Microcystins cause embryonic toxicity in mice.

Microcystins produced by freshwater cyanobacteria are potent hepatotoxins and can cause animal intoxications and human illnesses. In the present study, the effects of microcystins on the embryonic development of Kunming mice were determined using cell extracts of Microcystis aeruginosa from the Nanwan reservoir, China. Forty-eight pregnant mice were divided into four groups of 12 mice. Pregnant mice in three experimental groups were injected intraperitoneally with cell extracts at doses equivalent to 3, 6, or 12 microg microcystins/kg body weight daily from gestational days 6-15, while the mice in the control group were injected on the same schedule with sterilized saline. Mice were killed on the 18th day of gestation and embryonic and fetal developmental indexes checked. The fetal mice were also examined for anomalies of external, skeletal, and internal organs. The results demonstrated a significant decrease in body weight gain of pregnant mice in the 12 microg/kg dose group when compared to the control group (p<0.05). Differences in mean body weight, body length, and tail length of the fetuses were also found in these two groups (p<0.05). However, no significant difference in these characteristics was detected in the 6 or 3 microg/kg dose groups when compared to the control group (p>0.05). Four fetuses in the 6 microg/kg body dose group were found to have a curving tail. Additionally, petechial hemorrhage and hydropic degeneration were observed in the livers of fetuses in the 6 and 12 microg/kg experimental groups. These results suggested that microcystins had both maternal and embryonic toxicity in mice.

Chromium level and intake from Chinese made tea.

Tea is a popular drink around the world. It is also one of the sources of metal intake. The objectives of this study were to assess chromium (Cr) intake from popular green, oolong, black and Pu-erh tea. In total, 128 Chinese made teas were analysed and concentration differences among four types of tea were explored. Black tea contained highest total Cr, which varied between 0.63 and 17.60 mg/kg. The lowest content was found in the green tea samples, between 0.26 and 1.30 mg/kg. Cr(III) and Cr(VI) in black tea were higher than in other types of tea. Cr(III), Cr(VI) and total Cr concentration in different tea infusions were also analysed. The results suggest that drinking tea is an effective way for Cr intake and the risk of adults and children being chronically intoxicated by tea infusions is low.