Incremental cost-effectiveness of incorporating oestriol evaluation in down syndrome screening programmes

As screening for Down syndrome becomes increasingly sophisticated, it is important to evaluate the newer technologies in terms of their cost-effectiveness. One recent addition to Down syndrome screening programmes is maternal serum unconjugated oestriol (uE₃), especially when used in conjunction with maternal serum α-fetoprotein and human chorionic gonadotropin. Using assumptions used in a California proposal to justify an expanded screening programme for Down syndrome, we calculated both the average and the incremental cost-effectiveness of adding uE₃. Using the base case assumptions, including an $8 fee for the uE₃, the incremental cost-effectiveness of adding uE₃ to the proposed California programme is $119 100 per case detected, a value that compares favourably with other Down syndrome screening programmes. The sensitivity analysis supports this conclusion over a wide range of assumptions. However, because of the uncertainty with some key data, it is still too early to fully support the inclusion of uE₃ in Down syndrome screening programmes.     

CONTRIBUTION OF PRECIPITATION TO QUALITY OF URBAN STORM RUNOFF1

Precipitation and runoff samples were collected for 13 storms in a nonindustrial urban area in Central Pennsylvania between July 1980 and June 1981. Runoff was collected from tree surfaces, a residential roof and street, a shopping mall parking lot, a downtown business district alley, and a heavily traveled street. Analysis of the water samples showed 10 to 25 percent of the nitrogen, 25 percent of the sulfate, and less than 5 percent of the phosphorus, potassium, and calcium in water below a tree was deposited by the precipitation. The residential roof caused insignificant changes in water chemistry. The results for the four paved areas showed that all the nitrogen, and from 16 to 40 percent of the sulfate and 13, 4, and 2 percent of the phosphorus, potassium, and calcium, respectively, in runoff was deposited by the precipitation. Precipitation can also be an important source of sulfate and phosphorus in runoff. All of the surfaces raised the pH of the runoff, with the largest increases, from a pH of 4 to about 7, occurring in runoff from the paved areas. Precipitation and runoff chemistry was not related to antecedent conditions such as the length of the preceding dry period.     

Rainfall timing and frequency influence on leaching of Escherichia coli RS2G through soil following manure application

The time between swine (Sus scrofa) manure application to soil as a crop fertilizer, the first rainfall event, and the frequency of rainfall events should influence leaching potential of fecal pathogens. Soil microcosms were inoculated in the lab with a swine manure isolate of Escherichia coli, strain RS2G, expressing green fluorescent protein, to examine how timing and frequency of rainfall events influences RS2G leaching and survival in soil. Liquid swine manure inoculated with RS2G was applied to intact soil cores (20 cm in diameter x 30 cm long) 4, 8, or 16 d before the first rainfall event (50.8 mm over a 4-h period), and each core received one to three rainfall events. Manure application methods (no-till surface-broadcast, broadcast and incorporated, and tilled before broadcast) had no affect on leaching, although there was greater survival in soils when the manure had been incorporated. Most of the RS2G in the leachate appeared following the first rainfall event and RS2G leaching decreased with increasing time between manure application and the first rainfall, although leachates contained as much as 3.4 to 4.5 log colony forming units (CFU) 100 mL(-1) of RS2G when the first rainfall occurred 16 d after manure application. With increasing frequency of rainfalls there was a decrease in subsequent concentrations of RS2G in the leachate. There was no correlation between leachate RS2G and total coliforms or fecal streptococci concentrations. Soil RS2G numbers were 1 to 10% of the inoculum regardless of the length of time between manure application and the first rainfall. RS2G leaching was mostly influenced by the time between manure application and first rainfall event, and significant leaching and survival in soil was possible even if the first rain occurred 16 d after manure application.     

Metal distribution and stability in constructed wetland sediment

The A-01 wetland treatment system (WTS) is a surface flow wetland planted with giant bulrush [Schoenoplectus californicus (C.A. Mey.) Palla] that is designed to remove Cu and other metals from the A-01 National Pollution Discharge Elimination System (NPDES) effluent at the Savannah River Site near Aiken, SC. Copper, Zn, and Pb concentrations in water were usually reduced 60 to 80% by passage through the treatment system. The Cu concentrations in the wetland sediments increased from about 4 to 205 and 796 mg kg(-1), respectively, in the organic and floc sediment layers in cell 4A over a 5-yr period. Metal concentrations were higher in the two top layers of sediment (i.e., the floc and organic layers) than in the deeper inorganic layers. Sequential extraction was used to evaluate remobilization and retention of Cu, Pb, Zn, Mn, and Fe in the wetland sediment. Metal remobilization was determined by the potentially mobile fraction (PMF) and metal retention by the recalcitrant factor (RF). The PMF values were high in the floc layer but comparatively low in the organic and inorganic layers. High RF values for Cu, Zn, and Pb in the organic and inorganic layers indicated that these metals were strongly bound in the sediment. The RF values for Mn were lower than for the other elements especially in the floc layer, indicating low retention or binding capacity. Retention of contaminants was also evaluated by distribution coefficient (Kd) values. Distribution coefficient (Kd) values were lower for Cu and Zn than for Pb, indicating a smaller exchangeable fraction for Pb.     

Scientific research, stakeholders, and policy: continuing dialogue during research on radionuclides on Amchitka Island, Alaska

It is increasingly clear that a wide range of stakeholders should be included in the problem formulation phase of research aimed at solving environmental problems; indeed the inclusion of stakeholders at this stage has been formalized as an integral part of ecological risk assessment. In this paper, we advocate the additional inclusion of stakeholders in the refinement of research methods and protocols and in the execution of the research, rather than just at the final communication and reporting phase. We use a large study of potential radionuclide levels in marine biota around Amchitka Island as a case study. Amchitka Island, in the Aleutian Island Chain of Alaska, was the site of three underground nuclear tests (1965-1971). The overall objective of the biological component of the study was to collect a range of marine biota for radionuclide analysis that could provide data for assessing current food safety and provide a baseline for developing a plan to monitor human and ecosystem health in perpetuity. Stakeholders, including regulators (State of Alaska), resource trustees (US Fish and Wildlife Service, State of Alaska), representatives of the Aleut and Pribilof Island communities, the Department of Energy (DOE), and others, were essential for plan development. While these stakeholders were included in the initial problem formulation and approved science plan, we also included them in the refinement of protocols, selection of bioindicators, selection of a reference site, choice of methods of collection, and in the execution of the study itself. Meetings with stakeholders resulted in adding (or deleting) bioindicator species and tissues, prioritizing target species, refining sampling methods, and recruiting collection personnel. Some species were added because they were important subsistence foods for the Aleuts, and others were added because they were ecological equivalents to replace species deleted because of low population numbers. Two major refinements that changed the research thrust were (1) the inclusion of Aleut hunters and fishers on the biological expedition itself to ensure that subsistence foods and methods were represented, and (2) the addition of a fisheries biologist on a NOAA research trawler to allow sampling of commercial fishes. Although the original research design called for the collection of biota by Aleut subsistence fishermen, and by a commercial fishing boat, the research was modified with continued stakeholder input to actually include Aleuts and a fisheries biologist on the expeditions to ensure their representation. The inclusion of stakeholders during the development of protocols and the research itself improved the overall quality of the investigation, while making it more relevant to the interested and affected parties. Final responsibility for the design and execution of the research and radionuclide analysis rested with the researchers, but the process of stakeholder inclusion made the research more valuable as a source of credible information and for public policy decisions.     

Seasonal variation in microbial communities and organic malodor indicator compound concentrations in various types of swine manure storage systems

Anaerobic manure storage systems are one of the major contributors to the odor and environmental pollution associated with swine (Sus scrofa) production systems. The microbial ecology of manure storage systems and the relationships between microbial communities and odor production are largely unknown. In this study, we used community fatty acid methyl ester (FAME) analysis to generate lipid profiles to assess seasonal differences among microbial communities inhabiting various types of outdoor swine manure storage systems. Concurrently, we measured manure concentrations of several malodor indicator compounds as well as pH, temperature, and solids content. Principal components analysis (PCA) showed that there are differences in FAME profiles among the swine manure storage systems examined and most of the variation was in the relative abundance of 18:0, 18:1omega7t, 18:1omega7c/omega9t/omega12t, and 16:1omega7t/i15:0 2OH FAMEs. The PCA of the FAME profiles revealed that the phototrophic systems were more similar to each other and that the nonphototrophic systems were more similar to each other than they were to phototrophic lagoons. There were seasonal changes in the FAME profiles in the phototrophic systems and the concrete nonphototrophic basin (CNPB), and in one phototrophic system, the FAME profiles more closely resembled a CNPB FAME profile during the winter than the other phototrophic lagoons. In the phototrophic lagoon systems, there was a direct correlation between the abundance of the FAMEs identified in the PCA and manure concentrations of phenol, p-cresol, and 4-ethyl phenol. In the CNPB, there was a negative correlation between the total phenolics concentration and the 18:1omega7t FAME. Our results indicate that community FAME profiles could be used as a diagnostic tool for obtaining preliminary evidence that management practices are altering the system's microbial community to one that favors less air pollution potential.     

Impact of the toxicity of Cylindrospermopsis raciborskii (Woloszynska) Seenayya & Subba Raju on laboratory rats in vivo

In vivo laboratory studies of toxicity were performed on Wistar rats using a methanol extract produced by the natural population of Cylindrospermopsis raciborskii (abundance of 2.13 × 10⁵ trichomes mL⁻¹) collected at Aleksandrovac Lake (Serbia). HPLC analysis showed that the extract contains 6.65 μg cylindrospermopsin (CYN) mg⁻¹. The rats were killed 24 or 72 h after a single intraperitoneal injection of C. raciborskii extract in concentrations of 1500, 3000, 6000 and 12,000 μg kg⁻¹ body weight (bw) and an equivalent amount of CYN as present in the highest dose of the extract (79.80 μg CYN kg⁻¹ bw). The genotoxic effect on the livers treated with C. raciborskii was evaluated using comet assay and potential induction of oxidative stress as the toxicity mechanism associated with the presence of CYN in extract. The results from the analyses of DNA damage in the comet tail length, tail moment and percentage of DNA in the tail in the liver indicated that administration of extract and CYN present statistically significant difference when compared with the negative control group. Although an increase in the frequency of selected parameters induced by the CYN was observed in the liver, this damage was less than the damage resulting from the administration of the highest dose of extract. The changes in the biochemical parameters of the hepatic damage showed that the application of single doses of the extract and CYN did not cause serious liver damage in rats. The extract and CYN significantly increased oxidative stress in rats’ liver after a single exposure.

     

Upward movement of plutonium to surface sediments during an 11-year field study

An 11-year lysimeter study was established to monitor the movement of Pu through vadose zone sediments. Sediment Pu concentrations as a function of depth indicated that some Pu moved upward from the buried source material. Subsequent numerical modeling suggested that the upward movement was largely the result of invading grasses taking up the Pu and translocating it upward. The objective of this study was to determine if the Pu of surface sediments originated from atmosphere fallout or from the buried lysimeter source material (weapons-grade Pu), providing additional evidence that plants were involved in the upward migration of Pu. The ²⁴⁰Pu/²³⁹Pu and ²⁴²Pu/²³⁹Pu atomic fraction ratios of the lysimeter surface sediments, as determined by Thermal Ionization Mass Spectroscopy (TIMS), were 0.063 and 0.00045, respectively; consistent with the signatures of the weapons-grade Pu. Our numerical simulations indicate that because plants create a large water flux, small concentrations over multiple years may result in a measurable accumulation of Pu on the ground surface. These results may have implications on the conceptual model for calculating risk associated with long-term stewardship and monitored natural attenuation management of Pu contaminated subsurface and surface sediments.     

CONTAMINANT LEVELS IN PRECIPITATION AND URBAN SURFACE RUNOFF1

ABSTRACT: Precipitation and resultant runoff were sampled for a series of storm events over the period of one year. The test site was the parking lot of a large suburban shopping mall in the Syracuse, New York, area. Both precipitation and runoff were tested for lead, zinc, copper, cadmium, and petroleum hydrocarbons: substantial amounts were detected in each. No correlation was found between precipitation contaminant concentration and the length of the antecedent dry period. A weak, but apparently inverse relationship was noticed between concentration and amount of precipitation. Poor correlations were obtained between runoff contaminant concentration and the antecedent dry period. The variability attributable to different precipitation volumes was removed by converting to a unit-area basis. The variability attributable to precipitation contaminant load was removed by subtraction. The resultant value, dryfall accumulation, then correlated well with the length of the antecedent dry period. Metal ions were found in both precipitation and runoff and were hypothesized to come from atmospheric fallout as a result of distant emissions and from very localized sources, primarily vehicle traffic on the parking facility. Petroleum residues were believed to be the sole result of automobile losses, since none could be detected in precipitation samples.     

An investigation of aqueous activity coefficients at low concentrations

The activity of a chemical in solution determines its tendency to move into other media. At low concentrations (<0.01M) it is generally considered to be linearly related to concentration. A hypothetical model based on the structure of liquid water is discussed which could cause deviations from this linearity in the ppb region, a concentration much lower than that normally investigated thermodynamically, but one of great importance environmentally. Headspace experiments are reported with carbon tetrachloride and chloroform in water at concentrations down to ～10^?3 ppb but no such deviations were discerned.