Cadmium stress alters gene expression of DNA mismatch repair related genes in Arabidopsis seedlings

Cadmium (Cd) is a non essential element, and is a widespread environmental pollutant. Exposure to Cd can result in a variety of adverse health effects in plant and humans. In the current study, Arabidopsis seedlings were used as a bio-indicator of Cd pollution. Seedlings were grown on MS media containing 0-6.0 mg L(-1) Cd for 18 days, and the gene expression patterns were used to link increased Cd exposure with progressive biological effects. Reduction of total soluble protein content in shoots of the Arabidopsis seedlings occurred with increase in Cd concentrations. For the gene expression patterns, seven genes known to be involved in cell division and DNA mismatch repair (MMR) system were investigated by semi-quantitative RT-PCR, and normalized using 18S rRNA gene expression. Expression of the proliferating cell nuclear antigen 2 (atPCNA 2), MutS 3 homolog (atMSH 3) and MutL1 homolog (atMLH1) genes in shoots of Arabidopsis was strongly induced by exposure to 0.75 mg L(-1) Cd, but were repressed by other Cd concentrations whereas exposure to 0.75-6 mg L(-1) of Cd resulted in a decreased expression of atPCNA1, atMSH 2, 6 and 7 genes independently of any observable biological effects, including survival, fresh weight and chlorophyll level of shoots. This work demonstrated that specific gene expression changes could serve as useful molecular biomarkers indicative of Cd exposure and related biological effects.     

Approaching the binding between Cu(II) and aerobic granules by a modified titration and µ-XRF

Interactions between metals and activated sludge can substantially affect the fate and transport of heavy metals in wastewater treatment plants. Therefore, it is important to develop a simple, fast and efficient method to elucidate the interaction. In this study, a modified titration method with a dynamic mode was developed to investigate the binding of Cu(II), a typical heavy metal, onto aerobic granules. The titration results indicated that pH and ionic strength both had a positive effect on the biosorption capacity of the granular sludge. The µ-XRF results demonstrated that the distribution of metals on the granular surface was heterogeneous, and Cu showed strong correlations and had the same “hot spots” positions with other metal ions (e.g., Ca, Mg, Fe etc.). Ion exchange and complexing were the main mechanisms for the biosorption of Cu(II) by aerobic granules. These results would be beneficial for better understanding of Cu(II) migration and its fate in wastewater treatment plants.     

Quality assessment of groundwater from the south-eastern Arabian Peninsula

Assessment of groundwater quality plays a significant role in the utilization of the scarce water resources globally and especially in arid regions. The increasing abstraction together with man-made contamination and seawater intrusion have strongly affected groundwater quality in the Arabia Peninsula, exemplified by the investigation given here from the United Arab Emirates, where the groundwater is seldom reviewed and assessed. In the aim of assessing current groundwater quality, we here present a comparison of chemical data linked to aquifers types. The results reveal that most of the investigated groundwater is not suitable for drinking, household, and agricultural purposes following the WHO permissible limits. Aquifer composition and climate have vital control on the water quality, with the carbonate aquifers contain the least potable water compared to the ophiolites and Quaternary clastics. Seawater intrusion along coastal regions has deteriorated the water quality and the phenomenon may become more intensive with future warming climate and rising sea level.     

Microbial flocculant and its application in environmental protection

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Technological system for sustainable development of Chinese agriculture

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用液相催化法和脱硫除尘器脱除烟气中SO_2

在由旋风水膜和两块旋流塔板组成的处理气量为７５０ｍ￣３／ｈ的二级脱硫除尘器中，进行了用含催化剂Ｍｎ￣（２＋）的水溶液吸收ＳＯ_２的扩大试验。结果表明，在确定的条件下，脱硫率达到７３％，板效率为０．２５～０．２８。在同一设备中同时完成除尘与脱硫过程，设备投资少；以水为吸收剂，运行费用低；中性条件下吸收，长期运转不结垢，可靠性高。     

Adjusting the effect of seasonal variability in the bioassessment of streams

Bioassessment tools should distinguish between the effects of anthropogenic degradation in communities and natural temporal changes. The present study tests the influence of natural seasonal variability on macroinvertebrate stream communities assessed by a predictive model (PORTRIV) and a multimetric index (IPtI) calibrated for spring. The scores of PORTRIV decreased significantly between spring and autumn, and between spring and winter (ca. 37 to 53 %, respectively), while those of IPtI did not change significantly between seasons. For non-reference samples, the results of the predictive model also indicate no significant differences. A correction factor (CF) was calculated to adjust the existing differences in the model assessments between seasons, based on the percentage of variation of reference site scores from spring to autumn and winter. After the application of the CF to the OE50 scores of spring reference samples, the differences were no longer significant. Independent reference validation sites confirmed this tendency. This method has the advantage of avoiding large efforts required for the construction of databases from other seasons and the development of new models to allow the assessment of streams in seasons other than spring. Further tests with models developed in regions with more marked seasonal changes should be done to confirm its wider applicability.     

三峡库区水华优势藻类生长动力学的普适性研究

从蓝绿藻中选取绿藻门的普通小球藻(Chlorella vulgaris,CV藻)为研究对象,应用Monod方程考察氮、磷营养盐对CV藻生长的影响,分别计算出CV藻对TP、TN的半饱和常数KSP和KSN结果表明KSN>>KSP,说明TP对CV藻生长的影响明显大于TN.CV藻生长速率对磷质量浓度反应很灵敏:与空白值相比,在0.002 mg·L-1的低浓度下u就有提高,而浓度到0.2 mg.L-1时,u明显增大;但在0.000-0.050 mg·L-1氮浓度范围内u几乎没有变化.通过系统比较CV藻与优势蓝绿藻,甚至海水藻的生长动力学特征,探讨了CV藻与其它蓝绿藻的动力学普适性和共同性,证实这些藻类都具有非常类似的生长动力学和生态学特征.因此,推测CV藻生长动力学模型可以从整体上反映和代表库区优势蓝绿藻的生长行为.同时分析和归纳了蓝绿藻生长模型的相似性和规律性,得出三峡库区优势藻类生长行为存在普遍一致性的初步结论.     

CALPUFF模型在大气环境容量测算中的应用研究

本研究利用CALPUFF空气质量扩散模式模拟了凉山州2007年气象场和s02浓度场,通过现状监测结果与模拟结果的比较评述了模型的适用性;并根据西昌市现状污染源和虚拟污染源情况,通过CALPUFF模拟建立大气污染物传递矩阵,结合线性优化模型测算了西昌市大气环境容量。