Human remains have been interred in burial grounds since historic times. Although the re-use of g... more Human remains have been interred in burial grounds since historic times. Although the re-use of graveyards differs from one country, region or time period to another, over time, graveyard soil may become contaminated or enriched with heavy metal elements. This paper presents heavy metal element soil analysis from two UK church graveyard study sites with contrasting necrosols, but similar burial densities and known burial ages dating back to the sixteenth century and some possibly older than 1,000 years. Portable X-ray fluorescence element laboratory-based analyses were undertaken on surface and near-surface soil pellets. Results show elevated levels of Fe, Pb, Mn, Cr, Cu, Zn and Ca in both necrosols when compared with background values. Element concentration anomalies remained consistently higher than background samples down to 2 m, but reduced with distance away from church buildings. Element concentration anomalies are higher in the clay-rich necrosol than in sandy necrosol. Study...
The clarification of drinking water leads to the production of large quantities of water treatmen... more The clarification of drinking water leads to the production of large quantities of water treatment residuals (WTRs). DNA was extracted from six WTR samples collected from water treatment plants within the UK to compare their bacterial communities and examine whether factors such as coagulant usage (aluminium versus iron salt), the type of water source (reservoir or river), or leachable chemical composition influence these communities. Bacterial 16S variable region 4 (V4) was amplified and sequenced using Illumina MiSeq sequencing. The most abundant phyla in WTR samples were Proteobacteria, Actinobacteria, Bacteroidetes, Acidobacteria, and Firmicutes, collectively representing 92.77–97.8% of the total bacterial sequences. Statistical analysis of microbial profiles indicated that water source played a significant role in microbial community structure, diversity, and richness, however coagulant type did not. PERMANOVA analysis showed that no single chemical variable (pH, organic matter...
International Journal of Environmental Science and Technology, 2021
Drinking water treatment residuals (WTRs) are wastes generated when water is clarified using alum... more Drinking water treatment residuals (WTRs) are wastes generated when water is clarified using aluminium or iron salts. They are increasingly being considered as a resource with potential reuse value, particularly in relation to soil or water remediation. Adsorption–desorption capacity of Al-based (Al-WTR) and Fe-based (Fe-WTR) materials was investigated here for Pb and Zn, both separately and in combination, as a preliminary trial to assess their utility for immobilising contaminant metals in environmental settings. Maximum adsorption observed at the highest test solution concentrations imposed (400 mg/L) was similar for each WTR type and each metal; Al-WTRs sorbed Zn at 3579 mg/kg and Pb at 4025 mg/kg, while Fe-WTRs sorbed Zn and Pb at 3579 mg/kg and 3980 mg/kg, respectively. Equilibrium adsorption data were tested against Langmuir, Freundlich, and Temkin isotherm models, which indicated a substantial reserve capacity for further Pb sorption and that multiple sorption mechanisms wer...
During clarification processes of raw water, a vast amount of by‐product known as “drinking water... more During clarification processes of raw water, a vast amount of by‐product known as “drinking water‐treatment residuals” (WTRs) are produced, being principally composed of hydroxides of the Al or Fe salts added during water treatment plus the impurities they remove. Aluminum‐based (Al‐WTR) and iron‐based (Fe‐WTR) materials were applied at 10% w/w to degraded, bare (unvegetated) soils from a restored coal mining site in central England (pH <3.9) to study their potential amelioration effects on earthworm mortality, biomass yield of seedling plants, and element concentrations in plant tissues, earthworm tissues, and soil solutions. A separate treatment with agricultural lime was also conducted for comparison to evaluate whether any observed improvements were attributable to the liming capacity of the WTRs. After completion of the trials, all samples were subjected to a wet–dry cycle, and the experiments were repeated (i.e., simulating longer‐term effects in the field). Both types of W...
Ecotoxicology and environmental safety, Jan 10, 2018
Drinking water treatment residuals (WTRs), the by-product of water clarification processes, are r... more Drinking water treatment residuals (WTRs), the by-product of water clarification processes, are routinely disposed of via landfill however there is a growing body of research that demonstrates the material has great potential for beneficial use in environmental applications. Application to agricultural land is one option showing great promise (i.e. a low cost disposal route that provides organic matter input to soils and other potential benefits), however questions remain as to the impact such applications may have on earthworm survival and behaviour and also on the potential effects it may have on soil porewater chemistry. This study examined the leachability of elements within two types of WTRs (one Al- and one Fe- based) from England via 0.001 M CaCl solution, at varying pH, and via the Community Bureau of Reference (BCR) sequential extraction scheme. Earthworm avoidance, survival, growth, reproduction and element concentrations were examined in WTR-amended sandy soils (0%, 5%, 1...
The effects of soil properties and zinc (Zn) availability on the toxicity of Zn to soil microbial... more The effects of soil properties and zinc (Zn) availability on the toxicity of Zn to soil microbial processes are poorly understood. Three soil microbial processes--potential nitrification rate (PNR), substrate (glucose)-induced respiration (SIR), and a maize residue respiration (MRR)--were measured in 15 European topsoils (pH 3.0-7.5; total Zn 7-191 mg/kg) that were freshly spiked with ZnCl2. The Zn toxicity thresholds of 20 to 50% effective concentrations (EC20s and EC50s) based on total concentrations of Zn in soil varied between 5- and 26-fold among soils, depending on the assay. The Zn toxicity thresholds based on Zn concentrations in soil solution varied at least 10-fold more than corresponding total metal thresholds. Soil pH had no significant effect on soil total Zn toxicity thresholds, whereas significant positive correlations were found between these thresholds and background Zn for the PNR and SIR test (r = 0.74 and 0.71, respectively; log-log correlations). No such trend was found for the MRR test. Soil solution-based thresholds showed highly significant negative correlations with soil pH for all assays that might be explained by competition of H+ for binding sites, as demonstrated for aquatic species. The microbial assays were also applied to soils collected under galvanized pylons (three sites) where concentrations of total Zn were up to 2,100 to 3,700 mg Zn/kg. Correlations between concentrations of total Zn and microbial responses were insignificant at all sites even though spiking reference samples to equivalent concentrations reduced microbial activities up to more than 10-fold. Differences in response between spiked and field soils are partly but not completely attributed to the large differences in concentrations of Zn in soil solution. We conclude that soil pH has no significant effect on Zn toxicity to soil microbial processes in laboratory-spiked soils, and we suggest that community tolerance takes place at both background and elevated Zn concentrations in soil.
Cadmium (Cd) contaminated soils from the Mae Sot district in northwest Thailand, a region in whic... more Cadmium (Cd) contaminated soils from the Mae Sot district in northwest Thailand, a region in which rice Cd concentrations often exceed health limits (0.4 mg/kg) set by the World Health Organisation, were examined for isotopically exchangeable Cd (Cd E values using a Cd spike) to determine how this rates as a predictor of rice grain Cd in comparison with soil total Cd and solution extractable Cd (using the commonly applied BCR scheme and, in an attempt to distinguish carbonate bound forms, the Tessier soil sequential extraction scheme reagents). Step 1 of the BCR scheme (0.11 M CHCOOH) and step 1 of the Tessier scheme (1M MgCl) showed the highest R values in regressions with rice Cd (91% and 90%, respectively), but all predictors were strongly linked to rice Cd (p < 0.001) and could be used for prediction purposes. One soil, of the six tested, was an exception to this, where all predictors over-estimated grain Cd by a factor of 2.5-5.7, suggesting that rice grain Cd had been restr...
Human remains have been interred in burial grounds since historic times. Although the re-use of g... more Human remains have been interred in burial grounds since historic times. Although the re-use of graveyards differs from one country, region or time period to another, over time, graveyard soil may become contaminated or enriched with heavy metal elements. This paper presents heavy metal element soil analysis from two UK church graveyard study sites with contrasting necrosols, but similar burial densities and known burial ages dating back to the sixteenth century and some possibly older than 1,000 years. Portable X-ray fluorescence element laboratory-based analyses were undertaken on surface and near-surface soil pellets. Results show elevated levels of Fe, Pb, Mn, Cr, Cu, Zn and Ca in both necrosols when compared with background values. Element concentration anomalies remained consistently higher than background samples down to 2 m, but reduced with distance away from church buildings. Element concentration anomalies are higher in the clay-rich necrosol than in sandy necrosol. Study...
The clarification of drinking water leads to the production of large quantities of water treatmen... more The clarification of drinking water leads to the production of large quantities of water treatment residuals (WTRs). DNA was extracted from six WTR samples collected from water treatment plants within the UK to compare their bacterial communities and examine whether factors such as coagulant usage (aluminium versus iron salt), the type of water source (reservoir or river), or leachable chemical composition influence these communities. Bacterial 16S variable region 4 (V4) was amplified and sequenced using Illumina MiSeq sequencing. The most abundant phyla in WTR samples were Proteobacteria, Actinobacteria, Bacteroidetes, Acidobacteria, and Firmicutes, collectively representing 92.77–97.8% of the total bacterial sequences. Statistical analysis of microbial profiles indicated that water source played a significant role in microbial community structure, diversity, and richness, however coagulant type did not. PERMANOVA analysis showed that no single chemical variable (pH, organic matter...
International Journal of Environmental Science and Technology, 2021
Drinking water treatment residuals (WTRs) are wastes generated when water is clarified using alum... more Drinking water treatment residuals (WTRs) are wastes generated when water is clarified using aluminium or iron salts. They are increasingly being considered as a resource with potential reuse value, particularly in relation to soil or water remediation. Adsorption–desorption capacity of Al-based (Al-WTR) and Fe-based (Fe-WTR) materials was investigated here for Pb and Zn, both separately and in combination, as a preliminary trial to assess their utility for immobilising contaminant metals in environmental settings. Maximum adsorption observed at the highest test solution concentrations imposed (400 mg/L) was similar for each WTR type and each metal; Al-WTRs sorbed Zn at 3579 mg/kg and Pb at 4025 mg/kg, while Fe-WTRs sorbed Zn and Pb at 3579 mg/kg and 3980 mg/kg, respectively. Equilibrium adsorption data were tested against Langmuir, Freundlich, and Temkin isotherm models, which indicated a substantial reserve capacity for further Pb sorption and that multiple sorption mechanisms wer...
During clarification processes of raw water, a vast amount of by‐product known as “drinking water... more During clarification processes of raw water, a vast amount of by‐product known as “drinking water‐treatment residuals” (WTRs) are produced, being principally composed of hydroxides of the Al or Fe salts added during water treatment plus the impurities they remove. Aluminum‐based (Al‐WTR) and iron‐based (Fe‐WTR) materials were applied at 10% w/w to degraded, bare (unvegetated) soils from a restored coal mining site in central England (pH <3.9) to study their potential amelioration effects on earthworm mortality, biomass yield of seedling plants, and element concentrations in plant tissues, earthworm tissues, and soil solutions. A separate treatment with agricultural lime was also conducted for comparison to evaluate whether any observed improvements were attributable to the liming capacity of the WTRs. After completion of the trials, all samples were subjected to a wet–dry cycle, and the experiments were repeated (i.e., simulating longer‐term effects in the field). Both types of W...
Ecotoxicology and environmental safety, Jan 10, 2018
Drinking water treatment residuals (WTRs), the by-product of water clarification processes, are r... more Drinking water treatment residuals (WTRs), the by-product of water clarification processes, are routinely disposed of via landfill however there is a growing body of research that demonstrates the material has great potential for beneficial use in environmental applications. Application to agricultural land is one option showing great promise (i.e. a low cost disposal route that provides organic matter input to soils and other potential benefits), however questions remain as to the impact such applications may have on earthworm survival and behaviour and also on the potential effects it may have on soil porewater chemistry. This study examined the leachability of elements within two types of WTRs (one Al- and one Fe- based) from England via 0.001 M CaCl solution, at varying pH, and via the Community Bureau of Reference (BCR) sequential extraction scheme. Earthworm avoidance, survival, growth, reproduction and element concentrations were examined in WTR-amended sandy soils (0%, 5%, 1...
The effects of soil properties and zinc (Zn) availability on the toxicity of Zn to soil microbial... more The effects of soil properties and zinc (Zn) availability on the toxicity of Zn to soil microbial processes are poorly understood. Three soil microbial processes--potential nitrification rate (PNR), substrate (glucose)-induced respiration (SIR), and a maize residue respiration (MRR)--were measured in 15 European topsoils (pH 3.0-7.5; total Zn 7-191 mg/kg) that were freshly spiked with ZnCl2. The Zn toxicity thresholds of 20 to 50% effective concentrations (EC20s and EC50s) based on total concentrations of Zn in soil varied between 5- and 26-fold among soils, depending on the assay. The Zn toxicity thresholds based on Zn concentrations in soil solution varied at least 10-fold more than corresponding total metal thresholds. Soil pH had no significant effect on soil total Zn toxicity thresholds, whereas significant positive correlations were found between these thresholds and background Zn for the PNR and SIR test (r = 0.74 and 0.71, respectively; log-log correlations). No such trend was found for the MRR test. Soil solution-based thresholds showed highly significant negative correlations with soil pH for all assays that might be explained by competition of H+ for binding sites, as demonstrated for aquatic species. The microbial assays were also applied to soils collected under galvanized pylons (three sites) where concentrations of total Zn were up to 2,100 to 3,700 mg Zn/kg. Correlations between concentrations of total Zn and microbial responses were insignificant at all sites even though spiking reference samples to equivalent concentrations reduced microbial activities up to more than 10-fold. Differences in response between spiked and field soils are partly but not completely attributed to the large differences in concentrations of Zn in soil solution. We conclude that soil pH has no significant effect on Zn toxicity to soil microbial processes in laboratory-spiked soils, and we suggest that community tolerance takes place at both background and elevated Zn concentrations in soil.
Cadmium (Cd) contaminated soils from the Mae Sot district in northwest Thailand, a region in whic... more Cadmium (Cd) contaminated soils from the Mae Sot district in northwest Thailand, a region in which rice Cd concentrations often exceed health limits (0.4 mg/kg) set by the World Health Organisation, were examined for isotopically exchangeable Cd (Cd E values using a Cd spike) to determine how this rates as a predictor of rice grain Cd in comparison with soil total Cd and solution extractable Cd (using the commonly applied BCR scheme and, in an attempt to distinguish carbonate bound forms, the Tessier soil sequential extraction scheme reagents). Step 1 of the BCR scheme (0.11 M CHCOOH) and step 1 of the Tessier scheme (1M MgCl) showed the highest R values in regressions with rice Cd (91% and 90%, respectively), but all predictors were strongly linked to rice Cd (p < 0.001) and could be used for prediction purposes. One soil, of the six tested, was an exception to this, where all predictors over-estimated grain Cd by a factor of 2.5-5.7, suggesting that rice grain Cd had been restr...
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