Metal Concentrations In Soils Research Articles

Heavy metals in onion (Allium cepa L.) and environmental and health risks

ABSTRACT This study aimed to determine heavy metal content in soil and selected cultivars of onion. Cd content in soil exceeded the limit 2.43 times. Bioavailable forms of Pb and Cd in soil exceeded the critical value 5.9 times and 1.9 times, respectively. Analysed cultivars were not bioaccumulators of monitored heavy metals. However, Pb and Cd content in cultivars Nanas F1, Kappa and Daytona F1 exceeded the maximum limit set by the EU regulation. For Pb this was also the case for the Spirith cultivar. Based on health risk assessment it could be concluded that moderate consumption of onions from the studied localities does not pose a risk to consumers.

Assessment of depth wise distribution, enrichment, contamination, ecological risk and sources of soil heavy metals over an Industrial area in Southern India

Assessing the depth-wise distribution of heavy metals in soil can provide valuable insights into the extent of enrichment, contamination, and the possible sources of pollutants. A study was conducted in parts of Patancheru Industrial areas of Hyderabad, India to assess the vertical distribution of heavy metal content in soil, focusing on enrichment, contamination, and pollutant sources. Sixty soil samples from 15 sites, spanning four depths (0–15 cm, 15–30 cm, 30–50 cm, 50–100 cm) were analyzed for total Fe, Mn, Zn, Cu, Pb, Cr, Co and Ni concentrations. The concentrations of Fe, Mn, Zn, Cu, Pb, Cr, Co, and Ni, regardless of the study depths and sites, range from 2570–10,667, 22.5–439, 11.6–47.2, 3.47–14.2, 5.53–31.7, 36.0–63.1, 2.99–17.5 to 10.5–47.3 mg kg−1respectively. The mean concentrations of all the measured heavy metals showed minor variation across depths, except for Zn and Pb. Moreover, the mean concentration of all the measured heavy metals at various soil depths was within the threshold or target limits except for total Ni. At certain sampling depths and locations, Ni content exceeded the permissible threshold of 35 mg kg−1 in the soil. Surface soils (0–15 cm) exhibited moderate to significant enrichment of Pb, Zn, Cr, and Co. The enrichment factor for the overall Pb concentration varies from 3.02 to 24.73, indicating a range of moderate to very high enrichment throughout the soil depths. Following Pb, Cr exhibits enrichment levels ranging from 2.31 to 9.35, while Co ranges from 1.07 to 5.58.The sites within the study area varied in contamination levels, spanning from moderate contamination to a slight degree of pollution, as assessed by the contamination/pollution index of each element. Principle component analysis and enrichment factor values show that Cu originated primarily from natural sources; while Pb and Cr were likely to be anthropogenic to purely anthropogenic and Zn, Mn, Ni, and Co had both crustal and like to be anthropogenic origins. The maximum and minimum ecological risk index (ERI) values were recorded for Pb and Zn content, respectively. The maximum PERI value of 15.8 was recorded in the study area, indicating a low ecological risk level. However regular monitoring of the heavy metal concentration in soils is recommended over the study area to maintain a low level of ecological risk via reclamation interventions.

A comparison of characterisation and modelling approaches to predict dissolved metal concentrations in soils

Environmental context It is useful to know the concentration of ‘labile’, or chemically active, metal in soils because it can be used to predict metal solubility and environmental impact. Several methods for extracting the labile metal from soils have been proposed, and here we have tested two of these to see how well the resulting data can be used to model metal solubility. Such mixed approaches can be applied to different soil types with the potential to model metal solubility over large areas. Rationale Predicting terrestrial metal dynamics requires modelling of metal solubility in soils. Here, we test the ability of two geochemical speciation models that differ in complexity and data requirements (WHAM/Model VII and POSSMs), to predict metal solubility across a broad range of soil properties, using differing estimates of the labile soil metal concentration. Methodology Using a dataset of UK soils, we characterised basic properties including pH and the concentrations of humic substances, mineral oxides and metals. We estimated labile metal by extraction with 0.05 mol L−1 Na2H2EDTA and by multi-element isotopic dilution (E-value). Dissolved concentrations of Ni, Cu, Zn, Cd and Pb were estimated in 0.01 mol L−1 Ca(NO3)2 soil suspensions using the total metal ({M}total), the EDTA-extracted pool ({M}EDTA) and the E-value ({M}E) as alternative estimates of the chemically reactive metal concentration. Results Concentrations of {M}EDTA were highly correlated with values of {M}E, although some systematic overestimation was seen. Both WHAM/Model VII and POSSMs provided reasonable predictions when {M}EDTA or {M}E were used as input. WHAM/Model VII predictions were improved by fixing soil humic acid to a constant proportion of the soil organic matter, instead of the measured humic and fulvic acid concentrations. Discussion This work provides further evidence for the usefulness of speciation modelling for predicting soil metal solubility, and for the usefulness of EDTA-extracted metal as a surrogate for the labile metal pool. Predictions may be improved by more robust characterisation of the soil and porewater humic substance content and quality.

Evaluating metal phytorremediation and biondication potential of Spartina alterniflora in a South American estuary

Soil metal pollution has been widely studied in salt marshes but mainly regarding non-essential metals. The aim of this study was to assess the levels of two essential metals (Fe and Mn) and one non-essential one (Cd) in Spartina alterniflora salt marshes in a South American estuary in order to evaluate the potential of this species as a phytoremediator and/or bioindicator of Fe, Mn and Cd and to analyze the distribution of these metals according to the edaphic conditions. The metals present in the soils varied among the three sites studied according to the content of organic matter and fine sediments. In comparison with other Spartina-dominated salt marshes worldwide, in this study Fe and Mn were approximately in the same range, whereas Cd levels were always lower, with a high number of samples below the method detection limit (MDL). All metals were highly correlated with each other suggesting an association of Cd with Mn and Fe oxides/hydroxides or sulfides and/or a common anthropogenic source. Metals in plant tissues also varied from site to site and between the aboveground and belowground tissues. Compared to the metal levels in Spartina tissues in other salt marshes, our levels of Fe and Mn were in the same range, whereas the Cd levels were lower, among most samples, especially those from aboveground tissues that were below the MDL. The bioconcentration factor (metal in belowground tissues/metal in soil) was always lower than one for Fe and Mn meaning that there is no accumulation of these metals in belowground tissues, but this factor for Cd was sometimes higher than one, even as high as 3.45, implying that S. alterniflora can accumulate this metal in its tissues, pointing to a potential role of this species in Cd phytoremediation. Translocation factors (metal in aboveground tissues/metal in belowground tissues) were always lower than one for Fe and could not be calculated for Cd but were usually higher than one for Mn, showing the role of this element in photosynthetic tissues and a possible function of this species for phytoextraction of Mn. In most samples the Fe levels in plant tissues were higher than the permissible levels reported in the literature, suggesting a potential role of S. alterniflora in Fe phytoremediation. No correlation was observed between metal concentrations in soils and aboveground tissues; therefore, S.alterniflora is not a good bioindicator for the metals studied. Although our results are not conclusive, they reinforce the importance of local edaphic conditions on the behavior of metals in salt marshes and shed light on the potential role of S. alterniflora in the phytoremediation of highly toxic metals such as Cd or poorly studied metals such as Fe and Mn.

Heavy Metal Pollution Assessment in the Agricultural Soils of Bonao, Dominican Republic

Heavy metal content in agricultural soils potentially impacts the food chain and human health. The present study assessed the levels of heavy metals in topsoil samples collected within an agricultural region situated in Bonao, Dominican Republic. The Energy-Dispersive X-ray Fluorescence (EDXRF) technique was utilized to measure the concentrations of iron (Fe), manganese (Mn), chromium (Cr), copper (Cu), nickel (Ni), zinc (Zn), lead (Pb), and arsenic (As) in the samples. The assessment of soil pollution status and potential ecological risk (RI) involved the utilization of various soil pollution indices, such as the single pollution index (PI), integrated pollution index (IPI), and enrichment factor (EF). The average total concentrations of Fe, Mn, Cr, Cu, Ni, Zn, Pb, and As were 103,000, 2000, 347, 36, 92, 32, 9.6, and 4.2 mg·kg−1, respectively. The results showed that the Mn, Ni, Cu, and As levels exceeded the Food and Agriculture Organization (FAO)’s recommended levels for healthy agricultural soils. The distribution pattern of each individual metal was different, indicating they had different sources of origin. The average pollution indices indicated low-to-moderate pollution, and the potential ecological risk obtained was low. This study emphasizes the need for soil management practices to mitigate heavy metal contamination for food safety and environmental health.

Effect of Biochar on the Content of Heavy Metals in Agrosoddy-Podzolic Sandy Loamy Soil: Laboratory Vegetation Experiment

Effect of Biochar on the Content of Heavy Metals in Agrosoddy-Podzolic Sandy Loamy Soil: Laboratory Vegetation Experiment

Content and Mobility of Metals in Oligotrophic Peat Soils of the Cryolithozone in Western Siberia

Content and Mobility of Metals in Oligotrophic Peat Soils of the Cryolithozone in Western Siberia

Patterns of accumulation and baseline values for metals in agricultural soils from a copper mining region in southern Peru

As global copper demand surges, it's vital to conduct a thorough analysis of metal concentrations in the agricultural soils of mining districts. This is especially pertinent for the Andean region, where, in the face of clear soil degradation, there's a notable lack of in-depth research. This study is the first attempt to characterize variations in the concentration of 17 metals in the agricultural soils of Moquegua – a region with a long history of mining activity that contributes significantly to Peru's position as the world's second-largest producer of copper. The surface horizons of 336 agricultural soils under vegetable crops were sampled between 9 and 3,934 m above sea level (m.a.s.l.) to determine the total content of metal nutrients (MNs) (Ca, Mg, K, Na, Fe, Cu, Mn, Zn) and heavy metals (HMs) (Cd, Cr, Ni, Pb, As, Co, Ba, V, Al) by inductively coupled plasma-optical emission spectrometry (ICP-OES). The accumulation of metals was found to increase with altitude. The study identified hotspots with a high concentration of metals and spatial patterns in their geographic distribution. The observed median values for As (70.9 mg/kg), Cd (7.1 mg/kg), and Pb (89.7 mg/kg) represent the highest metal concentrations among the identified clusters. Notably, these values surpass the Environmental Quality Standards (ECA) set for agricultural soils in Peru. As there are no local standards for all the metals studied, our results can serve as reference values for guiding land management practices, particularly in the context of copper mining.

Concentration, spatial distribution, and source apportionment of heavy metals in agricultural soils from the Yarlung Zangbo River Basin, Tibetan Plateau

In this study, 112 agricultural topsoil samples were collected from the Yarlung Zangbo River Basin (YZRB) and its two tributaries, and the concentrations, spatial distribution, source apportionment, and potential ecological risk of eight heavy metals (Cd, Hg, Pb, Cr, Cu, Zn, Ni and As) were analyzed. The mean concentrations of Cu, Pb, Zn, Cr, Ni, Cd, As, Hg and Pb were 33.91, 28.21, 86.93, 109.04, 73.58, 0.12, 21.49 and 0.05 mg/kg, respectively. Except for Pb, the concentration of heavy metals in soil exceeded the corresponding local background values, but did not exceed the national soil pollution risk screening values. In terms of spatial distribution, it showed that the heavy metals were enriched in the Nianchu River, and followed by Lhasa River and YZRB mainstream. Furthermore, the ecological risks were ordered as Hg > Cd > As > Ni > Cu > Pb > Cr > Zn, and the potential ecological risk index of the YZRB fell in the range of moderate ecological risk. The high-risk areas were in the facility agriculture fields of the Nianchu River, which was mainly related to agricultural activities. In addition, the positive matrix factorization results showed traffic, agricultural activities, natural weathering of the parent minerals, and atmospheric transport sources were the four sources in soils of the YZRB. This work will provide a scientific reference to develop appropriate pollution control measures and facility farmlands management in the YZRB of Tibetan Plateau.

Analysis of Heavy Metal Contaminants and Mobility in Sewage sludge-soil Mixtures for Sustainable Agricultural Practices

This study presents a comprehensive analysis of the potential utilization of sewage sludge in agriculture, focusing on the assessment of heavy metal contaminants and their mobility in sewage sludge-soil mixtures. The innovative approach of investigating heavy metal fractions in these mixtures sheds light on their environmental implications. In this study, sludge and soil samples from three different soil categories were collected, and the mobility of heavy metals was investigated using sequential BCR analysis. A thorough assessment of the risk of environmental contamination associated with the agricultural use of sludge was also carried out. This study included the calculation of various risk indicators, such as the Geoaccumulation Index of heavy metals in soil (Igeo), the risk assessment code (RAC), and the author’s element mobility ratio (EMR), which included a comparison of the overall metal concentrations in sludge, soil, and mixtures. This study demonstrates that the key to using sludge is to know the form of mobility of the metals present in the sludge and how they behave once they are introduced into the soil.

Study on the migration behaviour of heavy metals at the improved mine soil-plant rhizosphere interface

ABSTRACT With the increasing shortage of land resources and the aggravation of soil pollution in mining areas, the remediation of soil in abandoned mining areas has gradually attracted people's attention. The remediation of heavy metal contaminated soil in mining areas is the key to reduce the harm of heavy metals to the environment and human health. In this study, municipal sludge and phytoremediation technology were combined to investigate the migration and transformation of heavy metals at the soil-plant interface in improved mining areas through indoor pot experiments. The results showed that heavy metals in non-rhizosphere soil entered the rhizosphere environment with the growth of plants, leading to the increase of heavy metal content in rhizosphere soil. The cumulative amounts of Cu, Zn, Pb and Cd were 1299.32, 832.10, 347.89 and 71.34 mg/kg, respectively. The content of oxidized Cu and Zn decreased with increasing planting days, while the oxidized Pb and Cd showed an increasing trend. Under acidic conditions, H+ is easy to compete with heavy metal ions for exchangeable positions in the clay mineral layer, so that the reducible heavy metals are easy to be converted into exchangeable states. In this paper, the effects of various factors on the distribution of heavy metals were discussed by adjusting soil pH, adding humic acid and root exudates, so as to analyse the migration and transformation mechanism of heavy metals at the soil-plant interface, and provide a reliable theoretical basis for soil remediation in mining areas.

X-Ray Fluorescence Monitoring Metal Content and Nutrient Elements for Predicting Soil Fertility Parameters Based on pH in Ultisol Soil

Soil fertility parameters, including macronutrients, micronutrients, and metal content, are very important for optimizing agricultural and plantation land management. Ultisol is a type of soil that is commonly used as a planting medium for oil palm plantations, rubber, and various types of vegetables. Continuous land use causes variations in nutrient and metal content. This change is also caused by the fertilization process and the characteristics of the plants grown in the area. In this study, an analysis of soil fertility parameters (macronutrients, micronutrients, and metal content) was analyzed using X-Ray Fluorescence (XRF) on Ultisol soil taken from Muara Jambi Regency, Indonesia. This analysis was conducted across land-use areas (Palm, Rubber, Vegetables, and Forest). Subsequently, the obtained measurements were used to model correlations with soil pH values to predict soil fertility parameters. The quantitative results showed that the metal content values were reasonably consistent across all locations regarding metal types and their percentage concentrations. However, locations 1 (T1) and 2 (T2) have higher aluminum (Al) content than locations 3 and 4 and lower magnesium (Mg) content. The modeling, when correlated with pH values, indicated that metal elements correlated 0.938, macronutrients 0.934, and micronutrients 0.767. From these correlations, it can be qualitatively inferred that there is a strong relationship between pH and the presence of metal content, macronutrients, and micronutrients. In the future, this can serve as a model for estimating the presence of soil fertility parameters.

Would it be better for partition prediction of heavy metal concentration in soils based on the fusion of XRF and Vis-NIR data?

Heavy metal (HM) contamination in soil necessitates effective methods to diagnose suspected contaminated areas and control rehabilitation processes. The synergistic use of proximal sensors demonstrates significant potential for rapid detection via accurate surveys of soil HM pollution at large scales and high sampling densities, and necessitates the selection of appropriate data mining and modeling methods for early diagnosis of soil pollution. The aim of this study is to evaluate the performance of a subarea model based on geographically partitioned and global models based on high-precision energy dispersive X-ray fluorescence (HD-XRF) and visible near-infrared (vis-NIR) spectra using a random forest model for predicting soil Cu and Pb concentrations. A total of 166 soil samples are acquired from a contaminated plot in Baiyin, Gansu Province, China. The soil samples are subjected to HM analysis and proximal sensor scanning in a laboratory. Vis-NIR spectral data are preprocessed using the Savitzky Golay (SG) and first-order derivative with Savitzky Golay (SGFD) methods. The results show that for predicting Cu and Pb concentrations in soil, the subarea models performs better than the global models in terms of quantitative prediction, based solely on individual HD-XRF data. For the subarea and global models, the R2 values are 0.961 and 0.981, respectively; the RMSE values are 27.8 and 79.6, respectively; and the RPD values are 4.96 and 7.38, respectively. However, making use of the random forest algorithm trained with data fusion obtained from the HD-XRF and vis-NIR sensors, the global model achieves the best predictions for Cu and Pb concentrations via HD-XRF + vis-NIR (SGFD) and HD-XRF + vis-NIR (SG), respectively. The results will provide a new perspective for modeling approaches to rapidly invert HM concentrations based on proximal sensor data fusion within a large scope of the study area.

Trace Metal Contents in Farm Soils and Potato Tubers Grown in Mymensingh District of Bangladesh and Their Implications for Human Health

Trace Metal Contents in Farm Soils and Potato Tubers Grown in Mymensingh District of Bangladesh and Their Implications for Human Health

Exploring the impact of transportation on heavy metal pollution: A comparative study of trains and cars

This study aimed to investigate the impact of road and rail traffic on the soil through the analysis of the presence of heavy metals in soil samples collected next to a busy highway, local roads, and next to an active railway line. Results showed that cars emitted higher levels of heavy metals than trains. Soil samples near the highway had higher levels of Cu, Ni, and Hg. The values of the calculated indices like geo-accumulation index, potential toxicity response index, ecological risk factor, contamination factor, pollution load index, Nemerow's pollution index, and degree of contamination confirm that the soil samples sampled near the highway are the most polluted and highway have the greatest negative impact on the soil environment. These results suggest that controlling car emissions through strict regulations and promoting public transportation could effectively reduce the heavy metal concentrations in soil, particularly from highway emissions.

Physico-Chemical and Thermodynamic Adsorption Studies of A Few Soils from Delta and Oyo State, Nigeria

Comprehensive study of the physico-chemical properties and interactions of cations with soils is a crucial research need for the development of more sustainable agricultural systems. The analysis of physico-chemical and thermodynamic adsorption studies of various soils from Delta and Oyo State, Nigeria, is the main emphasis of this paper. Two surface soils from the Cocoa Research Institutes of Nigeria (CRIN) and the Isoko North Local Government of Delta State were compared for their physico-chemical properties and heavy metal speciation. The effects of adsorption duration, pH, initial sorbate concentration, and ionic strength were also studied in relation to the adsorption of Cd2+, Pb2+, Cu2+, and Zn2+ ions. On the equilibrium and thermodynamics of the adsorption process, more investigation was conducted. The physico-chemical studies revealed that soil from CRIN had a pH of 6.1 in water and 5.4 in KCl, whereas soil from Isoko North had a pH of 4.3 in water and 3.0 in KCl. The largest percentages of organic matter are found in the soil from Isoko North (3.07%) and CRIN (3.82%). For both soils, the order of exchangeable bases was Ca > K > Mg > Na. The heavy metal concentrations in both soils were in the following order: Zn > Cu > Ni > Pb > Cd = Al; CRIN: 3.82meq/100g for CEC; Isoko North: 2.85meq/100g for CEC. In contrast to CRIN soil, Isoko North soil showed a larger bulk density and a superior hydraulic conductivity. Extractable elements were present in both soils in the following order: Mn > Fe > Zn > Cu. The base saturation in the CRIN soil was higher than the base saturation in the Isoko North soil, which was lower at 60.73%. Zn, Pb, and Cd were the outcomes of the heavy metal speciation for both soils. The equilibrium adsorption data, which were closely related to the Langmuir isotherm model, showed that the maximum capacity of lead for soil from Isoko North was 5.8140 mmol/g and for soil from CRIN was 7.6335 mmol/g. Thermodynamic investigations showed that the adsorption process was spontaneous for simply Cu2+ (for soil from CRIN) and non-spontaneous for other metal ions from both soils. Metal ions from both soils displayed exothermic and endothermic adsorption, respectively, for Cd2+ and Cu2+ (for soil from CRIN).

Environmental pollution status and health risk assessment of selective heavy metal(oid)s in Iran's agricultural soils: A review

The assessment of heavy metal(oid) concentrations in agricultural soil holds significant importance due to its impact on crop safety and quality, as well as the potential risks it poses to human health. This review utilized secondary online published data to evaluate the contamination levels of seven HMs (As, Cd, Cu, Cr, Ni, Pb, and Zn) in Iranian farmland soils. As a result, 31 research papers were collected to compile a dataset offering a comprehensive analysis of HM concentrations, distribution, sources, ecological risks, and potential health risks. The findings indicated that mean concentrations of Ni and Cd exceeded their corresponding permissible levels in farmland soils, while other HMs remained below this threshold. The mean Igeo (geoaccumulation index) values followed the sequence Ni > As > Cu > Cr > Zn > Pb > Cd, with Igeo values suggesting low to slight enrichment for the studied HMs. Pollution index (PI) results revealed notable contamination of As in various provinces, including Kurdistan, Hamedan, Tehran, Mazandaran, West Azerbaijan, Kermanshah, Hormozgan, Golestan, and the Kamfiruz region of Fars. Elevated contamination of Pb and Cd was observed in Fars (Shiraz region), and Cr and Ni in the Sabzevar area farmland soils. As, Cd, and Cu exhibited higher ecological risks (EI) compared to Zn, Cr, Ni, and Pb. The potential ecological risks (PER) ranged from 9.9 to 244.6, indicating low to moderate risk levels. Non-carcinogenic assessments indicated that ingestion was the primary exposure pathway to HMs in Iranian farmland soils, followed by inhalation and dermal contact. Total hazard index (HI) values for studied HMs did not exceed 1, indicating no significant non-carcinogenic risk for both population age groups. This study highlights the current lack of well-documented scientific reports on the status of HMs in agricultural farmland soils across 12 other provinces in Iran, emphasizing the need for further investigation. Moreover, the bioavailability of HMs in agricultural soils significantly influences HM content in crops, underscoring the need for future research to ascertain HM concentrations in different soil fractions.

Is the use of a geotextile a necessary rehabilitation strategy to mitigate tailings contamination in soil cover materials? A 7-year field study

The potential pollution risk associated with poor management of mine tailings includes metal pollution of the surrounding environment from dusting and runoff. Thus, the establishment of a vegetation cover (rehabilitation) is viewed as an effective management strategy. Mine tailings can be inhibitory to plant growth due to their physico-chemical characteristics such as extreme pH, high salinity and potential high metal(loid) content, and the provision of a cover soil (≥ 30 cm) is usually recommended. This requires significant volumes of topsoil, which are often in limited supply at mine sites. An alternative may be the use of engineered soil (using organic and/or inorganic additives to improve physico-chemical properties) and placement of a barrier layer to prevent migration of tailings water or fines into the soil cover medium.Metal(loid)s content in soil cover treatments and vegetation uptake were evaluated after 7 years of rehabilitation in 1 m3 plots on a Pb/ Zn TSF. Final 30 cm covers included unamended tailings, subsoil material and subsoil amended with organic wastes (Spent Mushroom Compost (SMC) and Compost like output (CLO)). Treatments were divided into with/without geotextile inclusion. Soil samples were taken at 0–10 cm and 10–20 cm and analysed for pH, salinity (EC), and metal(loid)s/elements (As, Pb, Zn, Ca, Mg, Mn and, K) content. Vegetation was sampled after 1 yrs. growth (2015) and again after 7 years (2021) and analysed for their metal(loid)s/element content.Unamended tailings showed high metal(loid)s content at both depths, but concentrations were much lower in soil treatments. Herbage samples analysed in 2015 showed a higher concentration of metals than for 2021, highlighting the effectiveness and sustainability of amendments over a long period. Vegetation grown in unamended tailings showed the highest content of metal(loid)s, with significantly lower content in soil treatments. No significant difference was found for soil or vegetation metal(loid) content between geotextile inclusion/ exclusion. Results, highlight the relatively shallow soil covers without geotextile provide long term success with no evidence of metal(loid) contamination from underlying tailings.

Evaluation Heavy Metals Pollution in the Soil from some Regions of Al-Diwaniyah City / Iraq

Soil is the surface layer of the earth’s crust in which plant roots grow and some animals and other microorganisms live in it and it is considered the basis of the ecosystem, so its contamination negatively impact the health of all living organisms, especially humans who are at the top of the food chain. Heavy metals are considered among the most prominent inorganic pollutants in the soil, so this study came to evaluate the concentrations of some toxic heavy metals in areas with different activities in the city of Diwaniyah. The results of the study showed that the concentrations of heavy metals in the surface soil ranged between (0.958-2.292 mg/kg) and (19.132-73.907 mg/kg), (14.882 - 50.012 mg/kg) and (29.689-62.109mg/kg) for cadmium, lead, copper and chromium, respectively, and their concentrations in the soil at depth of 30 cm ranged between (1.529-1.971 mg/kg), (22.160 - 99.885 mg/kg), (12.790-55.630 mg/kg) and (41.278-75.467 mg/kg) for cadmium, lead, copper and chromium, respectively. Soil pollution was evaluated by using some pollution indices such as the geological accumulation index, pollution load index, contamination factor and degree of pollution. The results of pollution indices showed that the surface soil of the surface study sites and depth of 30 cm is contaminated with a very high degree of cadmium. Medium pollution with lead and little pollution with copper and chromium, and this requires great attention in order to reduce soil pollution with heavy metals, especially cadmium and lead.

Use of Some Natural Materials to Reduce Concentrations of some Heavy Metals in Polluted Water and Possibility of Using Them for Irrigation in Calcareous Agricultural Soils

To evaluate efficiency of some natural materials in using them as filters to reduce concentrations of some heavy elements in polluted water, and possibility of using them for irrigation in calcareous agricultural soils, two experiments were conducted, first is laboratory, which is treatment of various polluted waters, namely industrial water, gray water, and river water using three natural treatment materials as filters, which are activated charcoal, Eichhornia crassipes plant powder, Ceratophyllum plant powder. Poles made of polyethylene were used with a length of 100 cm and a diameter of 10 cm equipped with a tap from bottom, a layer of glass wool was placed at bottom, and then treatment materials were placed on top of it at a height of 50 cm. A piece of gauze cloth was placed over it for filter polluted water from solids. Polluted water was passed after filtering from top of column and left for 24 hours for equilibrium, then filtrate was collected from bottom of column. Second experiment, it is biology, as an experiment was conducted in pots of 20 kg capacity, using calcareous soil with a Loamy texture, and Dodonaea seedlings (one of fence plants) were planted. NPK fertilizers were added to it according to fertilizer recommendation, and irrigation was done with tap water after 50% of available water was depleted by gravimetric method. Results showed the following: 1-High concentrations of heavy metals, each of Lead, Ccadmium, Zinc and Nickel in industrial water, where they reached 5.190, 0.043, 3.727 and 0.371 mg L-1, respectively, exceeding limits allowed by World Food and Health Organization for each of Cadmium, Zinc and Nickel, while concentrations of Lead is within internationally permitted limits. As for gray water, Cadmium concentrations exceeded internationally permitted limits, while concentrations of Lead, Zinc and Nickel were within internationally permitted limits. In river water, they were within internationally permitted limits. 2. Decreased concentrations of heavy metals in polluted water treated with various natural treatment materials compared to their concentrations before treatment. The materials used in treatment can be arranged according to their efficiency in adsorption of heavy metals from industrial and gray water as follows: -activated charcoal > Eichhornia crassipes powder > Ceratophyllum powder > Arundo donax plant_powder. 3-High available concentrations of heavy metals in soils passed through polluted water compared to soils irrigated with treated water. Total concentrations were 34.436, 18.227, 8.064 mg kg-1 soil, 31.064, 16.884, 6.190 mg kg-1 soil, 32.860, 12.670, 4.930 mg kg-1 soil, 0.465, 3.680, and 0.590 mg kg-1 soil for Lead and Cadmium elements and Zinc and Nickel in succession and industrial water and gray water and river water successively, after 100 days of cultivation. 4-High concentrations of heavy metals in plants irrigated with different polluted water compared to plants irrigated with different treated water after 100 days of cultivation. Plants irrigated with polluted and treated water can be arranged according to concentration of heavy metals in them as follows: - industrial water > gray water > river water.