Tea is a non-alcoholic beverage popular among Chinese people. However, due to the application of chemical and organic fertilizers in the tea planting process, the environment pollutionaround the tea plantation, and the instruments used in the processing, heavy metal elements will accumulate in the tea, which brings health risks for tea consumers. This study summarized heavy metal concentrations from 227 published papers and investigated the current contamination status of tea and tea plantation soils, and, finally, the risk of heavy metal exposure to tea consumers in China is assessed, in terms of both non-carcinogenic and carcinogenic risk. The average contamination of six heavy metals in tea-arsenic (As), cadmium (Cd), chromium (Cr), copper (Cu), mercury (Hg), and lead (Pb)-were 0.21, 0.14, 1.17, 14.6, 0.04, and 1.09 mg/kg, respectively. The areas with high concentrations of heavy metals in tea were concentrated primarily in southwest China, some areas in eastern China, and Shaanxi Province in northwest China. The non-carcinogenic risks of heavy metals in tea are all within safe limits. The national average HI value was 0.04, with the highest HI value of 0.18 in Tibet, which has the largest tea consumption in China. However, the carcinogenic risks of Cd in Shaanxi Province, Anhui Province, and southwest China exceed the acceptable range, and due attention should be given to these areas.

Bioaerosol is a new type of pollutant, which is related to the spread of many diseases. In particular, the bioaerosol produced in the hospital sewage treatment process contains many pathogenic bacteria, which will impact patients and surrounding residents. In this study, the biochemical tank (BRT) of the hospital sewage treatment station (HSTS) and municipal wastewater treatment plant (MWTP) were used as sampling points. The results showed that the concentration of bacteria (1843 CFU/m3) in bioaerosol produced by BRT of HSTS was higher than that in the air at BRT of MWTP (1278 CFU/m3). The proportion of small-size bacteria (<3.3 µm) in the air of HSTS and MWTP was similar. However, the abundance of small-size pathogenic bacteria in HSTS was higher than that in MWTP, such as Acinetobacter and Arcobacter. The dominant bacteria in HSTS and MWTP were different under different particle sizes. The dominant bacterial genera of bioaerosol in HSTS under different particle sizes were similar (Acinetobacter, Arcobacter, Comamonas); There were significant differences in the dominant bacterial genera of bioaerosol in MWTP under different particle sizes. The dominant strains with particle sizes ranging from 0 ∼ 0.43 µm were Acinetobacter (23.22%). Kocuria (15.13%) accounted for a relatively high proportion in the aerosol of 0.43 µm ∼ 0.65 µm. The dominant strains with particle sizes of 0.65 µm ∼ 1.1 µm and 1.1 µm ∼ 2.1 µm were relatively single, and Exiguobacterium and Paenibacillus accounted for 51.51% and 60.15%, respectively. Source tracker showed that most of the pathogenic bacteria in bioaerosols came from sewage. One hour later, the concentration of particulate matter in the place 200 m away from BRT of HSTS (1 × 10-10 mg/m3) was higher than that in MWTP (1 × 10-11 mg/m3). The hazard quotient (HQ) of people around HSTS (HQmale: 1.70 × 10-1; HQfemale: 1.36 × 10-1) was higher than that of MWTP (HQmale: 1.18 × 10-1; HQfemale: 9.40 × 10-2). Pathogenic bacteria (Acinetobacter, Arcobacter) were detected in HSTS and MWTP and the BugBase phenotype prediction results showed potential pathogenicity. More attention should be paid to the protection of the people. It is suggested to strengthen the air sterilization treatment near HSTS according to the diffusion trajectory of bioaerosol, and the surrounding personnel should wear N95 and other protective masks.

Air in subway stations is typically more polluted than ambient air, and particulate matter concentrations and compositions can vary greatly by location, even within a subway station. However, it is not known how the sources of particulate matter vary between different areas within subway stations, and source-specific health risks in subway stations are unclear. We analyzed the spatial characteristics of particulate matter by source and calculated source-specific health risks on subway platforms and concourses and in station offices by integrating source apportionment with health risk assessments. A total of 182 samples were collected in three areas in six subway stations in Nanjing, China. Enrichment factors and the positive matrix factorization receptor model were used to identify major sources. The carcinogenic and non-carcinogenic health risks to subway workers and passengers were evaluated to determine control priorities. Seven sources of particulate matter were identified in each area, with a total of four subway sources and six outdoor sources over all the areas. The source contributions to total element mass differed significantly from the source contributions to human health risks. Overall, subway sources contributed 48% of total element mass in the station office and 75% and 60% on the concourse and platform, respectively. Subway-derived sources accounted for 54%, 81%, and 71% of non-carcinogenic health risks on station platforms, concourses, and office areas, respectively. The corresponding values for carcinogenic risks were 51%, 86%, and 86%. Among the elements, cobalt had the largest contributions to carcinogenic and non-carcinogenic risks, followed by manganese for non-carcinogenic risks and hexavalent chromium for carcinogenic risks. Reducing emissions from subway sources could effectively protect the health of subway workers and passengers.