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Over the past decades, contamination of terrestrial environments with antimony (Sb) has aroused a great deal of public concern. In this research, the efficacy of Fe(III)-modified montmorillonite (Mt) (Fe-Mt) for the removal of Sb(V) from aqueous solutions with Sb(V) concentration in the range of 0.2–1 mmol L−1 and immobilization of Sb(V) in soils spiked with 250 mg Sb(V) kg−1 was investigated. The immobilizing mechanisms of the modified clay were assessed by fitting the experimental sorption data with the Langmuir and Freundlich sorption models and a series of single and sequential extraction studies. The results showed that the adsorption data had a better fit with the Langmuir equation (R2: 0.99) and Fe-Mt could efficiently remove up to 95% of Sb(V) at lower concentration ranges. The concentrations of Sb(V) in exchangeable fraction of modified Community Bureau of Reference (BCR) sequential extraction and distilled water extracts of the amended soils decreased dramatically by up to 60% and 92%, respectively. Furthermore, the bioaccessibility of Sb(V) in simulated human gastric juice reduced remarkably by 52% to 60%, depending upon the soil fraction sizes. The results confirmed that Fe-Mt could be a promising candidate for the removal of Sb(V) from aqueous solutions and immobilization of Sb(V) in terrestrial environments.

Assessing the bioavailability of various Sb substances plays a crucial role in human health and the ecological risk assessment of contaminated soils. However, fate, behaviour and bioavailability of different Sb compounds in soils are insufficiently known. Therefore, in this present study, the effects of soil properties and ageing on bioavailability of four different Sb compounds (C8H4K2O12Sb2, Sb2S3, Sb2O3 and Sb2O3 nanoparticles) were evaluated during 120 days ageing time. A black soil (BS) with approximately 12% organic matter (OM) and a red soil (RS) with less than 1% OM were amended with 1000 mg Sb kg−1 of different Sb compounds and subjected to single extractions with distilled (DI) water, 2M HNO3, Simplified Bioaccessibility Extraction Test (SBET) and a modified Community Bureau of Reference (BCR) sequential extraction method. The results revealed that there are substantial variations in dissolution rate of various Sb sources, depending upon soil type and Sb compound. The amounts of DI water extractability of Sb during the incubation time varied between

This study investigated the effectiveness of 6 different types of naturally occurring manganese, aluminum and iron oxides for stabilization of As and Sb in a calcareous soil spiked with 50mgkg(-1) of As or Sb and two dosages of treatments (2% and 5%). The resulting contaminated soils were subjected to a series of chemical extraction studies including sequential extraction, single step extraction with DTPA and Simplified Bioaccessibility Extraction Test (SBET) for estimation of bioaccessible fraction of As and Sb in soil and a greenhouse experiment using barley as the test crop. The results showed that Fe-associated and carbonate-bound fraction of As and Sb were predominant fractions. However, the amounts of labile fractions were higher in As contaminated soils, whereas the percentage of Sb associated with crystalline Fe-oxide and residual fractions were higher. The results revealed that application of natural metal oxides reduced DTPA and SBET extractable amounts and plant uptake of As and Sb. After application of amendments, the exchangeable fraction of As decreased dramatically by up to 82% while Sb exchangeable fraction decreased by up to 60% depending upon the additive. The results of chemical extractions and plant uptake confirmed that Sb had lower bioavailability, compared with As.

Over the past few decades, many countries have issued legislation for risk based management of contaminated soils, sediments and water. Establishing appropriate guidelines for risk based management of antimony contaminated environments is of great importance due to its toxicological properties. Antimony (Sb) is a toxic metalloid with a wide range of industrial applications that can cause adverse effects on natural ecosystems and human health. There are numerous soil and water national and international toxicity guidelines, legislation and clean up target values for evaluating the risks and health hazards associated with Sb contaminated soils and water. Although they are not accurate definitive indices of environmental hazards, they can be used as a surrogate tool for estimating harmful effects of contaminants. In this summary report, five common soil and sediment toxicity guidelines set by the USA, Canada, Australia, the Netherlands and Finland as well as some of water toxicity guidelines and their derivation methods are compared. There are, however, substantial variations between toxicity threshold values due to the different scientific bases, software models and ecotoxicological criteria used for developing these guidelines. It is evident from the literature that site specific factors e.g. redox potential, pH and ageing may greatly affect the environmental availability of Sb. Hence, establishing universally acceptable regulatory guidelines and toxicity essays with an array of bioavailability based approach and site specific considerations would greatly improve the reliability and robustness of the current techniques used for environmental management and remediation of contaminated soils.