Elemental Composition Of Soils Research Articles

Linkages Between Mineral Element Composition of Soils and Sediments With Hyporheic Zone Dissolved Organic Matter Chemistry Across the Contiguous United States

AbstractThe hyporheic zone is a hotspot for biogeochemical cycling where interactions with mineral metals preserve the release and biodegradation of organic matter (OM). A small fraction of OM can still be exchanged between localized sediments and the overlying water column, and recent evidence suggests there exists a longitudinal structuring in sediment dissolved OM (DOM) chemistry across the continental United States (CONUS). In this study, we tested a hypothesis that water extractable sediment DOM chemistry could be explained by sediment metal contents and integrative watershed scale features at the CONUS scale. Crowdsourced samples were characterized for high resolution mass spectrometry and coupled with sediment metals determined via x‐ray fluorescence as well as with land cover and soil elemental information obtained from national databases. Our results highlight weak relationships between DOM chemistry and elemental composition at the CONUS scale indicating limited transferability of organo‐metal linkages into multi‐scale hydrobiogeochemical models.

Impacts of anthropogenic activities and glacial processes on the distribution of chemical elements in Billefjord, Svalbard, Arctic

The Arctic region is undergoing rapid and extensive transformations due to global climate change. This study investigated the spatial distribution of 31 chemical elements in eight locations in Billefjord, Svalbard, Arctic, with varying degrees of anthropogenic and glacial influences. The west coast of Billefjord has experienced a greater historical anthropogenic impact, while the east coast has larger glaciers and shows less visible evidence of direct human impact. Over 450 topsoil samples collected in the west (abandoned mining town Pyramiden, and glacial valleys of Elsa, Ferdinand, Sven) and east coast of the fjord (glacial valleys of Ebba, Pollock, Ragnar and nearby the Nordenskiöld glacier). These samples were extracted and analyzed by ICP-OES. The results revealed complex distributions of elements among the locations. Nordenskiöld glacier area, along with other locations in the eastern part of the Billefjord, had significantly higher levels of most elements (20 out of 31; As, B, Ca, Cd, Co, Cr, Cu, K, Li, Mg, Mo, Sb, Se, Sn, Sr, Ti, Tl, U, V, Zr). In contrast, Ferdinand Valley and other locations on the western side of the fjord had the lowest mean concentrations of most elements (18 out of 31; B, Ca, Cu, Cd, K, Li, P, Mg, Mo, Sb, Se, Sn, Sr, Ti, Tl, U, V, Zr). These findings highlight the significant influence of glacial processes on the elemental composition of soils within the region. The meltwater flow originating from glaciers in the sampled valleys contributes to the local element load, while the loss of glacier mass is associated with decreased element concentrations within these valleys. These results underscore the complexity of element distribution in the study area and emphasize the necessity for continuous monitoring efforts in this unique and environmentally sensitive region.

Neolithic long barrows were built on the margins of settlement zones as revealed by elemental soil analysis at four sites in the Czech Republic

Past human activities can be reflected in the elemental composition of contemporary soils. The paper is tackling the problem whether it is possible to distinguish prehistoric residential and ritual activities based on the elemental composition of soils. Specifically, the paper is addressing the question of whether Neolithic long barrows were built near habitation zones. An extensive set of 1085 soil samples was used, collected from four barrow sites of the Funnel Beaker Culture in the Czech Republic (and a prehistoric settlement as a reference site). Their elemental composition showed significant differences in the amount of P (phosphorus) and other anthropogenic elements (Ca, Cu, Mn, Zn) between the prehistoric habitation zone and the sites of long barrows. This difference was detected both in the A horizon (ploughed) and B horizon (sub-soil), thus, the additional conclusion of this study is that the ploughed A horizon, which is typically neglected by archaeologists, may also contain information about prehistoric land-use. The results of the geochemical analysis were confirmed by magnetometric surveys, recording, on the one hand, the absence of residential features in the vicinity of the barrows and, on the other hand, showing the presence of later funerary/ritual features. It was possible to conclude that the investigated barrows were built from local materials and that there were no human activities related to the accumulation of ash and waste in their surroundings at the time of construction, use or abandonment, which suggests that they were built in separation from Neolithic habitation zones. They continued to influence land-use and the perception of the landscape for thousands of years.

The trace element distribution in peat soils affected by natural burning events: A proxy of the original composition and metals mobility assessment

This work evaluates for the first time the effects on the trace element composition of peat soils affected by natural burning events, a recurrent phenomenon in the reclaimed wetland of the Mezzano Lowland (Padanian plain, NE Italy). The trace element distribution of two neighboring soil profiles, one pristine and one deeply affected by burning events, were compared to identify the original geochemical fingerprint of saltmarsh peat environment. The pre-combustion composition of the fired profile was reconstructed to infer the physico-chemical changes occurred as a consequence of the burning event, with a special attention to the mobility of elements of environmental concern, such as potentially toxic trace metals. The increase in concentration of potentially toxic elements (PTE) was particularly evident in two layers of the fired profile. V, Cr, Cu, Zn, Pb, and As contents progressively increase toward intermediate depths (30–75 cm) together with Th, Sr, Ba, U. On the contrary, Tl, Bi and Cd show a concentration peak in a thin, shallower (14–17 cm depth) horizon. The trace element composition of the unfired profile allowed the identification of specific ratios between immobile elements that can be used as geochemical fingerprint of the soils horizons with different soil organic matter (SOM) content. On the basis of Sr/Rb, Th/U and Ba/Sr it was possible to classify three types of sedimentary deposits characterizing both the unfired and fired profile, as well as to delineate the fire severity trends occurred in the different soil horizons of the fired profile. The distribution of immobile trace element, representative of the organic (U) and mineral (silicate, Th, Ba, REE and non-silicate, Sr) soil fractions with organic matter and bulk density in the non-fired profile, allowed the reconstruction of the original physico-chemical composition of the fired/burned profile and the accurate determination of the relative CO2 lost during the burning event. Moreover, the distribution of PTE with respect to immobile trace elements, used to estimate the element redistribution and mobility after burning in the fired profile, suggested that elements such as Cr, Ni, Zn, V were mainly immobile, whereas Pb, Mo and in particular Tl and Bi suffered a significant redistribution along the burned profile. Nonetheless, results of the gain/loss calculation for the whole soil profile suggested that no significant entry or leak of these elements occurred, limiting their redistribution inside the investigated soil system.

Compost-assisted revegetation of highly phytotoxic sulfidic tailings with Medicago sativa L. plants grown from the seed to seedpod stage under greenhouse experimental mesocosms conditions

The revegetation of highly phytotoxic sulfidic tailings is a challenging task which may often be successfully accomplished only following the addition of soil amendments. This study evaluated the use of green compost at increasing rates (10, 25 and 50% v/v) for the revegetation of extremely acidic sulfidic tailings of the North Mathiatis mine, Cyprus, with the use of alfalfa (Medicago sativa L.) plants, under greenhouse conditions. Alfalfa seeds were successfully germinated in tailings amended either with 25% or 50% (v/v) compost (52 and 85%, respectively). Plants managed to complete their life cycle and produce seeds only in the tailings amended with 50% (v/v) compost, since plants grown in tailings amended with lower rates of compost (i.e., 10 or 25% v/v) showed severe symptoms of phytotoxicity and eventually died. The amendment of tailings with 50% (v/v) green compost resulted in increased pH values, water holding capacity and organic content levels, soil respiration rates, as well as changes in soil elemental composition compared with tailings alone treatment, which in turn facilitated the growth and development of alfalfa plants during the whole experimental period (140 days). Plants managed to reach the late seedpod growth stage, indicating their potential regeneration and continual existence to the amended tailings, simultaneously uncovering the development of favorable conditions in the rhizosphere for the successful revegetation of studied tailings.

Arsenic contamination and rare earth element composition of acid mine drainage impacted soils from South Africa

Acid mine drainage (AMD) impacted soils occur as soils near weathered pyritic mine tailings, directly receiving AMD or in proximity to AMD polluted waters. They pose environmental and human health risks and present challenges to restoration strategies for better land use management. This study investigated the chemical composition and geochemical evidence of AMD impact in four top soils from gold and coal mining regions near Johannesburg, South Africa with a focus on characterising metal contamination and rare earth element (REE) content. Soil physico-chemical properties (pH, electrical conductivity, texture, cation exchange capacity, carbon content, and sulfate) were measured and analysed and pseudo-total elemental contents were determined from a microwave digestion analysed by ICP-MS. The results showed evidence of soil acidification and exceedingly high sulfate (>7000 mg kg−1) and calcium (>200 g kg−1) contents. High arsenic contents (>300 mg kg−1) were found for some of the samples, exceeding the national soil screening value of 23 mg kg−1. Total REE content ranged from 51.7 to 110 mg kg−1 and favoured the light over heavy rare earth elements. The results suggest that there are complex dynamics between AMD and soil element fractions. Arsenic was unexpected as it had not previously been well documented in AMD polluted groundwater, surface waters, or mine seepage from the region, and REEs, with which AMD is often enriched, were not retained in the topsoil samples. These novel findings indicate major challenges to post-mining land rehabilitation.

Elemental Composition of Soils in the Heterogeneous Geological Setting of the Mzymta River Basin on the Russian Black Sea Coast

Elemental Composition of Soils in the Heterogeneous Geological Setting of the Mzymta River Basin on the Russian Black Sea Coast

Impact of heavy metal polluted wastewater sediment on element content and enzyme activity of Sudan grass

Growth chamber pot experiment was set up with two varieties of Sudan grass. Plants were grown in uncontaminated (control) topsoil of the former wastewater settling pond from Debrecen, which was amended with 10% (m/m) of wastewater sediment (P: 5125; Fe: 22756, Pb: 287; Cr: 1027; Zn: 888 mg/kg). The elemental composition of soil and shoots of plants and activities of some enzymes in leaves were measured. It can be concluded that the roots and shoots of plant individuals of both varieties consistently took up higher concentrations of each of the elements from the medium "enriched" with wastewater sediment. The elevated element concentrations were found in some cases in the roots, and in other cases in the leaves (K: ~2000 (soil) - ~13000 (root) - ~30000 (shoot) mg/kg; Cr: ~330 (soil) - ~3,30 (root) - ~0,189 (shoot) mg/kg). The excessive accumulation of toxic elements was not observed. The activities of four enzymes were measured in the leaves of plants (glucose 6-phosphate dehydrogenase, G6PDH; isocitrate-dehydrogenase, ICDH; peroxidase, POX; catalase, CAT). The enzyme activities of POX increased meanwhile that of CAT decreased significantly, in spite of slight differences. As a trend, the specific activity for G6PDH increased by 26% (GK Csaba) and 36% (Akklimat), while values for ICDH became higher by 28% (GK Csaba) and 41.5% (Akklimat), for the two varieties studied, respectively. The latter results were not statistically supported.

Biogeochemical Features of Landscapes of the Nadym Region of YANAO

The purpose of the study is to reveal the biogeochemical features of soils (illuvial-ferruginous podzols, podzols, cryozems, oligotrophic peat frozen soils, alluvial gray-humus and lacustrine-alluvial soils) and vegetation (Betula nana L., Chamaedaphne calyculata (L.) Moench, Vaccinium uliginosum L., Ledum palustre L., Sphagnum sp L.) of the Nadym region. To achieve the goal, the following tasks were set and implemented: to determine the total content and radial differentiation of elements in the studied soils; to reveal the features of the biological accumulation of elements by the dominant types of vegetation cover. The elemental composition of soils and plants was determined on a serial X-ray fluorescence spectrometer S6 JAGUAR according to the method for determining the mass fraction of metals and metal oxides in powder samples. It has been established that the soils of the Nadym region are characterized by a low content of macroelements, including potassium, calcium, and phosphorus necessary for the mineral nutrition of plants. Calculation of soil-geochemical coefficients shows that the studied soils have an average degree of weathering and leaching moisture regime, peat-gley and cryozems are classified as more fertile soils. Ca, P, and S are accumulated in organic soil horizons, and Co, Cr, and Ni are accumulated in mineral horizons. The radial geochemical structure of cryozems combines features of eluvial-illuvial differentiation and biogenic accumulation. In podzols, the distribution of all elements is eluvial-illuvial, with a minimum in the podzolic horizon. Among plants, the leader in the accumulation of elements is dwarf birch (the maximum accumulation of Ca, K, P, Mg, Zn, Ni), in mosses, on the contrary, the minimum accumulation of elements was found. The elements of energetic and strong accumulation (Kb=n-100n) include Pb, Mo, Cd, Cl, S.

Sources, distribution and decomposition of soil organic matter based on an effective biomarker in the pastoral areas of Zoige Plateau, China

The degradation of organic matter in soils plays an important role in the carbon cycle. Lignin is the main source of soil organics and it can be used to trace the source, distribution and turnover of organic matter. In this study the distribution and degradation of lignin were investigated to identify the source and degradation of soil organic matter during the succession of China's Zoige Plateau. Lignin monomers were determined by gas chromatography-mass spectrometry with alkaline CuO oxidation and the soils' δ13C and δ15N contents were interpreted to explore the turnover rate of lignin and organic matter. The main source of organics was identified as C3 non-woody angiosperm tissues. Lignin in the topsoil (0–30 cm) was derived from litter and roots, and it then migrated vertically to the deep soil (30–80 cm). Correlations of δ13C/δ15N with the soil's elemental composition showed that the organics degraded more quickly in meadow soil than in bog soil. The soil communities in the meadow and bog soils were generally similar, but there were certain differences in the dominant microbial phyla at different depths. The meadow soil's effectiveness as a carbon sink was gradually weakened, while that of the bog soil strengthened with depth. These results provide a scientific basis for accurately assessing the carbon sink capacity of the soils in Zoige Plateau.

BIOGEOCHEMICAL PROPERTIES OF SALINE GRASSLAND SOILS AND SALT MARSHES AND THE BENEFITS OF USING MICRO FERTILIZERS

The elemental composition of soils and the biogeochemical processes taking place in them are shown in the article. Opinions are given on the composition of microelements of saline meadow soils and salt marshes and the biophilicity of these elements. Microfertilizers are substances that contain microelements and are used in small amounts for the normal growth of plants. The presence of most of the elements in D.I. Mendeleev's periodic system of elements in the soil, plants and living organisms. However, the measurement of their quantity is about making a very wide range n "10-3- n "10-5 and even n "10-9- n "10-10 %.

Effect of medieval farming activities on elemental composition of soils – case study of deserted village Regenholz (Czech Republic)

Regenholz is a deserted medieval village existing approximately between the 13th and 15th centuries. It originated in the colonisation period when the villages were usually founded in upland regions of Central Europe in the High Middle Ages. The study presents the results of a research based on geochemical and spatial analyses of one of the village’s field areas. The aim of the study was to reveal the spatial characteristics of the elemental composition of the previously ploughed soils which are now covered by forest. The analysed field area comprised bundles of 13 strip plots, which were approximately from 30 to 40 meters (up to 60 meters in two cases) wide and 300 meters long. The village and its fields were adjacent to the village Lovětín, which was analysed and published earlier. This made it possible to compare the geochemistry of the deserted fields of both villages with the same natural conditions and historical development. The soil samples were measured for elemental composition by portable XRF. The composition was dominated by elements generally interpreted as past human activity indicators: P, Zn, Mn, and Sr. Past human presence was represented mainly by Cu and partially by Mn content (P and Sr showed similar trends). The obtained results were compared with the data from the adjacent village Lovětín: the results were similar just by comparing the PCA data. The past human activity indicators reached less spatial diversity than those of natural factors.

Legacy of agrochemicals in the circular food economy: Glyphosate-based herbicides introduced via manure fertilizer affect the yield and biochemistry of perennial crop plants during the following year

Conventional agricultural practices favoring the use of glyphosate-based herbicides (GBHs) increase the risk of GBH residues ending up in animal feed, feces, and, eventually, manure. The use of poultry manure as organic fertilizer in the circular food economy increases the unintentional introduction of GBH residues into horticultural and agricultural systems, with reportedly negative effects on the growth and reproduction of crop plants. To understand the potential lasting effects of exposure to GBH residues via organic manure fertilizers, we studied strawberry (Fragaria x vescana) plant performance, yield quantity, biochemistry, folivory, phytochemistry, and soil elemental composition the year after exposure to GBH. Although plants exposed to GBH residues via manure fertilizer were, on average, 23% smaller in the year of exposure, they were able to compensate for their growth during the following growing season. Interestingly, GBH residue exposure in the previous growing season led to a trend in altered plant size preferences of folivores during the following growing season. Furthermore, the plants that had been exposed to GBH residues in the previous growing season produced 20% heavier fruits with an altered composition of phenolic compounds compared to non-exposed plants. Our results indicate that GBHs introduced via manure fertilizer following circular economy practices in one year can have effects on perennial crop plants in the following year, although GBH residues in soil have largely vanished.

Spotted knapweed (Centaurea stoebe) creates a soil legacy effect by modulating soil elemental composition in a semi-arid grassland ecosystem.

Invasive plants such as spotted knapweed (Centaurea stoebe) are particularly detrimental to fragile ecosystems like semi-arid grasslands in the interior British Columbia, impacting aboveground and belowground ecology. Physical removal of C. stoebe has been one of the most popular invasive species management strategies, but the impact of C. stoebe removal on soil has hardly been studied. Here, we examine the legacy effect of C. stoebe on soil elemental composition and ecosystem function following its removal in the Lac Du Bios Grasslands Protected Area, British Columbia. First, we selected 40 paired C. stoebe invaded and control (uninvaded) plots and removed all vegetation from these plots. We planted Festuca campestris seedlings in these plots and harvested and weighed the biomass after four months. Additionally, we quantified total carbon and nitrogen in soil. We observed that C. stoebe invaded plots had significantly lower F. campestris biomass. Moreover, the total carbon and nitrogen content, and carbon/nitrogen ratio were significantly lower in C. stoebe invaded plots. We further analyzed 12 common soil elements and found the elemental composition was significantly different in C. stoebe invaded plots compared to controls. We investigated the impact of elemental composition on soil ecosystem functions (such as total soil carbon, total soil nitrogen, and F. campestris productivity). Our analysis revealed significant relationships amongst the elemental composition and total soil carbon and nitrogen, and F. campestris productivity. The results indicate that C. stoebe exerts a legacy effect by altering the soil elemental composition that may subsequently impacts soil ecosystem functions such as plant productivity and total carbon and nitrogen content.

Clay and soil organic matter drive wood multi-elemental composition of a tropical tree species: Implications for timber tracing

Forensic methods to independently trace timber origin are essential to combat illegal timber trade. Tracing product origin by analysing their multi-element composition has been successfully applied in several commodities, but its potential for timber is not yet known. To evaluate this potential the drivers of wood multi-elemental composition need to be studied. Here we report on the first study relating wood multi-elemental composition of forest trees to soil chemical and physical properties.We studied the reactive soil element pools and the multi-elemental composition in sapwood and heartwood for 37 Azobé (Lophira alata) trees at two forest sites in Cameroon. A total of 46 elements were measured using ICP-MS. We also measured three potential drivers of soil and wood elemental composition: clay content, soil organic matter and pH. We tested associations between soil and wood using multiple regressions and multivariate analyses (Mantel test, db-RDA). Finally, we performed a Random Forest analysis of heartwood elemental composition to check site assignment accuracy.We found elemental compositions of soil, sapwood and heartwood to be significantly associated. Soil clay content and organic matter positively influenced individual element concentrations (for 13 and 9 elements out of 46 respectively) as well as the multi-elemental composition in wood. However, associations between wood and topsoil elemental concentrations were only significant for one element. We found close associations between element concentrations and composition in sapwood and heartwood. Lastly, the Random Forest assignment success was 97.3 %.Our findings indicate that wood elemental composition is associated with that in the topsoil and its variation is related to soil clay and organic matter content. These associations suggests that the multi-elemental composition of wood can yield chemical fingerprints obtained from sites that differ in soil properties. This finding in addition to the high assignment accuracy shows potential of multi-element analysis for tracing wood origin.

Assessment of the Effect of Soil Sample Preparation, Water Content and Excitation Time on Proximal X-ray Fluorescence Sensing.

X-ray fluorescence (XRF) spectroscopy offers a fast and efficient method for analysing soil elemental composition, both in the laboratory and the field. However, the technique is sensitive to spectral interference as well as physical and chemical matrix effects, which can reduce the precision of the measurements. We systematically assessed the XRF technique under different sample preparations, water contents, and excitation times. Four different soil samples were used as blocks in a three-way factorial experiment, with three sample preparations (natural aggregates, ground to ≤2 mm and ≤1 mm), three gravimetric water contents (air-dry, 10% and 20%), and three excitation times (15, 30 and 60 s). The XRF spectra were recorded and gave 540 spectra in all. Elemental peaks for Si, K, Ca, Ti, Fe and Cu were identified for analysis. We used analysis of variance (anova) with post hoc tests to identify significant differences between our factors and used the intensity and area of the elemental peaks as the response. Our results indicate that all of these factors significantly affect the XRF spectrum, but longer excitation times appear to be more defined. In most cases, no significant difference was found between air-dry and 10% water content. Moisture has no apparent effect on coarse samples unless ground to 1 mm. We suggested that the XRF measurements that take 60 s from dry samples or only slightly moist ones might be an optimum option under field conditions.

Wood ash effects on soil properties and Lactuca sativa growth in soils amended with digestate and poultry litter

The evaluation of the impact of wood ash, on metal uptake and transfer factor of lettuce grown on soil amended with poultry litter, digestate and its fraction was carried out. Positive (inorganic fertilizer) and negative (unamended soil) fertilization controls were included and impacts on soil fertility and crop productivity, as well as potential toxic elements’ levels, were assessed at pre and post planting period. Soil properties (e.g., plant available N and P, and water soluble elements), plant morphometry, elemental composition (e.g., total nitrogen, total carbon, total phosphorus) and nutrient uptake were determined using standard methods. There was higher nutritive content of the soil amended with whole digestate than fiber digestate resulting in its largest weight of lettuce. Ash significantly improved the impact of the amendments on the properties of the soil which was reflected in better lettuce productivity and was most applicable to the poultry litter. Based on the transfer factor and uptake of the trace metals, results show lower potential toxicity in the lettuce from the organic treatments in comparison to the inorganic fertilizer. Wood ash had positive ameliorative effects on the amended soils which makes it a suitable nutrient booster for organic fertilizers and alternative to inorganic fertilizers for leafy vegetables.

Vegetation Regulates Element Composition of Soils by Enhancing Organic Matter Accumulation in the Salt Marshes of Liao River Delta, China

The purpose of this study was to evaluate if vegetation regulates soil biogeochemistry in coastal salt marshes, here measured as element concentrations (43 elements) and organic matter content of the soils. We selected seven sampling sites in Liao River Delta, China, within each of which three areas existed in close proximity of each other, characterized as ‘bare, unvegetated sediments’, ‘Phragmites australis marsh’, and ‘Suaeda heteroptera marsh’. We recorded sampling locations and measured soil element concentrations, organic matter content, soil pH, soil salinity, soil water content, and soil electrical conductivity. All but four of element concentrations of soils varied by wetland type, and concentrations of 35 elements, and organic matter content increased from bare, unvegetated sites to Phragmites marshes to Suaeda marshes. Redundancy analysis (RDA) identified that organic matter content explained most variance. Organic matter content was positively related with most elements including nutrients and metals, negatively related with Sr, Ba and Na. However, further analysis of element concentrations revealed significant differences also between Phragmites-dominated and Suaeda-dominated sites, even though they did not differ significantly in organic matter content. This information highlights the importance of vegetation in regulating soil element composition and biogeochemical processes in coastal salt marshes.

Coastal salt marsh restoration drives element composition of soils toward its original state by recovering soil organic matter

AbstractLarge areas of coastal wetlands have been restored recently throughout the world; it is important to know if restoration practice recovers original levels of biogeochemical functioning in coastal wetlands. We did samplings in five sites in the Liaohe River Delta, China. Each site had three salt marsh types: natural, restored, and degraded. We measured the concentrations of 43 elements and environmental variables including soil organic matter, soil electrical conductivity, soil pH, soil salinity, and soil water content. Concentrations of 39 elements differed significantly between salt marsh types. The values of the concentrations of 39 elements in the restored salt marshes were all in between those of natural and degraded salt marshes. Soil organic matter and the relative abundance of most elements including nutrients and metals increased simultaneously during restoration. Redundancy analysis indicated that soil organic matter explained 72.1% of the total variation in element composition. Our findings indicated that the recovery of soil biogeochemical functioning in salt marshes was driven by the accumulation of soil organic matter during restoration. It may take a very long time for the soil composition and biogeochemistry to reach the original levels prior to disturbance.

Isolation of Heterotrophic and Hydrocarbon-Utilizing Fungi from Selected Mechanic Workshops in Port Harcourt

Spent engine oil wastes in soils are currently considered one of the most serious environmental problems. This type of pollution decreases or fully destroys soil fertility, changes the elemental composition of soil. After their introduction into soil, hydrocarbons affect soil microorganisms directly or indirectly. In this study the population of heterotrophic and hydrocarbon utilizing fungi was investigated in soils from different mechanic workshop in Port Harcourt, Rivers State. Soil physicochemical parameters such as pH, temperature, nitrate, phosphorous, potassium, total hydrocarbon content and heavy metals like Pb and Cd were also determined. Standard procedures were followed in the mycological and physicochemical parameters determination. In the soil samples, counts of the total heterotrophic fungi ranged from 0.87±3.62 to 6.9±3.37 ×104 cfu/g soil while counts of the hydrocarbon utilizing fungi ranged from 0.85 ±1.91 to 2.75±1.26 ×103 cfu/g soil. The control soil sample recorded more total heterotrophic fungal counts with significant difference while the soil from the mechanic workshops recorded more hydrocarbon utilizing fungal counts than the control soil sample and was significantly different. Eight fungal genera were isolated and they include Mucor, Aspergillus, Penicillium, Blastomyces, Scedosporium, Microsporium, Candida and Scopulariopsis. Fungal genera such as Microsporium, Candida and Scopulariopsis were not isolated from soils from the mechanic workshops but only isolated from the control soil sample. The pH values ranged between 5.81 to 7.91, temperature ranged from 27.7 to 30 oC, nitrate value ranged from 0.04 to 0.21 mg/kg, PO4 ranged from 1.10 to 3.42 mg/kg, total hydrocarbon content (THC) value ranged from 0 to 170.01 mg/kg, potassium (K) value ranged from 5.063 to 17.013 mg/kg. The heavy metals analyzed were Pb (Lead) and Cd (Cadmium). The Pb ranged from 0.10 to 5.12463 mg/kg, cadmium ranged from 0.13 to 1.65072 mg/kg. The soil samples from mechanic workshops were contaminated with hydrocarbons, and the fungal isolates were primarily hydrocarbon utilizers that may be exploited for contaminated soil bioremediation.