ABSTRACT
This study developed the 2-step extraction method which eluted the Pb adsorbing on the surface of sediments in the first solution by aqua regia and extracted the Pb absorbed inside particles into the second solution by mixed acid of nitric acid, hydrofluoric acid and hydrogen peroxide solution. We applied the method to sediments in the enclosed water area and found out that the isotope ratios of Pb in the second solution represented those of natural origin. This advantage of the method makes it possible to distinguish the Pb between natural origin and anthropogenic source on the basis of the isotope ratios. The results showed that the method was useful to discuss the Pb sources and that anthropogenic Pb in the sediment samples analysed was mainly derived from China because of transboundary air pollution.
Subject(s)
Geologic Sediments , Lead , China , Environmental Monitoring , IsotopesABSTRACT
After the severe accident at the Fukushima-1 Nuclear Power Plant in March 2011, radioactive contamination of food has become a matter of serious concern in Japan. There is considerable information about radioactive iodine and cesium, but little is known about uranium contamination. We determined uranium content in spinach by the Japanese official method (Manual on Radiation Measurement of Food in Emergency Situations). In the preliminary study, we confirmed that the use of a microwave digestion system for preparing the test solution of spinach could shorten the testing time and give acceptable results. The manual recommends the use of two elements (Tl and Bi) as internal standards for measurement of uranium by ICP-MS. We found that Tl was more suitable than Bi to quantify trace amounts of uranium in spinach. However, it was necessary to determine Tl or Bi concentrations in the sample before analysis, since some samples of spinach contained significant amounts of these elements. The uranium contents of 9 spinach samples bought in April and May 2011 were less than 10 µg/kg, which are very low compared to the provisional regulatory limit in Japan.
Subject(s)
Food Analysis/methods , Food Contamination, Radioactive/analysis , Food Safety/methods , Food/standards , Mass Spectrometry/methods , Spinacia oleracea/chemistry , Uranium/analysis , Food Analysis/instrumentation , Fukushima Nuclear Accident , Microwaves , Radioactive Hazard Release , Time FactorsABSTRACT
Waste on the roadside, 'poi-sute' waste, was collected in a typical suburb in Japan (Ueda city, the sampling course: 3.2 km). The distribution, characterization of the 'poi-sute' waste and the loading of pollutants from the waste were studied. The average number of pieces of total waste was 690 pieces a month, and 220 pieces of waste were dumped a month per km. There was a tendency for much waste to be discarded around shops staying open until late at night. Regarding the sorts of the waste, cigarette butts are the most prevalent (the average was 150 cigarette butts/km/mo), and second was plastic materials. As for the weight, cigarette butts, plastics and papers were at a similar level (about 90 g/km/mo). The elution of arsenic (0.041 mg/L) and nicotine (3.8 mg/L) was ascertained by a dissolution test of 'poi-sute' cigarette butts obtained by sampling. Furthermore, the loading of heavy metals, such as lead, copper, chromium and cadmium, and polycyclic aromatic hydrocarbons (PAHs) from cigarette butts into the environment was confirmed. The load potentials of heavy metals were 0.020-1.7 mg/km/mo, and that of total-polyaromatic hydrocarbons was 0.032 mg/km/mo. These results indicate that the 'poi-sute' waste has a harmful influence on the environment.
