Sorption and photolysis studies in soil and sediment of the herbicide napropamide

Abstract

The influence of soil and sediment composition on sorption and photodegradation of the herbicide napropamide [N, N‐diethyl‐2‐(1‐naphthyloxy)propionamide] was investigated. Five soils and one sediment were selected for this study and the clay fractions were obtained by sedimentation. Sorption‐desorption was studied by batch equilibration technique and photolysis in a photoreactor emitting within 300–450 nm wavelenght with a maximum at 365 nm. Sorption increased with clay content and was not related to organic matter *content. High irreversibility of sorption was related to the greater montmorillonite content. The presence of soil or sediment reduced photolysis rate due to screen effect and this process did not depend on solid composition but on particle size distribution.     

On-Road Measurement of Vehicle Tailpipe Emissions Using a Portable Instrument

Abstract

A study design procedure was developed and demonstrated for the deployment of portable onboard tailpipe emissions measurement systems for selected highway vehicles fueled by gasoline and E85 (a blend of 85% ethanol and 15% gasoline). Data collection, screening, processing, and analysis protocols were developed to assure data quality and to provide insights regarding quantification of real-world intravehicle variability in hot-stabilized emissions. Onboard systems provide representative real-world emissions measurements; however, onboard field studies are challenged by the observable but uncontrollable nature of traffic flow and ambient conditions. By characterizing intravehicle variability based on repeated data collection runs with the same driver/vehicle/route combinations, this study establishes the ability to develop stable modal emissions rates for idle, acceleration, cruise, and deceleration even in the face of uncontrollable external factors. For example, a consistent finding is that average emissions during acceleration are typically 5 times greater than during idle for hydrocarbons and carbon dioxide and 10 times greater for nitric oxide and carbon monoxide. A statistical method for comparing on-road emissions of different drivers is presented. Onboard data demonstrate the importance of accounting for the episodic nature of real-world emissions to help develop appropriate traffic and air quality management strategies.     

The Impact of a Building Implosion on Airborne Particulate Matter in an Urban Community

Abstract

In response to community concerns, the air quality impact of imploding a 22-story building in east Baltimore, MD, was studied. Time- and space-resolved concentrations of indoor and outdoor particulate matter (PM) (nominally 0.5–10 µm) were measured using a portable nephelometer at seven and four locations, respectively. PM₁₀ levels varied in time and space; there was no measurable effect observed upwind of the implosion. The downwind peak PM₁₀ levels varied with distance (54,000–589 µg/m³) exceeding pre-implosion levels for sites 100 and 1130 m 3000- and 20-fold, respectively. Estimated outdoor 24-hr integrated mass concentrations varied from 15 to 72 µg/m³. The implosion did not result in the U.S. Environmental Protection Agency (EPA) National Ambient Air Quality Standard (NAAQS) for PM₁₀ being exceeded. X-ray fluorescence analysis indicated that the elemental composition was dominated by crustal elements: calcium (57%), silicon (23%), aluminum (7.6%), and iron (6.1%). Lead was above background but at a low level (0.17 µg/m³). Peak PM₁₀ concentrations were short-lived; most sites returned to background within 15 min. No increase in indoor PM₁₀ was observed even at the most proximate 250 m location. These results demonstrate that a building implosion can have a severe but short-lived impact on community air quality. Effective protection is offered by being indoors or upwind.     

Global warming is breeding social conflict: The subtle impact of climate change threat on authoritarian tendencies

Climate change can increase societies’ propensity to conflict by changes in socio-structural conditions (e.g., resource scarcity, migration). We propose an additional, subtle, and general effect of climate change threat via increases in authoritarian attitudes. Three studies in Germany and the UK support this suggestion. Reminding participants of the adverse consequences climate change may have for their country increased the derogation of societal groups that may threaten the collective (e.g., criminals) as well as general authoritarian attitudes. Salient climate change threats also led to system justification and approval of system supporting groups (e.g., judges) in those people who were highly identified with their nation. We discuss the implications of these findings for the explanation of authoritarian attitudes and the question of how societies may cope with the subtle social psychological effects of climate change.     

Ultraviolet irradiation effects incorporation of nitrate and nitrite nitrogen into aquatic natural organic matter

One of the concerns regarding the safety and efficacy of ultraviolet radiation for treatment of drinking water and wastewater is the fate of nitrate, particularly its photolysis to nitrite. In this study, N NMR was used to establish for the first time that UV irradiation effects the incorporation of nitrate and nitrite nitrogen into aquatic natural organic matter (NOM). Irradiation of (15)N-labeled nitrate in aqueous solution with an unfiltered medium pressure mercury lamp resulted in the incorporation of nitrogen into Suwannee River NOM (SRNOM) via nitrosation and other reactions over a range of pH from approximately 3.2 to 8.0, both in the presence and absence of bicarbonate, confirming photonitrosation of the NOM. The major forms of the incorporated label include nitrosophenol, oxime/nitro, pyridine, nitrile, and amide nitrogens. Natural organic matter also catalyzed the reduction of nitrate to ammonia on irradiation. The nitrosophenol and oxime/nitro nitrogens were found to be susceptible to photodegradation on further irradiation when nitrate was removed from the system. At pH 7.5, unfiltered irradiation resulted in the incorporation of (15)N-labeled nitrite into SRNOM in the form of amide, nitrile, and pyridine nitrogen. In the presence of bicarbonate at pH 7.4, Pyrex filtered (cutoff below 290-300 nm) irradiation also effected incorporation of nitrite into SRNOM as amide nitrogen. We speculate that nitrosation of NOM from the UV irradiation of nitrate also leads to production of nitrogen gas and nitrous oxide, a process that may be termed photo-chemodenitrification. Irradiation of SRNOM alone resulted in transformation or loss of naturally abundant heterocyclic nitrogens.     

Farming the battlefield: the meanings of war, cattle and soil in South Kivu, Democratic Republic of the Congo

Prior to 1996 and the Congolese wars, exploitative land policies pushed farmers in the eastern highlands of the Democratic Republic of the Congo (DRC) into a vulnerable position, with cattle manure sustaining intensive cultivation. This exposed households to a complete breakdown in mixed farming as cattle became targets of war. This study of villages in South Kivu offers an inside understanding of continuity and change in farming practices in a region where there are no easy solutions, and it assesses how the province lost its present and where farmers look when they glance to the future. For farmers, who hold a broad view of soil fertility, the casualties of war were not only people and cattle but also the land itself, which has enduring scars. Perceiving a rupture in tradition, South Kivu farmers are searching desperately for new livelihoods that are built on education instead of livestock, setting aside old ethnic signifiers to seek a future beyond protracted conflict.     

The United Nations Conference on the Human Environment Its Implications for Air Pollution Prevention Associations

In today's world of misunderstanding, confusion, and conflict man is sadly in need of some force for pulling together and unifying his efforts for peace, progress, safety, and health upon his native Planet. During the latter days of the Conference, when delegates from large nations and small nations and rich nations and poor nations were working tirelessly to reach agreement on a Declaration on the Human Environment, and during the closing hours of the Conference when the Declaration was approved by unanimous vote, it appeared to many persons that the environment might well be such a unifying force for mankind. Throughout the early days of the Stockholm sessions, the conflict of ideologies and political Dr. Barthel is the Director of the Institute of Environmental Sciences, Miami University, Oxford, Ohio 45056. He attended the Stockholm Conference as an accredited representative of the International Union of Air Pollution Associations. principles and severe disagreement on specific issues relating to the environment were all too apparent, but through pertinacity and splendid Conference leadership, differences were resolved and wide-scale agreements reached.     

Data Analysis Procedures for the Ozone NAAQS Statistical Format

The Clear Air Act of 1970 established the authority to control hazardous air pollutants. Section 112 of the legislation requires the Administrator to publish, and from time to time revise, a list of hazardous air pollutants for which he intends to establish emission standards, and to establish emission standards for those pollutants. These national emission standards for hazardous air pollutants are commonly referred to as “NESHAP” standards. All of the NESHAP that have been promulgated as of April 1984 are summarized in the table which accompanies this article. Two types of references are included in the table. The first reference identifies the issue of the Federal Register in which the NESHAP is explained in detail. The second reference identifies the background information document (BID) which contains the technical and economic information developed to support the NESHAP.     

Analyzing the Impacts of Off-Road Vehicle (ORV) Trails on Watershed Processes in Wrangell-St. Elias National Park and Preserve,Alaska

Trails created by off-road vehicles (ORV) in boreal lowlands are known to cause local impacts, such as denuded vegetation, soil erosion, and permafrost thaw, but impacts on stream and watershed processes are less certain. In Wrangell-St. Elias National Park and Preserve (WRST), Alaska, ORV trails have caused local resource damage in intermountain lowlands with permafrost soils and abundant wetlands and there is a need to know whether these impacts are more extensive. Comparison of aerial photography from 1957, 1981, and 2004 coupled with ground surveys in 2009 reveal an increase in trail length and number and show an upslope expansion of a trail system around points of stream channel initiation. We hypothesized that these impacts could also cause premature initiation and headward expansion of channels because of lowered soil resistance and greater runoff accumulation as trails migrate upslope. Soil monitoring showed earlier and deeper thaw of the active layer in and adjacent to trails compared to reference sites. Several rainfall-runoff events during the summer of 2009 showed increased and sustained flow accumulation below trail crossings and channel shear forces sufficient to cause headward erosion of silt and peat soils. These observations of trail evolution relative to stream and wetland crossings together with process studies suggest that ORV trails are altering watershed processes. These changes in watershed processes appear to result in increasing drainage density and may also alter downstream flow regimes, water quality, and aquatic habitat. Addressing local land-use disturbances in boreal and arctic parklands with permafrost soils, such as WRST, where responses to climate change may be causing concurrent shifts in watershed processes, represents an important challenge facing resource managers.     

Nanoscale zero-valent iron (nZVI): aspects of the core-shell structure and reactions with inorganic species in water

Aspects of the core-shell model of nanoscale zero-valent iron (nZVI) and their environmental implications were examined in this work. The structure and elemental distribution of nZVI were characterized by X-ray energy-dispersive spectroscopy (XEDS) with nanometer-scale spatial resolution in an aberration-corrected scanning transmission electron microscope (STEM). The analysis provides unequivocal evidence of a layered structure of nZVI consisting of a metallic iron core encapsulated by a thin amorphous oxide shell. Three aqueous environmental contaminants, namely Hg(II), Zn(II) and hydrogen sulfide, were studied to probe the reactive properties and the surface chemistry of nZVI. High-resolution X-ray photoelectron spectroscopy (HR-XPS) analysis of the reacted particles indicated that Hg(II) was sequestrated via chemical reduction to elemental mercury. On the other hand, Zn(II) removal was achieved via sorption to the iron oxide shell followed by zinc hydroxide precipitation. Hydrogen sulfide was immobilized on the nZVI surface as disulfide (S(2)(2-)) and monosulfide (S(2-)) species. Their relative abundance in the final products suggests that the retention of hydrogen sulfide occurs via reactions with the oxide shell to form iron sulfide (FeS) and subsequent conversion to iron disulfide (FeS(2)). The results presented herein highlight the multiple reactive pathways permissible with nZVI owing to its two functional constituents. The core-shell structure imparts nZVI with manifold functional properties previously unexamined and grants the material with potentially new applications.