Concentrations of total and inorganic arsenic were determined in 180 samples of polished and brown rice of three rice types, namely white, jasmine, and sticky, and 44 samples of rice bran from these three rice types purchased in Thailand. Concentrations (expressed in nanograms per gram) of inorganic arsenic in polished white, jasmine, and sticky rice were 68.3 ± 17.6 (with a range of 45.0 to 106), 68.4 ± 15.6 (41.7 to 101), and 75.9 ± 24.8 (43.5 to 156), respectively, while those in the three brown rice samples were 124 ± 34.4 (74.5 to 193), 120 ± 31.6 (73.1 to 174), and 131 ± 35.6 (78.0 to 188), respectively. Inorganic arsenic concentrations (expressed in nanograms per gram) in rice bran produced from the three rice types were 633 ± 182 (375 to 919), 599 ± 112 (447 to 824), and 673 ± 195 (436 to 1,071), respectively. Rice bran contained concentrations of total and inorganic arsenic approximately seven and nine times higher, respectively, than those found in the corresponding polished rice. The levels of inorganic arsenic in the three rice types of both polished and brown rice were within the only published regulatory limit of 200 ng/g.

Concentrations of aflatoxin M1 (AFM1) were determined in 150 pasteurized milk samples from the School Milk Project in Thailand. Milk samples were collected from 50 schools in the Central region of Thailand in three seasons: summer (May to June 2006), the rainy season (August to September 2006), and winter (December 2006 to January 2007). AFM1 was isolated by using an immunoaffinity column and quantified by high-performance liquid chromatography. All of the 150 pasteurized milk samples were contaminated with AFM1, and the concentrations were within the U.S. regulatory limit of 0.5 microg/liter. The highest concentration of AFM1 found in school milk samples was 0.114 microg/liter. The mean concentration of AFM1 in milk samples collected in winter was significantly higher than the mean concentrations found in the rainy season and summer. Further monitoring of school milk to evaluate the status of contamination of AFM1 is necessary, with a special emphasis on samples collected in the rainy season and winter. Thailand is one of several countries that have no regulatory limits for AFM1 in milk and milk products. The results of this study suggest that safety limits for AFM1 are needed for regulating and ensuring the quality of milk and milk products in Thailand.

Aflatoxin M(1) (AFM(1)) was found in all of the 240 raw milk samples collected from milk tanks of 80 dairy farms at a collecting center in the central region of Thailand. Milk samples from individual farms were collected in three seasons. The average concentration of AFM(1) in milk samples collected in winter (0.089 +/- 0.034 microg/L) was significantly higher than those in rainy season (0.071 +/- 0.028 microg/L) and summer (0.050 +/- 0.021 microg/L). The present study suggests that regulatory limits for AFM(1) are needed to regulate and ensure the quality of raw milk and milk products in Thailand.

The arsenic accumulation in rhizomes of Zingiberaceous plants was determined by atomic absorption spectrometry interfaced with hydride generation system (HG-AAS). The raw herbal materials, rhizomes, were collected from different regions of Thailand between December 2011 and January 2012. Six well-known Zingiberaceous plants, 16 samples from each and a total of 96 samples, were analyzed Alpinia galanga (Khaa), Boesenbergia rotunda (Kra-chaai), Curcuma longa (Khamin-chan), Curcuma zedoaria (Khamin-oi), Zingiber cassumunar (Plai) and Zingiber officinale (Ginger). Concentrations of total arsenic based on dry weight were 92.4 ± 9.2, 103.5 ± 20.8, 61.7 ± 12.5, 89.8 ± 17.5, 106.7 ± 19.5 and 69.3 ± 11.8 ng/g, respectively and inorganic arsenic were 48.8 ± 7.0, 66.3 ± 12.7, 25.5 ± 5.0, 38.7 ± 4.7, 71.2 ± 11.6, and 38.5 ± 5.5 ng/g, respectively. Among these, Plai and Kra-chaai exhibited the highest levels of total arsenic and inorganic arsenic accumulation that remind consumers to be aware of excess consuming of these rhizomes. On the contrary, the lowest value found in Khamin-chan indicating natural dietary supplements and herbal medicines comprising Kamin-chan are safe from arsenic poison. All investigated amounts of total and inorganic arsenic were much lower than limits recommended by Thai Food and Drug Administration.

Concentrations of seven heavy metals were determined in green mussels (Perna viridis) collected between April and June 1995 from eight locations along the costal area of the Gulf of Thailand. The average concentrations (n = 96) of the heavy metals detected in mussel samples, on the basis of dry weight, were 1.20 mg kg-1 cadmium, 0.78 mg kg-1 for chromium, 9.85 mg kg-1 for copper, 1.09 mg kg-1 for lead 2.78 mg kg-1 for manganese, 1.54 mg kg-1 for nickel, and 94,48 mg kg-1 for zinc. The levels of cadmium, chromium, nickel, and lead found in green mussels from four locations in the Upper Gulf were significantly (P < 0.05) higher than those detected in mussels from four locations in the Lower Gulf, while the levels of copper, manganese, and zinc did not differ significantly (P > 0.05) between the Upper and Lower Gulf. Comparison with earlier studies revealed that the concentrations of some metals in the mussels collected from the Upper Gulf are increasing. The concentrations of heavy metals in green mussels from the Gulf of Thailand were within acceptable levels for human consumption.