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991.
Linglong Wang Haochang Su Xiaojuan Hu Yu Xu Wujie Xu Xiaoshuai Huang 《Journal of environmental science and health. Part. B》2019,54(3):211-218
Although research regarding antibiotic resistance genes (ARGs) in aquaculture environments has gained increasing scientific interest, further studies are required to understand the abundances and removal mechanisms of ARGs during the entire rearing period of shrimp aquaculture. Thus, in this study, abundances, distributions and removal rates of ARGs in different environmental compartments of intensive shrimp farms in South China were investigated during the entire rearing period. The results indicated that sul1 and cmlA were the predominant ARGs in the water and sediment samples. Additionally, the total abundance of ARGs was higher in shrimp pond water than in the source water and farm effluent. Moreover, sediment samples indicated significantly higher ARG abundances than water samples from the shrimp ponds (P?<?0.05). Environmental factors were found to significantly affect the distribution of ARGs in shrimp rearing environments. Furthermore, stable ponds aided the removal of ARGs from shrimp pond water. This study accounted for temporal variations in ARG abundances as well as removal of ARGs in different environmental compartments during the entire shrimp rearing period. However, additional research is required to optimize the water treatment process for removal of ARGs from the aquaculture. 相似文献
992.
Shestopaloff Konstantin Xu Wei Escobar Michael D. 《Environmental and Ecological Statistics》2020,27(3):447-465
Environmental and Ecological Statistics - In this paper we present a weighted mixture distribution component counts (MDCC) approach for estimating total number of species. The proposed method... 相似文献
993.
Na Wang You-Gan Wang Shuwen Hu Zhi-Hua Hu Jing Xu Hongwu Tang Guangqiu Jin 《Environmental Modeling and Assessment》2018,23(6):779-786
We introduce robust procedures for analyzing water quality data collected over time. One challenging task in analyzing such data is how to achieve robustness in presence of outliers while maintaining high estimation efficiency so that we can draw valid conclusions and provide useful advices in water management. The robust approach requires specification of a loss function such as the Huber, Tukey’s bisquare and the exponential loss function, and an associated tuning parameter determining the extent of robustness needed. High robustness is at the cost of efficiency loss in parameter loss. To this end, we propose a data-driven method which leads to more efficient parameter estimation. This data-dependent approach allows us to choose a regularization (tuning) parameter that depends on the proportion of “outliers” in the data so that estimation efficiency is maximized. We illustrate the proposed methods using a study on ammonium nitrogen concentrations from two sites in the Huaihe River in China, where the interest is in quantifying the trend in the most recent years while accounting for possible temporal correlations and “irregular” observations in earlier years. 相似文献
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在城市发展中,人口增多和居民生活方式的变化都加大了城市污水量的增加,现代城市污水已经对地下水体产生了污染,人们的生活用水受到了严重影响。在国家环保要求下,利用先进污水处理式方法对城市污水进行处理至关重要,本文对城市污水特点进行了分析,并重点对生化法污水处理工艺进行了分析,希望能为行业内人士提供参考,提高城市污水的净化能力,促进城市的持续发展。 相似文献
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采用复合共聚法制备一种新型无机高分子絮凝剂凹凸棒-聚硅酸铁锌(APSFZn),并应用于富营养化湖泊型原水的实验研究。考察了水体p H、投加量、搅拌强度影响因素对絮凝效果的影响。研究表明,APSFZn具有较宽的p H使用范围。当p H为7.6、投加量为20 mg/L、搅拌强度为快搅速度200 r/min,快搅时间2 min,慢搅速度50 r/min,慢搅时间15 min时,APSFZn絮凝剂对Chl-a、CODMn、TP和TN的去除率分别为91.57%、87.11%、93.48%和48.98%。与传统絮凝剂PAC、PFS、PSFZn对比,APSFZn的絮凝效果明显优于传统絮凝剂。该絮凝剂制备简单、具有良好的稳定性和絮凝特性、工艺无二次污染,将APSFZn应用于富营养化湖泊型原水具有良好的絮凝效果。 相似文献