Soil heavy metal pollution from Pb/Zn smelting regions in China and the remediation potential of biomineralization.

Smelting activities pose serious environmental problems due to the local and regional heavy metal pollution in soils they cause. It is therefore important to understand the pollution situation and its source in the contaminated soils. In this paper, data on heavy metal pollution in soils resulting from Pb/Zn smelting (published in the last 10 years) in China was summarized. The heavy metal pollution was analyzed from a macroscopic point of view. The results indicated that Pb, Zn, As and Cd were common contaminants that were present in soils with extremely high concentrations. Because of the extreme carcinogenicity, genotoxicity and neurotoxicity that heavy metals pose, remediation of the soils contaminated by smelting is urgently required. The primary anthropogenic activities contributing to soil pollution in smelting areas and the progressive development of accurate source identification were performed. Due to the advantages of biominerals, the potential of biomineralization for heavy metal contaminated soils was introduced. Furthermore, the prospects of geochemical fraction analysis, combined source identification methods as well as several optimization methods for biomineralization are presented, to provide a reference for pollution investigation and remediation in smelting contaminated soils in the future.

Remediation of arsenic-contaminated paddy field by a new iron oxidizing strain (Ochrobactrum sp.) and iron-modified biochar.

Iron-oxidizing strain (FeOB) and iron modified biochars have been shown arsenic (As) remediation ability in the environment. However, due to the complicated soil environment, few field experiment has been conducted. The study was conducted to investigate the potential of iron modified biochar (BC-FeOS) and biomineralization by a new found FeOB to remediate As-contaminated paddy field. Compared with the control, the As contents of GB (BC-FeOS), GF (FeOB), GFN (FeOB and nitrogen fertilizer), GBF (BC-FeOS and FeOB) and GBFN (BC-FeOS, FeOB and nitrogen fertilizer) treatments in pore water decreased by 36.53%-80.03% and the microbial richness of iron-oxidizing bacteria in these treatments increased in soils at the rice maturation stage. The concentrations of available As of GB, GF, GFN, GBF and GBFN at the tillering stage were significantly decreased by 10.78%-55.48%. The concentrations of nonspecifically absorbed and specifically absorbed As fractions of GB, GF, GFN, GBF and GBFN in soils were decreased and the amorphous and poorly crystalline hydrated Fe and Al oxide-bound fraction was increased. Moreover, the As contents of GB, GF, GFN, GBF and GBFN in rice grains were significantly decreased (*P < 0.05) and the total As contents of GFN, GBF and GBFN were lower than the standard limit of the National Standard for Food Safety (GB 2762-2017). Compared with the other treatments, GBFN showed the greatest potential for the effective remediation of As-contaminated paddy fields.

Microbial driven iron reduction affects arsenic transformation and transportation in soil-rice system.

The microbe-driven iron cycle plays an important role in speciation transformation and migration of arsenic (As) in soil-rice systems. In this study, pot experiments were used to investigate the effect of bacterial iron (Fe) reduction processes in soils on As speciation and migration, as well as on As uptake in soil-rice system. During the rice growth period, pH and electrical conductivity (EC) in soil solutions initially increased and then decreased, with the ranges of 7.4-8.8 and 116.3-820 mS cm-1, respectively. The concentrations of Fe, total As and As(III) showed an increasing trend in the rhizosphere and non-rhizosphere soil solutions with the increasing time. Fe concentrations were significantly positively correlated with total As and As(III) concentrations (***p < 0.001) in the soil solutions. The abundances of the arsenate reductase gene (arsC) and the As(III) S-adenosylmethionine methyltransferase gene (arsM) in rhizosphere soils were higher than those in non-rhizosphere soils, while the abundance of the Fe-reducing bacteria (Geo) showed an opposite trend. Moreover, it showed that the Geo abundance was significantly positively correlated with that of the arsC (***p < 0.001) and arsM (**p < 0.01) genes, respectively. The abundances of Geo, arsC and arsM genes were significantly positively correlated with the concentrations of Fe, total As and As(III) in the soil solutions (*p < 0.05). Moreover, the abundances of arsC and arsM genes were significantly negatively correlated with total As and As(III) in rice grains (*P < 0.05). These results showed that the interaction of bacterial Fe reduction process and radial oxygen loss from roots promoted the reduction and methylation of As, and then decreased As uptake by rice, which provided a theoretical basis for alleviating As pollution in paddy soils.

Effects of bleomycin A5 on caspase-3, P53, bcl-2 expression and telomerase activity in vascular endothelial cells.

OBJECTIVE: The aim of this study was to investigate the molecular mechanism of bleomycin A5 in inducing the apoptosis of human umbilical vein endothelial cells (ECV304). MATERIALS AND METHODS: ECV304 cells were cultured and passaged, and then were divided into control group and three treatment groups. The later three groups were treated with 15, 75, and 150 µg/ml bleomycin A5 for 24 hours, respectively. The expressions of caspase-3, p53, and bcl-2 in ECV304 cells were detected by flow cytometry, and the activity of telomerase was determined using telomere repeat amplification protocol (TRAP)-silver staining method. RESULTS: After treatment with different concentrations of bleomycin A5, the expression of caspase-3 in ECV304 cells was increased. It was significantly decreased with the increase of bleomycin A5 concentration, but the difference between 75 µg/ml and 150 µg/ml groups was not significant. Bleomycin A5 could significantly increase the expression of p53, with concentration dependence. It had no obvious effect on bcl-2 expression. There was high expression of telomerase in control group. After treatment with different concentration of bleomycin A5, the telomerase activity was significantly decreased. CONCLUSION: Bleomycin A5 can increase caspase-3 and p53 levels and inhibit telomerase activity to induce ECV304 apoptosis.

[The clinical analysis of cat scratch diseases with enlarged masses].

OBJECTIVE: In order to raise awareness of CSD and reduce misdiagnosis, we study the manisfection and treatment of CSD with enlarged masses. METHOD: A retrospective study was carried out among the 10 identified patients with CSD on the basis of compatible clinical presentation and confirmatory pathology results for CSD. RESULT: All the 10 patient's first symptoms were masses at some part of the body, more common in the neck. The ratio was 5% at neck, 3% at armpit, 1% at upper, 1% at groin. Two patients had low heat, increased leukocyte and larger masses of more than 2 cm in diameter After surgical resection, and anti-inflammatory treatment. All the patients were cured after surgery and postoperative anti-inflammatory treatment, and there was no recurrence during the 7-year follow-up. CONCLUSION: If patients were diagnosed and treated timely, the prognosis will be good. For the cases with extremely enlarged lymphonodus, surgical operation followed by antimicrobial chemotherapy will be a effective treatment.

[Intratumor bleomycin-A5 injection under electrolaryngoscope for treatment of large laryngopharyngeal and laryngeal hemangioma].

OBJECTIVE: To study the therapeutic effect of bleomycin-A5 injection under eletrolaryngoscope for treatment of large laryngopharyngeal and laryngeal hemangioma. METHODS: Intratumor bleomycin-A5 injection under eletrolaryngoscope was performed in 18 cases of large laryngopharyngeal and laryngeal hemangioma with surface anaesthesia, for totally 7 to 14 (mean 10.2) injections in each case. RESULTS: Twelve patients were cured and 6 showed obvious improvement. Follow-up of the patients for over one year found no recurrence of the hemangioma. CONCLUSION: Bleomycin-A5 injection is a minimal invasive procedure for treatment of large laryngopharyngeal and laryngeal hemangioma, causing less pain and better preserving the laryngeal function without the necessity of tracheotomy.