[Bioaccessibility and Health Risks of the Heavy Metals in Soil-Rice System of Southwest Fujian Province].

The bioaccessibility and health risks of heavy metals in soil-rice system of southwestern Fujian province were studied by combining a simple bioavailability extraction method (SBET) with a health risk assessment model. The results showed that some heavy metals in the agricultural soils and rice of southwestern Fujian province were enriched. The contents of Cd, Zn, Pb, and Cu were greater than the screening value of soil pollution risk for agricultural land (GB 15618-2018) by 32.4%, 15.5%, 14.1%, and 12.7% in the study areas, respectively. The accumulation ability of heavy metals was different and followed the approximately decreasing order of Cd > Zn > Cu > Ni > Hg > As > Cr > Pb. The bioaccessibility of heavy metals in soils and rice were quite different. The bioaccessibility of each heavy metal in rice was greater than the bioaccessibility of the heavy metals in soil, which indicated that the heavy metals in rice were more easily absorbed by the human body. The comprehensive non-carcinogenic risk index (HI) of heavy metals to adults and children was 2.71 and 4.06, respectively, indicating that there were non-carcinogenic risks. The comprehensive carcinogenic risk index (TCR) of heavy metals to adults and children was 1.42×10-3 and 5.28×10-4, respectively, indicating that there was a carcinogenic risk present. The non-carcinogenic risks were mainly due to As, while the carcinogenic risks were mainly contributed by Cd. The non-carcinogenic risk of children was higher than that of adults, while the carcinogenic risk of children was lower than that of adults. This result may be related to physiological characteristics, exposure period, and dietary intake. The dietary intake route may be the main pathway for heavy metals in the soil-rice system of southwest Fujian province to cause health risks. Therefore, more attention should be paid to the risks of dietary exposure in the risk management of heavy metals.

[Source Appointment of Heavy Metals in Agricultural Soils of the Jiulong River Basin Based on Positive Matrix Factorization].

In order to study the source appointment of heavy metals in agricultural soils of the Jiulong River Basin, Fujian Province, China. 71 agricultural soil samples were collected in July 2017. The concentrations of heavy metals in agricultural soils were determined by inductively coupled plasma mass spectrometry (ICP-MS) and atomic fluorescence spectrometry (AFS). Here, we use a positive matrix factorization (PMF) model for the source appointment of heavy metals in the sampled soils. The results showed that most of the heavy metal concentrations in the sampled agricultural soils were higher than soil background concentrations for the Fujian Province. The concentrations of Cd, Zn, Pb, and Cu in some soil samples were greater than the screening value of the Chinese soil pollution risk levels for agricultural land (GB 15618-2018). The spatial distributions of heavy metals showed a moderate variation across three regions of the study area (i.e., the North River watershed, West River watershed, and the estuary area). The highest concentration of Cr, Ni, Cu, Zn, and Cd were found in Longyan City (North River watershed), the highest concentrations of Pb were found in the West River watershed, and the highest concentrations of Co, Hg, and As were found in the estuary area. The non-negative properties of the source component spectrum and source contribution rate (obtained by the PMF model), as well as the significant correlation between the measured and PMF predicted concentrations, indicated that the results of the PMF model were relatively reasonable and can meet research needs. The source apportionment results of the PMF model showed that natural sources, agricultural sources, coal combustion, and industrial sources were the four major potential sources for heavy metals in the sampled agricultural soils, contributing 37.0%, 26.7%, 17.6%, and 18.7%, respectively.

[Assessment of the Speciation and Pollution of Heavy Metals in Paddy Soils from the Jiulong River Basin].

Speciation characteristics of twelve heavy metals in 71 paddy soils from the Jiulong River Basin were analyzed using inductively coupled plasma mass spectrometry (ICP-MS) and the modified BCR protocol. The risk assessment coding method (RAC), ratio of secondary phase and primary phase (RSP), and geoaccumulation index (Igeo) were applied to evaluate the pollution degree of heavy metals in the area. The results show that most of these elements are abundant in the paddy soils and the speciation characteristics of different heavy metals vary. The elements Cd and Mn mainly exist as acid soluble fractions in the soils, with a mean proportion of 46.2% and 35.2%, respectively; Fe and Pb mainly exist as reducible fractions in the soils, with a mean proportion of 64.5% and 41.5%, respectively; and V, Cr, Ni, As, Co, Sr, Zn, and Cu mainly exist as residual fractions in the soils, with a mean proportion of 79.6%, 78.4%, 73.1%, 67.7%, 51.9%, 49.7%, 45.3%, and 38.4%, respectively. The three pollution assessment methods focus on the acid-soluble phase, secondary phase, and total amount of heavy metals, respectively. All have their own application value and disadvantages of incompletion. The comprehensive analysis of these three pollution assessment methods helps to more accurately and comprehensively assess the pollution characteristics of the heavy metals. The results show that the paddy soils are moderately to severely polluted with Cd; the Mn and Sr pollution is mild to severe; the Zn, Pb, Cu, and Co pollution is mild to moderate; the As and Ni pollution is absent or moderate; and V, Fe, and Cr pollution is non-existent or mild.

Allergic airway inflammation disrupts interleukin-17 mediated host defense against streptococcus pneumoniae infection.

Despite decreasing rates of invasive pneumococcal disease caused by vaccine serotypes, the prevalence of invasive pneumococcal pneumonia in asthmatic patients remains high. However, little is known about the mechanisms underlying the susceptibility of the asthmatic airway to bacterial infections. In this study, we used a combined model of allergic airway inflammation and Streptococcus pneumoniae lung infection to investigate the association between persistent allergic inflammation in the airway and antibacterial host defenses against S. pneumoniae. When challenged with S. pneumoniae, allergic mice exhibited higher airway bacterial burdens, greater eosinophil infiltration, lower neutrophil infiltration, and more severe structural damage than non-allergic mice. In sensitized mice, S. pneumoniae infection elicited higher IL-4 but lower IFN-γ, IL-17 and defensin-ß2 expression than in control mice. These results indicate that persistent allergic inflammation impaired airway host defense against S. pneumoniae is associated with the insufficient IL-17 responses. To elicit IL-17 induced-anti-bacterial immune responses, mice were intranasally immunized with rIL-17. Immunized mice exhibited fewer bacterial colonies in the respiratory tract and less severe lung pathology than unimmunized mice. rIL-17 contributed to airway host defense enhancement and innate immune response promotion, which was associated with increased IL-23, MIP-2 and defensin-ß2 expression. Administration of exogenous IL-17 (2 µg/mouse) suppressed eosinophil-related immune responses. The results demonstrate IL-17 plays a key role in host defenses against bacterial infection in allergic airways and suggest that exogenous IL-17 administration promotes the anti-becterial immune responses and attenuates the existed allergic inflammation.

[Genetic analysis of the nonstructural gene (NS1) of H9N2 avian influenza viruses isolated in China].

The nonstructural genes (NS1) of nine H9N2 subtype avian influenza viruses isolated from diseased chickens on different farms during 1998-2005 were amplified by RT-PCR and completely sequenced. The nucleotide and deduced amino acid sequences of NS1 genes of these isolates were compared. The results showed that NS1 genes of all H9N2 isolates contained 654 bp and encoded 217 amino acids. The homologies of the nucleotide and deduced amino sequences of the isolates were 95.4%-99.8% and 93.6%-100%, respectively. Comparison of the amino acid sequences of NS1 proteins of these isolates with other H9N2 viruses demonstrated that NS1 proteins of the nine strains had a deletion of 13 amino acid residues at the carboxyl terminus, which may be the molecule mark of the isolates in mainland China. Phylogenetic analysis revealed that the NS1 genes of these isolates fell into the same lineage and belonged to allele A. Eight out of nine isolates belonged to the CK/SH/F/98-like lineage while only Ck/HN/A3/98 strain belonged to the Ck/HK/Y280/97-like linease. All the isolates were derived from Ck/BJ/1/94 strain which was the first isolate is mainland China in 1994. The results indicated that H9N2 subtype AIV appeared differentiation following the passage of time and the viruses belonging to Ck/SH/F/98-like acquired an epidemic spread advantage in chicken population in mainland China.