Harmful Elements In Soils Research Articles

Environmental Assessment of Harmful Elements in Soil and Flora around Electrical and Electronic Equipment Waste Dumpsite in Rivers State, Nigeria

Environmental Assessment of Harmful Elements in Soil and Flora around Electrical and Electronic Equipment Waste Dumpsite in Rivers State, Nigeria

Fourteen years of compost application in a commercial nectarine orchard: effect on microelements and potential harmful elements in soil and plants

The objective of this experiment was to valuate, after 14 years, the impact of annual compost applications on micronutrient and potentially toxic trace elements on nectarine tree uptake and soil fertility. The study was performed in the Po valley, Italy, on the variety Stark RedGold (grafted on GF677). Since orchard planting, the following treatments were applied, in a randomized complete block design, with four replicates: 1. unfertilized control; 2. mineral fertilization (N was supplied as NO3NH4 at 70–130 kg ha−1 year−1); 3. compost at 5 t DW ha−1 year−1; 4. compost at 10 t DW ha−1 year−1. The actual rate of application was 12.5 (LOW) and 25 (HIGH) t ha−1, since compost was concentrated in the tree row. Compost was made from domestic organic wastes mixed with pruning material from urban ornamental trees and garden management and stabilized for 3 months.The supply of compost HIGH induced an enrichment of soil total Cu, Zn and Cd, and a decrease of Fe and Co concentration; with values always below the European threshold limits for heavy metals in the soil. In addition, compost (at both rates) increased availability (DTPA-extractable) of Fe, Mn and Zn, Cd, Ni, and Pb in the top soil (0–0.15 m).Total micronutrient and trace element tree content was not affected by fertilization treatments; however, the recycled fraction returned to the soil at the end of the season through abscised leaves and pruned wood of Cu, Fe, Mn and Zn was increased by mineral fertilization; Fe and Zn also by compost HIGH. Our data show that the introduction of compost at both 12.5 and 25 t ha−1 year−1 in the row did not increase the risk of pollution related to potentially toxic trace elements and at the same time increased the bioavailability of Fe, Mn and Zn.

Potentially harmful elements and their health implications in cultivable soils and food crops around lead-zinc mines in Ishiagu, Southeastern Nigeria

This study assessed the concentrations of potentially harmful elements (Cu, Pb, Zn, Mo, Ni, Co, Cd, Cr, Mn and As) in agricultural soils and plants (tubers, fruity and leafy vegetables) and their possible health risk implications on human in the lead-zinc mining districts of Ishiagu, Nigeria. The concentration of potentially harmful elements in the soils varies according to the order Pb > Mn > Zn > Co > Cu > Ni > Cr > Cd > As > Mo. The potential ecological risk assessments show that the agricultural soils are contaminated by Pb, Zn and Cd and exceeded recommended limits. The concentration of Pb and to some extent Zn, Cr and Cd are higher in the leafy vegetables compared to the tubers and exceeded EU and WHO/FAO maximum allowable limits. Plant concentration factor (PCF) was identified to be higher in Cd, followed by Zn > Cu > Mo > Cr > Ni > Pb > Mn > Co > As. The Daily In-Take of Metals (DIM) values for the PHEs through the ingestion of tubers, fruit, and leafy vegetables were generally below 1; the sequence of DIM values for adults and children for all the plants studied in the order: Zn > Mn > Pb > Cu > Cr > Ni > Cd > As; also, the DIM values were higher for the children compared to the adults, in consistent with the observation of previous workers. The DIM values for Pb, Mn and Cd for all the plants exceeded the USEPA IRIS (2006) threshold limits. The health risk indices indicate that Pb, Mn and Cd contamination in the food crops have greater potential to pose serious health risk to the consumers, including decrease in immune system and dysfunction of vital organs, rise in Pb levels in the blood of children, kidney damage and development of carcinogenic cells in the body, with more prevalence in the leafy vegetables. Development and implementation of effective monitoring and regulation of the activities of mining industries and land use types in the area, massive sensitization campaign for the inhabitants and miners on mining best practices, are recommended for reducing these negative effects of mining in the environment; application of lime-rich soils can be adopted to limit the mobility of the PHEs to some extent.

Distribution of potentially harmful elements in soils around a large coal-fired power plant.

An understanding of the spatial distribution and contribution of a power plant to local soil contamination is important for the planning of soil use and prioritizing remedial actions for public safety. Consequently, the aim of this study was to map the spatial distribution of potentially hazardous elements (PHEs; Cu, Pb, Zn, Ni, Cr, Fe, Mn, Cd, As, and Se) in soils around a large (796MW) coal-fired power plant in Brazil. For the purpose, 33 soil samples were collected in the area within a radius of approximately 17.5km from the plant and subsequently analyzed for PHEs. The frequency and direction of winds were also obtained from a meteorological station in the region. The sampling area was divided into four quadrants (northwest: N-NW; northeast: N-NE; southeast: S-SE; southwest: S-SW), and there were significant negative correlations between the distance and the concentrations of Se in the S-SE quadrant and As in the S-SW and S-SE quadrants. There were positive correlations between distance from the plant and the concentration of Mn in the N-NE quadrant and the concentration of Cd in the S-SW quadrant. The dominant direction of the winds was N-NE. The indexes used in this study showed low-to-moderate enrichment factor, but detailed analysis of the dominant quadrant of the winds showed a correlation with higher concentrations in the soils closer to the power plant for at least seven of the PHEs analyzed, especially with regard to As. Therefore, we conclude that the distribution of the metalloid As can be used as a marker of the spatial distribution of contamination from the thermoelectric plant, but the dynamics of the other elements suggests that the presence of other sources of contamination may also compromise the quality of local soils.

Content of the potentially harmful elements in soil around the major coal-fired power plant in Serbia: relation to soil characteristics, evaluation of spatial distribution and source apportionment

The concentrations and spatial distribution of nine potentially harmful elements (PHEs), namely Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb and Zn, and their relation to soil properties were investigated in thirty soil profiles (0–50 cm depth) sampled around the largest Serbian coal-fired power plant (CFPP) “Nikola Tesla A.” Soil properties were determined following standard procedures, and total contents of PHEs were analyzed by atomic absorption spectrometer. Concentrations of Cd, Co, Fe, Mn, Pb and Zn were the highest in soil profiles sampled 1 km away from the CFPP, concentrations of Ni and Cu gradually increased up to 4 km, and the highest Cr concentrations were measured in samples taken 6 km away from the CFPP. The highest concentration of PHEs analyzed, except Mn, corresponded with predominant wind directions. Depth did not show significant impact on distribution of any PHEs investigated. Among soil properties, the total organic carbon showed the closest relationship with the PHEs. Data were processed by a principal component analysis which enabled distinguishing anthropogenic from natural influences on soil properties and PHE contents. Although the impact of CFPP operations is obvious, assets of principal component analysis did not allow clear distinction of CFPP’s contribution from parent material in enrichment of PHE contents in the soil in the study area.

Environmental and hereditary effects in plant nutrition: our collaboration with RISSAC Budapest

Imre Kádár (29th July 1943 - 1st March 2018), a world renowned retired scientist in the field of agrochemistry and plant nutrition from the Research Institute of Soil Science and Agricultural Chemistry (RISSAC) of the Hungarian Academy of Science (HAS) in Budapest, passed away suddenly in March 2018. Our collaboration has about a 30 year-long tradition. Intensive collaboration started in connection with the beginning of the Homeland war in Croatia (1991-1995). Imre’s broad -minded soul was shown by his offer to make plant and soil analyses in RISSAC agrochemical laboratory for a price covering only the costs of chemicals and sample preparing. He made the offer after visiting Osijek and witnessing the total destruction of lecture rooms in the new building of Faculty and Institute, located on the southern outskirts of Osijek, and distanced only 0.5 km from the frontline. Until the end of 2012, we recorded about 6000 plant and soil samples for elemental analyses sent from the Faculty of Agriculture and Agricultural Institute Osijek to RISSAC Budapest. The outcome of this collaboration is numerous scientific and review articles. Until the end of 2016, Imre was included in 51 scientific, review articles and abstracts in total. Topics of our common articles can be divided into three parts: fertilization and liming effects on soil and plants, heavy metals and harmful elements in soil and plants, and hereditary impacts in maize nutrition. There is still unpublished data from the analyses made in RISSAC. We hope that, in the near future, some of the articles will be published including Imre in our team. Imre may have passed away, but his soul remains with us until our last breath. His rich legacy of development of environmental and genetic aspects of plant nutrition at the Faculty of Agriculture in Osijek and Agricultural Institute Osijek will be inspirational for many generations to come.

Reference values for potentially harmful elements in soils from Atlantic Rainforest, Brazil

Soil formation processes and the parent rock lead to differences in potentially harmful elements (heavy metals) contents in soil and sediments distribution patterns. The Brazilian legislation demands that natural baseline values must be defined for each specific environment or each state in the country. In this work natural baseline values of potentially harmful elements (PHE) in soils from Parana's Coast Plain (Atlantic Rainforest) were established and correlations with soil properties were verified. The sampling points were defined by geological and soil maps information crossing. We performed soil fertility, texture and Fe oxides (crystalline and amorphous) analysis. Pseudo-total metal concentrations were obtained by microwave-assisted digestion using the EPA3051A method. There were positive correlations between PHE and clay in the soils. The pedogenetic Fe oxides had important role in the adsorption and maintenance of PHE in soil. Natural baseline values were higher in comparison with other states of Brazil and with other foreign studies. The increase in PHE content in the sandy soils of Coastal Plain was attributed to the heavy flow of vehicles for centuries towards the coast of Paraná state. The background PHE values for Parana's Coast plain from 75 percentiles, in mgkg−1, were: Ag (0,29); As (4,78); Ba (111,4); Cd (1,02); Co (<0.17); Cr (48,8); Cu (17,9); Mo (1,44); Ni (17,2); Pb (16,9); Sb (3,12); V (60,2); and Zn (52,5). Special attention should be given to Sb due to its lower critical environmental level. When confronted to other values we confirm the necessity to regional (inside a state) baseline reference values.

Background Concentrations of Potentially Harmful Elements in Soils of the Kette-Batouri Region, Eastern Cameroon

Background Concentrations of Potentially Harmful Elements in Soils of the Kette-Batouri Region, Eastern Cameroon

Assessment of pollution of potentially harmful elements in soils surrounding a municipal solid waste incinerator, China

We assessed the contamination levels of Mn, Zn, Cr, Cu, Ni, Pb, As and Hg and the risks posed by these potentially harmful elements in top-soils around a municipal solid waste incinerator (MSWI).We collected 20 soil samples, with an average pH of 8.1, and another fly ash sample emitted from the MSWI to investigate the concentrations of these elements in soils. We determined the concentrations of these elements by inductively coupled plasma–optical emission spectrometer (ICP-OES), except for Hg, which we measured by AF-610B atomic fluorescence spectrometer (AFS). We assessed the risks of these elements through the use of geoaccumulation index (I geo), potential ecological risk index (RI), hazard quotient (HQ i ) and cancer risk (Risk i ). The results showed that concentrations of potentially harmful elements in soil were influenced by the wind direction, and the concentrations of most elements were higher in the area northwest of the MSWI, compared with the area southeast of the incinerator, with the exception of As; these results were in accordance with those results acquired from our contour maps. According to the I geo values, some soil samples were clearly polluted by Hg emissions. However, the health risk assessment indicated that the concentrations of Hg and other elements in soil did not pose non-carcinogenic risks to the local populations. This was also the case for the carcinogenic risks posed by As, Cr, and Ni. The carcinogenic risk posed by As was higher, in the range 6.49 × 10–6–9.58 × 10–6, but this was still considered to be an acceptable level of risk.

Potentially harmful elements in soils and holm-oak trees (Quercus ilex L.) growing in mining sites at the Valle de Alcudia Pb-Zn district (Spain)–Some clues on plant metal uptake

This work is aimed to the establishment of some clues concerning metal uptake by the holm oak (Quercus ilex L.) in abandoned base metals (Pb-Zn) mining sites from central Spain. The study is based on total contents of potentially harmful elements (PHEs), including Pb, Zn, Cu, As, Sb, Cd and Hg, in leaves from holm-oak trees as well as in the corresponding soils, in three different sites included in the Alcudia Valley Mining District. Besides, we present other analytical data for the corresponding soils: pH; electrical conductivity; organic matter; and selective extractions: i) Modified Geological Survey Field Leach Test (using deionized water); extraction with ammonium acetate solution at two different pH values; EPA Method 1312 (using a H2SO4:HNO3 solution); and extraction with an EDTA solution. This is aimed to search for relationships between PHE concentrations in the leaves and the different parameters measured in the corresponding soil, in order to determine bioavailability of PHE in this type of environments. The results show areas impacted by different degrees of PHE; in the most polluted area Pb concentrations reach 300 times the regional baseline and background values indicated by World Health Organization. Also, detected concentrations of the elements in leaves show that the holm-oak tree is a species with a very low bioaccumulation capacity, as shown by a selective uptake of PHE, favouring Zn, Cd and Cu with respect to Pb and As, and with Hg as a peculiar case, influenced by foliar uptake. However, metal concentrations in leaves reach levels above published toxicity levels thresholds, in particular for Pb and Zn. After this study, the soil to plant transfer capacity depends on different parameters for each element, being extremely difficult to generalise a common scenario favouring or preventing this process. Instead, we have found a complex case, conditioned by the soil proprieties (reactivity, salt contents and presence and concentration of organic matter) and to lesser extent, by PHE speciation in the soils.

Geochemistry of potentially harmful elements in topsoils around Kerman city, southeastern Iran

A multi-element geochemical soil survey was performed to assess the geochemical baseline and the environmental impacts of some potentially harmful elements in soils of the Kerman city. In doing so, a total of 175 samples, including residual (5), evaporate (6), silty–clay plain (42), urban (15), archaeological (3), road side (12), runway side (3), rail road side (7), agricultural (34), machinery battery manufacturing station (10), gasoline station (17), machinery paint working station (17) and cemetery (4) soil samples were collected on the 1:50,000 scale map of the Kerman city. The soil samples were analysed by ICP-OES for Ag, As, Bi, Cd, Co, Cr, Cu, Hg, Li, Mo, Ni, Pb, Se, Sn, V, W and Zn. The resulting elemental values in non-contaminated residual soils are similar to that of global background soil level (Salimen et al. Geochemical atlas of Europe. Part 1, Background information, methodology and maps. Finland Geological Survey, p 526, 2006; Lindsay Chemical equilibria in soils. Wiley, p 449, 1979). However, the soils close to the gasoline stations are enriched in Pb with variations up to 202 mg/kg. Soils developed around the machinery battery manufacturing stations also give a very high concentration of Pb as high as 60,445 mg/kg. The anomalous contents of Pb in soil samples close to the machinery paint working places range from 0.27 to 692 mg/kg. Some high values of Zn up to 1655 mg/kg are related to the agricultural soils in Pistachio gardens. The results highlight that the most anomalous harmful elements include Pb, Sn, Cd, Cu, Zn, Sb, As and Mo, which is supported by their high enrichment factors.

Potentially harmful elements in soil–plant interactions

Purpose Fenugreek (Trigonella foenum-graecum L.) is a medicinal plant with antidiabetic effects. Chromium has been related to better glucose tolerance in humans. The objective of this study was to determine whether tannery sludge could be used for Cr biofortification of fenugreek. Materials and methods Soil was mixed with tannery sludge containing 6.03 g Cr kg. All Cr was in the form of Cr(III). Three treatments were disposed: control without sludge, and two treatments with 10 and 20 g sludge kg, respectively. Control and the 10 g sludge kg treatments received NPK fertilizer to adjust the concentrations of major mineral nutrients to similar levels in all treatments. Soils were potted and planted with fenugreek. Plants harvested at the initial flowering stage were analysed for total Cr, Fe, Zn and Pb. Sequential soil extraction was applied to obtain operationally defined soil Cr fractions. Results and discussion Total Cr in all treatments was below or within the allowable range for agricultural soils (100– 150 mg kg). In control soils, most Cr was in the residual fraction (HF/HClO4 digest). Tannery sludge-amended soils incorporated most Cr into the moderately reducible fraction (oxalic acid/ammonium oxalate extract). In fenugreek shoots, Cr concentrations reached 3.2 mg Cr kg, a higher concentration than that reported for other leafy vegetables. Lead concentrations in plant shoots from this treatment were enhanced but hardly exceeded 1 mg Pb kg. Conclusions Tannery sludge-amended soils containing Cr within the range of permissible concentrations can increase shoot Cr in fenugreek. Only sludge with low Pb concentrations should be used for Cr biofortification of fenugreek.

Assessment of a geochemical extraction procedure to determine the solid phase fractionation and bioaccessibility of potentially harmful elements in soils: A case study using the NIST 2710 reference soil

Three mineral acid sequential extraction regimes (HNO3 only, HNO3 followed by HCl and aqua regia) were applied to the NIST 2710 contaminated reference soil. The major and trace element chemical analysis data from the extractions were subjected to a chemometric self-modelling mixture resolution procedure which identified that 12 distinct physico-chemical components were extracted. The fractionation of As, Cd, Ni and Pb between these components were determined. Tentative assignments of the mineralogical sources of the components were made. The human ingestion bioaccessible fraction of As, Cd and Pb were determined using the in vitro BARGE UBM bioaccessibility test and were found to be 51.6%, 68.0% and 68.4% respectively. The relationship between the lability of the physico-chemical components and the bioaccessible fraction of the soils was investigated and the bioaccessible fractions were assigned to specific components. The extraction scheme using aqua regia was found to be the most suitable as it was the only one which extracted the iron sulphide phase in the soil.

The Handling of Hazard Data on a National Scale: A Case Study from the British Geological Survey

This paper reviews how hazard data and geological map data have been combined by the British Geological Survey (BGS) to produce a set of GIS-based national-scale hazard susceptibility maps for the UK. This work has been carried out over the last 9 years and as such reflects the combined outputs of a large number of researchers at BGS. The paper details the inception of these datasets from the development of the seamless digital geological map in 2001 through to the deterministic 2D hazard models produced today. These datasets currently include landslides, shrink-swell, soluble rocks, compressible and collapsible deposits, groundwater flooding, geological indicators of flooding, radon potential and potentially harmful elements in soil. These models have been created using a combination of expert knowledge (from both within BGS and from outside bodies such as the Health Protection Agency), national databases (which contain data collected over the past 175 years), multi-criteria analysis within geographical information systems and a flexible rule-based approach for each individual geohazard. By using GIS in this way, it has been possible to model the distribution and degree of geohazards across the whole of Britain.

High geochemical background of potentially harmful elements in soils and sediments: implications for the remediation of contaminated sites

Geochemical background concentrations of potentially harmful elements and species (PHES) may have a high spatial variability and their natural levels can be higher than those caused by anthropogenic sources of pollution. Therefore, the use of a threshold value for assessing contamination can be inadequate and local variability should be considered. In Europe, soil quality standards are widely variable. In Italy concentration levels exceeding threshold values (TVs) are allowed only if the natural concentrations for a given area are higher than those specified by law. For sediments, in Italian law TVs have not been yet established but TVs with local validity are used for contamination assessment in areas with different geochemistry. A short outline of the worldwide regulatory frameworks is presented with the intent of singling out suitable approaches and priority actions needed to tackle the weak points in law, following the indications of the scientific community and stressing the importance of assessing the real hazard using tools for the evaluation of site-specific mobility and toxicity of PHES. Cases of areas with high PHES background concentration are presented as evidence of this widespread phenomenon and of the need to find effective approaches and solutions.

In SituLeaching of Trace Elements in a Coal Ash Dump and Time Dependence Laboratory Evaluation†

This paper investigates the leaching behavior of trace elements in a typical ash dump in the Guizhou province of western China. The ash samples obtained from a power plant were sieved into three sizes: <45, 45−71, and >71 μm. Column leaching tests were performed for the size-classified fly ash samples. The HCl solution of pH 4.5 was used to simulate local precipitation. The flow rate was chosen as 1 mL/min. Leaching time intervals were selected in a range from 15 min to 40 days. The results show that the surrounding soil is strongly affected by the ash dump, and the concentrations of some harmful elements in soil are much higher than the background values. The maximal single element pollution index of the soil sample is 134.81 for Cd. In comparison to the concentrations of trace elements in the upstream water, Cr, Cd, Pb, Zn, and Co are greatly enriched in the downstream water. The pollution of the underground water is mitigated by the use of leakproof film. The column leaching test results show that the concentrations of Pb and Cd fluctuate in short-time column leaching. The concentrations of Cd are kept stable after 16 days in three size-classified fly ash samples. However, the concentrations of Pb increase from 1 day to 40 days in the fly ash with a small particle size but are kept stable after 16 days for large particle size fly ash. In comparison to Cd and Pb, the concentrations of Zn in short-time column leaching increase significantly with relatively small fluctuations.

Preliminary Assessment of a Unified Bioaccessibility Method for Potentially Harmful Elements in Soils

MS1 Symposium Title: Childhood Exposures to Bioavailable Metals in Soil and Household Dust in Residential Environments Symposium Organizers: Pat Rasmussen, Joanna Wragg, and Mark Cave MS1-01 Introduction: When considering the direct ingestion of soil in risk assessment, total concentrations of potentially harmful substances (PHS) are often considered to be a gross overestimate of the amount of PHS entering the body. The human gastrointestinal tract only makes a fraction of the PHS accessible for absorption. U.K. technical guidance, however, permits the use of site-specific estimates of oral bioaccessibility. This presentation describes 2 initiatives being undertaken by the BGS and the Bioaccessibility Research Group of Europe (BARGE) for standardized and validated procedures for measuring bioaccessibility by: 1) preparation of a reference soil to allow testing laboratories to monitor the QA of bioaccessibility measurement; and 2) development of a unified and validated in vitro bioaccessibility test. Reference Soil Description and Methodology: A total of 0.5 tonne of soil, of a similar type to the Banbury series (ferritic brown earth), was collected from North Lincolnshire. The sample was dried, ground, homogenized, and characterized and the total As concentration was found to be 87.1 ± 4.7 mg kg-1 with the bioaccessible As c.5 mg kg-1. Results: The proposed unified procedure has been derived from the RIVM physiologically based in vitro extraction test.1 The performance of the method has been tested on 9 soils for which in vivo arsenic bioavailability data has been obtained using a swine model.2 The soils have been provided by Professor Nick Basta of the Ohio State University, Columbus, Ohio. The soils are calcine and iron slag soils with total As concentrations ranging from approximately 400 to 18000 mg kg-1 and relative bioavailabilities from approximately 4% to 40%. Initial studies have shown that the gastric phase bioaccessibility values from the unified procedure have a correlation coefficient of 0.907 and a regression line slope of 1.2 with the absolute bioavailability data.

Soil Contamination Due to Heavy Metals from an Industrial Area of Surat, Gujarat, Western India

The pollution of soil is a source of danger to the health of people, even to those living in cities. The anthropogenic pollution caused by heavy industries enters plants then goes through the food chain and ultimately endangers human health. In the context, the knowledge of the regional variability, the background values and anthropogenic vs. natural origin of potentially harmful elements in soils is of critical importance to assess human impact. The present study was undertaken on soil contamination in Surat, Gujarat (India). The aims of the study were: i) to determine extent and distribution of heavy metals (Ba, Cu, Cr, Co, Ni, Sr, V and Zn) ii) to find out the large scale variability, iii) to delineate the source as geogenic or anthropogenic based on the distribution maps and correlation of metals in soils. Soil samples were collected from the industrial area of Surat from top 10 cm layer of the soil. These samples were analysed for heavy metals by using Philips PW 2440 X-ray fluorescence spectrometer. The data reveal that soils in the area are significantly contaminated, showing higher levels of toxic elements than normal distribution. The heavy metal loads of the soils in the study area are 471.7 mg/kg for Ba, 137.5 mg/kg for Cu, 305.2 mg/kg for Cr, 51.3 mg/kg for Co, 79.0 mg/kg for Ni, 317.9 mg/kg for Sr, 380.6 mg/kg for V and 139.0 mg/kg for Zn. The higher concentrations of these toxic metals in soils need to be monitored regularly for heavy metal enrichment.

Multivariate statistical and GIS-based approach to identify heavy metal sources in soils

The knowledge of the regional variability, the background values and the anthropic vs. natural origin for potentially harmful elements in soils is of critical importance to assess human impact and to fix guide values and quality standards. The present study was undertaken as a preliminary survey on soil contamination on a regional scale in Piemonte (NW Italy). The aims of the study were: (1) to determine average regional concentrations of some heavy metals (Cr, Co, Ni, Cu, Zn, Pb); (2) to find out their large-scale variability; (3) to define their natural or artificial origin; and (4) to identify possible non-point sources of contamination. Multivariate statistic approaches (Principal Component Analysis and Cluster Analysis) were adopted for data treatment, allowing the identification of three main factors controlling the heavy metal variability in cultivated soils. Geostatistics were used to construct regional distribution maps, to be compared with the geographical, geologic and land use regional database using GIS software. This approach, evidencing spatial relationships, proved very useful to the confirmation and refinement of geochemical interpretations of the statistical output. Cr, Co and Ni were associated with and controlled by parent rocks, whereas Cu together with Zn, and Pb alone were controlled by anthropic activities. The study indicates that background values and realistic mandatory guidelines are impossible to fix without an extensive data collection and without a correct geochemical interpretation of the data.