Restoration of hyper-eutrophic water with a modularized and air adjustable constructed submerged plant bed

A modularized and air adjustable constructed submerged plant bed (CSPB) which can be used to restore the eutrophic water is introduced in this paper. This plant bed helps hydrophyte grow under poor conditions such as frequently changed water depth, impaired water transparency, algae bloom and substantial duckweed in summer, which are not naturally suitable for growing hydrophyte. This pilot study in Waihuan River of Tianjin, China, revealed that reduction of Chemical Oxygen Demand (COD), Total Nitrogen (TN) and Total Phosphorus (TP) by the use of CSPB could be reached 30%–35%, 35%–40%, 30%–40% respectively in the growing season (from March to October) and 5%–10%, 5%–15%, 7%–20% respectively in the winter (from November to February) when the detention time was 6 d. The relationships between the concentration of COD, TN, TP and the detention time fit the first-order kinetic equation well and the coefficients of determination (R²) were all above 0.9. The attenuation coefficients k of the kinetic equation were a function of the water temperature. When the water temperature was quite low or quite high, k was not significantly changed with increasing or decreasing water temperature. While when the temperature was in a moderate range, an increase or decrease of water temperature would lead to a rapid increase or decrease in k.     

Pesticide in the Mississippi River floodplain and its possible linkage to colon cancer risk in the US

Result of this study shows that elevated colorectal cancer risk in Mississippi River floodplain of the United States is likely linked to historically high pesticide application. Mississippi River basin produces about 80% of major US crops and has about two-thirds of US pesticides used for agriculture. Historically, heavy pesticide application and agricultural irrigation were reported to result in high pesticide residues in surface water, fish and wells of Mississippi embayment. Risk ratio of colorectal cancer incidence in 86 counties of Mississippi River floodplain was about 29% higher than that of other counties in the 48 contiguous states. Risk ratio of colon cancer mortality in 63 counties of Mississippi embayment was 33% higher than that of other counties in the 48 states between 1999 and 2016. Risk ratios of colorectal cancer incidence and colon cancer mortality in Mississippi River floodplain are higher after smoking and diabetes factors were filtered off. Previous studies have linked exposure to pesticide with type-II diabetes and the latter was linked to increasing colon cancer risk by about 27%. Result here suggests that pesticide may be an independent risk factor directly associated with elevated colon cancer risk in Mississippi River floodplain.     

The smell of desperadoes? Beavers distinguish between dominant and subordinate intruders

Olfactory signals can contain information, such as age and social status, and play a vital role in competitor assessment. In many territorial species, subordinates must leave their natal colony to obtain their own territory and mate. These individuals could be aggressive opponents in agonistic encounters, as they will have little to lose (the desperado effect). In this study, we tested the hypothesis that dominance and age are coded in the anal gland secretion (AGS) of the monogamous and highly territorial Eurasian beaver (Castor fiber), and if this information is used by conspecifics to evaluate the potential threat posed by an intruder. Territorial intrusions were simulated by presenting residents with a two-way choice test of AGS from an unknown male territory owner (i.e., dominant) and his son (i.e., subordinate; either 1 or ≥2 years old). Residents spent more time investigating AGS from subordinates than their fathers and responded more aggressively to subordinates than their fathers when subordinates were ≥2 years old. Chemical analyses gas chromatography and multivariate data analysis supported our behavioral findings and revealed differences between chemical profiles of territory owners and subordinates, as well as between the subordinates in different age classes. This study reveals that information about age and social status is coded in AGS of beavers and that this information is used to determine the level of an eventual future response to the signaler.     

pH值对垃圾渗滤液中溶解有机物检测的影响及分析

在恒定温度下,研究了不同pH值时垃圾渗滤液中有机物检测结果的变化并分析了原因。实验得出:在pH=7.17时UV254值最低;在酸性条件下,UV254值随pH值增加而下降;在碱性条件下,UV254值随pH值的增加而增加;UV410值基本不随pH的变化而变化;溶解性有机物荧光强度在pH=3.95处和pH=12.06处都产生比较强的荧光值,而在pH=9处荧光强度最弱。建议在进行垃圾渗滤液中有机物检测时保证pH恒定。     

软锰矿浆烟气同步脱硫脱硝资源化利用新工艺

燃煤烟气中的SO2和NOx是大气中重要的污染物,开发高效、经济的同步脱硫脱硝技术是环保领域的研究热点。针对现有同步脱硫脱硝技术存在的氧化剂成本较高和产物不能资源化利用等突出问题,提出了软锰矿浆烟气同步脱硫脱硝,并副产硫酸锰和硝酸锰的资源化新工艺。研究结果表明:软锰矿浆可以有效的脱除烟气中的SO2和NOx,反应产物分别为硫酸锰和硝酸锰。在烟道中注入臭氧,将难溶于水的NO快速氧化为NO2,可大大提高脱硝效率,在O3/NO=1.2的条件下可以达到72%的脱硝率、90%的脱硫率和85%的锰浸出率;吸收液经过空气氧化除铁和加入铜试剂除重金属后,结晶分离溶液得到的硫酸锰和硝酸锰可分别达到HG/T 2962—1999标准的硫酸锰产品和HG/T 3817—2006标准的工业硝酸锰产品要求。该工艺实现了SO2和NOx污染治理与低品位软锰矿资源化利用的双重目的,为SO2和NOx的资源化污染治理技术的开发和应用提供了新的思路。     

液氮冻融破碎生物污泥制备生物絮凝剂

利用城市剩余生物污泥,采用液氮冻融破碎、提取液提取的方法制备了生物污泥絮凝剂。对絮凝剂的制备条件及其絮凝性能进行了研究,结果表明:采用液氮冻融破碎,pH为1.0的稀盐酸溶液作为提取液提取所制备的絮凝剂,对高岭土悬浮液的絮凝效率可达98.5%。液氮冻融破碎的次数对絮凝剂制备没有明显影响。同时考察了絮凝剂投加量以及絮凝体系的pH对絮凝剂絮凝活性的影响。     

Acidity of machine-made snow and its effect on pH and aluminum speciation in New England streams during spring thaw

The pH of machine-made snow and its effect on an acid-sensitive watershed in Vermont were studied. Spring runoff from snowmaking was found to be less acidic and to contain less dissolved inorganic aluminum. Dissolved inorganic aluminum has been associated with damage to aquatic life. The extensive use of machine-made snow by the ski industry in most of the northeast region of the US may be beneficial to aquatic life.     

Preliminary Evaluation of the Use of Phosphogypsum for Reef Substrate. I. A Laboratory Study of Bioaccumulation of Radium and Six Heavy Metals in an Aquatic Food Chain

Phosphogypsum (PG), a solid by-product of phosphoric acid production, contains radionuclides and trace metals in concentrations which may pose a potential hazard to human health and the environment. to investigate the possibility of bioaccumulation of radium and six heavy metals over time when aquatic organisms experience both trophic and environmental exposure to PG, we designed a laboratory experiment representing three levels of an aquatic food chain. During the 135 day experiment, a meiobenthic copepod species (Amphiascoides atopus) was cultured in the presence of PG. the copepods were subsequently fed to grass shrimp (Palaemonetes vulgaris and P. pugio) which were in turn fed to gulf killifish (Fundulus grandis); both the grass shrimp and the killifish also experienced an environmental PG exposure. Other than elevated radium levels in the experimental grass shrimp, the experiment demonstrated little effect of environmental or trophic exposure to PG on microinvertebrates, macroinvertebrates, or fishes that could be attributed to PG. in all cases where increased concentrations were indicated within the experimental group, roughly equivalent increases in metal concentrations also occurred in the control group.     

Biodegradability of organic substances by ATP test

The aerobic biodegradability of organic substances in water is characterized by determination of energy change ‐ ATP content in microbial cells during biodegradation. A satisfactory result is obtained under the following conditions: the initial concentration of tested substance is 100mg/l (as DOC), the amount of the inoculum in the biological medium is 500mg/l (as MLSS), and the duration of test time is 14 days. The evaluating system (peak time, peak height and IA index) is proposed to assess the biodegradability of 46 organic compounds and 7 wastewaters.     

The political ecology of Yukon forestry: managing the forest as if people mattered

Over the past several decades a growing interest has emerged in the relationship between forest dependent communities and their use of non-timber forest resources (NTFR—i.e. berries, roots, barks). Motivated in large part by international concerns over the loss of biological and cultural diversity, efforts are now being made to conserve the world's remaining forests by repositioning NTFR to the forefront of the forest management process. Together with the Little Salmon Carmacks First Nation, we have undertaken an assessment that: 1) addresses the role of NTFR in fulfilling basic human necessities and well-being of community members, and 2) identifies the perceptual differences that exist among First Nation and non-First Nation community members regarding the security and future availability of forest resources. Based on our findings, we argue that if the true value of the forest is to be understood, and thus sustained, those involved in management must consider the full array of products and services the forest provides. Thus the conventional and over-simplified view that the forest is to provide primarily for commercial timber must be challenged in light of the multiplicity of values community members gain from forest use.