[Characterization and Health Risk Assessment of Heavy Metals in PM2.5 in Xiamen Port].

PM2.5 samples at Haitian and Songyu container terminals in Xiamen Port were collected in summer and autumn/winter in 2020 and analyzed for 20 elements to investigate their temporal-spatial distribution features, sources, and health risk. The results showed that the levels of PM2.5 were relatively low and did not show significant spatial and diurnal differences. Ca and Si were the main crustal elements, and Zn and Mn were the main heavy metals in PM2.5. Compared with GB 3095-2012 guidelines, Cr(Ⅵ) was in the range of 27.4-28.6 times above the standard. Under the influence of monsoon and port throughput, the concentrations of some elements in summer were higher than those in autumn/winter. Significant diurnal variations were observed for Cu, Zn, SO2, and NO2 but not for V and Ni. Industrial sources were identified as the primary contributor (55.2%-59.4%), followed by traffic (28.7%-31.3%), ship emissions (7.1%-7.7%), and sea salt plus construction dust (4.8%-5.8%). The results of health risk assessment showed that heavy metals in PM2.5in Xiamen Port had potential carcinogenic risk (ECR>1(10-5) to people living near the port, and Cr(Ⅵ), V, and As together accounted for 97.3%-97.5% of the total risks; however, the non-carcinogenic risk was negligible (HI<1), and the major contributors were V, Mn, Ni, and As (89.6%-91.2%). The relative contributions of each contributor to ECR was in the order of traffic (47.2%-49.4%)>industrial (23.8%-24.2%)>ship emissions (16.9%-20.8%)>sea salt plus construction dust (5.7%-12.1%), and the relative contribution to HI was in the order of traffic (38.7%-42.3%)>industrial (24.5%-28.2%)>ship emissions (24.1%-27.2%)>sea salt plus construction dust (5.4%-9.6%).

Size distributions and dry deposition fluxes of water-soluble inorganic nitrogen in atmospheric aerosols in Xiamen Bay, China.

Size-segregated aerosol particles were collected using a high volume MOUDI sampler at a coastal urban site in Xiamen Bay, China, from March 2018 to June 2020 to examine the seasonal characteristics of aerosol and water-soluble inorganic ions (WSIIs) and the dry deposition of nitrogen species. During the study period, the annual average concentrations of PM1, PM2.5, PM10, and TSP were 14.8 ± 5.6, 21.1 ± 9.0, 35.4 ± 14.2 µg m-3, and 45.2 ± 21.3 µg m-3, respectively. The seasonal variations of aerosol concentrations were impacted by the monsoon with the lowest value in summer and the higher values in other seasons. For WSIIs, the annual average concentrations were 6.3 ± 3.3, 2.1 ± 1.2, 3.3 ± 1.5, and 1.6 ± 0.8 µg m-3 in PM1, PM1-2.5, PM2.5-10, and PM>10, respectively. In addition, pronounced seasonal variations of WSIIs in PM1 and PM1-2.5 were observed, with the highest concentration in spring-winter and the lowest in summer. The size distribution showed that SO4 2-, NH4 + and K+ were consistently present in the submicron particles while Ca2+, Mg2+, Na+ and Cl- mainly accumulated in the size range of 2.5-10 µm, reflecting their different dominant sources. In spring, fall and winter, a bimodal distribution of NO3 - was observed with one peak at 2.5-10 µm and another peak at 0.44-1 µm. In summer, however, the fine mode peak disappeared, likely due to the unfavorable conditions for the formation of NH4NO3. For NH4 + and SO4 2-, their dominant peak at 0.25-0.44 µm in summer and fall shifted to 0.44-1 µm in spring and winter. Although the concentration of NO3-N was lower than NH4-N, the dry deposition flux of NO3-N (35.77 ± 24.49 µmol N m-2 d-1) was much higher than that of NH4-N (10.95 ± 11.89 µmol N m-2 d-1), mainly due to the larger deposition velocities of NO3-N. The contribution of sea-salt particles to the total particulate inorganic N deposition was estimated to be 23.9-52.8%. Dry deposition of particulate inorganic N accounted for 0.95% of other terrestrial N influxes. The annual total N deposition can create a new productivity of 3.55 mgC m-2 d-1, accounting for 1.3-4.7% of the primary productivity in Xiamen Bay. In light of these results, atmospheric N deposition could have a significant influence on biogeochemistry cycle of nutrients with respect to projected increase of anthropogenic emissions from mobile sources in coastal region. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s10874-021-09427-8.

Size distributions and health risks of particle-bound toxic elements in the southeast coastland of China.

Size-fractionated samples were collected at five coastal urban sites in Fujian Province, southeast China, in 2016 and 2017 to determine the trace elements using ICP-MS. Ca, Fe, Al, Mg, and K were the most abundant elements among the studied elements in TSP, much higher than those of heavy metals. The annual mean concentrations of Pb, As, V, Ni, Cd, and Mn were within the acceptable limits of the World Health Organization and the Ministry of Ecology and Environment of China while Cr(VI) exceeded the limits. Most elements exhibited clear seasonal patterns with maxima over the cold season and minima over the warm season. The spatial variabilities in concentrations of the measured elements were not significant except Ni and V. However, the size distribution pattern of each element was quite similar across the region. Characteristic size distributions of elements allowed identification of three main groups: (a) unimodal distribution in the coarse fraction for Ca, Al, Mg, and Ba; (b) unimodal distribution in the fine fraction for Pb, Se, As, Ag, V, Ni, Zn, and Cd; and (c) bimodal or multimodal distribution for Fe, Mn, Cr, K, and Cu. The combination of the size-fractionated concentrations, enrichment factors, correlation coefficients, and factor analysis offered the identification of mixed sources such as vehicular exhaust and wear, heavy fuel oil combustion, and resuspension of road dust. Non-carcinogenic health risks associated with inhalable exposure to airborne metals were higher than the safety threshold (hazard index > 1) across the region, suggesting non-carcinogenic health risks via inhalation. Mn, V, and Ni contributed 74-83% of the total non-carcinogenic risk. The assessment investigation of carcinogenic health risks revealed V and Cr(VI) as elements with the largest carcinogenic risks, accounting for more than 95% of the overall inhalation risk. Nevertheless, the carcinogenic risks for children and adults were between 10-6 and 10-4, within the range considered acceptable by the US EPA. In terms of the size-fractionated risk, PM2.5 contributed 43-50% and 39-44% of the total non-carcinogenic and carcinogenic risks, respectively, indicating the potential health hazard of coarse particle-bound toxic metals was not negligible.

Consideration of species-specific diatom indicators of anthropogenic stress in the Great Lakes.

Robust inferences of environmental condition come from bioindicators that have strong relationships with stressors and are minimally confounded by extraneous environmental variables. These indicator properties are generally assumed for assemblage-based indicators such as diatom transfer functions that use species abundance data to infer environmental variables. However, failure of assemblage approaches necessitates the interpretation of individual dominant taxa when making environmental inferences. To determine whether diatom species from Laurentian Great Lakes sediment cores have the potential to provide unambiguous inferences of anthropogenic stress, we evaluated fossil diatom abundance against a suite of historical environmental gradients: human population, agriculture, mining, atmospheric nutrient deposition, atmospheric temperature and ice cover. Several diatom species, such as Stephanodiscus parvus, had reliable relationships with anthropogenic stress such as human population. However, many species had little or no indicator value or had confusing relationships with multiple environmental variables, suggesting one should be careful when using those species to infer stress in the Great Lakes. Recommendations for future approaches to refining diatom indicators are discussed, including accounting for the effects of broad species geographic distributions to minimize region-specific responses that can weaken indicator power.

Historical watershed stressors for the Laurentian Great Lakes.

This report provides a detailed set of historical stressor data for 60 watersheds comprising the Laurentian Great Lakes basin. Archival records were transcribed from public records to create quantitative data on human activities: population, mining, deforestation, and agriculture. Yearly records of stressors are provided from 1780 through 2010. These data may be used to track historical impacts on Great Lakes coastal and open water conditions. They may further be used to examine corresponding effects on response variables such as biological communities quantified during monitoring and palaeoecological programmes. OPEN PRACTICES: This article has earned an Open Data badge for making publicly available the digitally-shareable data necessary to reproduce the reported results. The data is available at https://doi.org/10.1594/PANGAEA.885879. Learn more about the Open Practices badges from the Center for Open Science: https://osf.io/tvyxz/wiki.