[Analysis of incidence characteristics and trend of pneumoconiosis in Ningbo City from 1967 to 2019]

Objective: To understand the incidence of pneumoconiosis in Ningbo city from 1967 to 2019, and to analyze the distribution characteristics and change trend of pneumoconiosis. Methods: In February 2021, the data of pneumoconiosis patients in Ningbo city from 1967 to 2019 were sorted out. The data from 1967 to 1987 were from historical case files of Zhejiang Center for Disease Control and Prevention, the data from 1988 to 2005 were from the historical case files of Ningbo Center for Disease Control and Prevention, and the data from 2006 to 2019 were from the pneumoconiosis report card in China Disease Prevention and Control Information System; Followed up and supplement relevant information, including basic information, basic information of employers and information related to pneumoconiosis diagnosis, and comprehensively analyze the composition and development trend, population characteristics and industry characteristics of pneumoconiosis. Results: From 1967 to 2019, a total of 1715 cases of pneumoconiosis were reported in Ningbo City, including 1254 cases of stageⅠpneumoconiosis, 258 cases of stageⅡpneumoconiosis, 172 cases of stage Ⅲpneumoconiosis. 1202 cases of silicosis (70.09%) , 296 cases of asbestosis (17.26%) , 40 cases of welder's pneumoconiosis (2.33%) , 32 cases of graphite pneumoconiosis (1.87%) were reported. There were 1296 male cases (75.57%) and 419 female cases (24.43%) were reported. Silicosis (91.15%, 1102/1209) and welder's pneumoconiosis (100.00%, 40/40) were the most common pneumoconiosis in males, while asbestosis (90.24%, 268/297) and graphite pneumoconiosis (87.50%, 28/32) were the most common pneumoconiosis in females. The average age was (49.71±10.90) years old and the average length of service was (10.98±6.96) years. The top three reported pneumoconiosis cases were construction industry (336 cases, 19.59%) , ferrous metal smelting and rolling industry (317 cases, 18.48%) and non-metallic mineral products industry (315 cases, 18.37%) . The top three reported pneumoconiosis cases were 414 cases (24.14%) in Ninghai County, 294 cases (17.14%) in Yuyao City and 272 cases (15.86%) in Yinzhou District. Conclusion: With the development of industries in Ningbo City, government departments should strengthen supervision and management of enterprises involving silica dust and welding fume to curb the high incidence of pneumoconiosis.

Effects of physicochemical factors on Cr(VI) removal from leachate by zero-valent iron and alpha-Fe(2)O(3) nanoparticles

The effects of nanoparticle dosage, initial hexavalent chromium concentration, pH value, reaction temperature, and initial concentration of humic acid (HA) on chromate (CrO(4)(2-)) removal from landfill leachate by nanoscale zero-valent iron (NZVI) and hematite (alpha-Fe(2)O(3)) nanoparticles were examined in the present investigations. The Cr(VI) removal rate decreased as the initial Cr(VI) concentration and the reaction temperature increased, whereas corresponding removal rate by NZVI was higher than that of alpha-Fe(2)O(3). The optimum pH for the removal of Cr(VI) by NZVI was found to be 5.0 and more than 99.0% of Cr(VI) was removed within 5 h. However, the removal rate by alpha-Fe(2)O(3) decreased as pH increased. Presence of HA resulted in substantial reduction in the rate and extent of Cr(VI) removal by NZVI, whereas Cr(VI) removal rate by alpha-Fe(2)O(3) did not significantly decrease as HA concentration increased from 0.5 g/L to 3.0 g/L. Increasing the dosage of nanoparticles enhanced the rate constant and the removal of Cr(VI) by NZVI and alpha-Fe(2)O(3) followed pseudo-first-order reaction kinetics. The information should be very useful for the successful application of NZVI and alpha-Fe(2)O(3) for the treatment of groundwater or raw wastewater.