Distribution of arsenic and risk assessment of activities on a golf course fertilised with arsenic-containing Ascophyllum nodosum seaweed

The use of seaweed fertilisers in sports green maintenance has become a common practice across the globe due to its image as an “eco-friendly” alternative to chemical fertilisers. The aim of this study was to characterise the risk of human exposure to arsenic (As), via dermal absorption, from golfing activities on a private golf course in the UK, where As contaminated seaweed fertiliser (~ 100 mg/kg d.wt.) is applied. This was fulfilled by, 1) determining As concentrations in shallow soils with GIS geo-statistical analysis, 2) measuring As concentrations from an on-site borehole groundwater well, and (3) developing a risk assessment calculation for golfing activities based on field and questionnaire data. Total As concentrations in shallow soils were less than the UK threshold for domestic soils, however, frequent and sustained dermal contact between site-users and surface soil attributed to a maximum carcinogenic risk value of 2.75 × 10− 4, which is in the upper limit of the acceptable risk range. Arsenic concentrations in underlying groundwater exceeded the WHO's permissible drinking water standard, demonstrating the risk of groundwater contamination following the application of seaweed fertiliser to golf course soils. This is the first risk study on dermal As absorption via the application of a seaweed fertiliser.

Arsenic Bioaccessibility in Cooked Rice as Affected by Arsenic in Cooking Water

Rice can easily accumulate arsenic (As) into its grain and is known to be the highest As-containing cereal. In addition, the As burden in rice may increase during its processing (such as when cooking using As-polluted water). The health risk posed by the presence of As in cooked rice depends on its release from the matrix along the digestive system (bioaccessibility). Two types of white polished long-grain rice, namely, nonparboiled and parboiled (total As: 202 and 190 mu g As kg(-1), respectively), were cooked in excess of water with different levels of As (0, 10, 47, 222, and 450 mu g As L-1). The bioaccessibility of As from these cooked rice batches was evaluated with an in vitro dynamic digestion process. Rice cooked with water containing 0 and 10 mu g As L-1 showed lower As concentrations than the raw (uncooked) rice. However, cooking water with relatively high As content (>= 47 mu g As L-1) significantly increased the As concentration in the cooked rice up to 8- and 9-fold for the nonparboiled and parboiled rice, respectively. Parboiled rice, which is most widely consumed in South Asia, showed a higher percentage of As bioaccessibility (59% to 99%) than nonparboiled rice (36% to 69%) and most of the As bioaccessible in the cooked rice (80% to 99%) was released easily during the first 2 h of digestion. The estimation of the As intake through cooked rice based on the As bioaccessibility highlights that a few grams of cooked rice (less than 25 g dry weight per day) cooked with highly As contaminated water is equivalent to the amount of As from 2 L water containing the maximum permissible limit (10 mu g As L-1).

Arsenic Contents in Spanish Infant Rice, Pureed Infant Foods, and Rice

It seems there is a positive correlation between rice content and arsenic level in foods. This is of extraordinary importance for infants below 1 y of age because their diet is very limited and in some cases is highly dependent on rice-based products; this is particularly true for infants with the celiac disease because they have no other option than consume gluten-free products, such as rice or corn. Arsenic contents were significantly higher (P <0.001) in gluten-free infant rice (0.057 mg kg-1) than in products with gluten, based on a mixture of cereals (0.024 mg kg-1). Besides, especial precaution must be taken when preparing rice-based products at home, because arsenic content in Spanish rice was high, with levels being above 0.3 mg kg-1 in some cases.

Arsenic Speciation in Food and Estimation of the Dietary Intake of Inorganic Arsenic in a Rural Village of West Bengal, India

Arsenic (As) species were quantified by HPLC-HG-AFS in water and vegetables from a rural area of West Bengal (India). Inorganic species predominated in vegetables (including rice) and drinking water; in fact, inorganic arsenic (i-As) represented more than 80% of the total arsenic (t-As) content. To evaluate i-As intake in an arsenic affected rural village, a food survey was carried out on 129 people (69 men and 60 women). The data from the survey showed that the basic diet, of this rural population, was mainly rice and vegetables, representing more than 50% of their total daily food intake. During the periods when nonvegetarian foods (fish and meat) were scarce, the importance of rice increased, and rice alone represented more than 70% of the total daily food intake. The food analysis and the food questionnaires administrated led us to establish a daily intake of i-As of about 170 mu g i-As day(-1), which was above the tolerable daily intake of 150 mu g i-As day(-1), generally admitted. Our results clearly demonstrated that food is a very important source of i-As and that this source should never be forgotten in populations depending heavily on vegetables (mainly rice) for their diet.

Arsenic biogeochemistry as affected by phosphorus fertilizer addition, redox potential and pH in a west Bengal (India) soil

This laboratory experiment systematically examines arsenic, iron, and phosphorus solubilities in soil suspensions as affected by addition of phosphorus fertilizer under different redox potential (Eh) and pH conditions. Under aerobic conditions, As solubility was low, however, under moderately reducing conditions (0, -150 mV), As solubility significantly increased due to dissolution of iron oxy-hydroxides. Upon reduction to -250 mV, As solubility was controlled by the formation of insoluble sulfides, and as a result soluble As contents significantly decreased. Soluble Fe concentration increased from moderate to highly anaerobic conditions; however, it decreased under aerobic conditions likely due to formation of insoluble oxy-hydroxides. A low pH, 5.5, led to increased soluble concentrations of As, Fe, and P. Finally, addition of P-fertilizers resulted in higher soluble P and As, even though the concentration of As did not increased after an addition rate of 600 mg P kg(-1) soil. (c) 2006 Elsevier B.V. All rights reserved.

Note. Speciation of arsenic in licorice confectionery products and estimation of health risks

Total-arsenic (T-As) and arsenic (As) species were determined by HPLC-HG-AAS in ten different confectionery products: nine throat pearls and an industrial licorice extract. The Spanish legislation sets a maximum total-As content in confectionery products at 0.1 mu g/g. T-As concentrations were above the permitted maximum limit (mean of 0.219 +/- 0.008 mu g/g). All As was present in the form of toxic inorganic species. The daily consumption of licorice-confections in Spain is 1.1 g and leads to a daily intake of inorganic-As of 0.23 mu g (0.2% of the tolerable daily intake of inorganic As for a teenager). These experimental results proved that even though high total-As concentrations were found in licorice throat pearls and that all the As found was present as inorganic species, no significant risks for health are expected just by considering this As source.

Effect of cooking method and rice type on arsenic concentration in cooked rice and the estimation of arsenic dietary intake in a rural village in West Bengal, India

Arsenic (As) contamination of rice plants can result in high total As concentrations (t-As) in cooked rice, especially if As-contaminated water is used for cooking. This study examines two variables: (1) the cooking method (water volume and inclusion of a washing step); and (2) the rice type (atab and boiled). Cooking water and raw atab and boiled rice contained 40 g As l-1 and 185 and 315 g As kg-1, respectively. In general, all cooking methods increased t-As from the levels in raw rice; however, raw boiled rice decreased its t-As by 12.7% when cooked by the traditional method, but increased by 15.9% or 23.5% when cooked by the intermediate or contemporary methods, respectively. Based on the best possible scenario (the traditional cooking method leading to the lowest level of contamination, and the atab rice type with the lowest As content), t-As daily intake was estimated to be 328 g, which was twice the tolerable daily intake of 150 g.

Contribution of water and cooked rice to an estimation of the dietary intake of inorganic arsenic in a rural village of West Bengal, India

Arsenic contamination of rice plants by arsenic-polluted irrigation groundwater could result in high arsenic concentrations in cooked rice. The main objective of the study was to estimate the total and inorganic arsenic intakes in a rural population of West Bengal, India, through both drinking water and cooked rice. Simulated cooking of rice with different levels of arsenic species in the cooking water was carried out. The presence of arsenic in the cooking water was provided by four arsenic species (arsenite, arsenate, methylarsonate or dimethylarsinate) and at three total arsenic concentrations (50, 250 or 500 mu g l(-1)). The results show that the arsenic concentration in cooked rice is always higher than that in raw rice and range from 227 to 1642 mu g kg(-1). The cooking process did not change the arsenic speciation in rice. Cooked rice contributed a mean of 41% to the daily intake of inorganic arsenic. The daily inorganic arsenic intakes for water plus rice were 229, 1024 and 2000 mu g day(-1) for initial arsenic concentrations in the cooking water of 50, 250 and 500 g arsenic l(-1), respectively, compared with the tolerable daily intake which is 150 mu g day(-1).

Effect of two different rice dehusking procedures on total arsenic concentration in rice

Pollution of subterranean water by arsenic (As) in Asia has resulted in the worst chemical disaster in human history. For populations living on subsistence rice diets, As contamination of rice grain contributes greatly to dietary As exposure. The main objectives of this study were to compare two dehusking processes: (a) wet process (soaking of rice, boiling and mechanical hulling) and (b) dry process (mechanical hulling), and recommend the method leading to a lower As content in commercial rice. In general, hulling of paddy rice (373 mu g As kg(-1)) significantly decreased As content in rice grain (311 mu g As kg(-1)). The final As concentrations in boiled rice (final product of the wet process) and atab rice (dry process) were 332 and 290 mu g kg(-1). Thus, the dry method is recommended for dehusking paddy rice if not As-free water is available. However, villagers can reduce the As content in the wet system by discarding the soaking water and using new water for the light boiling. Finally, it is not recommended to use rice husk for feeding animals because the As concentration is very high, approximately 1,000 mu g As kg(-1).

Application of colloidal gas aphron suspensions produced from Sapindus mukorossi for arsenic removal from contaminated soil

Colloidal gas aphron dispersions (CGAs) can be described as a system of microbubbles suspended homogenously in a liquid matrix. This work examines the performance of CGAs in comparison to surfactant solutions for washing low levels of arsenic from an iron rich soil. Sodium Dodecyl Sulfate (SDS) and saponin, a biodegradable surfactant, obtained from Sapindus mukorossi or soapnut fruit were used for generating CGAs and solutions for soil washing. Column washing experiments were performed in down-flow and up flow modes at a soil pH of 5 and 6 using varying concentration of SDS and soapnut solutions as well as CGAs. Soapnut CGAs removed more than 70% arsenic while SDS CGAs removed up to 55% arsenic from the soil columns in the soil pH range of 5–6. CGAs and solutions showed comparable performances in all the cases. CGAs were more economical since it contains 35% of air by volume, thereby requiring less surfactant. Micellar solubilization and low pH of soapnut facilitated arsenic desorption from soil column. FT-IR analysis of effluent suggested that soapnut solution did not interact chemically with arsenic thereby facilitating the recovery of soapnut solution by precipitating the arsenic. Damage to soil was minimal arsenic confirmed by metal dissolution from soil surface and SEM micrograph.

Urinary excretion of arsenic following rice consumption

Patterns of arsenic excretion were followed in a cohort (n = 6) eating a defined rice diet, 300 g per day d.wt. where arsenic speciation was characterized in cooked rice, following a period of abstinence from rice, and other high arsenic containing foods. A control group who did not consume rice were also monitored. The rice consumed in the study contained inorganic arsenic and dimethylarsinic acid (DMA) at a ratio of 1:1, yet the urine speciation was dominated by DMA (90%). At steady state (rice consumption/urinary excretion) similar to 40% of rice derived arsenic was excreted via urine. By monitoring of each urine pass throughout the day it was observed that there was considerable variation (up to 13-fold) for an individual's total arsenic urine content, and that there was a time dependent variation in urinary total arsenic content. This calls into question the robustness of routinely used first pass/spot check urine sampling for arsenic analysis. (C) 2014 Elsevier Ltd. All rights reserved.

Improved diffusive gradients in thin films (DGT) measurement of total dissolved inorganic arsenic in waters and soils using a hydrous zirconium oxide binding layer

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A high-capacity diffusive gradients in thin films (DGT) technique has been developed for measurement of total dissolved inorganic arsenic (As) using a long shelf life binding gel layer containing hydrous zirconium oxide (Zr-oxide). Both As(III) and As(V) were rapidly accumulated in the Zr-oxide gel and could be quantitatively recovered by elution using 1.0 M NaOH for freshwater or a mixture of 1.0 M NaOH and 1.0 M H2O2 for seawater. DGT uptake of As(III) and As(V) increased linearly with deployment time and was independent of pH (2.0–9.1), ionic strength (0.01–750 mM), the coexistence of phosphate (0.25–10 mg P L–1), and the aging of the Zr-oxide gel up to 24 months after production. The capacities of the Zr-oxide DGT were 159 μg As(III) and 434 μg As(V) per device for freshwater and 94 μg As(III) and 152 μg As(V) per device for seawater. These values were 5–29 times and 3–19 times more than those reported for the commonly used ferrihydrite and Metsorb DGTs, respectively. Deployments of the Zr-oxide DGT in As-spiked synthetic seawater provided accurate measurements of total dissolved inorganic As over the 96 h deployment, whereas ferrihydrite and Metsorb DGTs only measured the concentrations accurately up to 24 and 48 h, respectively. Deployments in soils showed that the Zr-oxide DGT was a reliable and robust tool, even for soil samples heavily polluted with As. In contrast, As in these soils was underestimated by ferrihydrite and Metsorb DGTs due to insufficient effective capacities, which were likely suppressed by the competing effects of phosphate.

Localized Flux Maxima of Arsenic, Lead, and Iron around Root Apices in Flooded Lowland Rice

In wetland-adapted plants, such as rice, it is typically root apexes, sites of rapid entry for water/nutrients, where radial oxygen losses (ROLs) are highest. Nutrient/toxic metal uptake therefore largely occurs through oxidized zones and pH microgradients. However, the processes controlling the acquisition of trace elements in rice have been difficult to explore experimentally because of a lack of techniques for simultaneously measuring labile trace elements and O2/pH. Here, we use new diffusive gradients in thin films (DGT)/planar optode sandwich sensors deployed in situ on rice roots to demonstrate a new geochemical niche of greatly enhanced As, Pb, and Fe(II) mobilization into solution immediately adjacent to the root tips characterized by O2 enrichment and low pH. Fe(II) mobilization was congruent to that of the peripheral edge of the aerobic root zone, demonstrating that the Fe(II) mobilization maximum only developed in a narrow O2 range as the oxidation front penetrates the reducing soil. The Fe flux to the DGT resin at the root apexes was 3-fold higher than the anaerobic bulk soil and 27 times greater than the aerobic rooting zone. These results provide new evidence for the importance of coupled diffusion and oxidation of Fe in modulating trace metal solubilization, dispersion, and plant uptake.

Production of porous aluminium and iron sulphated oxyhydroxides using industrial grade coagulants for optimised arsenic removal from groundwater

The optimisation of Fe and Al oxyhydroxide materials produced using industrial grade coagulants is presented in this work. The effects of synthesis pH and post-synthesis washing procedure onto the arsenic adsorption capacity of the materials were investigated. It was shown that the materials produced at higher pH were more efficient in removing As(V), especially after cleaning procedure. The materials produced at lower pH were less efficient in removing As(V) but the higher presence of sulphate groups in the materials produced at lower pH enhanced As(III) adsorption. Most performing materials can remove up to 84.7 mg As(V) g^-1 or 77.9 mg As(III) g^-1.