No full-text available
To read the full-text of this research,
you can request a copy directly from the authors.
The influence of a NAPL on the loss and biodegradation of 14C-phenanthrene residues in two dissimilar soils
Abstract
This study was carried out to assess the influence of diesel, applied over a log concentration range, on the loss and extractability of phenanthrene (measured as putative 14C-phenanthrene residues) in two different soils. The influence of diesel on the ability of a cyclodextrin based extraction method to predict the microbial bioavailability of 14C-residues was also assessed. An increase in loss of 14C-residues with increasing diesel concentration from 0 to 2000 mg kg-1 was generally observed with time in both soils. It is suggested that this trend is attributable to competitive sorption for soil sorption sites and to a lesser extent to displacement of 14C-residues from soil sorption sites by diesel resulting in greater compound availability and therefore greater loss by degradation via the actions of indigenous microorganisms. However, in the 20000 mg kg-1 diesel treatments of both soils, results indicated a delayed loss. It is suggested that this retarded loss was due to the formation of a discrete NAPL-phase into which 14C-phenanthrene residues partitioned, thereby decreasing their availability and as a consequence their degradation. Furthermore, it is suggested that nutrient limitation may have slowed down degradation rates as diesel concentrations increased. Comparison between cyclodextrin-extractability and microbial mineralisation supported the use of cyclodextrin to assess microbial bioavailability of 14C-residues after 50 d or more ageing up to diesel concentrations of 2000 mg kg-1. However, results suggested that at high diesel concentrations (specifically 20000 mg kg-1) co-extraction of 14C-phenanthrene residues may have occurred as a result of the combined solvation powers of both the cyclodextrin and the diesel. Furthermore, mineralisation of 14C-phenanthrene residues may have been affected by extreme nutrient limitation in this treatment.
... 6. Correlation between extent of 14 C-naphthalene mineralised and 14 C-naphthalene extracted with (A) CaCl 2 (B) HPCD (C) methanol after 24 h with BioC2 amendment. Swindell and Reid, 2007;Oleszczuk, 2008). However, HPCD and methanol extractions overestimated bioavailability, thus they do not illustrate the chemically active fraction but HPCD extraction illustrated the bioaccessible fractions irrespective of the concentration and type of biochar. ...
This study investigated the impact of two different wood biochars (BioC1 and BioC2) on the extractability and biodegradation of C-naphthalene in soil. Both biochars had contrasting properties due to difference in feedstocks and pyrolytic conditions (450–500 C and 900–1000 C, designated as BioC1 and BioC2, respectively). This study investigated effects of biochar on the relationship between C-naphthalene mineralisation and calcium chloride (CaCl ), hydroxypropyl- -cyclodextrin (HPCD) or methanol extraction in soil amended with 0%, 0.1%, 0.5% and 1% BioC1 and BioC2 after 1, 18, 36 and 72 d contact times. Total extents of C-naphthalene mineralisation and extraction were reduced with increasing concentrations of biochar; however, BioC2 showed greater sorptive capacity. Good linear correlation existed between total extents of C-naphthalene mineralisation and HPCD extractions in BioC1 (slope 0.86, r 0.92) and BioC2 (slope 0.86, r 0.94) amended soils. However CaCl and methanol extractions underestimated and overestimated extents of mineralisation, respectively. These results indicate that biochar can reduce the bioaccessibility of PAHs and the corresponding risk of exposure to biota, whilst HPCD extraction estimated the bioaccessible fraction of PAHs in soil. Bioaccessibility assessment is vital in evaluation of biodegradation potential and suitability of bioremediation as a remediation option.
... The shape of the desorption kinetics obtained here with sediment was similar to those observed by previous authors using the same or similar mild extraction techniques either with model sorbents (Cornelissen et al. 1998b), sediments (Cornelissen et al. 2001;Cornelissen et al. 1997a;Greenberg et al. 2005;Spasojević et al. 2015) or with contaminated soils (Hawthorne et al. 2002;Rhodes et al. 2012;Swindell and Reid 2006). ...
In this study, wastewater from municipal services, such as a port wastewater reception facility (PRF-WW) and a municipal solid waste plant (MSWP), was tested for the presence of the suspected endocrine-disrupting compounds phthalates (PAEs) and bisphenol A (BPA). PAEs and BPA were found in this study in high concentrations in raw wastewater obtained from passenger ships (RMT-WWs) (up to 738 μg/L and 957 μg/L, respectively) collected in the Port of Gdynia and in landfill leachates (LLs) (up to 536 μg/L and up to 2202 μg/L, respectively) from a MSWP located near Gdynia. In particular, the presence of reprotoxic di(2-ethylhexyl) phthalate (DEHP, up to 536 μg/L in LLs and up to 738 μg/L in RMT-WWs) requires further action because if this compound, as well as other PAEs and BPA, is not degraded by activated sludge microorganisms, it may reach receiving waters and adversely impact aquatic organisms. Therefore, PAEs and BPA should be removed either during the onsite pretreatment of tested industrial wastewater or during tertiary treatment at municipal wastewater treatment plants (WWTPs, representing end-of-pipe technology).
Graphical abstract
... Additionally, the presence of NAPL, observed at time of sample collection, could have affected PAH fate in the TW sediment . It is proposed that the enhanced loss of PAHs from TW sediment may be also due to competitive sorption for a limited number of sorption sites between PAH residues and NAPL and, to a lesser extent, due to displacement of these residues from sorption sites by the NAPL (Swindell and Reid, 2007b). and on various factors controlling this solubility , such as ratio of sample, dispersing agent and water volume within the ASE extraction cell, further discussion would be clearly speculative. ...
This copy of the thesis has been supplied on condition than anyone who consults it is understood to recognise that its copyright rests with the author and that no quotation from the thesis, nor any information derived therefrom, may be published without the author's prior, written consent.
... However, non-aqueous phase liquid (NAPL) was observed in the landfarm sediments at the time of construction, which was expected to substantially increase the nutrient demand on the system due to decreased carbon bioavailability in the non-aqueous phase (Swindell and Reid, 2006). As a result, the target nutrient ratio was decreased to 40:10:1. ...
The USACE-Norfolk District (NAO) and the City of Petersburg, VA are working toward restoring the former Appomattox River Federal Navigation Channel. In this effort, ~350,000 cubic yards of deposited sediment will be removed from -14 feet MLLW up to + 6 feet MLLW over a ~1 mile reach of the Appomattox River. Historical industrial uses have resulted in PAH contamination exceeding 500 mg/kg on average, with hotspots detected in excess of 5,000 mg/kg based on USACE 2004 analytical data. To support the NAO with its assessment of contaminant distribution, upland source control measures, dredge sequencing, sediment capping requirements to address residual contaminants and beneficial reuse options for the dredged material have been evaluated. In support of beneficial reuse as agricultural soil, a lab treatability study has been completed to assess biodegradation potential. Total PAH concentrations in three laboratory test pans after 46 weeks of treatment indicated an overall 80% contaminant reduction using an enhanced bioremediation process. The results of this bench-scale study were used as the basis for the design of a pilot field-scale landfarm study demonstration undertaken during July 2007. After five months of treatment, LMW PAHs in landfarm material appear to have degraded first while HMW PAHs are degrading more slowly, a process which generally mimics the results of the laboratory investigation. Conclusions based on the laboratory and landfarm activities as well as the technical and regulatory issues that must be resolved to allow eventual placement of the material at a mine reclamation site for revegetation purposes will be presented.
... In each instance, HPCD extractions demonstrated a near 1:1 relationship (r 2 = 0.99, n = 60) (Fig. 4). Furthermore, HPCD extractability has been shown to predict the mineralizable fraction of phenanthrene in laboratory spiked soil amended with transformer oil [98], cable insulating oil [91] co-contaminants [93,99] diesel [100] or petroleum hydrocarbons [101]. In addition, -cyclodextrin has recently demonstrated an ability to accurately predict the mineralization of 14 C-phenanthrene by indigenous micro-fauna in soil contaminated with multiple hydrocarbons [102]. ...
Risk assessment and remediation of contaminated land is inherently dependent on the contaminants present and their availability for interaction with soil biota. An ever-growing body of evidence suggests that current regulatory procedures over-estimate the 'true' fraction available to biota. Thus, a procedure that predicts the 'bioavailable fraction' would be useful for predicting 'actual' exposure limits and provide a more relevant basis for risk assessment. The aim of this paper is to address several important questions: "How should bioavailability be defined?" "What factors affect bioavailability measurement?" "To what extent have existing protocols measured bioavailability?" "What is actually measured by chemical techniques purported to determine bioavailability?" We offer two definitions (namely 'bioavailability' and 'bioaccessibility') and review commonly employed chemical extraction techniques to measure putative bioavailability. Relative advantages and disadvantages of the techniques are highlighted to elucidate underlying factors for the wide range of conclusions observed in the literature. Although the concept of bioavailability is implicit to contaminated land risk assessment and remediation, explicit reference to and use of adjustment factors is rare amongst regulatory bodies and remediators. Use of chemical determinants for bioavailability, applicable within current legislation and due consideration to inherent variability, are proposed and barriers to their implementation discussed.
... In addition, the presence of a NAPL, observed at time of sample collection, could have affected PAH fate in the TW sediment. It was anticipated that higher extractions of PAHs from TW sediment may be also due to competitive sorption for a limited number of sorption sites between PAH residues and NAPL and, to a lesser extent, due to displacement of these residues from sorption sites by the NAPL (Swindell and Reid, 2007). To summarise differences between extractions from dissimilar samples used in this study K-means cluster analysis was performed (Table 3). ...
A rapid sequential subcritical (superheated) water extraction method for polycyclic aromatic hydrocarbons (PAHs) in contaminated soil and sediment is presented. Decreasing the polarity of water by successive increase of the extraction temperature from 50 degrees C to 200 degrees C at the moderate pressure (10.3MPa) enabled selective, non-exhaustive extractions to be performed. Concurrent with increasing temperatures to 150 degrees C there was an increase in PAH extraction efficiencies. For the majority of determinations no significant differences between extractions at 150 degrees C and 200 degrees C were observed. Varied extraction efficiencies of PAHs at the same extraction conditions reflected dissimilarities between environmental matrices investigated. Selective subcritical water extraction of PAHs was proportional to their octanol-water partition coefficients. This technique may be applicable in evaluation of risks associated with PAH contaminated sites and in assessments of their bioremediation potential.
... Additionally, the presence of NAPL, observed at time of sample collection, could have affected PAH fate in the TW sediment (Pollard et al., 2008). It is proposed that the enhanced loss of PAHs from TW sediment may be also due to competitive sorption for a limited number of sorption sites between PAH residues and NAPL and, to a lesser extent, due to displacement of these residues from sorption sites by the NAPL (Swindell and Reid, 2007b). 4.2. ...
Advances towards sustainable land management necessitate application of a broader portfolio of decision-support tools that improve evaluation of contaminated land. Over the last decade regulators have directed concerted effort towards rationalization of risk-based contaminated land policies recognizing bioavailability and bioaccessibility as concepts to be incorporated into risk assessments. The desire for a precise and rapid method to inform consideration of bioavailability and bioaccessibility to support risk assessment of contaminated land has never been greater. This study presents a comprehensive appraisal of both emerging non-exhaustive extraction techniques (subcritical water extraction and Brij 700 extraction) developed to reflect polycyclic aromatic hydrocarbon (PAH) bioaccessibility to microorganisms as well as formerly demonstrated methodologies (the use of cyclodextrins and butanol extraction). Application of unified evaluation criteria across different techniques enabled comparison not only from the bioaccessibility prediction perspective but also analysis of economical (cost of extraction) and practical (such as extraction time) measures. Whilst the use of cyclodextrins was the best predictor of the bioaccessible fraction for the majority of compounds, other methods appeared more cost- and time-effective. Juxtaposition of the techniques presented in this study assists establishing cost-benefit trade-offs of different non-exhaustive extraction techniques and contributes to tailoring information on contaminant bioaccessibility to support risk evaluation on contaminated sites.
Bioavailability is an important process that controls the uptake and, hence, the biodegradability and toxicity of organic pollutants in soils and sediments. The development of analytical tools for measuring bioavailability and/or bioaccessibility has become an important concept among contaminated land risk assessment and remediation. A considerable number of studies have investigated the use of chemical extractions as methods for determining putative bioavailability by linking extraction to a biological endpoint, such as biodegradation. The difficulty is that bioavailability is organism specific and, as such, no single chemical extraction technique has been identified with the capability to predict bioavailability as opposed to bioaccessibility. The aims of this review are (1) to introduce the concepts of bioavailability and bioaccessibility; (2) to present a brief overview of the different approaches used to predict bioaccessibility of organic contaminants in soil and sediment; and (3) to consider the role of bioavailability and bioaccessibility in risk assessment and bioremediation of contaminated land.
Brominated flame retardants (BFRs), such as polybrominated diphenyl ethers (PBDEs), hexabromocyclododecanes (HBCDs), and tetrabromobisphenol-A (TBBP-A), have routinely been added to consumer products for several decades in an effort to reduce fire-related injury and property damage. Yet, concerns for this class of chemicals have risen because of their occurrence in the environment, wildlife, and humans. Here, we briefly present the major scientific issues related to analytical, toxicological, and environmental aspects of these BFRs and discuss data gaps. Regarding geographical or temporal trends in the environmental levels of BFRs, few general remarks may be deducted: (a) Concentrations of BFRs in general are often elevated by at least one order of magnitude in the vicinity of point sources. (b) Detection of BFRs in remote location implies long-range transport and detection in air samples. (c) In general, the continental market demands seem to be reflected in different environmental residue levels and trends.
In this chapter, we present evidence that the environmental behavior of brominated flame retardants (BFRs) is similar to the behavior of persistent organic pollutants: BFRs are persistent, bioaccumulate, and biomagnify in the aquatic and terrestrial food chains. Therefore, we systematically reviewed the literature on the bioaccumulation and biomagnification of BFRs. Both, classical BFRs, such as polybrominated diphenyl ethers or hexabromocyclododecanes, and "novel" BFRs are included in this chapter. We have also reviewed the information on the degradation pathways of BFRs and their transformation products. Debromination of BFRs was the dominant degradation pathway in abiotic media (such as soil, sediment, dust, or solvent), while main degradation pathways of BFRs in biota include reductive debromination and phase I oxidative metabolism. The biotransformation of BFRs together with their bioaccumulation and biomagnification properties results in profiles of compounds in agreement with those in wildlife and humans.
Soil contamination by persistent organic pollutants (POPs) is a problem faced in many countries as a result of rapid industrialisation. The suitability of Fenton oxidation for degradation of recalcitrant POPs as a short-term remediation approach has led to intense research within the field over the last few decades. In this review article, the fundamental principles and governing factors of Fenton oxidation for treating soils contaminated with POPs such as polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), polychlorinated dibenzo-p-dioxins and furans (PCDD/Fs), are firstly discussed. Current practices of soil remediation through Fenton oxidation based on studies reported in the specialised literature are then reviewed with a focus on the potential of Fenton-bioremediation and electrokinetic (EK)-Fenton treatments in conjunction with in situ applications. An exhaustive bibliography on column studies is also covered in this work with emphasis on the technical approaches used. Finally, the last section of the article is focused on assisting soil scientists and environmental professionals in implementing in situ Fenton oxidation (ISFO) and provides some insights into future development of ISFO.
One of the first books to cover transformation products, rather than primary compounds, Transformation Products of Emerging Contaminants in the Environment gathers, specifies, synthesizes, and advances existing knowledge of the most important transformation product (TPs) of the main groups of emerging contaminants with potential concern to human health and the environment. This two-volume set for researchers and professionals covers the sources of TPs of emerging contaminants and their environmental behavior, their occurrence and effects on urban and marine environments, risk assessment and management, and technologies and strategies available for control.
The effects of loading and aging pyrene in soils in the presence of four environmentally common nonaqueous-phase liquids (NAPLs) (hexadecane, 2,2,4,4,6,8,8-heptamethylnonane [HMN], toluene, and dimethyl phthalate [DMP]) on its subsequent desorption from those soils, earthworm accumulation, biodegradation, and extractability were tested by using two dissimilar soils. The presence of each of the four NAPLs increased fractions and rates of pyrene desorption, and hexadecane slowed the effects of aging on these same parameters. Loading with hexadecane and HMN caused earthworm accumulation of pyrene to decrease. These results contrast with generally observed faster desorption rates resulting from NAPL addition, suggesting that additional factors (e.g., association of pyrene with NAPL phases and NAPL toxicities to earthworms) may impact bioaccumulation. The presence of HMN and toluene increased pyrene biodegradation, whereas hexadecane and DMP had the opposite effects. These results correlate with changes in the extractability of pyrene from the soils. After aging and biodegradation, hexadecane and DMP substantially increased pyrene residues extractable by methanol and decreased nonextractable fractions, whereas HMN and toluene had the opposite effects.
The development of phenanthrene catabolism in four soils amended with varying concentrations of activated charcoal (AC) (0%, 0.1%, 1% and 5%), a type of black carbon, was investigated. Mineralisation of (14)C-phenanthrene was monitored after 1, 25, 50 and 100 d soil-PAH contact time; lag phases, rates and extents of mineralisation of the (14)C-phenanthrene to (14)CO(2) were determined. At concentrations >0.1% AC rates and extents of mineralisation were reduced by more than 99%. This revealed that the presence of >0.1% AC in soils may substantially diminish the rate at which the catabolic activity of indigenous soil microflora develops in contaminated soil. Soil C, which had the highest organic carbon (OC) content, consistently exhibited the highest extents of degradation. It is suggested that, in accordance with other researchers, OC may have blocked available phenanthrene sorption sites. This enhanced phenanthrene availability ultimately facilitated a greater level of catabolic activity within this soil. Such results reflect the complex nature of interactions between soil, biota and contaminants and their influence on the degradation of contaminants in the environment.
Ferrous iron solid mixture (ISM) containing Fe(II), Fe(III), and Cl was synthesized for degradation of tetrachloroethene (PCE) as a dense non-aqueous phase liquid (DNAPL), and an extraction procedure was developed to measure concentrations of PCE in both the aqueous and non-aqueous phases. This procedure included adding methanol along with hexane in order to achieve the high extraction efficiency, particularly when solids were present. When PCE was present as DNAPL, dechlorination of PCE was observed to decrease linearly with respect to the total PCE concentration (aqueous and non-aqueous phases) and the concentration of PCE in the aqueous phase was observed to be approximately constant. In the absence of DNAPL, the rate of PCE degradation was observed to be the first-order with respect to the concentration in the aqueous phase. A kinetic model was developed to describe these observations and it was able to fit experimental data well. Increasing the concentration of Fe(II) in ISM increased the values of rate constants, while increasing the concentration of PCE DNAPL did not affect the value of the rate constant. The reactivity of ISM for PCE dechlorination might be close to that of Friedel's salt, and the accumulation of trichloroethylene (TCE) might imply the lower reactivity of ISM for degradation of TCE or the necessity of large amount of Fe(II) in ISM. TCE (the major chlorinated intermediate), ethene (the major non-chlorinated compound), acetylene and ethane were detected, which implied that both hydrogenolysis and beta-elimination were pathways of PCE DNAPL degradation on ISM.
Traditionally, soil extraction techniques have been concerned with the determination of “total” organic contaminant concentrations, following an “exhaustive” extraction. However, in light of the increasing body of knowledge relating to organic contaminant availability and aging, such methods have little relevance to the amount of contaminant that may pose an ecological risk i.e., the “bioavailable” portion. Less exhaustive techniques have therefore been the subject of more recent approaches in the hope that they may access the “labile” or bioavailable pool. The use of an aqueous-based extraction technique utilizing hydroxypropyl-β-cyclodextrin (HPCD) is presented here for the extraction of PAHs from soil. The optimization of the method is described in terms of HPCD concentration, extraction time, and solution buffering. The procedure is then tested and validated for a range of 14C-labeled PAHs (phenanthrene, pyrene, and benzo[a]pyrene) added at a range of concentrations to a range of soil types. The amounts of soil-associated phenanthrene mineralized by catabolically active microorganisms were correlated with total residual phenanthrene concentrations (r 2 = 0.889; slope of best fit line = 0.763; intercept = −5.662; n = 24), dichloromethane (DCM)-extractable phenanthrene concentrations (r 2 = 0.986; slope of best fit line = 0.648; intercept = 0.340; n = 24), butan-1-ol (BuOH)-extractable phenanthrene concentrations (r 2 = 0.957; slope of best fit line = 0.614; intercept = 0.544; n = 24), and HPCD-extractable phenanthrene concentrations (r 2 = 0.964; slope of best fit line = 0.997; intercept = 0.162; n = 24). Thus, in this study, the microbially bioavailable concentrations of soil-associated phenanthrene were best predicted using the optimized HPCD extraction technique. In contrast, the DCM Soxhlet extraction and the BuOH shake extraction both overestimated phenanthrene bioavailability by, on average, >60%.
It has been observed that as soil-pollutant contact time increases, pollutant bioavailability and extractability decreases. This phenomenon has been termed 'ageing'. Decreased chemical extractability with increased soil-chemical contact time is evident where both 'harsh' techniques, e.g. dichloromethane Soxhlet extraction, and 'non-exhaustive' techniques, e.g. butanol shake extraction, have been used. It has also been observed that the amount of chemical extracted by these techniques varies considerably over time. Similarly, decreases in bioavailability with increased soil-pollutant contact time have been described in bacterial, earthworm and other organism studies. From these investigations, it has been shown that the fraction of pollutant determined to be bioavailable can vary between organisms. Thus, there is an immediate definition problem, what is bioavailability? Additionally, if bioavailability is to be assessed by a chemical means, which organisms should (or can) be mimicked by the extraction procedure? This review provides a background to the processes inherent to ageing, a discussion of its consequences on bioavailability and ends with some reflections on the appropriateness of chemical extraction techniques to mimic bioavailability
This study investigated the use of an aqueous hydroxypropyl-beta-cyclodextrin (HPCD) shake extraction to predict the degree of microbial degradation of polycyclic aromatic hydrocarbons (PAHs) in soils. Three different aged PAH-contaminated soils were studied: A soil from a former coke works (CW) and two artificially contaminated soils (AC1 and AC2). First, the catabolic activity of the indigenous soil microflora was assessed with 14C-respirometry, using a range of 14C-labeled aromatic compounds. Extensive mineralization of several compounds occurred in the CW and the AC2 soils, suggesting that both soils contained catabolically active microorganisms. No significant mineralization occurred in the AC1 soil, implying that either it did not contain an indigenous PAH-degrading microbial population or that degradation, but not mineralization, occurred. The soils then were subjected to three sets of analyses: dichloromethane (DCM) soxhlet extraction, six-week biodegradation assay followed by DCM extraction, and extraction with HPCD followed by DCM extraction. A general decrease in PAHs present in the soils occurred after the biodegradation assay. In the CW and the AC1 soils, strong correlations were observed between the amount of PAHs biodegraded and the fraction of PAHs removed from the soils using the HPCD extraction. However, the AC2 soil showed a more modest correlation between the biodegradable fraction and the HPCD extractable fraction, with the HPCD extraction slightly underestimating the extent of PAH biodegradation. The results of this study indicated that an aqueous HPCD extraction may be a useful tool in assessing the microbial availability of aged contaminant mixtures in soils, although further validation is required.
Less of the desorption-resistant fractions of phenanthrene and naphthalene than freshly added phenanthrene and naphthalene was mineralized in columns of aquifer solids, loam, or muck. Slurrying columns of hydrocarbon-amended aquifer solids, loam, or muck enhanced the rate and extent of mineralization of desorption-resistant phenanthrene and naphthalene, but degradation was still less than in slurries amended with fresh compound. A substantial portion of the desorption-resistant compound remained undergraded in the slurry. A surfactant and methanol increased the mineralization of resistant phenanthrene in slurries of loam. A mixed culture of microorganisms enriched on desorption-resistant phenanthrene degraded twice as much of this fraction of compound as a pseudomonad. The authors suggest that predictions of the environment fate of toxic chemicals require information on the biodegradability of the fraction of a compound that is resistant to desorption.
The dual-mode (partition/hole-filling) model of soil organic matter (SOM) as a heterogeneous polymerlike sorbent of hydrophobic compounds predicts that a competing solute will accelerate diffusion of the primary solute by blocking the holes, allowing the principal solute to move faster through the SOM matrix. The authors tested this hypothesis with phenanthrene as the primary solute and pyrene as the competing solute in two sterile soils of widely different organic carbon content. Two- and 33-d isotherms of phenanthrene in both soil were nonlinear indicating a heterogeneous distribution of sites. Pyrene suppressed phenanthrene sorption and increased the linearity of its isotherm. Uptake (adsorption) rates were measured in batch systems after preincubating with pyrene. Desorption was measured by the sequential dilution technique at constant pyrene concentration in the supernatant. The design of the experiment precluded comparison of adsorption rates, but desorption rates increased significantly (but not dramatically) as a function of pyrene concentration. Moreover, the effect was noticeable even at low and roughly equimolar concentrations of the two compounds. The effect was qualitatively similar in the two soils, implicating SOM as the matrix in which the effect takes place. The results suggest that the competing solute excludes the primary solute from less mobile sorption domains in SOM. Interpreted according to the polymer model, this exclusion is postulated to occur by a hole-plugging (competitive displacement) mechanism possibly in concert with penetrant-induced plasticization of SOM which leads to destruction of holes.
In this report the authors show that residual polychlorobiphenyl (PCB) oil present in soils heavily contaminated with PCB mixtures (Aroclors) functions as a highly effective partitioning medium accounting for the sorptive uptake of 2-chlorobiphenyl from water. A PCB-oil normalized partition coefficient (K{sub PCB}) was evaluated from the experimental sorption data of 2-chlorobiphenyl onto four PCB-oil contaminated soils which had PCB-oil contents ranging from 2.17 g/kg to 7.67 g/kg (2,170 ppm-7,670 ppm). This K{sub PCB} value (114,000) indicates that the residual PCB-oil phase in soils, as a partitioning medium for 2-chlorobiphenyl, is approximately 67 times more effective per unit mass than natural soil organic matter (K{sub OM} = 1,700) and 3.5 times more effective than octanol (K{sub ow} = 32,400). Our results suggest a threshold PCB concentration in soil of about 0.2% (w/w), above which the PCB mixutre forms a separate sorptive phase. The threshold concentration may correspond to the solubility of the liquid PCB mixutre in natural soil organic matter. Because of its greater sorptive effectiveness, the PCB-oil phase, once formed, will primarily determine the soil-water distribution of individual PCB congeners. Accurate prediction of the soil-water distribution of PCB congeners in such soils can be obtained by considering the additive sorptive effects of the anthropogenic and natural organic matter phases.
A study of the nanoporosity of soils was conducted to determine the correlation between several soil properties and nanoporosity as measured by mercury-intrusion porosimetry. The volume of pores with diameters < 104 nm and the surface area of these nanopores differed greatly among 16 soils. The volume and surface area of nanopores in some soils were mainly in pores of diameters < 100 nm. In others, the volume and surface area were associated chiefly with pores of 103-104 nm diameter. The volume was correlated with organic C content for pores of diameters of 103-104 nm and 102-103 nm (r values of 0.583 and 0.688, respectively) and clay content for pores with diameters < 102 nm (r value of 0.512). The surface area of the soils was correlated with volume of pores < 100 nm (r = 0.956). As a result of the abundance of nanopores and the large surface areas associated with them, we suggest that additional research be conducted to assess their importance in soil toxicology.
The purpose of this study was to assess the suitability of various spiking procedures for the introduction of persistent organic pollutants (POPs) into soil environments. 14C-radiolabeled analogues of two representative polycyclic aromatic hydrocarbons (PAHs), phenanthrene (Phe), and benzo[a]pyrene (B[a]P), were introduced into soil using different spiking techniques, and the homogeneity of compound distribution in subsamples was assessed. It was established that under analogous spiking procedures dry soil could be spiked with greater homogeneity than wet soil. The procedure which gave the most homogeneous distribution of compound involved a single spiking/rehydration operation conducted on dry soil. Relative standard deviations of 2.40% for 14C-9-Phe and 3.65% for 14C-7-B[a]P were obtained for this procedure. An optimum procedure for the spiking of wet soil was established, giving relative standard deviations of 4.1% for 14C-9-Phe and 3.7% for 14C-7-B[a]P. This procedure employed a highly spiked wet soil inoculum to distribute the compound throughout the soil system. The influence of carrier solvent on microbial cell numbers determined as colony forming units was also evaluated and shown to have a dramatic negative impact at high volumes.
The desorption kinetics of PCBs and chlorobenzenes have been studied at 5, 20, and 60 °C for model sorbents in which either micropore diffusion (zeolite, montmorillonite, and XAD-8) or organic matrix diffusion/entrapment (rubbery polyacetal and glassy polystyrene) could occur. Also, a sediment was studied whose organic matter (OM) had been completely removed. All sorbents exhibited slow desorption (rate constants (1−5 × 10-3 h-1). The sediment without OM showed significantly smaller slowly desorbing fractions (factor 3−8) than the original sediment (about 6% OM). Sorbent−water distribution ratios of the microporous sorbents and the sediment without OM were 10−100 times lower than the ones of the original sediment. So, although the presence of both mineral micropores and/or OM can result in slow desorption behavior of organic compounds from soils and sediments, OM is more important for slow desorption than mineral micropores in sediments with more than about 0.1−0.5% OM. The sorption and desorption parameters measured for the sorbents were compared to the ones measured for sediment. This analysis showed that the observations for XAD-8 (in which slow desorption is assumed to be caused by slow diffusion along hydrophobic pore walls) were most similar to the ones for the sediment, indicating that diffusion through pores in the organic matter or pores coated with organic material play roles in slow desorption.
Phenanthrene was rapidly and extensively mineralized by a bacterium in the presence of glass or polystyrene beads with no pores, silica beads with 2.5−15 nm pores, 3-aminopropyl-bonded silica beads with 6-nm pores, and diatomite beads with 5.4 μm pores. These beads sorbed 10−99% of the compound in 15 h, but 48−100% of the sorbed hydrocarbon was desorbed in 240 h. Although little phenanthrene was desorbed from octadecyl-bonded silica beads with 6-nm pores, the hydrocarbon was rapidly and extensively degraded. In contrast, the bacterium mineralized <7% of the phenanthrene sorbed to polystyrene beads with 5- or 300−400-nm pores, and little of the compound was desorbed. These findings are consistent with the hypothesis that sequestration and reduced bioavailability occur when hydrophobic compounds enter into nanopores having hydrophobic surfaces.
The widely accepted dissolution (partition) model of sorption to soil organic matter (SOM) has been challenged by evidence that SOM has a non-uniform sorption potential. This study presents data supporting a previously sug gested alternative dual-mode model of sorption in which dissolution and hole-filling mechanisms take place concurrently, as in glassy organic polymers. The holes are postulated to be nanometer-size voids within the organic matrix that provide complexation sites. The main focus was on sorption of chlorobenzene, 1,2-dichlorobenzene, and 1,3-dichlorobenzene, but some experiments were carried out also on 2,4-dichlorophenol and the herbicide metolachlor. Sorption from water to high-organic soils, humic acid particles, and poly(vinyl chloride) is nonlinear, competitive, and predictably responsive to conditions that affect hole populations such as temperature and co-solvent addition. Sorption to a peat soil and its components became progressively nonlinear and competitive in the order humic acid, native peat, humin; this order reflects the increasing “glassy”i.e., rigid, condensednature of organic matter according to modern concepts of humic structure. Gas adsorption isotherms (N2 at 77 K and CO2 at 273 K) reveal the presence of internal microvoids accessible only by diffusion through the solid phase. The degree of nonlinearity and competition correlate with the CO2-measured microvoid volumes of the sorbents. The hole-filling mech anism is more important for the kinetically slow fraction.
Bioavailability of oil components in contaminated soils is an important regulating factor for biodegradation rates. Changes in the composition of mineral oil can provide information regarding the bioavailability restrictions in contaminated soils. The fate of oil components was studied in a lysimeter experiment and laboratory incubations. A shift in the n-alkane ratios in the range n-C16:n-C20 was observed around 4.0 g kg-1, indicating that two different mechanisms control the bioavailability of the oil. At higher concentrations, the bioavailability was controlled by solubilization from a non-aqueous-phase liquid into the aqueous soil water phase. The ratios remained constant with decreasing oil concentration in this stage. Below 4.0 g kg-1, desorption and diffusion became rate-limiting factors: a shift was observed in the n-alkane ratios, showing that biodegradation rates of n-alkanes increased with decreasing carbon number. The monitoring of n-alkane ratios can be used to improve the efficiency of bioremediation treatments.
A study was conducted to determine the feasibility of devising a chemical assay to predict the bioavailability of organic compounds that become sequestered in soil. The recovery of atrazine and phenanthrene freshly added to soil varied appreciably among individual solvents, but the quantity extracted by each solvent declined as the test compounds persisted in soil. The percentage recovered by some extractants approximated either the percentage uptake by earthworms or bacterial degradation. Recovery by one extractant predicted bioavailability to both organisms. The data suggest that it is feasible to predict bioavailability of persistent organic compounds in soil by chemical procedures.
Biodegradation of phenanthrene, biphenyl, or di(2 ethylhexyl) phthalate initially present in a variety of nonaqueous phase liquids (NAPLs) was slow in samples of soil and aquifer solids The NAPLs were hexadecane, dibutyl phthalate, 2,2,4,4,6,8,8-heptamethylnonane, cyclohexane, commercial oils, crude oil, creosote, and kerosene Slurrying the soil or aquifer solids markedly enhanced the rate and extent of mineralization of the test compounds initially in many of the NAPLs Both the low rate and the extent of mineralization of the three compounds initially in dibutyl phthalate in soil slurries and of di(2 ethylhexyl) phthalate in heptamethylnonane present in slurries of aquifer solids were increased by inoculation of acclimated microbial cultures Increasing the NAPL volume decreased phenanthrene biodegradation in soil, but the effect of larger NAPL volume could be alleviated by slurrying and inoculation The rate or extent of mineralization in aquifer slurries of di(2-ethylhexyl) phthalate initially in some NAPLs was increased by addition of N and P, and inoculation further enhanced the degradation
A study was conducted to determine the effects of biodegradability of nonaqueous-phase liquids (NAPLs) and microbial competition on the biodegradation in soil of a constituent of the NAPLs. The rates of mineralization of phenanthrene dissolved in 8 mg of 2,2,4,4,6,8,8-heptamethylnonane (HMN), di(2-ethylhexyl) phthalate (DEHP), or pristane per g of soil were faster than the rates when the compound was dissolved in hexadecane or dodecane. Addition of inorganic N and P to the soil increased the mineralization rate in the first two but not the last two NAPLs. N and P addition did not enhance mineralization of phenanthrene when added in 500 μg of hexadecane, pristane, or HMN per g of soil. Hexadecane was rapidly degraded, pristane was slowly metabolized, DEHP was still slower, and HMN was not mineralized in the test period. Mixing the soil stimulated mineralization of phenanthrene dissolved in HMN but not in hexadecane. Mineralization of phenanthrene dissolved in HMN was the same if the gas phase contained 21%, 2.1%, or traces of O2. In contrast, the biodegradation of phenanthrene dissolved in hexadecane, although the same at 21 and 2.1% O2, was not observed if traces of O2 were present. The mineralization was slower in unshaken soil–water mixtures if phenanthrene was added in hexadecane than in HMN or pristane, but the rates with the 3 NAPLs were increased by shaking the suspensions. We suggest that the biodegradability of major components of NAPLs and microbial competition for N, P, or O2 will have a major impact on the rate of transformation of minor constituents of NAPLs.
A study was conducted to determine the relationship between bioavailability of unaged and aged polycyclic aromatic hydrocarbons (PAHs) in soil and the amounts detected by mild solvent extraction. More aged than unaged anthracene remained in Lima loam following introduction of earthworms (Eisenia foetida), a mixed culture containing anthracene-degrading microorganisms, or earthworms or wheat after bacterial biodegradation of the compound. Aging decreased the percentage of anthracene recovered by mild extraction with n-butanol from soil following introduction of earthworms, growth of wheat, biodegradation by bacteria, or when maintained sterile. Biodegradation resulted in a marked decrease in the percentage of aged and unaged anthracene recovered from soil by mild extraction with n-butanol or ethyl acetate. Aging of fluoranthene and pyrene decreased the amount removed by mild extraction with n-butanol, ethyl acetate, and propanol. The uptake of aged and unaged anthracene, fluoranthene, and pyrene by earthworms was correlated with the amounts recovered from soil by mild extraction with n-butanol, propanol, and ethyl acetate (r values in the range 0.911–0.992). The retention of aged and unaged anthracene by wheat and barley was correlated with the amounts recovered from soil by the same procedure (r values in the range 0.892–0.945). We suggest that mild extraction with organic solvents can be used to predict the bioavailability of PAHs in soil.
Less of the desorption-resistant fractions of phenanthrene and naphthalene than freshly added phenanthrene and naphthalene was mineralized in columns of aquifer solids, loam, or muck. Slurrying columns of hydrocarbon-amended aquifer solids, loam, or muck enhanced the rate and extent of mineralization of desorption-resistant phenanthrene and naphthalene, but degradation was still less than in slurries amended with fresh compound. A substantial portion of the desorption-resistant compound remained undegraded in the slurry. A surfactant and methanol increased the mineralization of resistant phenanthrene in slurries of loam. A mixed culture of microorganisms enriched on desorption-resistant phenanthrene degraded twice as much of this fraction of compound as a pseudomonad. We suggest that predictions of the environmental fate of toxic chemicals require information on the biodegradability of the fraction of a compound that is resistant to desorption.
This paper describes the validation and application of a simple flask-based 14C-respirometer system designed to assess mineralisation of 14C-labelled substrates under defined conditions. Validation of this respirometer system indicated stoichiometric CO2 trapping up to a maximum of 400 μmol of CO2 (in a single trap). Polycyclic aromatic hydrocarbon (PAH)-degrading bacteria were used to measure growth-linked biodegradation of [14C]naphthalene to 14CO2. A 14C activity balance of 101.7±8.9% (n=6), after 74 h incubation time and 10 respirometer-opening events, indicated the suitability of the system for monitoring substrate mineralisation. This respirometric apparatus was then successfully applied to assess: (i) the PAH catabolism of microbes in a field contaminated soil, where naphthalene and phenanthrene were rapidly mineralised and (ii) soil-associated organic contaminant bioavailability, where increased soil–phenanthrene contact time resulted in a reduction in phenanthrene mineralisation in the soil. The described respirometer system differs from existing respirometer systems in that the CO2 trap can be removed and replaced quickly and easily. The system is efficient, reproducible, adaptable to many situations, easy to construct and simple to use, it therefore affords advantages over existing systems.
A study was conducted to find ways to increase the biodegradability of compounds that have aged in soil or aquifer material and become less bioavailable. Slurrying enhanced the rate and extent of biodegradation by individual bacterial strains of aged and unaged phenanthrene and di(2-ethylhexyl) phthalate in soils and aquifer solids. After bacterial degradation of aged phenanthrene in unslurried soil had largely ceased, the residual compound was metabolized if the soil was slurried and reinoculated with a phenanthrene-degrading bacterium. The rate and extent of biodegradation of aged phenanthrene by Pseudomonas sp. were enhanced when anthracene or pyrene was added to the soil at the same time as the bacterium, although the organism could not metabolize anthracene or pyrene. Moreover, anthracene or pyrene increased the amount of aged phenanthrene removed from soil by a mild extractant. The data show that the bioavailability of organic compounds that become sequestered by aging can be altered by appropriate soil treatments.
A study was conducted to determine the mineralization in soil and subsoil of hydrophobic organic compounds present in several nonaqueous-phase liquids (NAPLs). When present in soil in some NAPLs, di(2-ethylhexyl) phthalate (DEHP) was not appreciably mineralized, phenanthrene was slowly transformed after an acclimation phase, and hexadecane and naphthalene were biodegraded rapidly. The extent of suppression of biodegradation of test compounds varied with different solvents as NAPLs. The rate of mineralization in subsoil of phenanthrene dissolved in some NAPLs was very slow, but additions of N and P enhanced the degradation. The addition of N and P to soil did not increase the mineralization of DEHP dissolved in NAPLs. The existence of a NAPL in polluted environments may thus markedly affect the susceptibility of organic compounds to biodegradation.
Competitive sorption to natural solids among mixtures of organic compounds has been documented in the literature. This study was conducted to determine co-solute competitive effects on the biological and physical availability of polycyclic aromatic hydrocarbons in soils after long contact periods (aging). Sterile suspensions of Mount Pleasant silt loam (Mt. Pleasant, NY, USA) and Pahokee peat soils were spiked with phenanthrene and allowed to age for 3 or 123 d before inoculation with a phenanthrene-degrading bacterium in the presence or absence of the nonbiodegradable co-solute pyrene. As expected, mineralization decreased with aging in the samples not amended with pyrene. However, addition of pyrene just prior to inoculation at 123 d significantly mitigated this decrease; that is, the extent of mineralization was greater in the 123-d pyrene-amended samples than in the 123-d nonamended samples. Parallel experiments on sterile soils showed that pyrene increased the physical availability of phenanthrene by competitive displacement of phenanthrene from sorption sites. First, the addition of pyrene increased recovery of 123-d-aged phenanthrene by mild solvent extraction. Second, addition of pyrene (at three concentrations) dramatically reduced the apparent distribution coefficient (Kappd) of several concentrations of 60-, 95-, and 111-d-aged phenanthrene. At the lowest phenanthrene and highest pyrene concentrations, reductions in the Kappd of phenanthrene in the peat soil reached 83%. The competitive displacement effect observed in this study adds further support to the dual mode model of sorption to soil organic matter. The displacement of an aged contaminant by a nonaged co-solute might also prove useful in the development of novel remediation strategies.
A study was conducted to determine whether the time that a compound remains in a soil affects its biodegradability and the ease of its extraction. Phenanthrene and 4-nitrophenol were aged in sterilized loam and muck, and bacteria able to degrade the compounds were then added to the soils. increasingly smaller amounts of phenanthrene in the muck and 4-nitrophenol in both soils were mineralized with increasing duration of aging. Aging also increased the resistance of phenanthrene to biodegradation in nutrient-amended aquifer sand. The rate of miner- alization of the two compounds in both soils declined with increasing periods of aging. The amount of phenanthrene and 4-nitrophenol added to sterile soils that was recovered by butanol extraction declined with duration of aging, but subsequent Soxhlet extraction recovered phenanthrene from the loam but not the muck. The extents of mineralization of phenanthrene previously incubated for up to 27 days with soluble or insoluble organic matter from the muck were similar. Less aged than freshly added phenanthrene was biodegraded if aggregates in the muck were sonically disrupted. The data show that phenanthrene and 4-nitrophenol added to soil become increasingly more resistant with time to biodegradation and extraction.
Sorption kinetics of hydrophobic organic chemicals to and from suspended sediment and soil particles is described by a radial diffusive penetration model modified by a retardation factor reflecting microscale partitioning of the sorbate between intraaggregate pore fluids and the solids making up the aggregate grains. In light of this and other sorption kinetics models, a closed-loop-stripping apparatus with a photoionization detector operating in-line was used to examine the effects of sorbate hydrophobicity, sorbent particle size, and system temperature on solid-solution exchange over times of seconds to days. The authors results indicate that a single effective diffusivity parameter, which is predictable from compound solution diffusivity, octanol-water partition coefficient, and sorbent organic content, density, and porosity, can be used to quantify the sorption kinetics.
Fitzpatrick first published a text book on soils in 1971, and it has been completely rewritten for this new edition. The problem of the many classifications of soils used in the world has led the author to use three sets of terminlogy simultaneously, although the first 4 chapters are presented without the need to resort to such jargon. As far as classification is concerned the large number of systems are described while chapter 6 dicusses the soil classes of the world in alphabetical order using the FAO nomenclature - this consists of about one third of the book. -Keith Clayton
This paper describes the validation and application of a simple flask-based (14)C-respirometer system designed to assess mineralisation of (14)C-labelled substrates under defined conditions. Validation of this respirometer system indicated stoichiometric CO(2) trapping up to a maximum of 400 micromol of CO(2) (in a single trap). Polycyclic aromatic hydrocarbon (PAH)-degrading bacteria were used to measure growth-linked biodegradation of [(14)C]naphthalene to (14)CO(2). A (14)C activity balance of 101.7+/-8.9% (n=6), after 74 h incubation time and 10 respirometer-opening events, indicated the suitability of the system for monitoring substrate mineralisation. This respirometric apparatus was then successfully applied to assess: (i) the PAH catabolism of microbes in a field contaminated soil, where naphthalene and phenanthrene were rapidly mineralised and (ii) soil-associated organic contaminant bioavailability, where increased soil-phenanthrene contact time resulted in a reduction in phenanthrene mineralisation in the soil. The described respirometer system differs from existing respirometer systems in that the CO(2) trap can be removed and replaced quickly and easily. The system is efficient, reproducible, adaptable to many situations, easy to construct and simple to use, it therefore affords advantages over existing systems.
A study was conducted to investigate whether cyclodextrins and surfactants can be used to predict polycyclic aromatic hydrocarbon (PAH) bioavailability in contaminated sediments. Two sediment samples were extracted with aqueous solutions of hydroxypropyl-beta-cyclodextrin (HPCD) and Triton X-100. PAH removal during extraction was compared with PAH removal during biodegradation and solid-phase extraction. The latter two methods were used as reference methods to establish which part of the PAHs could be biodegraded and to what extent biodegradation was governed by bioavailability limitations. It was demonstrated that HPCD extraction followed solid-phase extraction and removed primarily readily bioavailable PAHs, while Triton X-100 extracted both readily and poorly bioavailable PAHs. Moreover, HPCD did not affect the degradation of PAHs in biodegradation experiments, while Triton X-100 enhanced the degradation of low molecular weight PAHs. It was concluded that HPCD extraction may provide a good method for the prediction of PAH bioavailability. Triton X-100 extraction is unfit for the prediction of PAH bioavailability.
Oil is ubiquitous in aquatic sediments and may affect partitioning and bioavailability of hydrophobic organic chemicals (HOCs). In contrast to other sedimentary hydrophobic carbon phases (natural organic matter, soot-like materials), oil residues have hardly received any attention as far as it concerns effects on HOC sorption. This paper describes experimental work dealing with such effects of oil on polycyclic aromatic hydrocarbon (PAH) sorption to sediments. Three different oils were spiked to a marine sediment in concentrations between 0 and 100 g/kg. Sediment-water distribution coefficients (Kd) for six deuterated PAHs were then determined either directly after spiking the oil or after a semi-natural weathering process in the lab (lasting for more than 2 yr). Resulting Kd values demonstrated sorption-reducing (competitive) effects at relatively low oil concentrations and sorption-enhancing effects at high oil concentrations. The latter effects only occurred above a certain threshold [i.e., ca. 15% (w/w) of oil on a sedimentary organic carbon basis] marking the oil concentration at which the hydrocarbon mixture presumably starts forming separate phases. Assuming a two-domain (organic carbon + oil) distribution model, oil-water distribution coefficients (K(oil)) for PAHs were estimated. For fresh oils, log K(oil) values appeared to be very similar for different types of oils, proportional to log K(OW) values and indistinguishable from log K(OC) values. For weathered oils, K(oil) values were also rather independent of the type of oil, but the affinity of low molecular weight PAHs for weathered oil residues appeared to be extremely high, even higher than values reported for most types of soot. Because affinities of high molecular weight PAHs for oils had not changed upon weathering, sorption of all PAHs studied (comprising a log K(OW) range of 4.6-6.9) to the weathered oil residues appeared to be more or less constant (averaged log K(oil) = 7.0 +/- 0.24). These results demonstrate that it is crucial to take the presence of oil and its weathering state into account when assessing the actual fate of PAHs in aquatic environments.
The aim of this study was to investigate the influence of diesel on the loss and bioavailability of soil-associated [14C]phenanthrene with time. In addition, the temporal development of phenanthrene catabolic activity and the impact of co-contaminant mixtures on the soil microflora were also assessed. With respect to compound fate, the results suggested that competitive effects between dissimilar co-contaminants did influence [14C]phenanthrene loss. Where diesel was present at a concentration of 0, 20, 200 and 2000 mg kg(-1), increased phenanthrene loss was observed with increasing diesel concentrations. In the 20,000 mg kg(-1) diesel treatment, however, a significantly higher amount of the initial [14C]activity remained after 225 days. Furthermore, initial degradation of phenanthrene in this treatment was retarded as a result of repressed phenanthrene catabolic activity. These results were complemented by a 4-fold increase in total culturable bacterial cell numbers in the 20,000 mg kg(-1) treatment when compared with the 2000 mg kg(-1) after 225 days of incubation time.
Soils and their Use in Eastern England Organic chemicals in contaminated land: analysis, significance and research priorities. Land Contam
- C A H Hodge
- R G O Burton
- W M Corbett
- R Evans
- R S Seale
- Harpenden
- K C Jones
- R E Alcock
- D L Johnson
- G L Northcott
- K T Semple
- P J Woolgar
Hodge, C.A.H., Burton, R.G.O., Corbett, W.M., Evans, R., Seale, R.S., 1984. Soils and their Use in Eastern England. Harpenden. Jones, K.C., Alcock, R.E., Johnson, D.L., Northcott, G.L., Semple, K.T., Woolgar, P.J., 1996. Organic chemicals in contaminated land: analysis, significance and research priorities. Land Contam. Reclam. 4, 189–197.
Soils in Norfolk V, Soil Survey Record No. 64, Sheet TG11 (Attledbridge)
- D J Eldridge
Eldridge, D.J., 1980. Soils in Norfolk V, Soil Survey Record No. 64, Sheet TG11 (Attledbridge). Bartholomew Press.
Soils and their Use in Eastern England
- C A H Hodge
- R G O Burton
- W M Corbett
- R Evans
- R S Seale
Hodge, C.A.H., Burton, R.G.O., Corbett, W.M., Evans, R., Seale, R.S.,
1984. Soils and their Use in Eastern England. Harpenden.