Perfluorinated compounds, especially Perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS), are widely detected in water environments in China. Considering the potential health risks of drinking water exposure routes, PFOA and PFOS have been added to the water quality reference index of the newly issued "Standards for Drinking Water Quality (GB5749-2022)", with limit values of 40 and 80 ng/L, respectively. This study analyzed and discussed the relevant technical contents for determining the limits of the hygiene standard, including the environmental existence level and exposure status of PFOA and PFOS, health effects, derivation of safety reference values, and determination of hygiene standard limits. It also proposed prospects for the future direction of formulating drinking water standards.
Humans ; Water Quality ; Drinking Water ; Fluorocarbons/analysis* ; Caprylates/analysis* ; China ; Water Pollutants, Chemical/analysis*

BACKGROUND/AIMS: Lack of simple and repeatable tests hampers gastric emptying studies in rats. The aim of this study was to adapt the 14C-octanoate solid gastric emptying breath test for application in rats, and to validate it against radioscintigraphic method. METHODS: After ingestion of a meal containing 3 mCi 99mTc and 2 microCi 14C-octanoate, 23 male Wistar rats were placed on a gamma camera in a airflow container. Scintigraphic images were taken at regular intervals. The amount of 14CO2 in a regularly replaced hyamine hydroxide solution, capturing CO2 in the outflow air, was counted using liquid scintillation spectrometry. 99mTc gastric retention curves and 14CO2-excretion curves were fitted to their respective data. Three rats underwent the same procedures after administration of atropine. RESULTS: Overall Tr10% (time at which 10% of the original amount of 99mTc remained in the stomach) was 355 +/- 64 minutes; Te90% (time at which 90% of total amount of 14CO2 was excreted) was 325 +/- 106 minutes. Their correlation coefficient was 0.71, R-square 0.50 and P < 0.005. Tr1/2 (50% of original amount of 99mTc remained) was 124 +/- 28 minutes; Te1/2 (50% of total amount of 14CO2 excreted) 114 +/- 32 minutes. Their correlation coefficient was 0.83 with R-square of 0.69 and P < 0.00005. In 12 immobilized animals correlation was even better: correlation coefficient 0.84; R-square 0.71 and P < 0.001 (Tr10% was 388 +/- 117 minutes; Te90% 532 +/- 219 minutes; Tr1/2 of 165 +/- 54 minutes; Te1/2 of 175 +/- 67 minutes). Atropine significantly lengthened all emptying times: 904 +/- 307 and 1461 +/- 684 minutes for Tr10% and Te90%, respectively; and 432 +/- 117 minutes for Tr1/2 and 473 +/- 190 minutes for Te1/2. CONCLUSIONS: We adapted and validated the 14C-octanoate gastric emptying breath test for application in rats.
Animals ; Atropine ; Benzethonium ; Breath Tests ; Caprylates ; Eating ; Gamma Cameras ; Gastric Emptying ; Humans ; Hydroxides ; Male ; Meals ; Rats ; Rats, Wistar ; Retention (Psychology) ; Spectrum Analysis