Comparative Study between Imprinted Polymer Technology and Economic Adsorption Methodologies for the Removal of Arsenic Species from Water

Among the various arsenic sources in the environment, water may pose the greatest threat to human health. Arsenic and its compounds are known to have adverse health effects on humans, including skin cancer, bladder cancer, kidney cancer, and lung cancer, as well as vascular diseases of the legs and feet. There are a few separation methods that have been studied to remove arsenic species from water. Methods to remove arsenic species such as adsorption and ion exchange, coagulation and flocculation and membrane filtration have been developed to remove arsenic species from water. However, certain separation methods require a sophisticated equipment and are too expensive. From the different possible methods, this review is based in adsorption studies using imprinted polymer technology and economic sorbents as a media to remove arsenic from water. The details of adsorption processes for imprinted polymer technology have been discussed briefly and the comparative properties for arsenic species removal using different types of sorbents has been addressed significantly for being a user-friendly, highly extended and inexpensive methodology. However, a few drawbacks for each sorbent have been determined and the details was included in this review.

Toxic Metals and Subclinical Atherosclerosis in Carotid, Femoral, and Coronary Vascular Territories: The Aragon Workers Health Study

Objective: Studies evaluating the association of metals with subclinical atherosclerosis are mostly limited to carotid arteries. We assessed individual and joint associations of nonessential metals exposure with subclinical atherosclerosis in 3 vascular territories. Approach and Results: One thousand eight hundred seventy-three Aragon Workers Health Study participants had urinary determinations of inorganic arsenic species, barium, cadmium, chromium, antimony, titanium, uranium, vanadium, and tungsten. Plaque presence in carotid and femoral arteries was determined by ultrasound. Coronary Agatston calcium score ≥1 was determined by computed tomography scan. Median arsenic, barium, cadmium, chromium, antimony, titanium, uranium, vanadium, and tungsten levels were 1.83, 1.98, 0.27, 1.18, 0.05, 9.8, 0.03, 0.66, and 0.23 μg/g creatinine, respectively. The adjusted odds ratio (95% CI) for subclinical atherosclerosis presence in at least one territory was 1.25 (1.03–1.51) for arsenic, 1.67 (1.22–2.29) for cadmium, and 1.26 (1.04–1.52) for titanium. These associations were driven by arsenic and cadmium in carotid, cadmium and titanium in femoral, and titanium in coronary territories and mostly remained after additional adjustment for the other relevant metals. Titanium, cadmium, and antimony also showed positive associations with alternative definitions of increased coronary calcium. Bayesian Kernel Machine Regression analysis simultaneously evaluating metal associations suggested an interaction between arsenic and the joint cadmium-titanium exposure. Conclusions: Our results support arsenic and cadmium and identify titanium and potentially antimony as atherosclerosis risk factors. Exposure reduction and mitigation interventions of these metals may decrease cardiovascular risk in individuals without clinical disease.

Sorption of Monothioarsenate to the Natural Sediments and Its Competition with Arsenite and Arsenate

Monothioarsenate (MTAsV) is one of the major arsenic species in sulfur- or iron-rich groundwater, and the sediment adsorption of MTAsV plays an important role in arsenic cycling in the subsurface environment. In this study, batch experiments and characterization are conducted to investigate the sorption characteristic and mechanism of MTAsV on natural sediments and the influences of arsenite and arsenate. Results show that MTAsV adsorption on natural sediments is similar to arsenate and arsenite, manifested by a rapid early increasing stage, a slowly increasing stage at an intermediate time until 8 h, before finally approaching an asymptote. The sediment sorption for MTAsV mainly occurs on localized sites with high contents of Fe and Al, where MTAsV forms a monolayer on the surface of natural sediments via a chemisorption mechanism and meanwhile the adsorbed MTAsV mainly transforms into other As species, such as AlAs, Al-As-O, and Fe-As-O compounds. At low concentration, MTAsV sorption isotherm by natural sediments becomes the Freundlich isotherm model, while at high concentration of MTAsV, its sorption isotherm becomes the Langmuir isotherm model. The best-fitted maximum adsorption capacity for MTAsV adsorption is about 362.22 μg/g. Furthermore, there is a competitive effect between MTAsV and arsenate adsorption, and MTAsV and arsenite adsorption on natural sediments. More specifically, the presence of arsenite greatly decreases MTAsV sorption, while the presence of MTAsV causes a certain degree of reduction of arsenite adsorption on the sediments before 4 h, and this effect becomes weaker when approaching the equilibrium state. The presence of arsenate greatly decreases MTAsV sorption and the presence of MTAsV also greatly decreases arsenate sorption. These competitive effects may greatly affect MTAsV transport in groundwater systems and need more attention in the future.

Alcohol Consumption Moderated the Association Between Levels of High Blood Lead or Total Urinary Arsenic and Bone Loss

Metal exposure and lifestyle are important risk factors for osteoporosis. Our study aimed to investigate the association between red blood cell lead and cadmium, total urinary arsenic, and plasma selenium levels and bone mineral density (BMD). In addition, we explored whether alcohol and coffee consumption modified the association between BMD and metals and metalloids. In total, 437 participants who underwent adult or senile physical examinations were recruited. Bone loss was defined as a calcaneus BMD T-score of <-1. Blood cadmium and lead and plasma selenium levels were measured using inductively coupled plasma mass spectrometry. Levels of urinary arsenic species were determined using high-performance liquid chromatography–hydride generator–atomic absorption spectrometry. The total urinary arsenic level was defined as the sum of the levels of urinary arsenic species. The BMD T-scores decreased significantly with increasing blood lead levels. The BMD T-scores also showed a downward trend with increasing total urinary arsenic levels. The odds ratio (OR) and 95% confidence interval (CI) for bone loss in patients with blood lead levels >57.58 versus 35.74 μg/dL were 1.98 and 1.17–3.34. In addition, the greater the lead or arsenic exposure and alcohol intake was the higher the OR for bone loss with multivariate ORs of 2.57 (95% CI 1.45–4.56) and 2.96 (95% CI 1.67–5.22), respectively. To the best of our knowledge, this study is the first to demonstrate that high total urinary arsenic or blood lead levels and frequent or occasional alcohol consumption had a significant multiplicative interaction for increasing the OR for bone loss.

Adsorption Separation of Arsenic(III) and Arsenic(V) using Functionalized Silica Gels

A method for the adsorption separation of inorganic arsenic species (As(III)/As(V)) using sequentially connected preconcentrating columns filled with functionalized silica gels and their determination by inductively coupled plasma optical emission spectrometry was proposed. As(V) was effectively retained at pH 3.5–6.5 by an adsorbent containing groups of quaternary phosphonium bases on the surface and exhibiting the properties of an anion exchanger. In this pH range, As(III) was not extracted, which made it possible to separate As(V) from As(III). As(III) was retained in a wide pH range of 1–6 by a complexing adsorbent containing mercapto groups on the surface. Adsorbed As(V) was quantitatively eluted from the surface with 1M HNO3, and As(III) – with 5 % unithiol solution in 2M HCl. The use of «non-aggressive» eluents allows us to reuse adsorbents for preconcentration of As(III) and As(V) at least 5 times. The separation efficiency was confirmed by the analysis of model solutions

Elemental and Speciation Analyses of Different Brands of Yerba Mate (Ilex paraguariensis)

In this work, a methodology for determination of As(III), As(V), dimethylarsinic acid (DMA), Fe(II) and Fe(III) in fifty-eight samples (forty-nine products of thirteen brands from three countries) commercial yerba mate (Ilex paraguariensis) was performed. The hyphenated high performance liquid chromatography inductively coupled plasma optical emission spectrometry (HPLC-ICP OES) technique was used. Arsenic was determined below the quantification limit in 38 samples of yerba mate. As(III) was found at the level 0.09 and 0.08 mg kg−1. The As(V) content was in the range: 0.21 to 0.28 mg kg−1. The content of DMA was found the highest of the three arsenic species in the range: 0.21 to 0.47 mg kg−1. The content of Fe(II) and Fe(III) was found in the range: 0.61 to 15.4 mg kg−1 and 0.66 to 43.1 mg kg−1, respectively and the dominance of Fe(III) was observed. Moreover, total and extractable content of 16 elements were determined. The results have been subjected to statistical analysis in order to establish relationships between samples of the same origin (country), kind (type) and composition (purity).