Cyanobacterial toxins may pose a threat to human health through drinking water and recreational water exposure. The official guideline limits of cyanobacterial toxins have not been established. The human health effects, exposure routes, possible guideline limits and calculation method were introduced in the present paper. The knowledge will provide a base to undertake risk management for the toxins and will also contribute to establishing official guideline limits of cyanobacterial toxins in water and will be benefit for ensuring the safety of drinking water.

Objective To investigate the relationship among Helicobacter pylori (Hp) infection, serum gastrin level and colorectal carcinoma. Methods Fasting serum samples from 47 consecutive patients with colorectal carcinoma and 30 demoographically matched colonoscopy-negative controls were detected for serum gastrin levels and IgG antibodies against Hp (Hp IgG) by enzyme linked immunosorbent assay. Some of them accepted 14C urease breath test and/or rapid urease test after undergoing endoscopy. Hp infection was affirmed when at least two of the three tests were positive. Results The Hp infection incidence was significantly higher in patients with eoloreetal carcinoma (61.7%, 29/47) as compared with controls (36.7%, 11/30) (P<0.05). The Hp infection incidence in distal distribution of carcinoma was higher than that in controls, and in female carcinoma was higher than that in female controls(P <0.05). Mean fasting serum gas-trin levels were significantly higher in patients with coloreetal carcinoma[(139.7±53.3 ) ng/L]than those in controls [(89.5±26.1 ) ng/L] (P < 0.01 ). There was a significant association between hypergastrinemia and distal distribution of carcinoma. Conclusion Increasing serum gastrin levels, higher Hp infection incidence has a positive relationship with colorectal carcinoma.

Background The Qingcaosha Reservoir is facing issues of algal blooms and eutrophication, and the resulting increase in the level of chlorination disinfection by-products in the water has been a major concern. Objective To evaluate the impact of "Algae Monitoring and Control Program in Qingcaosha Reservoir" (hereinafter referred to as the program) on the control of trihalomethanes (THMs) in conventional finished water. Methods From 2011 to 2019, water samples were collected from the Lujiazui Water Plant once per season, one sample each time, and the concentrations of four THMs (trichloromethane, dichlorobromomethane, monochlorodibromomethane, and tribromomethane) were measured in the samples. Using 2014 when the program was implemented as a cut-off point, the entire study period was divided into two phases: pre-implementation (2011–2013) and post-implementation(2014–2019). Segmented linear regression with interrupted time series analysis was applied to assess the concentrations and trends of THMs in the finished water before and after the program launch. Results The concentration of total THMs in finished water increased by 1.561 µg·L⁻¹ (P=0.010) for each season of time extension before launching the program. The change in the concentration of total THMs in finished water was not statistically significant after the program launch, but the THMs concentration showed a decreasing trend as the slope was −0.626 (P=0.001). From 2017 until the end of 2019, the average concentration of THMs in finished water of Lujiazui Water Plant dropped to 10 μg·L⁻¹ or less. Conclusions The algae and eutrophication control measures in Qingcaosha Reservoir have achieved good results, controlling THMs in finished water at a low level, and the trend of THMs has changed from a yearly increase pattern before the program to a yearly decrease pattern after the program.

Objective To explore PM_2.5 concentration modeling and prediction based on the monthly average concentrations of PM_2.5 in Shanghai since 2015, and to provide new ideas about PM_2.5 prediction methods. Methods The seasonal factors were introduced into the Grey Model (GM). GM(1,1) model modified with seasonal factors was established and compared with seasonal autoregressive integrated moving average model (ARIMA) model. The data of 2015-2021 was used for modeling and prediction, and the data from January to October in 2022 was used as a validation set to evaluate the prediction effectiveness. The monthly average PM_2.5 concentrations in Shanghai from November to December in 2022 were predicted. Results Seasonal ARIMA model showed RMSE=4.02 and MAPE=15.50% in the validation set, while GM(1,1) model modified with seasonal factors showed RMSE=3.30 and MAPE=11.59%. GM(1,1) model modified with seasonal factors predicted the monthly average PM_2.5 concentrations in Shanghai from November to December in 2022 to be 24.99 and 34.83μg/m3, respectively. Conclusion The prediction effect of GM(1,1) model modified with seasonal factors has better predictive performance than seasonal ARIMA model. The grey prediction model modified with seasonal factors can be considered when predicting seasonal time series such as the concentration of PM_2.5.

OBJECTIVERisk assessment and risk control for occupational exposure to chemical toxicants were performed on an isophorone nitrile device with an annual production of 5,000 tons, based on improved Singaporean semi-quantitative risk assessment method, with consideration of actual situation in China and in the present project.

METHODSWith the use of engineering analysis and identification of occupational hazards in the improved Singaporean semi-quantitative risk assessment method, hazard rating (HR) and risk assessment were performed on chemical toxicants from an isophorone nitrile device with an annual production of 5,000 tons.

RESULTSThe chemical toxicants in the isophorone nitrile device were mainly isophorone, hydrocyanic acid, methanol, phosphoric acid, sodium hydroxide, and sodium cyanide; the HR values were mild hazard (2), extreme hazard (5), mild hazard (2), mild hazard (2), moderate hazard (3), and extreme hazard (5), respectively, and the corresponding exposure rating (ER) values were 2.09, 2.72, 2.76, 1.68, 2.0, and 1.59, respectively. The risk of chemical toxicants in this project was assessed according to the formula Risk = [HR×ER](1/2). Hydrocyanic acid was determined as high risk, sodium hydroxide and sodium cyanide as medium risk, and isophorone, methanol, and phosphoric acid as low risk. Priority in handling of risks was determined by risk rating. The table of risk control measure was established for pre-assessment of occupational hazards.

CONCLUSIONWith risk assessment in this study, we concluded that the isophorone nitrile device with 5,000 ton annual production was a high-occupational hazard device. This device is a project of extreme occupational hazard. The improved Singaporean semi-quantitative risk assessment method is a scientific and applicable method, and is especially suitable for pre-evaluation of on-site project with no analogy.

Cyclohexanones ; Humans ; Nitriles ; Occupational Exposure ; prevention & control ; Risk Assessment

Background A number of studies have shown that heavy metals in atmospheric PM_2.5 have impacts on human health, while studies on the impact of long-term and low-concentration exposure to lead in PM_2.5 on human health are limited. Objective To investigate the pollution characteristics of lead in ambient PM_2.5 and assess its chronic health risks. Methods Daily PM_2.5 concentration data in Jinan from 2014 to 2019 were collected, and the year-by-year trend of PM_2.5 concentration was analyzed. Licheng District (an industrial area) and Shizhong District (a residential area) were elected to install an ambient PM_2.5 monitoring stationrespectively. The sampling instrument was a 100 L·min⁻¹ high-flow PM_2.5 sampler, with a cumulative sampling time of 20-24 h per day, using a quartz fiber filter membrane for lead detection and a glass fiber filter membrane for PM_2.5 determination. The sampling frequency was 7 consecutive days per month from the 10^th to the 16^th (A total of 493 d were sampled and some were missing; 172 d during the heating period and 321 d during the non-heating period). Two PM_2.5 samples were collected in one monitoring site each day. A total of 986 samples were collected in one monitoring site. The lead content in PM_2.5 samples was detected by inductively coupled plasma mass spectrometry. The concentration of PM_2.5 was measured by weighing method. The annual average concentration and enrichment factor of lead in PM_2.5, the change trend of lead content per unit mass of PM_2.5, and the difference between heating period and non-heating period from 2014 to 2019 were estimated. Technical guide for environment health risk assessment of chemical exposure (WS/T 777-2021) was used to assess the health risks of exposure to lead in PM_2.5. Results The average annual concentration of lead in PM_2.5 ranged from 23.2 ng·m⁻³ to 154.7 ng·m⁻³. The average concentration in heating period from 2015 to 2019 was higher than that in non-heating period, and the differences in 2015, 2017, and 2019 were statistically significant (P < 0.01 or 0.001). The enrichment factors ranged from 200 to 1342 in 2014 to 2019. The average enrichment factors in heating period in 2015, 2017, and 2018 was higher than those in non-heating period, and the difference was statistically significant (P < 0.05 or 0.001). The lead contents per unit mass of PM_2.5 ranged from 493 ng·mg⁻¹ to 1944 ng·mg⁻¹, and the differences between heating period and non-heating period in 2014, 2017, and 2018 were statistically significant (P < 0.05 or 0.001). The average annual concentration and enrichment factor of lead in PM_2.5 showed a downward trend, and thus the lead content per unit mass of PM_2.5 also decreased. From 2014 to 2019, the carcinogenic risk of lead in PM_2.5 in Jinan ranged from 1.69×10⁻⁸ to 2.45×10⁻⁶, showing a significant downward trend year by year, and the 95^th percentile decreased by 3%-46% from the previous year. The carcinogenic risk level of lead was reduced to an acceptable level (<1×10⁻⁶) after 2017. Conclusion From 2015 to 2019, lead concentration and enrichment factor in PM_2.5 increase during heating period compared with non-heating period, but it is not completely consistent of lead content in PM_2.5 per unit mass. From 2014 to 2016, exposure to lead in PM_2.5 may elevate carcinogenic risk to human. After 2017, the carcinogenic risks of exposure to lead in PM_2.5 are at an acceptable level.