Spiked Soil Research Articles

Application of aqueous extracts of <i>Alternanthera brasiliana, Chromolaena odorata</i> and <i>Tridax procumbens</i> plants in remediating lead contaminated soils

Soil washing is an effective method of removing lead from contaminated soils. However, great limitations abound in the choice of washing solution that is ecologically sustainable for agricultural soils. In this study, applications of plant soluble extracts in remediating of Pb contaminated soils for ecological sustainability were carried out. Batch laboratory experiments were done using aqueous extracts of Alternanthera brasiliana, Chromolaena odorata, Tridax procumbens and water as control at varying soil-pulp-densities (SPD) of 3, 6, 9, 12, 15%, and washing time of 1, 3, 6, 12 h. For contaminated soil, percentage removal efficiency followed the order: Alternanthera brasiliana (38.1±0.28%) > Chromolaena odorata (21.8±0.12%) > Tridax procumbens (21.3±0.18%). The most appropriate ratio for contaminated soil was 3% SPD at 12 h washing time. Removal efficiency was found to be substantially depended on geochemical phase of Pb (exchangeable-4.04%) in contaminated soil and washing solution pH (5.68). Lead removal efficiency was observed to increased proportionally with increasing washing time, but decreased with increasing SPD. Spike soil with high exchangeable Pb-78.9% recorded significant Pb removal of 63.4±0.24% with Alternanthera brasiliana, 47.8±0.22% with Chromolaena odorata, 38.3±0.38% with Tridax procumbens and 52.0±0.26% with water. Analysis of variance at p=0.05 indicated a significant difference inpercentage Pb removal efficiency across all the four washing solutions. However, the statistical T-test indicated no significant difference at p=0.05 in percentage Pb removal efficiency between both soils. Also, moderately positive correlations were observed between contaminated and spiked soils for Alternanthera brasiliana (0.676), Chromolaena odorata (0.570) and Tridax procumbens (0.517) while negative correlation observed for water (0.485) which served as the control. The three plant extracts exhibited good potential characteristics as washing solutions for the treatment of Pb contaminated soils. Chemical modifications are recommended to enhance and improve their efficiencies when considering the geochemical phase of Pb in soil.

Accumulation and Speciation of Arsenic in Eisenia Fetida in Sodium Arsenite Spiked Soils - a Dynamic Interaction between Soil and Earthworms

Accumulation and Speciation of Arsenic in Eisenia Fetida in Sodium Arsenite Spiked Soils - a Dynamic Interaction between Soil and Earthworms

Comparison of the crude oil removal effects of different surfactants in electrokinetic remediation of low-permeability soil

Crude oil leakage during production, transportation and storage has polluted large soil areas. If improperly treated, this could seriously threaten human health. In this study, low-permeability soil was selected as the contaminated target because it has been proven to be hardly treated with common technologies. Spiked soil was treated in an EK cell at 1 V/cm for 15 days with different surfactants, including an anionic surfactant, sodium dodecyl sulfate (SDS), biosurfactant, rhamnolipid (Rham) and nonionic surfactant, Tween 80. Experimental dependent variables, including current, electroosmotic flow (EOF), gas volume, residual crude oil concentration and components in the restored soil were monitored and analyzed. The results indicated that the produced gas and current followed the sequence of SDS > Rham > Tween 80, but the overall efficiency of the surfactants regarding crude oil removal from soil followed the order of Tween 80> Rham > SDS, corresponding to 18.05%, 14.06%, and 9.35%, respectively, agreeing with the EOF sequence. It is proposed that the EOF is closely related to pollutant removal, and the relatively low SDS and Rham removal levels were mainly related to the electromigration/electrophoresis reduction in micelles. Furthermore, experimental result analysis revealed that the light oil phase proportion in the surfactant-treated samples decreased, while the heavy component proportion increased, regardless of the surfactant type. Hence, surfactant-enhanced EK remediation may be unsuitable for low-permeability soil with a high heavy oil proportion, which may be a notable limitation of this technology.

Porphyrin-based colorimetric sensing of perfluorooctanoic acid as proof of concept for perfluoroalkyl substance detection.

A functionalized porphyrin receptor was prepared to bind perfluorooctanoic acid. UV-Vis spectroscopic analysis showed the receptor gave a rapid colorimetric response that could also be detected visually at environmentally relevant concentrations. Spiked soil samples were used to demonstrate detection of perfluorooctanoic acid without intensive sample pre-treatment or laboratory instrument analysis.

Soil acidification and impacts over microbial indicators during attenuation of soybean biodiesel (B100) as compared to a diesel-biodiesel blend (B8)

Biodiesel presents a higher degradability than petroleum hydrocarbons in soils. Since microorganisms dominate biodegradation processes, impacts on soil microbiota provide information regarding the course of fuel attenuation. We aimed to evaluate the effects of biodiesel (B100) and a diesel–biodiesel blend (B8) on soil microbial indicators. In microcosms, an oxisol was spiked with B100 (5% and 10%, w w-1 dry soil) or B8 (5% and 10%, w w-1 dry soil). In addition to microbial parameters, phytotoxicity, pH, and fuel attenuation were assessed during 90 days. Spiked soils exhibited increased cumulative respiration than non-contaminated controls; however, it was lower with B100 (140–204%) than with B8 (347–420%). Initial pH (6.0) slightly diminished with B8 after 90 days (~5.7), but decreased to ~3.9 after 30 days with B100. Heterotrophic and B8-degrading bacteria were 1.6–2.4 and 1.5–2.5 Log higher with B8 as compared to controls; conversely, heterotrophic and B100-degrading populations were reduced by B100 (3.5–4.5 and 4.7–6.8 Log lower than controls). B100 resulted in more prominent negative impacts on microbial biomass, metabolic quotient and soil enzyme activities. Phytotoxicity towards cucumber seeds tended to be mitigated in B8-5% soil, whereas the opposite has been observed with B100. Biodiesel fatty acid methyl esters (FAME) were completely (or highly) attenuated in B8 microcosms; nonetheless, in B100 soils, partial attenuation occurred only for unsaturated FAME. These findings are particularly discussed considering the prominent acidification in B100-spiked soils. In addition to B8, the results indicate that heavy soil contaminations with biodiesel pose significant environmental hazards.

Impact of digestate and its fractions on mineralization of 14C-phenanthrene in aged soil.

The impact of whole digestate (WD) and its fractions (solid [SD] and liquid [LD]) on 14C-phenanthrene mineralization in soil over 90d contact time was investigated. The 14C-phenanthrene spiked soil was aged for 1, 30, 60 and 90d. Analysis of water-soluble nitrogen, phosphorus, total (organic and inorganic) carbon, and quantitative bacterial count were conducted at each time point to assess their impact on mineralization of 14C-phenanthrene in soils. Indigenous catabolic activity (total extents, maximum rates and lag phases) of 14C-phenanthrene mineralization were measured using respirometric soil slurry assay. The soil amended with WD outperformed the SD and LD fractions as well as showed a shorter lag phase, higher rate and extent of mineralization throughout the study. The digestates improved (P<0.05) the microbial population and nutritive content of the soil. However, findings showed that spiking soil with phenanthrene generally reduced the growth of microbial populations from 1 to 90d and gave a lower nutritive content in comparison with the non-spiked soil. Also, soil fertility and bacteria count were major factors driving 14C-phenanthrene mineralization. Particularly, the non-phenanthrene degraders positively influenced the cumulative mineralization of 14C-phenanthrene after 60d incubation. Therefore, the digestates (residue from anaerobic digestion) especially WD, which enhanced 14C-phenanthrene mineralization of the soil without minimal basal salts medium nor additional degraders should be further exploited for sustainable bioremediation of PAHs contaminated soil.

Phytoremediation of Pb Spiked Soils Amended with Iron Impregnated Rice Husk Ash Using Ricinus communis L. (Castor bean)

Heavy metals pose a serious risk to the environment and living biota. Pot studies were carried out to determine the competence of Fe-coated rice husk in Pb spiked soils vegetated with Ricinus communis. Physicochemical properties of Fe- coated rice husk ash (Fe-RHA) were characterized on dry weight basis. Pot experiments were carried out with seedlings of R.communis for 60 days amended with Fe-RHA (0, 2.5% and 5% w/w) and Pb(NO3) [0, 400 and 800 mg kg−1]. Addition of Fe-coated rice husk ash to Pb cntaminated soils improved soil pH and fertility. Treatment with 5% Fe-RHA decreased Pb accumulation in roots by 84%. Addition of FeRHA significantly (p&lt;0.05) increased plant physiological parameters such as height, leaf diameter, nodes, and leaf number by 64%, 49%, 62% and 66% and chlorophyll contents (12–29%) compared to unamended plants. Our findings conclude that Fe-RHA is a low-cost, environmentally friendly and efficient adsorbent for stabilization of Pb spiked soils.

Laboratory spiking process of soil with various uranium and other heavy metals

Laboratory studies using metal spiked soils are challenging due to soil heterogeneity. This work provides an easy, quick, precise, and accurate technique for the preparation of spiked soils for laboratory research. The process described spiking soil with various uranium species and other heavy metals for laboratory scale pilot experiments under various biogeochemical conditions. The procedure involves grinding both dry soil and metal chemicals into the fine powder. The spiked soil mixture was further homogenized through a modified splitting and combining of the sample by diagonal flipping using plastic sheeting. Comparison of measured concentrations with theoretical values were obtained with <20% precision and accuracy. However, tradition spiking method with metal solution often yielded high heterogeneous spiked soils due to strong metal adsorption in soils. Re-drying and re-grinding of soils were required following the spiking in order to homogenize treated soils, generating inhalable particulates. Thus appropriate personal protective equipment and practices are required for the safety concern. The present method with metal salt powder proved a safe, useful, quick, accurate and precise, and homogenized soil spiking method.•ability to prepare spiked soil with multiple elements•prepared soil at any level of loading•the spiked soil was homogenous for controlled studies

The role of soil mineralogy on oral bioaccessibility of lead: Implications for land use and risk assessment

Understanding the oral bioaccessibility of lead (Pb) present in soils in urbanized areas is important for the human exposure risk assessment. In particular, the role of the soil-mineralogy in the oral bioaccessibility has not been extensively studied. To investigate bioaccessibility, five types of periurban soils were collected, samples were spiked with the same amount of lead-chromates from traffic paint, and subjected to the in vitro Physiological Based Extraction Test (PBET). Ten samples of urban topsoils were collected at elementary schools playgrounds, Pb-bioaccessibility was measured, and a prediction equation for bioaccessibility was constructed. Mineralogy, and metal content were identified with a combination of X-ray powder diffraction, scanning electron microscopy, and portable X-ray fluorescence techniques. Traffic paint sample is made of 15% quartz (SiO2), 13% crocoite (PbCrO4), 55% calcite (CaCO3), and 17% kaolinite (Al2Si2O5(OH)4) and it contains high metal content (Pb, Cr, Zn, and Ca). Studied soils are characterized by variable amounts of acid-neutralizing minerals (carbonates) and low metal content. Spiked soils contained almost equal concentration of Pb, Cr, and Zn, because the contribution of these metals is from the added paint. However, obtained Pb-bioaccessibility at gastric and intestinal conditions are variable (40 to 51% gastric, 24 to 70.5% intestinal). Carbonate content shows significant correlation (p < 0.05) with Cr, Ca, calcite, crocoite, and Pb-bioaccessible at gastric conditions. Correlation of Pb-bioaccessible at intestinal conditions is significant (p < 0.05) with kaolinite.Variability of Pb-bioaccesibility in urban environments is commonly associated to differences in Pb-sources, however, our results show that the bioaccessibility of the same pollutant behaves different for each soil type. This suggests that soil mineralogy may play a role in Pb-releasing at gastrointestinal conditions. Soil information about mineralogical characteristics from this study may help to reduce exposure to lead from urban sources if data are incorporated into urban planning.

Uptake of Mercury by Marigold and Amaranthus on Spiked Soil

Uptake of Mercury by Marigold and Amaranthus on Spiked Soil

Combined application of biochar, compost, and bacterial consortia with Italian ryegrass enhanced phytoremediation of petroleum hydrocarbon contaminated soil

Petroleum hydrocarbons are extensively utilized in petrochemical industries and cause soil deterioration during exploration, transportation, refining and making petroleum products. We hypothesized that the combined use of compost, biochar and bacterial consortia as soil amendments may enhance the rhizoremediation potential of ryegrass by strengthening the plant rhizospheric effect for efficient total petroleum hydrocarbon removal. The present study focused on phytoremediation of hydrocarbons in spiked contaminated soil amended with biochar (5% v/v), and compost (5% v/v). Spiked soil was inoculated with consortia of four hydrocarbon degrading bacterial strains (Pseudomonas poae, Actinobacter bouvetii, Stenotrophomonas rhizophila and Pseudomonas rhizosphaerae). The spiked soil was prepared by spiking agricultural soil with 3.4% (w/w) of crude oil. Italian ryegrass (60 seeds pot−1) were sown and plants were harvested after 75 days.The highest hydrocarbon removal (85%) was observed in spiked soil amended with compost, biochar and consortia. Bacterial inoculation with biochar and compost showed significantly higher hydrocarbon degradation as compared to all other treatments. Highest TPHs degrading bacteria (5.74 × 107 cells g−1 of soil) were observed in rhizosphere of spiked soil amended with compost, biochar and consortia. The organic amendments improved plant growth and bacterial count in rhizosphere which resulted in higher removal of hydrocarbons. We concluded that plant-microbe interactions together with the organic soil amendments offer an emerging trend for remediation of hydrocarbons. Rhizoremediation is a green solution to overcome the quandary of total petroleum hydrocarbon contamination in soil.

Metal Extractability in Binary and Multi-metals Spiked Calcareous Soils

ABSTRACTIn the present study, a laboratory experiment was designed to compare the 0.01 M calcium chloride (CaCl2) and diethylenetriaminepentaacetic acid (DTPA) extraction methods for their ability to predict cadmium (Cd), copper (Cu), iron (Fe), Manganese (Mn), nickel (Ni), and zinc (Zn) availability and mobility in five calcareous soils. The soils were spiked with different amounts of metals (0, 50, 100, 200, and 400 mg kg−1) both in binary (Cu and Zn; Ni and Cd; Fe and Mn) and in multi-systems (Cd, Cu, Fe, Mn, Ni, and Zn) and incubated for 1 months at field capacity. In metal-spiked soils, both extraction methods showed a linear relationship of extractable to total metals for all soils. The fraction of total metals extracted by DTPA was much higher than the fraction extracted by CaCl2, which was attributed to the formation of soluble metal-complexes in the complexing extracts calculated by the Visual Minteq program. DTPA extraction method showed higher selectivity for Cu over other metals both in binary and in multi-systems. Different order of metals extractability was found in binary and multi-systems for both extraction methods. Solid/solution distribution coefficient (Kd) was calculated by the ratio of the solid phase to soil solution concentration of metals extracted by CaCl2 or DTPA extraction methods. Both in binary and in multi-systems, the average Kd (l kg−1) of metals by soils were in the order of Mn (5398) > Fe (4413) > Zn (3376) > Cu (2520) > Ni (969) > Cd (350) in the CaCl2-extractable metals and Fe (35) ≥ Ni (34) > Zn (18) > Mn (11.2) > Cu (6.3) > Cd (4) in the DTPA-extractable metals. Results showed that among the six studied metals, Cd had the lowest Kd, implying a relative higher mobility in these calcareous soils. The Visual Minteq indicated that in the CaCl2-extraction method and in both binary and multi-systems the dominant species for Cu, Mn, Ni, and Zn were Cu2+, Mn2+, Ni2+ and Zn2+, respectively, while for Cd and Fe, the dominant species were CdCl+ and Fe(OH)2+, respectively.

Influence of ageing on lead bioavailability in soils: a swine study.

Aging is a time-dependent process that causes metal bioavailability to decrease with time. The current study investigated the bioavailability change of Pb in four contrasting soils over a time period until the Pb relative bioavailability (RB) levels achieved a steady state to assess the extent of the following: firstly, bioavailability change in each soil and secondly, correlation of these changes with the soil properties. Relative bioavailability of soils spiked with 1500 mg Pb/kg were measured in swine that were fed these soils, throughout an aging period (56 days) to investigate relationships between soil properties and in vivo bioavailability of Pb. Spiked soils were used to minimize the effect of varying sources of Pb on RB. The RB of Pb in GTA, IWA, and MLA decreased from their initial Pb RB values until a steady state RB of 34, 45, and 59 % was reached, respectively, by the 56th day. In contrast, however, to these RB decreases, NTA soil indicated no change in RB over the whole aging period of the experiment. The lack of change in RB in the NTA soil over time was attributed to it achieving a steady state RB within a very short time due to its comparatively high sorptive capacity (K d = 112).

Effects of silver nanoparticles and silver nitrate in the earthworm reproduction test

The widespread use of silver nanoparticles (Ag-NPs), for example, in textiles and cleaning products, means that they are likely to reach the environment via biosolids or the effluent from wastewater treatment plants. The aim of the present study was to determine the ecotoxicity of Ag-NPs in the earthworm reproduction test using Eisenia andrei. In addition to the usual endpoints, the authors also investigated the uptake and accumulation of Ag by adult earthworms and the concentration of free Ag(+) in soil pore water. Silver nanoparticles and Ag nitrate showed similar toxicities in the earthworm reproduction test. The uptake of Ag from Ag-NPs in the earthworm was slightly higher than the uptake of Ag from Ag nitrate. Spiked soils showed a concentration-dependent effect on reproduction, but there was no concentration-dependent increase in the amount of Ag in earthworm tissues. The authors noted a concentration-dependent increase in the levels of free Ag(+) in the soil pore water regardless of the Ag source. The number of juveniles is a more suitable endpoint than biomass or mortality. The uptake of Ag does not appear to inhibit reproduction. Instead, inhibition seems to reflect Ag(+) released into the soil pore water, which affects cocoons and juveniles in the soil. Analysis of transformed Ag-NPs after purification in wastewater treatment plants would provide additional information.

A new procedure combining GC-MS with accelerated solvent extraction for the analysis of phthalic acid esters in contaminated soils

An optimized procedure based on gas chromatography-mass spectrometry (GC-MS) combined with accelerated solvent extraction (ASE) is developed for the analysis of six phthalic acid esters (PAEs), which are priority soil pollutants nominated by United States Environmental Protection Agency (USEPA). Quantification of PAEs in soil employs ultrasonic extraction (UE) (USEPA 3550) and ASE (USEPA 3545), followed by clean up procedures involving three different chromatography columns and two combined elution methods. GC-MS conditions under selected ion monitoring (SIM) mode are described and quality assurance and quality control (QA/QC) criteria with high accuracy and sensitivity for target analytes were achieved. Method reliability is assured with the use of an isotopically labeled PAE, di-n-butyl phthalate-d4 (DnBP-D4), as a surrogate, and benzyl benzoate (BB) as an internal standard, and with the analysis of certified reference materials (CRM). QA/QC for the developed procedure was tested in four PAE-spiked soils and one PAE-contaminated soil. The four spiked soils were originated from typical Chinese agricultural fields and the contaminated soil was obtained from an electronic waste dismantling area. Instrument detection limits (IDLs) for the six PAEs ranged 0.10–0.31 μg·L−1 and method detection limits (MDLs) of the four spiked soils varied from a range of 20–70 μg·kg−1 to a range of 90–290 μg·kg−1. Linearity of response between 20 μg·L−1 and 2 mg·L−1 was also established and the correlation coefficients (R) were all>0.998. Spiked soil matrix showed relative recovery rates between 75 and 120% for the six target compounds and about 93% for the surrogate substance. The developed procedure is anticipated to be highly applicable for field surveys of soil PAE pollution in China.

Modifications of bacterial populations in anthracene contaminated soil

Spiking soil with anthracene, a polycyclic aromatic hydrocarbon, inhibited soil microbial activity, so it remained to be seen if the bacterial population composition was affected. An initial PCR-DGGE analysis indicated that the bacterial population in the unamended soil was not affected by depth (0–2cm, 2–8cm and 8–15cm) or incubation time (0, 14 or 28 days) while it changed in the contaminated soil over the time and after 28 days in the soil profile. A phylogenetic analysis was done of the uncontaminated soil at day 0, and in the 0–2cm layer of the anthracene-spiked soil after 0, 14 and 28 days and in the 2–8cm layer after 28 days. Sequences belonged to six different phyla, i.e. Acidobacteria, Actinobacteria, Chloroflexi, Gemmatimonadetes, Nitrospirae and Proteobacteria. However, 10% of the sequences remained as unclassified bacteria. Bacteria belonging to the Proteobacteria (63.2%) were always the most dominant followed by the Acidobacteria (22.8%) and the Gemmatimonadetes (3.6%). The percentage of Actinobacteria (4.1%), Chloroflexi (1.3%), and Nitrospirae (0.1%) was low and sequences belonging to these phyla were not always detected. Contaminating the soil had a momentaneous effect on the bacterial population as the percentage of Alphaproteobacteria, i.e. Sphingomonadales, and Gammaproteobacteria, i.e. the Xanthomonadales, reduced strongly while the percentage of Actinobacteria and Acidobacteria more than doubled. Already after 14 days, however, the percentage of Sphingomonadales, Actinobacteria and Acidobacteria was similar as in the unamended soil at day 0. After 28 days, the percentage of Burkholderiales and Xanthomonadales more than doubled in the 0–2cm and 2–8cm layer compared to the unamended soil at day 0. It was found that spiking soil with anthracene, incubation time and soil layer had an effect on the bacterial population, but the effect of the contaminant was transient and changes in the bacterial population with depth were only detectable in the contaminated soil after 28 days.

Aging of Organochlorine Pesticides and Polychlorinated Biphenyls in Muck Soil: Volatilization, Bioaccessibility, and Degradation

An organic rich muck soil which is highly contaminated with native organochlorine pesticide (OCs) was spiked with known amounts of (13)C-labeled OCs and nonlabeled polychlorinated biphenyls (PCBs). Spiked soils were aged under indoor, outdoor, and sterile conditions and the change in volatility, surrogate bioaccessibility, and degradation of chemicals was monitored periodically over 730 d. Volatility was measured using a fugacity meter to characterize the soil-air partition coefficient (K(SA) = C(SOIL)/C(AIR)). The fraction of bioaccessible residues was estimated by comparing recoveries of chemical with a mild extractant, hydroxylpropyl-β-cyclodextrin (HPCD) vs a harsh extractant, DCM. K(SA) of the spiked OCs in the nonsterile (Indoor, Outdoor) soils were initially lower and approached the K(SA) of native OCs over time, showing reduction of volatility upon aging. HPCD extractability of spiked OCs and PCBs were negatively correlated with K(SA), which suggests that volatility can be used as a surrogate for bioaccessibility. Degradation of endosulfans, PCB 8 and 28 was observed in the nonsterile soils, and (13)C(6)-α-HCH showed selective degradation of the (+) enantiomer. Enantiomer fractions (EF) in air and HPCD extracts were lower than in nonsterile soils, suggesting greater sequestering of the (+) enantiomer in the soil during microbial degradation.

The dissipation rates of myclobutanil and residue analysis in wheat and soil using gas chromatography-ion trap mass spectrometry

The dissipation of myclobutanil (triazole fungicide) in wheat plant, grain and soil under the local weather and soil conditions was studied and fungicide residues were determined by GC-ITMS. Myclobutanil (25% EC) was applied at two dosages, 60 g a.i. ha−1 (recommended) and 120 g a.i. ha−1 (2 times of the recommended dosage) in the experimental fields in Shandong, Beijing and Henan provinces (experimental localities). The detection limit (LOD) and the limit of quantification (LOQ) of myclobutanil were 0.6 µg kg−1 and 2 µg kg−1 respectively, and they were much below the maximum residue limit (MRL 0.02 mg kg−1) in the EU. The average recoveries were 76.4–97.7, 82.6–92.6 and 75.0–94.4% with relative standard deviation (RSD) of 6.3–15.9, 3.8–17.3 and 3.0–19.7% in wheat plant at four spiking levels (0.01, 0.1, 0.5, 10 mg kg−1), wheat grain at four spiking levels (0.005, 0.01, 0.1, 10 mg kg−1) and soil at five spiking levels (0.002, 0.01, 0.1, 0.5, 10 mg kg−1), respectively. The results showed that the half-lives of myclobutanil in wheat plant and soil from Shandong, Beijing and Henan were 3.5–4.5 and 11.0–11.7 days, respectively. At harvest, wheat grain samples were found to contain myclobutanil well below the MRL following the recommended dosage and the interval of 20 days after last application.

Quantitative determination of octylphenol, nonylphenol, alkylphenol ethoxylates and alcohol ethoxylates by pressurized liquid extraction and liquid chromatography–mass spectrometry in soils treated with sewage sludges

Surfactants have one of the highest production rates of all organic chemicals. Non-ionic surfactants, especially alkylphenol ethoxylates, received most attention as precursors of estrogenic metabolic products generated during wastewater treatment. Alkylphenols (octyl and nonylphenol), alkylphenol polyethoxylates (APEOs), and alcohol ethoxylates (AEOs) have been determined in a Mediterranean forest soil (Mediterranean Rendzic Leptosol) amended with sludges from six waste water treatment plants (WWTPs) located in the Valencian Community. These compounds were isolated from soil by pressurized liquid extraction (PLE) using a mixture acetone-hexane (50:50 v/v), the extracts were cleaned up by solid-phase extraction (SPE) with C(18), and determined by liquid chromatography atmospheric pressure chemical ionization-mass spectrometry (LC-APCI-MS) using analytical standards for quantification. The method enabled high-reliable identification by monitoring the corresponding ammonium adduct [M+NH(3)](+) for AEOs and APEOs, and the deprotonated molecule [M-H](-) for octyl and nonylphenol. Recoveries, determined spiking soil samples at different concentrations, ranged from 89 to 94%, with limits of quantification from 1 to 100 microg kg(-1). Data obtained from a soil sample mixed with biosolids in the laboratory showed that these compounds are present at concentrations ranging from 0.02 to 5 mg kg(-1). According to these concentrations, levels of possible risk can be concluded for the presence of non-ionic surfactants in soil. However, further assessment will be necessary to establish the relationship between exposure and effect findings.

Matrix materials for proficiency testing: optimization of a procedure for spiking soil with gamma-emitting radionuclides

The IAEA Reference Materials Group of the Chemistry Unit, Agency's Laboratories Seibersdorf, has developed and optimized a procedure for spiking some environmental matrices with gamma-emitting radionuclides. This paper describes the spiking procedure, homogeneity testing of the spiked material, and assignment of property values and their associated uncertainties for the radionuclides 54Mn, 65Zn, 60Co, 109Cd, 134Cs, 137Cs, 210Pb, and 241Am. This procedure has already been successfully used in an IAEA proficiency test on the determination of 137Cs and 210Pb in spiked soil and has been found to be appropriate for production of soil materials for proficiency testing and internal quality control samples. The main advantage of this procedure is a low uncertainty arising from heterogeneity, which was found to be less than 1.2% for all the analytes studied.