In our previous investigation of dietary intake of chlordane (CHL), it was found that foods prepared in the houses which had undergone termite treatment were contaminated with CHL at levels 2 to 20 times higher than foods cooked in non-treated houses. Moreover, the pattern of 6 CHL components detected in foods from treated houses was very specific, indicating fresh contamination with technical CHL. Focusing on these results, further investigations were carried out in order to clarify the route of human exposure in the treated houses. Polished rice was left exposed to the air for 7 days under the sink in the kitchen of 3 treated houses. A high concentration of CHL (0.34ppm) was detected in the sample from the house which had been treated about one year before. In this house, the major route of dietary intake of CHL was inferred to be polished rice. The clearance rate of CHL from polished rice during cooking was found to be 64 percent overall. Fifty-two percent of the decrease was due to washing and 12 percent was due to boiling of the rice. Levels of atmospheric CHL in the treated houses varied over a wide range even at the same duration after termite control. In the house which gave the polished rice with 0.34ppm of CHL, however, atmospheric CHL under the sink was also very high compared to 4 other treated houses examined. CHL was not detected in air samples from non-treated houses. In the non-treated houses, fishes were the main source of human exposure to chlordane, as in the cases of PCB and DDT complex. On the other hand, rice and the inhalation of atmospheric CHL are the two major sources of human exposure in treated houses, and the exposure level through the former route is inferred to be almost the same as that of the latter or even a little higher, when the rice was stored under the sink in the kitchen or under the floor. Daily intakes of CHL in the treated houses were evaluated in comparison with the value of acceptable daily intake (ADI) proposed by FAO/WHO. Measures for the prevention of CHL exposure of humans in treated houses have also been suggested.
A new method to determine both sodium chlorite and sodium hypochlorite in mixtures of the two by two-step iodometry is described. When hypochlorite reacts with potassium iodide in the presence of sodium bicarbonate, iodine is liberated immediately. In the case of chlorite, however, the reaction does not proceed under these conditions. Therefore, at the first step, sodium hypochlorite is analyzed quantitatively by sodium thiosulfate titration in the test solution containing sodium bicarbonate and at the second step, after the addition of sulfuric acid solution, sodium chlorite is titrated. When determination of sodium chlorite and sodium hypochlorite was carried out by this method, the data were reproducible to less than ±5% on repeated runs. This method can be adapted for automatic potentiometric titration, and is simple, rapid and accurate. It should be useful for the determination of both food additives.
An analytical method for metolachlor in vegetables, potatoes and grains was developed by using a gas chromatograph with an electron capture detector (ECD-GC). Metolachlor was extracted from the sample with acetone, and purified by acetonitrile-hexane partition and a coagulating method after evaporation of the acetone. The extract was cleaned up by bi-layer (upper; silica gel, lower; 5% water-impregnated Florisil) column chromatography, and on a Sep-Pak C18 cartridge. The purified extract was measured by means of ECD-GC. Two samples (radish and sweet potato) could be cleaned up by bi-layer column chromatography alone. The recoveries of metolachlor from agricultural products spiked at the level of 0.1ppm were 87.0-94.8%. The detection limit of metolachlor was 0.005ppm in each sample. Metolachlor was not detected in vegetables, potatoes or grains in this study (total 30 samples).
An ion chromatographic method is described for the determination of inorganic bromides in Food Red No. 104 (R104; C.I. 45410, C.I. Acid Red 92). Conductivity detection under acidic solvent conditions (2.5mM phthalic acid and 2.4mM tris (hydroxymethyl) aminomethane) was chosen from the viewpoint of sensitivity (determination limit: 0.5ppm). The bromide ion was separated satisfactorily on a column of Shim-pack IC-Al with a guard columm of Shim-pack IC-GAl at a flow rate of 1.5ml/min at 40°C and the recovery of NaBr (0.0644mg) added to R104 standard (100mg) was 101.5%. Then, thirty-nine commercial samples of R104 made in Japan were analyzed by this method. All of the commercial R104 samples contained inorganic bromides above 0.01% (calculated as NaBr) and the highest and average contents were 0.329 and 0.159%, respectively. The bromide content average classified according to manufacturer showed large differences, taking account of the standard deviations. Since we observed an increase of inorganic bromides in a solution of R104 after storage without shielding from light, the differences might derive from the manufacturing conditions used by each maker during the synthesis of R104.