Establishing eutrophication assessment standards for four lake regions, China

The trophic status assessment of lakes in different lake regions may provide important and fundamental information for lake trophic state classification and eutrophication control. In this study, a region-specific lake eutrophication assessment standard was established through a frequency distribution method based on chlorophyll-a concentration. The assessment standards under the oligotrophic state for lakes in the Eastern plain, Yungui Plateau, Northeast Plain and Mountain Mongolia-Xinjiang regions are total phosphorus of 0.068, 0.005, 0.011, 0.005 mg/L; total nitrogen of 1.00, 0.16, 0.37, 0.60 mg/L; Secchi depth of 0.60, 8.00, 1.55, 3.00 m; and CODMn of 2.24, 1.00, 5.1 l, 4.00 mg/L, respectively. Moreover, a region-specific comprehensive trophic level index was developed to provide an understandable assessment method for the public. The results indicated that the frequency distribution analysis based on chlorophyll-a combined with trophic level index provided a useful metric for the assessment of the lake trophic status. In addition, the difference of eutrophication assessment standards in different lake regions was analyzed, which suggested that the sensitivities of algae to nutrients and the assessment standard of trophic status possessed significant regional differences for the four lake ecoregions. Lake eutrophication assessment standards would contribute to maximizing the effectiveness of future management strategies, to control and minimize lake eutrophication problems.     

Air pollution and body burden of persistent organic pollutants at an electronic waste recycling area of China

Environmental Geochemistry and Health - This paper reviews the concentrations of persistent organic pollutants (POPs) in atmosphere of an electronic waste (e-waste) recycling town, Guiyu, in...     

Acidic and basic properties and buffer capacity of airborne particulate matter in an urban area of Beijing

Particles with aerodynamic diameters <10  $\upmu $ m (PM₁₀) and particles with aerodynamic diameters <2.5  $\upmu $ m (PM_2.5) were sampled during summer 2006 in Beijing and mass concentrations, water-soluble ionic compounds concentrations, and acidic buffer capacity were analyzed. Results show that the mass concentration ranges of PM₁₀ and PM_2.5 were from 56.4 to 226.6  $\upmu $ g/m³ and from 31.3 to 200.7  $\upmu $ g/m³ during sampling days, respectively. Concentrations of F^???, Cl^???, NO $_{3}^{\,\,-}$ , NO $_{2}^{\,\,-}$ , SO $_{4}^{\,\,2-}$ , Ac^???, Ca^2?+?, Na^?+?, K^?+?, Mg^2?+?, and NH $_{4}^{\,\,+}$ in particles were analyzed by ion chromatography. Microtitration was adapted to determine the acidic?Cbasic property and the change of the buffering systems in different pH of the aqueous solution in which the PM is suspended. The major alkalinity and buffer capacity of particles were analyzed and calculated. The average carbonate buffer capacity was 0.3 mmol/g in PM_2.5 and 0.7 mmol/g in PM₁₀. The average acetic acid buffer capacity was 0.1 mmol/g in PM_2.5 and 0.3 mmol/g in PM₁₀. Carbonate and acetic acid are the main species for the buffer capacity in the particle phase. The average mass of carbonate was 71.0 mg/g in PM₁₀ and 46.7 mg/g in PM_2.5. The average mass of acetic acid was 11.2 mg/g in PM_2.5 and 20.0 mg/g in PM₁₀.     

炼化企业低温余热利用技术探讨＊

目前炼化企业有大量的低温余热需要回收,了解低温余热的来源、回收途径和技术,对提高低温余热利用效率十分重要。文章对炼厂低温余热的主要来源、利用途径和技术进行综合分析,提出炼厂低温余热回收利用的一些建议。     

镇江市征润州水源地水质自动监测网络的建设及应用研究

2012年2月3日,韩籍货轮苯酚泄漏造成镇江市自来水异味,造成市民的恐慌,严重影响着镇江市市民的正常生活,也引起镇江市市委市政府的高度重视。为了进一步实时动态监控水质变化状况,镇江市在征润州取水口上游新建两个水质自动站并结合原有的征润州水源水水质自动站,形成三点一线的长江沿岸的水质预警监测网络机制。在此着重介绍水源水水质自动监测系统的建设发展和应用,重视自动监测信息建设与数据共享问题,加强监控管理,质控管理体制和运行机制。     

氢氧化钙清液加氯化钙处理酸性高浓度含氟废水

研究了pH值、氯化钙投加量、搅拌时间及沉淀时间等因素对酸性高浓度含氟废水处理效果的影响;提出了采用氢氧化钙清液加氯化钙作为新型沉淀剂处理酸性高浓度含氟废水的工艺参数：pH值在8．5－9．5,按照nCa／F=0．7加入5％CaCl2溶液,搅拌45min、沉降90min;采用此工艺参数处理氟离子浓度为2600mg／L、pH值为2．97的废水,能把废水氟离子的浓度降至20mg／L以下,达到国家二级排放标准;采用本工艺取代传统工艺的好处是：沉渣中氟化钙纯度高,有利于废水中氟的回收利用。     

煤矸石在复垦土壤中的利用方式对水稻重金属含量的影响

本文通过以煤矸石为填充材料的复垦土壤上种植水稻的盆栽实验,研究在土壤复垦过程中煤矸石的填充方式和配比浓度对水稻籽粒和秸秆中重金属含量的影响。研究结果表明:在设定的煤矸石配比浓度范围内,水稻籽粒和秸秆中的重金属含量,都随煤矸石配比浓度的增加而增加,其中煤矸石配比浓度为40%时,增幅最大F元素在籽粒中的含量为0.921 mg/kg,是空白的1.12倍;在秸秆中的含量为9.064 mg/kg,是空白的4.19倍;煤矸石的两种填充方式下,水稻籽粒和秸秆中的重金属含量,大多呈现掺混式的大于垫底式的,其中煤矸石配比浓度为10%时,籽粒中差值最大的的F元素,含量相差了0.128 mg/kg,前者是后者的1.29倍;配比浓度为40%时,秸秆中差别最大的As元素,含量相差了0.352 mg/kg,掺混式的高于。垫底式的1.87倍。污染指数评价结果显示:籽粒中的重金属综合污染指数,皆小于1,未受到重金属污染,但在配比浓度为40%时,Hg的单项污染指数大于1,籽粒受到Hg的污染;秸秆的综合污染指数在1到3之间,重金属重污染程度严重,应对产出的秸秆妥善处理,以免对生态环境造成新的污染。     

The abundance,characteristics and diversity of microplastics in the South China Sea: Observation around three remote islands

• A high abundance of floating MPs was found in the southern South China Sea. • Transparent film and fiber were predominant in water and organisms, respectively. • 84.7% of floating MPs and 54.5% of MPs in vivo belonged to PP and PE. • Characteristics of MP in organisms were different from those of inshore ones. Surrounded by emerging markets with considerable plastic consumption, the South China Sea has been a focus area of microplastic research. A survey on the floating microplastics (>0.3 mm) and microplastics ingested by fish and mollusks was conducted around three remote islands here. Compared with the results from several previous studies, a high abundance of floating microplastics (with a median of 1.9 × 10⁵ items/km² or 0.7 items/m³) was observed, revealing another “hot spot” for microplastics. Polyolefin, especially polypropylene, was the main component. The diversity index and evenness index were calculated and evaluated based on the composition of microplastics. The characteristic peaks of Raman spectra concerning pigmented microplastics were provided. Transparent sheets/films were predominant in the water sample, which was quite different from a similar study in this sea area (8.9% for film), and only 16.4% of floating microplastics (>0.3 mm) were fibers/lines, implying that the main sources of floating microplastics (>0.3 mm) might be household/agricultural consumption activities. The transparent fiber/line was also dominant in organisms. It is suggested that the main sources of microplastics ingested by organisms might be both fabric fibers and fishing/aquaculture.     

Development of machine learning multi-city model for municipal solid waste generation prediction

● A database of municipal solid waste (MSW) generation in China was established. ● An accurate MSW generation prediction model (WGMod) was constructed. ● Key factors affecting MSW generation were identified. ● MSW trends generation in Beijing and Shenzhen in the near future are projected. Integrated management of municipal solid waste (MSW) is a major environmental challenge encountered by many countries. To support waste treatment/management and national macroeconomic policy development, it is essential to develop a prediction model. With this motivation, a database of MSW generation and feature variables covering 130 cities across China is constructed. Based on the database, advanced machine learning (gradient boost regression tree) algorithm is adopted to build the waste generation prediction model, i.e., WGMod. In the model development process, the main influencing factors on MSW generation are identified by weight analysis. The selected key influencing factors are annual precipitation, population density and annual mean temperature with the weights of 13%, 11% and 10%, respectively. The WGMod shows good performance with R² = 0.939. Model prediction on MSW generation in Beijing and Shenzhen indicates that waste generation in Beijing would increase gradually in the next 3–5 years, while that in Shenzhen would grow rapidly in the next 3 years. The difference between the two is predominately driven by the different trends of population growth.     

自制深井曝气设备处理屠宰废水试验研究

通过自制规模２５Ｌ深井曝光设备屠中宰废水进行处理，试验结果表明，在最佳操作条件下，曝气８ｈ，ＣＯＤ平均去除率可达８２．８３５，ＢＯＤ平均去除率可达８１．０９％，悬浮少平均去除率可达８５．２０％，动植物油平均去除率可达９４．５４％。出水水质可以达到肉类加工不工业水污染物排放标准ＧＢ１３４５７－９２的三组标准。而处理费用经估算仅为０．１５／ｍ＾３，是一种高效低耗处理屠宰废水的较