Nanoscale zero-valent iron coated with rhamnolipid as an effective stabilizer for immobilization of Cd and Pb in river sediments

In this study, surface soil and corn cob samples were collected from 15 different agricultural fields of Canakkale, Turkey. These samples were analysed to determine the concentration of Cd, Cu, Mn, Ni, Pb and Zn. BCR sequential extraction was used to extract the binding forms of the metals in the soil samples. At the same time, a wet digestion method was used to determine the total concentration of heavy metals in soil and corn grain samples. The metal concentrations in the extracted phase were measured with flame atomic absorption spectrometer. The accuracy of the methods was confirmed by using BCR-701 and SRM-1570a certified reference materials. The results revealed that the quantity of the mobile fractions (i.e., acid soluble, reducible, and oxidisable) of the Mn, Cd and Pb were higher than that of the immobile fractions (residual). This might be caused by the anthropogenic sources. Pearson’s correlation was applied to determine the correlations between the selected physicochemical properties o...

Investigation of heavy metal mobility and availability by the BCR sequential extraction procedure: relationship between soil properties and heavy metals availability

The present research was conducted to determine heavy metals in agricultural soils from Canakkale, Turkey, using a sequential extraction procedure (acid soluble, reducible, oxidizable, and residual) as proposed by the Community Bureau of Reference (BCR) of the European Commission. Soil samples were taken from 12 different cultivated sites and analyzed for Cd, Co, Cr, Cu, Mn, Ni, Pb, and Zn concentrations. The results revealed an order of Mn > Cd > Pb > Co > Ni > Cu > Zn > Cr for the heavy metals based on the sum of the first three fractions (acid soluble + reducible + oxidizable). The relationships between soil properties and each metal fraction were identified through Pearsons's correlation analysis. Hierarchical cluster analysis was performed to determine the behaviors and similarities of metals in each fraction. While Mn, Pb, and Zn exhibited subjective behaviors in the acid-soluble fraction, Cd, Co, Cu, Cr, and Ni exhibited similar behaviors with each other.

Characterization of Heavy Metal Fractions in Agricultural Soils by Sequential Extraction Procedure: The Relationship Between Soil Properties and Heavy Metal Fractions

Effects of soil chemical properties and fractions of Pb, Cd, and Zn on bacterial and fungal communities

Heavy metals of surface sediments in the Changjiang (Yangtze River) Estuary: Distribution, speciation and environmental risks

Quantification of heavy and trace metal contamination in soil can be arduous, requiring the use of lengthy and intricate extraction procedures which may or may not give reliable results. Of the many procedures in publication, some are designed to operate within specific parameters while others are designed for more broad application. Most procedures have been modified since their inception which creates ambiguity as to which procedure is most acceptable in a given situation. For this study, the Tessier, Community Bureau of Reference (BCR), Short, Galan, and Geological Society of Canada (GCS) procedures were examined to clarify benefits and limitations of each. Modifications of the Tessier, BCR, and GCS procedures were also examined. The efficacy of these procedures is addressed by looking at the soils used in each procedure, the limitations, applications, and future of sequential extraction.

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Heavy metal and trace metal analysis in soil by sequential extraction: a review of procedures.

Arsenic (As) contamination in soil and water is a global human health and environmental problem due to its common occurrence and high toxicity. At least four million people in Latin America have long-term exposure to As in drinking water. In northwestern Costa Rica, As has been measured in drinking water at concentrations ranging from 20 to over 80 µg As L−1. Arsenic contaminated drinking water can be treated using filter technologies; titanium dioxide (TiO2)-based drinking water filters decrease As concentration and help mitigate As exposure. However, this process creates an As-enriched TiO2 solid-phase waste product. An objective of this study is to determine the chemical forms of As in this waste product, which is commonly distributed on soil surfaces and throughout urban and rural areas adjacent to drinking water treatment facilities in the sample area. An additional objective is to determine biogeochemical changes in As speciation in filter waste and affected soils which may be induced through earthworm ingestion, which also occurs in the sample area. Arsenic concentrations in the solid-phase filter waste were measured to be up to 600 mg kg−1. There was a strong correlation between As and Ti (R2 > 0.90) indicating As accumulates within or on the surface of the TiO2 mineral. Earthworm castings enriched in TiO2 contained up to 530 mg As kg−1, which provided direct evidence soil macroorganisms ingest filter waste. X-ray diffraction (XRD) confirmed Ti is predominantly anatase with minor amounts of quartz and feldspar. These results are novel and innovative because they identify and characterize a previously unexplored problem of anthropogenic soil and sediment As contamination and redistribution in urban and rural environments. Additionally, dry windy seasons in the region increase potential risk of As and TiO2 exposure through dust inhalation. Earthworm consumption did not decrease As concentrations in earthworm castings. Synchrotron-based X-ray absorption spectroscopy (XAS), specifically X-ray absorption near edge structure (XANES) spectroscopy, indicated the dominant species of As in soil and sediment samples was arsenate [As(V)], which is similar to the chemical form of As in the groundwaters of this region. No evidence of arsenite [As(III)] was identified in any of the solid-phase samples, including earthworm castings.

Arsenic speciation in titanium dioxide (TiO2) waste produced via drinking water filtration: Potential environmental implications for soils, sediments, and human health

Abstract The objective of this study was to determine the effects of supplementing a commercial porous ceramic clay particle, with or without a blend of preservatives, on the performance and nutrient digestibility of weanling pigs. Fifteen weanling pigs of the Yorkshire, Landrace, and Duroc breeds were blocked by breed and randomly assigned to one of three treatments (n = 5): (1) Control, non-medicated diet with no additional feed additives (CON); (2) PowerGuard, basal diet with 0.25% of the DM consisting of a ceramic particle mixed into the pelleted feed (PG; MB Nutritional Sciences, Lubbock, TX, 79403); or (3) Power Guard + a blend of preservatives, basal diet with 0.3% of the DM consisting of the ceramic clay and preservatives mixed into the pelleted feed (PG-D). The facility was temperature controlled with an average temperature of 28.5 °C. Pigs were offered ad libitum access to feed and water and were housed individually in elevated crates. Body weights were collected upon enrollment on day 0 and at the end of the observation period on day 18. On day 15 , a 72-h total feed and fecal collection period began. Feed and fecal samples were analyzed for DM, CP, Ash, OM, ADF, NDF, zinc, copper, thiamin (vitamin B1), and retinol (vitamin A). Liver samples were collected immediately after harvest and frozen for later mineral analysis. Data were analyzed using Proc Mixed in SAS with dietary group as the main effect and block as the random effect (SAS 9.4, Cary, NC). There were no treatment differences in performance measures including final BW, ADG, or G:F (P ≥ 0.701). There were no treatment differences in diet nutrient digestibility for DM, CP, Ash, OM, ADF, or NDF (P ≥ 0.312). Additionally, there were no treatment effects on zinc, copper, or retinol digestibility (P ≥ .298); however, thiamin inclusion rate was increased for the PG-D treatment, thus leading to an increased digestibility for thiamin (P = 0.018) in the PG-D treatment. There were no treatment differences in hepatic mineral concentrations (P ≥ 0.532); however, there was a tendency for pigs fed PG-D to have increased hepatic concentrations of lead and mercury when compared with both PG and CON pigs (P ≤ 0.066). In summary, supplementation of a commercial ceramic particle with or without a blend of preservatives to weaned pigs did not affect performance or apparent nutrient digestibility.

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Amanda Jo Zimmerman

Papers

Heavy metal and trace metal analysis in soil by sequential extraction: a review of procedures.

Arsenic speciation in titanium dioxide (TiO2) waste produced via drinking water filtration: Potential environmental implications for soils, sediments, and human health

A porous ceramic particle with or without a preservative blend did not impair apparent digestibility of macro- and micro-nutrients of postweaned pigs