Safety Evaluation of Heavy Metal Contamination and Pesticide Residues in Coix Seeds in Guizhou Province, China.

The coix seed is a medicinal and edible plant with rich nutritional and medicinal values. With the expansion of the coix seed consumption market, the problem of coix seed safety has attracted attention worldwide. The aims of this work were to evaluate the contamination of mercury (Hg), lead (Pb), cadmium (Cd), arsenic (As), chromium (Cr) and 116 pesticides in coix seeds collected from 12 main producing regions of coix seeds in the Guizhou Province of China and to analyze the major contributors of heavy metal and pesticide contamination in coix seed. The results show that the average contents of Pb, Cd, As and Cr in the 123 coix seed samples were 0.0069, 0.0021, 0.0138 and 0.1107 mg/kg, respectively, while Hg was not detected in all coix seed samples. Among the five heavy metals detected, only the Cr contents of three samples were found to be higher than the contaminant limit of Chinese standard GB2762-2017 (CSGB). A total of 13 pesticides were detected in 29 samples from seven main production regions of coix seeds, accounting for 23.6% of all the samples. The detection rates of chlorpyrifos were the highest (8.13%), followed by fenpropathrin (4.06%), bifenthrin (2.43%) and phoxim (1.62%), while the detection rates of the remaining pesticides were below 1%. Moreover, the residual risk score of dichlorvos was the highest of all the pesticides detected. The pollution index and risk assessment of heavy metals and pesticide residues indicates that coix seeds were at safe levels for consumption. In the production process of coix seeds, the local government should control the soil in areas heavily polluted by heavy metals and strengthen the monitoring and guidance on the scientific and rational use of pesticides.

Adsorption behavior and performance of ammonium onto sorghum straw biochar from water.

Sorghum has been widely used for liquor production and brewing, but how to make efficiently utilize sorghum straw (SS) has become an urgent problem. Meanwhile, the wastewater produced by winemaking is typical organic wastewater with a high ammonium concentration. To solve the problem of resource utilization of SS and remove ammonium from water, SS was used to prepare biochar as an adsorbent for ammonium adsorption. Batch adsorption experiments were carried out to study the influencing factors and adsorption mechanisms of ammonium onto sorghum straw biochar (SSB). The results showed that the adsorption capacity of SSB was much higher than that of SS. The SSB pyrolyzed at 300 °C had the highest adsorption capacity. The favorable pH was 6-10, and the optimal dosage was 2.5 g/L. The adsorption process and behavior conformed to the pseudo-second-order kinetic and Langmuir isotherm adsorption models. The maximum ammonium adsorption capacity of SSB at 45 °C was 7.09 mg/g, which was equivalent to 7.60 times of SS. The ammonium adsorption of SS and SSB was mainly chemical adsorption. The regeneration test indicated that SSB had good regeneration performance after three adsorption-regeneration cycles. This work suggests that SSB could be potentially applied to sewage treatment containing ammonium to achieve the purpose of resource recycling.

Tibetan patients with essential hypertension caused by underlying oxidative metabolism dysfunction and depressed nitric oxide synthesis.

OBJECTIVE: To assess the role of oxidative metabolism and nitric oxide synthesis for elucidating their pathophysiological mechanisms in a Tibetan patient with essential hypertension. METHODS: The serum levels of total superoxide dismutase (T-SOD), malondialdehyde (MDA), total antioxidant capacity (T-AOC), nitric oxide (NO) and nitric oxide synthase (NOS) were assayed in sixty native Tibetans (thirty hypertensive patients and thirty healthy volunteers as control). RESULTS: The levels of T-SOD, T-AOC, NO and NOS were significantly lower in the patient group than in the control group (P < 0.01); MDA was significantly higher in the patient group than in the control group (P < 0.01). The level of MDA had a strong negative correlation with T-SOD, T-AOC, NO and NOS (r = -0.82, -0.76, -0.79, -0.73, respectively, P < 0.001 for all). CONCLUSION: Tibetan patients with essential hypertension (EH) may have underlying oxidative metabolism dysfunction and depressed NO synthesis, both responsible for the hypertensive process.