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1.
As(III) and As(V) in goldtailings and river-bedsediments from Obuasi were determined by distillationof arsenic as AsCl3. Results yielded 3750±426 mg kg-1 (45.2%) for As(V) and 3050±66 mg kg-1 (36.7%) for As(III) in the tailings. In the river-bed sediments, one spot yielded: As(III) 0 mg kg-1 (0%) and As(V) 1447±51 mg kg-1 (100%), whilst a second spot yielded: As(III) 0 mg kg-1 (0%) and As(V) 2976±51 mg kg-1 (100%). Using arsenic oxide standards, the recovery of As(III) and As(V) in the trioxide were 94.8 and 0.6% respectively. In a mixture of the two oxides, the recovery of As(III) was 87.6% with practically no interference from As(V). Total As content of the tailings was determined by neutron activation analysis (NAA) to be 8305±75 mg kg-1.  相似文献   

2.
The prediction of the mobility of arsenic (As) is crucial for predicting risks in soils contaminated with As. The objective of this study is to predict the distribution of As between solid and solution in soils based on soil properties and the fraction of As in soil that is reversibly adsorbed. We studied adsorption of As(V) in suspensions at radiotrace concentrations for 30 uncontaminated soils (pH 4.4–6.6). The solid–liquid distribution coefficient of As (Kd) varied from 14 to 4430 l kg?1. The logarithm of the concentration of oxalate‐extractable Fe explained 63% of the variation in log Kd; by introducing the logarithm of the concentration of oxalate‐extractable P in the regression model, 85% of the variation in log Kd is explained. Double labelling experiments with 73As(V) and 32P(V) showed that the As to P adsorption selectivity coefficient decreased from 3.1 to 0.2 with increasing degree of P saturation of the amorphous oxides. The addition of As(V) (0–6 mmol kg?1) reduced the Kd of 73As up to 17‐fold, whereas corresponding additions of P(V) had smaller effects. These studies suggest that As(V) is adsorbed to amorphous oxides in soils and that sites of adsorption vary in their selectivity in respect of As and P. The concentration of isotopically exchangeable As in 27 contaminated soils (total As 13–1080 mg kg?1) was between 1.2 and 19% (mean 8.2%) of its total concentration, illustrating that a major fraction of As is fixed. We propose a two‐site model of competitive As(V)–P(V) sorption in which amorphous Fe and Al oxides represent the site capacity and the isotopically exchangeable As represents the adsorbed phase. This model is fitted to 73As adsorption data of uncontaminated soils and explains 69% of the variation of log Kd in these soils. The log Kd in contaminated soils predicted using this two‐site model correlated well with the observed log Kd (r = 0.75). We conclude that solubility of As is related to the available binding sites on amorphous oxides and to the fraction of As that is fixed.  相似文献   

3.
The removal of As(III) from aqueous solutions at different concentrations, pH and temperatures by haematite has been carried out successfully. The maximum removal was found to be 96 % at concentration 13.34 μmol L?1, temperature 20 °C and pH 7.0. The process of uptake follows first-order adsorption rate expression and obeys the Langmuir's model of adsorption. The removal of As(III) by haematite is also partially diffusion controlled and mass transfer coefficients, diffusion coefficients and thermodynamic parameters have been determined to explain the results.  相似文献   

4.
Retention of vanadium (V) by three Finnish mineral soils   总被引：1，自引：0，他引：1  
Retention of V(V) by three Finnish mineral soils from 10?4m and 10?5m sodium vanadate solutions was investigated at room temperature in the pH range 2.3–7.5. In adsorption experiments, 0.02 m KCl was used as ionic medium, and the samples were left to equilibrate for 72 h. The solid: solution ration was 1:100 (m: v). Maximum adsorption occurred at pH ～4, where 70–80% of the added V (350–400 μg g?1 from 10?4m solution and 35–40 μg g?1 from 10?5m solution) was retained by each soil. Retention was significant even at pH 6, where adsorption of a similar anion, molybdate, is negligible. Desorption of the retained V was measured by adding 50.0 cm3 of 0.02 M KCl into weighed soil samples and shaking for 17 h in a mechanical stirrer. Only a minor part of retained V could be removed from each soil by the KCl treatment. Retention of different ionic species of V from 10?5m solution is approximated using values of log K obtained from the literature. In these calculations, kaolin is used as a reference material.  相似文献   

5.
The hydrous oxides of Mn, Fe, and Al avidly sorbed Sb from μM Sb(OH), solutions, with uptake levelling off as initial Sb concentration increased. Capacity values decreased along the sequence MnOOH > Al(OH)3 > FeOOH. The amount sorbed by each substrate decreased gradually at pH values > 6. Addition of 0.4M CH3COONa to the aqueous phase (to minimise retention of weakly bound Sb) had little effect on MnOOH uptake capacity (～160 mmol, kg?1 at pH < 7) but retention dropped rapidly at higher pH. With the other two substrates (pH 6–7) the calculated capacity values for specific Sb sorption were ～ 45 mmol kg?1 FeOOH and ～ 33 mmol kg? Al(OH)3; about a third of the total capacity values. On these substrates specific Sb sorption tended to peak in the pH 7 to 8 region. The pH response pattern was modified using Sb tartrate sorbate solutions. Factors influencing Sb sorption included substrate surface charge, chemical form of Sb and surface interactions. Formation of a sparingly soluble metal coating was indicated by the uptake plateaus observed when increasing amounts of solid were added to Sb solutions containing acetate.  相似文献   

6.

Purpose

The application of roxarsone (ROX), an arsenic-containing compound, as a feed additive in the animal production industry results in elevated soil levels of ROX and its metabolites, namely, monomethylarsonic acid (MMA), dimethylarsinic acid (DMA), arsenate (As(V)), and arsenite (As(III)). This study was conducted to study the extraction and speciation analysis of ROX-related arsenicals in soils with different physicochemical properties and the possible effects of soil properties on the extraction of ROX and its metabolites.

Materials and methods

Analytical method based on high-performance liquid chromatography (HPLC)-inductively coupled plasma–mass spectrometry (ICP-MS) was employed to determine the concentrations of As(III), DMA, MMA, As(V), and ROX extracted by different extraction solvents from different soils spiked by arsenicals. Validity of the developed method was assessed by the recovery efficiencies of arsenic species in soil-dissolved matter solutions containing 20 μg As?·?L?1 of each arsenic species. Effects of soil properties on the extraction of ROX and its metabolites were analyzed by Pearson’s correlation.

Results and discussion

Arsenic species were separated using gradient elution of water and 20 mmol?·?L?1 (NH4)2HPO4 + 20 mmol?·?L?1 NH4NO3 + 5 % methanol (v/v) within 27 min. The linear ranges of all arsenicals were 0–200 μg As?·?L?1 with R 2?>?0.9996. The developed method provided lower limits of detection for As(III), DMA, MMA, As(V), and ROX (0.80, 0.58, 0.35, 0.24, and 1.52 μg As?·?L?1, respectively) and excellent recoveries (92.52–102.2 %) for all five species. Arsenic speciation was not altered by 0.1 mol?·?L?1 NaH2PO4 + 0.1 mol?·?L?1 H3PO4 (9:1, v/v), which offered better average extraction efficiencies for As(III), As(V), DMA, MMA, and ROX (32.49, 92.50, 78.24, 77.64, and 84.54 %, respectively). Extraction performance of arsenicals was influenced by soil properties, including pH, cation exchange capacity (CEC), total Fe, and amorphous Fe.

Conclusions

ROX and its metabolites from soils could be satisfactorily separated by the developed method for the studied arsenicals. To extract arsenic species from soils, 0.1 mol?·?L?1 NaH2PO4 + 0.1 mol?·?L?1 H3PO4 (9:1, v/v) was recommended. Extraction efficiencies of arsenicals were influenced more by solvent composition than soil physicochemical properties. The present study provides a valuable tool and useful information for determining the concentrations of ROX and its metabolites in contaminated soils.
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7.
Total Hg and McHg concentrations have been determined in sediments and suspended particulate matter from one of the most Hg-polluted rivers of the world, the Elbe river in Northern Germany. Results of total Hg and McHg are presented. Total Hg concentrations in suspended particulate matter (SPM) are 30 mg kg?1 in the average and up to 150 mg kg?1 as the maximum value. Total Hg-fluxes ?1 calculated from measurements of an automatically operating station upstream Hamburg as about 17 ta?1 in suspended particles. A new McHg determination by HPLC chromatography and photometric detection was developed and verified. Methylmercury concentrations were up to 10% of the total Hg, i. e. 2.7 mg kg?1 (dw).  相似文献   

8.
The adsorption of As(V) on alumina, hematite, kaolin and quartz has been measured as a function of pH (2 to 10), and As concentrations (10?4 to 10 ?8 M; in the alumina and kaolin systems only). The effects of sulfate (0 to 80 mg L?1) and fulvic acid (0 to 25 mg L?1) were studied. The charge of the solid surface and the As speciation in solution (determined by pH) were the most important chemical parameters affecting the sorption behavior. At pH below PZC of the solid, there was a qualitative correlation between the adsorption and the anion exchange capacity of the solid. For hematite at low pH (below 5) there was a reduction of the adsorption possibly related to the formation of positively charged species. The presence of sulfate or fulvic acid reduced the adsorption.  相似文献   

9.
Sediment cores were taken from the remote Sagamore and Woods Lakes in New York State's Adirondack acid lake region and analyzed for 3 to 7 ring polycyclic aromatic hydrocarbons (PAHs) and Ag, Al, As, Be, Cd, Cr, Cu, Hg, Ni, Ph, Se, Sn, TI, V, and Zn. With the exception of perylene, all of the parental PAHs, e.g. those without sidechains, and several of the metals, Pb, As, and Cd, were found to be significantly increased in the sediments of both lakes compared to their natural integrated deposits (ng cm?2) and their background concentrations (μg g?1 or ng g?1 dry wt). Although the concentrations were generally much higher in Woods Lake, the total anthropogenic integrated depositions were about the same in both lakes for most of the metals and the 3 to 4 ring PAHs. The prime source of most of the 3 to 7 ring PAHs and trace elements measured is ascribed to anthropogenic combustion. Anthropogenically derived materials decreased in concentration with depth to baseline levels in sediment layers estimated by137Cs analyses to be ～30 yr old, while biogenic or crustal derived species remained constant or fluctuated with core depth.  相似文献   

10.
Phosphate-induced zinc retention in a tropical semi-arid soil   总被引：14，自引：0，他引：14  
Zinc (Zn) deficiency symptoms and sporadic responses to applied Zn are being observed frequently in the Nigerian savanna, and one cause is thought to be the growing use of phosphorus (P) fertilizers. This study was designed to test the hypothesis of P-induced Zn retention in the soils. Soil mixed eith P was incubated at field capacity for 3 weeks at 30 ± 2°C. P levels added to the soil were 0, 500, 1000 and 2000 mg per kg soil. After 3 weeks of incubation, water-soluble Zn in soil decreased by 92% and exchangeable Zn by 78% with 2000 mg kg?1 of applied P. Zn levels ranging from 0 to 200 mg kg?1 were added to the P-incubated soil to determine the Zn sorption isotherm and retention capacity. The P-treated soil retained 93 ± 2% of added Zn compared with 52 ± 2% of the control soil. P treatment changed the Zn sorption isotherm from an L-curve isotherm to an H-curve isotherm, indicating strong affinity of P-treated soil for Zn, probably as a result of the formation of Zn-phosphate complexes on the soil surface and precipitation at sufficiently large concentrations of P and Zn. At 2000 mg P kg?1, up to 90% of Zn retained by the soil was bound in solid form as ZnHPO4. Varying the soil pH from 3.5 to 9.0, Zn retention by the soil was related to Zn hydrolysis with maximum adsorption occurring at pH 7.3 ± 0.2. The dependence of sorbed Zn on Zn(OH)2° at pH 3.5–7.4 of P-treated soil indicated that significant van der Waals forces might be involved in Zn retention. The implication of the results of this study for the region is that fertilizer-P placement around a growing crop plant, commonly practised to maximize fertilizer-P efficiency, can potentially limit Zn solubility and availability.  相似文献   

11.
High As groundwater normally contained high concentrations of Cl? and HCO 3 ? . This study examined the effects of Cl?, HCO 3 ? , and As species on As uptake by hyperaccumulator Pteris vittata. Plants were exposed hydroponically to 5.0?mg/L As(III) or As(V) in the presence of 0, 0.5, 1, 2, 5, 10, and 20?mM of Cl? or HCO 3 ? for 10?days. Addition of high Cl? concentrations (>10?mM) slightly inhibited P. vittata growth (biomass), while generally had no significant effect on plant As uptake. High solution pH resulted in reduced plant growth and As uptake, which attributed to the inhibitory effects in HCO 3 ? treatments with the high pH of the high HCO 3 ? concentration. It was speculated that addition of HCO 3 ? (<20?mM) would have no significant effect on plant growth and As uptake. The inhibitory effect of HCO 3 ? on As translocation was less apparent in the As(III) solutions than the As(V) solutions. For the high As groundwater with As(III) as the predominant species, high pH, instead of high concentrations HCO 3 ? and Cl?, was expected to inhibit As uptake. The results suggested that optimum plant growth and maximum As hyperaccumulation could be achieved by adjusting solution pH in the growth media (around 7.2).  相似文献   

12.
Elevated levels of As in contaminated water and soil could pose a major threat to the environment. Relatively high levels of As have been reported in agricultural drainage water and in evaporation pond sediments in Kern County, California. The objective of this study was to enumerate and isolate As-resistant microorganisms from agricultural drainage water and evaporation pond sediments and to assess their tolerance to metals, metalloids and antibiotics. The culture medium was amended with arsenite (III), arsenate (V), methylarsonic acid (MAA), and dimethylarsinic acid (DMA). Among the water samples, As(V), MAA, and DMA added to the medium at concentrations from 0.1 to 1000 mg L?1 showed no effect on the colony forming units (CFUs) compared with no As supplementation, while arsenite (III) (> 1.0 mg L?1) inhibited the population. The sediments showed three trends: (i) no effect on CFUs in the presence of As(V) up to 1000 mg kg?1, (ii) a decline in CFUs in the presence of > 100 mg kg?1, As(III), and (iii) an increase in CFUs upon the addition of MAA or DMA at > 25 mg kg?1, Arsenite (III) was much more toxic to the indigenous microflora than any other As species. Arsenite (III) inactivates many enzymes by having a high affinity for thiol groups of proteins. A plate diffusion method was used to assess the tolerance of the As-resistant bacteria to heavy metals, metalloids and antibiotics. Of 14 isolates tested, all were resistant to Co, Cu, Pb, Ni, Mo, Cr, Se(IV), Se(VI), As(III), As(V), Sb, Sn, and Ag (50 µg mL?1). The most toxic trace elements were Cd followed by Hg>Te>Zn. Multiple antibiotic tolerance (resistance to 2 or more antibiotics) was found among 43% of the isolates. The As-resistant bacteria showed a high tolerance to metals and antibiotics.  相似文献   

13.
The objective of this study was to study the influence of different ethylenediamine tetraacetate (EDTA), nitrilotriacetic acid (NTA) and oxalic acid (HOx) concentrations on tolerance and lead (Pb) accumulation capacity of carrot (Daucus carota). The results indicated that by increasing Pb, NTA and HOx concentrations in the soil, the shoot, taproot and capillary root dry matters increase effectively. In contrary, EDTA caused to reduce capillary roots biomass. EDTA was more effective than NTA and HOx in solubilizing soil Pb. The highest Pb content in shoots (342.2 ± 13.9 mg kg?1) and taproots (301 ± 15.5 mg kg?1) occurred in 10 mM EDTA, while it occurred for capillary roots (1620 ± 24.6 mg kg?1) in 5 mM HOx, when the soil Pb concentration was 800 mg kg?1. The obtained high phytoextraction and phytostabilization potentials were 1208 (±25.6) and 11.75 (±0.32) g Pb ha?1 yr?1 in 10 mmol EDTA kg?1 soil and no chelate treatments, respectively. It may be concluded that chelate application increases Pb uptake by carrots. Consequently, this plant can be introduced as a hyperaccumulator to phytoextract and phytostabilize Pb from contaminated soils.  相似文献   

14.
The short term acute toxicity of potassium chromate, potassium dichromate and chromium sulphate has been compared in a simple microbial bioassay. The test parameters were, decrease in viability, genotoxicity and metal uptake. The LC50 values of Cr(III), dichromate Cr(VI) and chromate Cr(VI) for Escherichia coli were 16, 10 and 1.2 μg mL?1, respectively. Among the test substances potassium chromate was most toxic and showed no bioaccumulation while potassium dichromate was less toxic but resulted in significant bioaccumulation. Chromium sulphate was least toxic. As evident from loss of plasmid, genotoxicity was exhibited only by Cr (VI).  相似文献   

15.
Xu  H.  Allard  B.  Grimvall  A. 《Water, air, and soil pollution》1991,57(1):269-278

Effects of acidification on adsorption and potential mobility of various As forms have been studied in batch-type distribution experiments. The adsorption of As on alumina decreased in the order As(V) > MMAA = DMAA > As(III) at pH below 6 and As(V) > As(III) > MMAA = DMAA at pH above 6. The adsorption reached a maximum around pH 5 for As(V), pH 7 for As(III) and pH 4 for MMAA and DMAA. The presence of a fulvic acid at concentration levels of 10 mg L?1 or higher generally reduced the As adsorption in the pH range 5 to 7. In light of both laboratory and field observations environmental acidification would increase the leaching of As from soils or sediments to surface and groundwaters under reducing conditions, but could also reduce the mobility due to enhanced adsorption under oxidizing conditions.

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16.
Cattle manure vermicompost has been used for the adsorption of Al(III) and Fe(II) from both synthetic solution and kaolin industry wastewater. The optimum conditions for Al(III) and Fe(II) adsorption at pH?2 (natural pH of the wastewater) were particle size of ≤250?µm, 1 g/10 mL adsorbent dose, contact time of 4 h, and temperature of 25°C. Langmuir and Freundlich adsorption isotherms fitted reasonably well in the experimental data, and their constants were evaluated, with R 2 values from 0.90 to 0.98. In synthetic solution, the maximum adsorption capacity of the vermicompost for Al(III) was 8.35 mg g?1 and for Fe(II) was 16.98 mg g?1 at 25°C when the vermicompost dose was 1 g 10 mL?1, and the initial adjusted pH was 2. The batch adsorption studies of Al(III) and Fe(II) on vermicompost using kaolin wastewater have shown that the maximum adsorption capacities were 1.10 and 4.30 mg g?1, respectively, at pH?2. The thermodynamic parameter, the Gibbs free energy, was calculated for each system, and the negative values obtained confirm that the adsorption processes were spontaneous.  相似文献   

17.

Purpose

Long-term manure applications can prevent or reverse soil acidification by chemical nitrogen (N) fertilizer. However, the resistance to re-acidification from further chemical fertilization is unknown. The aim of this study was to examine the effect of urea application on nitrification and acidification processes in an acid red soil (Ferralic Cambisol) after long-term different field fertilization treatments.

Materials and methods

Soils were collected from six treatments of a 19-year field trial: (1) non-fertilization control, (2) chemical phosphorus and potassium (PK), (3) chemical N only (N), (4) chemical N, P, and K (NPK), (5) pig manure only (M), and (6) NPK plus M (NPKM; 70 % N from M). In a 35-day laboratory incubation experiment, the soils were incubated and examined for changes in pH, NH4 +, and NO3 ?, and their correlations from urea application at 80 mg N kg?1(?80) compared to 0 rate (?0).

Results and discussion

From urea addition, manure-treated soils exhibited the highest acidification and nitrification rates due to high soil pH (5.75–6.38) and the lowest in the chemical N treated soils due to low soil pH (3.83–3.90) with no N-treated soils (pH 4.98–5.12) fell between. By day 35, soil pH decreased to 5.21 and 5.81 (0.54 and 0.57 unit decrease) in the NPKM-80 and M-80 treatments, respectively, and to 4.69 and 4.53 (0.43 and 0.45 unit decrease) in the control-80 and PK-80 treatments, respectively, with no changes in the N-80 and NPK-80 treatments. The soil pH decrease was highly correlated with nitrification potential, and the estimated net proton released. The maximum nitrification rates (K max) of NPKM and M soils (14.7 and 21.6 mg N kg?1 day?1, respectively) were significantly higher than other treatments (2.86–3.48 mg N kg?1 day?1). The priming effect on mineralization of organic N was high in manure treated soils.

Conclusions

Field data have shown clearly that manure amendment can prevent or reverse the acidification of the red soil. When a chemical fertilizer such as urea is applied to the soil again, however, soil acidification will occur at possibly high rates. Thus, the strategy in soil N management is continuous incorporation of manure to prevent acidification to maintain soil productivity. Further studies under field conditions are needed to provide more accurate assessments on acidification rate from chemical N fertilizer applications.  相似文献   

18.
This paper investigates the pollution load of selected trace elements in 32 soil samples collected around 21 different mining areas of the Iberian Pyrite Belt (Southwest Spain), integrating chemical data with soil parameters to help understand the partitioning and mobility of pollutants. The minesoils are depleted in acid neutralising minerals and show limiting physicochemical properties, including low pH values and very high anomalies of potentially hazardous metals. The total concentrations of As (up to 1,560 mg kg?1) and certain heavy metals (up to 2,874 mg kg?1 Cu, 6,500 mg kg?1 Pb, 6,890 mg kg?1 Zn, 62 mg kg?1 Hg and 22 mg kg?1 Cd) are two orders of magnitude above the soil background values. The close association of Cd and Zn with the carbonate content in lime-amended minesoils suggests metal immobilisation through adsorption and/or co-precipitation mechanisms, after acid neutralisation, whereas As and Pb are similarly partitioned into the soil and mostly associated with iron oxy-hydroxides.  相似文献   

19.
Abstract

Athyrium yokoscense, a type of fern that grows vigorously in mining areas in Japan, is well known as a Cd hyperaccumulator as well as a Cu, Pb and Zn tolerant plant. However, no information is available on As accumulation of A. yokoscense, although it often grows on soils containing high levels of both heavy metals and As. In this study, young ferns collected from a mine area were grown in media containing As-spiked soils or mine soil in a greenhouse for 21 weeks. Athyrium yokosense was highly tolerant to arsenate and survived in soils containing up to 500 mg As (V) kg?1. The addition of 100 mg As (V) kg?1 resulted in the highest fern biomass (1.95 g plant?1) among As-spiked soils. Although the As concentration of the fern was lower than other As hyperaccumulators, such as Pteris vittata, A. yokoscense could hyperaccumulate As in mature and old fronds. Arsenic was accumulated most efficiently in old fronds (922 mg kg?1) in the media containing 5 mg As (III) kg?1. Moreover, higher As accumulation was found in the roots of the ferns, with a range from 506 to 2,192 mg kg?1. In addition, in the mine soil with elevated concentrations of As and heavy metals, A. yokoscense not only hyperaccumulated As (242 mg As kg?1 in old fronds), but also accumulated Cd, Pb, Cu and Zn at concentrations much higher than those reported for other terrestrial plants. Athyrium yokoscense accumulated Cd mostly in fronds in high concentrations, up to 1095 mg kg?1, while it accumulated Cu, Zn and Pb mainly in the roots and the concentrations were 375, 2040 and 1165 mg kg?1, respectively.  相似文献   

20.

Purpose

Inorganic contaminants present a major challenge for the restoration of aquatic ecosystems. The objectives of this study were to determine the extent of trace metal contamination and investigate the influence of different plant communities on trace metal accumulation in the soils of the Florida Everglades.

Materials and methods

Soil samples (n?=?117) were collected from 0 to 10-cm depth using a stainless steel coring device from sites with three dominant plant communities—cattail, sawgrass, and slough—of Water Conservation Area-2A (43,281 ha) of Florida Everglades.

Results and discussion

The mean pH in soils collected from three plant communities was 6.75–6.82, whereas electrical conductivity was slightly greater in the sawgrass (0.69 dS m?1) than cattail (0.58 dS m?1) and slough (0.40 dS m?1). Mean reduction–oxidation potential was greatest in cattail (?113 mV) than sawgrass (?85.3 mV) and slough (?48.3 mV) soils. Among 11 trace metals (As, B, Co, Cr, Cu, Mn, Mo, Na, Ni, Pb, Zn) found in soil samples, Na had the greatest contents and was greater in cattail (2070 mg kg?1) and sawgrass (1735 mg kg?1) than slough (1297 mg kg?1). Four trace metals (B, Cu, Mo, Ni) were significantly greater in cattail than sawgrass and slough. Whereas, Mn was significantly lower in cattail (31 mg kg?1) than both sawgrass (84 mg kg?1) and slough (51 mg kg?1). Cattail also had significantly lower Cr (1.97 mg kg?1) and Pb (10 mg kg?1) than sawgrass (Cr 2.5 mg kg?1; Pb 20.8 mg kg?1). As (<6.9 mg kg?1), Co (<1.3 mg kg?1), and Zn (<17.2 mg kg?1) were not significantly different among soils collected from three plant community-dominant sites. Contents of Cd and Se were below the method detection limits (Cd 0.01 mg L?1; Se 0.2 mg L?1) and are not reported.

Conclusions

None of the trace metals in the soils exceeded the US Environmental Protection Agency sediment toxicity thresholds. Results from this study provided baseline concentrations of trace metals, which can be used to measure the success of restoration efforts in Florida Everglades.
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