compounds results in O ₂ decrease and CO ₂ increase in soil air, the measured soil gas CO ₂ -anomalies correspond quite well with the observed contamination pattern of the groundwater. Although soil-gas surveying is usually applicable to the most volatile organic compounds, at the test site only very low concentrations of VOCs have been detected in the soil gas above the contaminated groundwater. In order to understand the results of the field investigations, physical, chemical and microbial processes determining the VOC concentrations have been investigated in detail laboratory scale.     

Potential for activated persulfate degradation of BTEX contamination

The present study focused on evaluation of activated persulfate (PS) anion (S(2)O(8)(2-)) oxidative degradation of benzene, toluene, ethylbenzene, and xylene (constituents of gasoline and known collectively as BTEX) contamination. The results indicated that BTEX were effectively oxidized by PS in aqueous and soil slurry systems at 20 degrees C. PS can be activated thermally, or chemically activated with Fe(2+) to form the sulfate radical (SO(4)(-)) with a redox potential of 2.4V. The degradation rate constants of BTEX were found to increase with increased persulfate concentrations. For two PS/BTEX molar ratios of 20/1 and 100/1 experiments, the observed aqueous phase BTEX degradation half-lives ranged from 3.0 to 23.1 days and 1.5 to 20.3 days in aqueous and soil slurry systems, respectively. In the interest of accelerating contaminant degradation, Fe(2+) and chelated Fe(2+) activated persulfate oxidations were investigated. For all iron activation experiments, BTEX and persulfate degradations appear to occur almost instantaneously and result in partial BTEX removals. It is speculated that the incomplete degradation reaction may be due to the cannibalization of SO(4)(-) in the presence of excess Fe(2+). Furthermore, the effects of various chelating agents including, hydroxylpropyl-beta-cyclodextrin (HPCD), ethylenediaminetetraacetic acid (EDTA), and citric acid (CA) on maintaining available Fe(2+) and activating PS for the degradation of benzene were studied. The results indicated that HPCD and EDTA may be less susceptible to chelated Fe(2+). In contrast, CA is a more suitable chelating agent in the iron activated persulfate system and with a PS/CA/Fe(2+)/B molar ratio of 20/5/5/1 benzene can be completely degraded within a 70-min period.     

The Translocation of Some Herbicides between Soil and Water in a Small Catchment

This paper presents data on the distribution of four herbicides within an agricultural catchment. In the case of mecoprop, 2,4-dichlorophenoxyacetic acid and simazine, these data include concentrations in the soil, field drains and the stream, before and after applications of the herbicides following good agricultural practice. The concentrations of these herbicides in the soil were found to follow published degradation rates, and their concentrations in the stream and drains were elevated following rainfall with peak concentrations from 0.12 μg/1 to 68.0 μg/1. Atrazine was found at relatively high concentrations (peak 122 μg/1) when it had not been applied to any of the fields draining to the sampling point.
The data will be used to test models that may be used as one of a number of tools for the screening of new pesticides prior to their registration. One approach using the Mackay's fugacity model is outlined.     

Herbicides and herbicide degradates in shallow groundwater and the Cedar River near a municipal well field, Cedar Rapids, Iowa

Water samples were collected near a Cedar Rapids, Iowa municipal well field from June 1998 to August 1998 and analyzed for selected triazine and acetanilide herbicides and degradates. The purpose of the study was to evaluate the occurrence of herbicides and herbicide degradates in the well field during a period following springtime application of herbicides to upstream cropland. The well field is in an alluvial aquifer adjacent to the Cedar River. Parent herbicide concentrations generally were greatest in June, and decreased in July and August. Atrazine was most frequently detected and occurred at the greatest concentrations; acetochlor, cyanazine and metolachlor also were detected, but at lesser concentrations than atrazine. Triazine degradate concentrations were relatively small (< 0.50 microg/l) and generally decreased from June to August. Although the rate of groundwater movement is relatively fast (approx. 1 m per day) in the alluvial aquifer near the Cedar River, deethylatrazine (DEA) to atrazine ratios in groundwater samples collected near the Cedar River indicate that atrazine and DEA probably are gradually transported into the alluvial aquifer from the Cedar River. Deisopropylatrazine (DIA) to DEA ratios in water samples indicate most DIA in the Cedar River and alluvial aquifer is produced by atrazine degradation, although some could be from cyanazine degradation. Acetanilide degradates were detected more frequently and at greater concentrations than their corresponding parent herbicides. Ethanesulfonic-acid (ESA) degradates comprised at least 80% of the total acetanilide-degradate concentrations in samples collected from the Cedar River and alluvial aquifer in June, July and August; oxanilic acid degradates comprised less than 20% of the total concentrations. ESA-degradate concentrations generally were smallest in June and greater in July and August. Acetanilide degradate concentrations in groundwater adjacent to the Cedar River indicate acetanilide degradates are transported into the alluvial aquifer in a manner similar to that indicated for atrazine and DEA.     

Effects of energy retrofits on Indoor Air Quality in multifamily buildings

We assessed 45 multifamily buildings (240 apartments) from Finland and 20 (96 apartments) from Lithuania, out of which 37 buildings in Finland and 15 buildings in Lithuania underwent energy retrofits. Building characteristics, retrofit activities, and energy consumption data were collected, and Indoor Air Quality (IAQ) parameters, including carbon monoxide (CO), nitrogen dioxide (NO₂), formaldehyde (CH₂O), selected volatile organic compounds (benzene, toluene, ethylbenzene, and xylenes (BTEX), radon, and microbial content in settled dust were measured before and after the retrofits. After the retrofits, heating energy consumption decreased by an average of 24% and 49% in Finnish and Lithuanian buildings, respectively. After the retrofits of Finnish buildings, there was a significant increase in BTEX concentrations (estimated mean increase of 2.5 µg/m³), whereas significant reductions were seen in fungal (0.6‐log reduction in cells/m²/d) and bacterial (0.6‐log reduction in gram‐positive and 0.9‐log reduction in gram‐negative bacterial cells/m²/d) concentrations. In Lithuanian buildings, radon concentrations were significantly increased (estimated mean increase of 13.8 Bq/m³) after the retrofits. Mechanical ventilation was associated with significantly lower CH₂O concentrations in Finnish buildings. The results and recommendations presented in this paper can inform building retrofit studies and other programs and policies aimed to improve indoor environment and health.     

Integrative quantification and balancing of contaminant fluxes in urban groundwater, case study Darmstadt

The qualitative and quantitative impact of a city on groundwater is presented in the case study of Darmstadt. The impact of land use on groundwater quality in Darmstadt is higher than the impact of background geological processes. The occurrence of Cl, B and Fe is only influenced by land use, while EC, HCO₃ and PO₄ are controlled by geology and land use. An integrative, spatially differentiating quantification of mass fluxes shows that e. g. Cl and B are introduced from urban sources such as leaking sewers and road salting. Input is highest under industrial areas (Cl 317 mg/d?·?m², B 0,6 mg/d?·?m²). For N_tot agricultural input (114 mg/d?·?m²) is more important than urban input with a maximum of 14 mg/d?·?m². Comparing overall urban input with estimated urban input, it can be concluded that there are additional sources for HCO₃, Ca, Mg, SO₄, Na, Cl, B and NO₃, which are not included in the estimated input (e. g. geogenic sources, fill material, industrial sources & degradation processes). PO₄ and N_tot on the other hand are being degraded and COD is consumed. A decrease of concentrations downstream from the city can be ascribed to diving plumes.     

Removal of selected risk elements from wastewater in a horizontal subsurface flow constructed wetland

Removal of Pb, Cd, Cr, Mo, V, Be and Ba from municipal wastewater using a horizontal subsurface flow constructed wetland was studied. The removal efficiencies attained for these elements were 50, 86, 71, 59, ?53, 37 and 40%, respectively. The average inflow and outflow Pb concentrations were 1.5 and 0.7 µg/L. Similarly, the inflow and outflow concentrations of 0.14 and 0.02 µg/L were obtained for Cd. Cr inflow and outflow concentrations were 3.7 and 1.1 µg/L, respectively. Concentrations of 0.78 and 0.32 µg/L were measured for Mo. V was washed out from the system. Its average inflow and outflow concentrations were 4.8 and 7.4 µg/L, respectively. Be inflow and outflow concentrations were rather low (1.03 and 0.65 µg/L), however, the concentrations of Ba were significantly higher (189 and 113 µg/L). The main perspective of the constructed wetland is the removal of toxic elements forming insoluble compounds (e.g. CdS) depositing in the wetland bed.     

Probennahme und Quantifizierung von LHKW, Ethen und Methan in Grundwasser

The use of active (purge and sample, downhole type) and passive (diffusion type) sampling techniques for the quantification of VOC, ethene, and methane was evaluated from the viewpoint of public authorities and considering the reproducibility of measurement results. Based on groundwater contaminated with trichloroethene, 1,2-dichloroethene, and vinyl chloride, it was shown that passive sampling is restricted by low groundwater flow as well as by biological activity inside the well casing. Therefore, active sampling is the preferred method in case of unknown or insufficient flow conditions in the aquifer. The gas chromatographic procedure for vinyl chloride using the head space technique was extended to the quantification of methane and ethene. Practically relevant limits of quantification of 0.1 μg/l (vinyl chloride, ethene) and 5 μg/l (methane) were obtained. The expected tolerance limits for quantification of VOC including the sampling process in monitoring campaigns were estimated by validation of the analytical procedure and various sampling series. The variability in monitoring results should be considered by consulting engineers and public authorities during assessment of degradation processes of halogenated hydrocarbons in groundwater.     

Distribution of soil moisture and salinity in shelterbelts and its relationship with groundwater level in extreme arid area,northwest of China

Because of the shortage of water source in the extreme arid area, generally, there are several years of no irrigation on mature shelterbelts. In this study, the shelterbelt soil in different texture were compared based on distribution analysis of the soil moisture and salt levels of shelterbelts under large‐scale drip irrigation in Kalamiji Oasis in the lower reaches of Tarim River, Northwest China. The following conclusions were drawn. (1) In Kalamiji Oasis, the groundwater level declined at a rate of 0.5 m/a as a result of popularization of drip irrigation technology. (2) There was a larger heterogeneity in distribution for soil moisture in the sandy/loamy shelterbelt than in the clay shelterbelt. (3) Under non‐irrigation conditions, sandy/loamy shelterbelt has lower soil moisture and salinity, and clay shelterbelt has higher soil moisture and salinity. (4) The shelterbelt with the shallowest groundwater depth had highest soil moisture level, and the shelterbelt with the deepest groundwater level had the lowest soil moisture content. (5) In sandy and loamy shelterbelts, the shelterbelts with the shallowest groundwater depths had the lower salinity levels and the shelterbelts with the deepest groundwater depths had the highest salinity levels. (6) In clay shelterbelts, the shelterbelts with the shallowest groundwater depths had the highest salinity levels, and the shelterbelts with the deepest groundwater depths had the lowest salinity levels. Additionally, it is essential to implement irrigation at least once a year.     

Lead,Cadmium And Zinc Accumulation On Soil And Vegetation Along Some Selected Major Roads Of Eastern Cape

Surface soil and grass samples were collected in triplicates from seven locations perpendicular to three major roads in Eastern Cape. Total and available lead, cadmium and zinc were determined in the soil samples and total elements were determined in grass. Lead, cadmium and zinc concentrations declined with distance from road traffic. Significant correlation was also established between available elements in soil and in grass. Levels of total and available elements in the soils ranged from 1167-10834 v µg v g m 1 and from 200-" 5734 v µg v g m 1 , respectively. The levels of the element in grass varied between 200 v µg v g m 1 and 3900 v µg v g m 1 . Total and available cadmium levels in soil although lower than the levels are also significant with values ranging from 17-"2833 v µg v g m 1 and from 27 v µg v g m 1 and from 27-1867 v µg v g m 1 , respectively. The cadmium levels in grass varied between 7 v µg v g m 1 and 1100 v µg v g m 1 . The total and available zinc levels in soil ranged from 2833-8334 v µg v g m 1 and from 533-3600 v µg v g m 1 . The levels in grass varied between 0 and 2800 v µg v g m 1 . The degree of pollution measured would constitute a threat to livestock. Motor traffic appears to be the main source of the elements.