Field water balance of landfill final covers

Landfill covers are critical to waste containment, yet field performance of specific cover designs has not been well documented and seldom been compared in side-by-side testing. A study was conducted to assess the ability of landfill final covers to control percolation into underlying waste. Conventional covers employing resistive barriers as well as alternative covers relying on water-storage principles were monitored in large (10 x 20 m), instrumented drainage lysimeters over a range of climates at 11 field sites in the United States. Surface runoff was a small fraction of the water balance (0-10%, 4% on average) and was nearly insensitive to the cover slope, cover design, or climate. Lateral drainage from internal drainage layers was also a small fraction of the water balance (0-5.0%, 2.0% on average). Average percolation rates for the conventional covers with composite barriers (geomembrane over fine soil) typically were less than 12 mm/yr (1.4% of precipitation) at humid locations and 1.5 mm/yr (0.4% of precipitation) at arid, semiarid, and subhumid locations. Average percolation rates for conventional covers with soil barriers in humid climates were between 52 and 195 mm/yr (6-17% of precipitation), probably due to preferential flow through defects in the soil barrier. Average percolation rates for alternative covers ranged between 33 and 160 mm/yr (6 and 18% of precipitation) in humid climates and generally less than 2.2 mm/yr (0.4% of precipitation) in arid, semiarid, and subhumid climates. One-half (five) of the alternative covers in arid, semiarid, and subhumid climates transmitted less than 0.1 mm of percolation, but two transmitted much more percolation (26.8 and 52 mm) than anticipated during design. The data collected support conclusions from other studies that detailed, site-specific design procedures are very important for successful performance of alternative landfill covers.     

Enhancing the effectiveness of graduated driver licensing legislation

PROBLEM: Many states have enacted graduated driver licensing (GDL) systems in an effort to reduce the very high crash rates of young beginning drivers. This article addresses how to achieve the maximum benefit from GDL by ensuring compliance with protective restrictions. ENHANCING GDL THROUGH SYSTEM STRUCTURE: The major crash reductions due to GDL systems result from the protective restrictions during the initial two levels, which isolate novice drivers from the highest risk driving situations. Accordingly, GDL systems should include protective restrictions that adequately control the greatest dangers facing young drivers: multiple teen passengers and night driving before midnight. ENCOURAGING COMPLIANCE THROUGH SYSTEM STRUCTURE: Including protective restrictions that are supported by parents and teens will encourage compliance. Furthermore, linking a teen's advancement through GDL to demonstrated responsible driving will likely encourage compliance more than threatening punishment for violations. ENCOURAGING COMPLIANCE THROUGH ENFORCEMENT: Parents are in a prime position to enforce most GDL restrictions, but there is some evidence they do not enforce those restrictions that they consider too extreme. Little is currently known about the involvement of law enforcement in GDL systems, but there is potential for high visibility law enforcement activities to encourage compliance with restrictions. IMPACT ON RESEARCH, PRACTICE, AND POLICY: There is a need for better designed GDL systems in many states; more research is needed to examine compliance with restrictions and to evaluate enforcement efforts by parents and law enforcement.     

Soil sorption of acidic pesticides: modeling pH effects

A model of acidic pesticide sorption in soils was developed from theoretical modeling and experimental data, which initially considered a combination of a strongly acidic pesticide and a variable-charge soil with high clay content. Contribution of 2,4-D [(2,4-dichlorophenoxy) acetic acid] anionic-form sorption was small when compared with molecular sorption. Dissociation of 2,4-D was not sufficient to explain the variation in Kd as a function of pH. Accessibility of soil organic functional groups able to interact with the pesticide (conformational changes) as a function of organic matter dissociation was proposed to explain the observed differences in sorption. Experimental 2,4-D sorption data and K(oc) values from literature for flumetsulam [N-(2,6-difluorophenyl)-5-methyl [1,2,4] triazolo [1,5-a] pyrimidine-2-sulfonamide] and sulfentrazone [N-[2,4-dichloro-5-[4-(difluromethyl)-4,5-dihydro-3-methyl-5-oxo-1H-1,2,4-triazol-1-yl] phenyl] methanesulfonamide] in several soils fit the model.     

Radioactivity in environmental samples: Calibration standards measurement methods,quality assurance,and data analysis

The numerous environmental radioactivity measurements made by and for the U.S. Environmental Protection Agency (U.S. EPA) include measurements on samples of water, urine, food, milk, and air filters. Calibration standards are listed which are available in the form of water solutions and soils for a wide range of radionuclides. Method validation procedures for U.S. EPA approval include protocol development and single-laboratory and multiple-laboratory evaluation for precision and accuracy. Interlaboratory comparison studies are conducted for both cross-check and performance evaluation samples and involve 295 federal, state, and local laboratories. For water samples, 80%–90% of the participating laboratories are within the control limits for most of the radionuclides measured; however, some problem areas exist, especially for radium-228 and strontium-89 and -90. For milk and food samples, more than 90% of the laboratories are within control limits for cobalt-60 and cesium-137 but some problems exist for the measurement of strontium-90, iodine-131, and potassium-40. For tritium, 91% of the laboratories are within the control limit for water samples and 87% are within the control limits for the urine samples. The laboratory performance for air filter samples shows some problems for gross beta, strontium-90 and cesium-137 measurements.     

Materials policy — planning for consensus : Henniker V

The 1978 Henniker Conference on materials policy attracted a record number of participants from the USA and abroad. The week-long biennial gathering brought together 110 high-level materials administrators, policy makers, and researchers from government and private sectors. Henniker V, 30 July-4 August 1978, Henniker, New Hampshire.     

An implementation assessment of China’s Environmental Information Disclosure Decree

China’s 2007 Open Government Information Regulations is widely considered as a milestone in the country’s information policy history and is praised as a “sunshine program”. The Environmental Information Disclosure Decree was the first to operationalize these general regulations into a sectoral information disclosure system on environment. This study assessed the implementation of the environmental information disclosure system about six months after the Decree took e ect on May 1, 2008. Through reviewing the websites of all 31 provincial Environmental Protection Bureaus and the Ministry of Environmental Protection, conducting an experiment with actual information disclosure request, and through interviews with all provincial Environmental Protection Bureaus, this article concluded that the implementation of the environmental information disclosure system still falls short. Future improvements should focus on further publicity of the regulations and decree to enhance public participation, the establishment of an independent evaluation and supervision system for information disclosure, the exchange of experiences and best practices among provincial Environmental Protection Bureaus, and on strengthening the legal status of environmental information disclosure.