Survey of arsenic content in edible seaweeds and their health risk assessment.

Since humans are especially sensitive to arsenic exposure, predominantly through diet, a strict control of the most widely consumed seaweeds is mandatory. Total arsenic contents and arsenic species in twenty-five different seaweeds from five different origins were studied. Seaweeds selected, included Phaeophyta (brown seaweed), Chlorophyta (green seaweed) and Rhodophyta (red seaweed) genera. The highest arsenic content appears in the Phaeophyta seaweed in the range from 11 to 162 mg kg-1 dried weight. Arsenosugars were found to be the predominant species of arsenic in most seaweeds, being up to 99.7% of total arsenic in some samples. The arsenic dietary intakes for seaweeds studied were assessed and the Target Hazard Quotients (THQ) and the Target Cancer Risk (TCR) were calculated, taking into account inorganic arsenic contents (iAs). iAs species in seaweeds showed low risk of arsenic intake except for Hizikia fusiforme samples.

Assessment of arsenic bioaccessibility in raw and cooked edible mushrooms by a PBET method.

The present study reports arsenic analysis in Lentinula edodes, Agaricus bisporus and Pleurotus ostreatus before and after being cooked. Furthermore, arsenic in raw and cooked mushroom was determined in the gastric and gastrointestinal bioaccessible fractions obtained after simulating human digestion by means of an in vitro physiologically based extraction test (PBET). Several certified reference materials (SRM 1568a, SRM 1570a, CRM 7503-a, BC211 and IPE-120) were analysed to evaluate the proposed methods. Total arsenic content was 1393, 181 and 335µgAskg(-1) for L. edodes, A. bisporus and P. ostreatus, respectively, and decreased by between 53% and 71% in boiled mushroom and less than 11% in griddled mushroom. High bioaccessibility was observed in raw, boiled and griddled mushroom, ranging from 74% to 89% and from 80% to 100% for gastric and gastrointestinal extracts, respectively, suggesting the need to consider the potential health risk of consumption of the mushrooms analysed.

Assessment of extractants for the determination of thallium in an accidentally polluted soil.

Thallium is a rare and easily dispersed element with high toxicity to organisms. Relatively high levels of thallium (approximately 9.58 mg kg(-1)) had been found in aqua regia soil extract of an accidentally polluted soil from south of Spain. To assess the available and leachable portions of thallium in the polluted soil, single and sequential extraction procedures have been utilized. Further, X-ray diffraction and scanning electron microscopic studies have also been used to find out the mineral phases. The amount of thallium extracted by the extracting agents in comparison to aqua regia, as well as the different phase associations are discussed.