Simulating the Impact of Cover Degradation on RCRA Landfill Performance

The ability of near‐surface disposal facility cover designs to meet percolation performance criteria is influenced by degradation occurring over long periods of time. This study was conducted to determine the effect of degradation on percolation based on probabilistic distributions derived from historical climate data. Water‐balance predictions were evaluated using the HELP model, employing several variations of degradation in a traditional Resource Conservation and Recovery Act disposal facility cover design over a 100‐year simulation period. Analysis results were evaluated relative to two different selected thresholds for annual percolation (1 mm and 3 mm). Approximately 20 percent of the results did not exceed both the 1‐mm and 3‐mm thresholds, while 10 percent of the realizations exceeded the 1‐mm threshold but not the 3‐mm threshold, with remaining cases exceeding the 3‐mm threshold. These results demonstrate the importance of considering degradation in designing near‐surface disposal facilities, especially given the very long performance periods desired by different regulators. © 2013 Wiley Periodicals, Inc.     

Comparison of LLW Disposal Facilities at Major Department of Energy Sites

Near surface disposal facility design and management are examined and compared using a systems approach that defines facility performance as a function of three components (or subsystems): the disposal facility design (cover systems and bottom liners); the properties of the waste (waste composition, waste form and waste package); and the site‐specific environmental features (climate, geology, and hydrology). We report an evaluation of five DOE near surface disposal facility case studies, selected to provide a “representative” sample that included disposal sites with a range of waste and environmental characteristics across the DOE. The facilities selected were the Savannah River E‐Area Engineered Trenches, Hanford Integrated Disposal Facility, Idaho Radioactive Waste Management Complex, Oak Ridge Environmental Management Waste Management Facility, and Nevada National Security Site Area 5. ©2015 Wiley Periodicals, Inc.     

Summer total phosphorus in lakes: A map of Minnesota,Wisconsin, and Michigan,USA

A map of summer total phosphorus in lakes has been compiled for Minnesota, Wisconsin, and Michigan to clarify regional patterns in attainable lake trophic state. Total phosphorus was used as a measure of lake trophic state because: (1) phosphorus plays a central role in controlling the overall fertility of most lakes, (2) total phosphorus values are available for a great number of lakes, and (3) phosphorus is measured in a consistent manner. The maps were compiled using patterns of total phosphorus data and observed associations between these data and geographic characteristics including physiography, land use, geology, and soils. Regions depicted on the map represent areas of similarity in phosphorus concentrations in lakes, or similarity in the mosaic of values, as compared to adjacent areas. Within each region, differences in total phosphorus can be compared to natural and anthropogenic factors to determine the types of lakes representative of each region, the factors associated with differences in quality, and the realistically attainable phosphorus levels for each type of lake.     

An assessment of the impact of ambient ozone on field-grown crops in New Jersey using the EDU method: part 2-soybean (Glycine max (L.) Merr.)

The yields of eleven commercially grown soybean cultivars were compared in ethylenediurea (EDU)-treated and non-treated field plots in New Brunswick, New Jersey, over a 4 year period. No statistically significant difference between treatments was found for any cultivar; the inference being ambient ozone did not adversely affect soybean yield. Succeeding field experiments supported this interpretation of the data. 'Sanilac' white bean, a legume known to be more sensitive to O(3) than soybean, was found to produce a significantly greater yield in EDU-treated than non-treated plots, unlike a companion planting of 'Williams 82' soybean which did not exhibit the differential response. The results indicated that the specific EDU protocol used in the soybean experiments is capable of detecting an ozone effect in a legume. Moreover, in a concurrent greenhouse experiment the yield of EDU-treated Sanilac white bean was not significantly different from non-treated plants in the absence of ozone pollution. In a dose-response field experiment during a year of unusually high O(3) pollution, yield of 'Williams 82' increased slightly with each EDU increment up to 500 ppm and decreased at 1000 ppm. The difference between non-treated and EDU-treated plants, however, was not statistically significant. There was no evidence to suggest that the EDU concentration (500 ppm) used in previous soybean experiments reduced seed yield. Fortuitously, the tolerance of commercially-grown soybean to ambient ozone is at least partially conditioned by the practce of not irrigating the crop. The New Jersey results are in agreement with reports from Maryland, Georgia and Tennessee in which an adverse impact of ambient O(3) was not found in soybean, but contrary to a current predictive model.     

Decline of the Shasta Crayfish (Pacifastacus fortis Faxon) of Northeastern California

Native freshwater faunas in North America are declining, principally due to the combined effects of habitat degradation and introduced species. Relatively little attention has been directed to the decline of freshwater invertebrates, which may be even more threatened than fishes. This paper chronicles recent changes in the distribution and abundance of the Shasta crayfish ( Pacifastacus fortis Faxon), a state and federally endangered species endemic to the midreaches of the Pit River system in northeastern California. We made snorkeling and SCUBA surveys for crayfish in 1990 and 1991 and examined various records for historic distributions. Shasta crayfish have been extirpated from much of their historic range by water impoundment and diversion, and they are further threatened by two introduced crayfish species ( Pacifastacus leniusculus Dana and Orconectes virilis Hagen). By 1990 Shasta crayfish were restricted to seven isolated populations, mostly in the headwaters of spring-fed tributaries to the Pit river. P. leniusculus had become established throughout much of the study area in about 12 years. In one site P. leniusculus probably contributed to the precipitous decline of Shasta crayfish, from 2000–3000 in 1980 to about 370 (± 135) in 1991. O. virilis , which occurred in only the most disturbed parts of the system, showed little range expansion in 30 years and had been replaced in a large stretch of the Pit River by P. leniusculus. P. leniusculus occupied sites with a broad range of habitat variables (temperature, pH, turbidity, substrate size) partly or wholly overlapping measures of sites with the other two species. The decline of the Shasta crayfish, like the extinction of its closest relative P. nigrescens in the San Francisco Bay area earlier this century, reflects the decline of its habitat and probably pressure from the aggressive exotic P. leniusculus .     

Growth in the bivalve Yoldia eightsi at Signy Island,Antarctica, determined from internal shell increments and calcium-45 incorporation

The growth rate of the infaunal nuculanid bivalve Yoldia eightsi at Factory Cove, Signy Island, South Orkney Islands (maritime Antarctica), was estimated from internal shell increments and ⁴⁵Ca incorporation of individuals collected monthly from December 1987 to April 1989. Acetate peels of etched shells revealed clear first-order increments, with less well defined, narrower, second-and third-order increments. The first-order increments were assumed to be annual, although there is no independent confirmation of this assumption. Unfortunately abrasion of the umbo region and the small thin shells of Y. eightsi meant that in no case could a complete sequence of increments be measured realiably on any individual shell. Measurements of 1043 first-order increments from 130 shells where a minimum of two consecutive increments could be detected were therefore pooled, and a population growth curve constructed from a Ford-Walford plot. This indicated a slow growth rate, with a maximum shell height of 22.3 mm (equivalent to a shell length of 35.6 mm) being reached at an age >60 yr. The size-frequency distribution of 1521 individuals pooled from winter (July to October) samples revealed a distinct lack of smaller (younger) individuals, possibly reflecting poor recruitment in areas of dense adult populations. The largest shell recovered in the samples was 33.5 mm in length, with an estimated age of 52 yr. Short-term ⁴⁵Ca-incorporation experiments indicated a mean daily rate of growth increment of 3.8 m for individuals of 12 mm shell height, which matches the proposed annual growth rate if growth is assumed to occur for about 150 d each year and the first-order increments are assumed to be annual.     

Similarity-based testing for community pattern: the two-way layout with no replication

The large, sparse arrays of species counts arising in both field and experimental community studies do not lend themselves to standard statistical tests based on multivariate normality. Instead, a valid and more revealing approach uses informal display methods, such as clustering or multi-dimensional scaling ordination (MDS), based on a biologically-motivated definition of pairwise similarity of samples in terms of species composition. Formal testing methods are still required, however, to establish that real assemblage differences exist between sites, times, experimental treatments, pollution states, etc. Earlier work has described a range of Manteltype permutation or randomisation procedures, making no distributional assumptions, which are termed ANOSIM tests because of their dependence only on (rank) similarities and the analogy to one and two-way ANOVA. This paper extends these tests to cover an important practical case, previously unconsidered, that of a two-way layoutwithout replication. Such cases arise for single samples (or pseudo-replicates) taken in a baseline monitoring survey of several sites over time, or a mesocosm experiment in which treatments are replicated only once within each experimental block. Significance tests are given for the overall presence of a treatment (or time) effect, based on a measure of concordance between rank similarities of samples within each block (or site); the role of the two factors can be reversed to obtain a test for block effects. As in the analogous univariate ANOVA test, the method relies on absence or relative weakness of treatment x block interactions. Its scope is illustrated with data from two experimental and two field studies, involving meiofaunal communities from soft-sediment and macro-algal habitats. It is seen also to accommodate a modest derree of missing data. Whilst the failure to replicate adequately is not encouraged—a richer inference is available with genuine replication—the paper does provide a limited way forward for hypothesis testing in the absence of replicates.     

Exploring the effects of state highway safety laws and sociocultural characteristics on fatal crashes

Objective: Distinguished from the traditional perspectives in crash analyses, which examined the effects of geometric design features, traffic factors, and other relevant attributes on the crash frequencies of roadway entities, our study focuses on exploring the effects of highway safety laws, as well as sociocultural characteristics, on fatal crashes across states.

Methods: Law and regulation related data were collected from the Insurance Institute for Highway Safety, State Highway Safety Offices, and Governors Highway Safety Association. A variety of sociodemographic characteristics were obtained from the U.S. Census Bureau. In addition, cultural factors and other attributes from a variety of resources are considered and incorporated in the modeling process. These data and fatal crash counts were collected for the 50 U.S. states and the District of Columbia and were analyzed using zero-truncated negative binomial (ZTNB) regression models.

Results: The results show that, in law and regulation–related factors, the use of speed cameras, no handheld cell phone ban, limited handheld cell phone ban, and no text messaging ban are found to have significant effects on fatal crashes. Regarding sociocultural characteristics, married couples with both husband and wife in the labor force are found to be associated with lower crash frequencies, the ratios of workers traveling to work by carpool, those driving alone, workers working outside the county of residence, language other than English and limited English fluency, and the number of licensed drivers are found to be associated with higher crash frequencies.

Conclusions: Through reviewing and modeling existing state highway safety laws and sociocultural characteristics, the results reveal new insights that could influence policy making. In addition, the results would benefit amending existing laws and regulations and provide testimony about highway safety issues before lawmakers consider new legislation.     

Use of the partition coefficient as an indicator of bioaccumulation tendency of dyestuffs in fish

Dyestuffs generally do not readily undergo aerobic biodegradation during sewage treatment processes and for new products an assessment of their bioaccumulation in fish is a requirement under certain environmental chemicals legislation. The results presented in this paper show that the partition coefficient in n-octanol/water is a useful indicator of the bioaccumulation tendency of dyestuffs, thus supporting its use as a screening test for bioaccumulation as proposed by the OECD Chemicals Testing Programme.