First-trimester maternal serum biochemical indicators in Down syndrome

A set of 21 early maternal serum samples (19 first-trimester and two at 14 weeks) from pregnancies resulting in a child with Down syndrome was matched for gestation and length of storage with 63 samples from unaffected pregnancies. The concentrations of alpha-fetoprotein (AFP), unconjugated oestriol (uE₃), human chorionic gonadotrophin (hCG), pregnancy-specific β₁–glycoprotein (SP₁), and placental alkaline phosphatase (PALP) were measured. The ratios of the medians for Down syndrome pregnancies compared with the medians for controls were AFP 0·71, uE₃ 0·67, hCG 1·43, SP₁ 0·79, and PALP 0·92. Although the differences between the medians for affected and unaffected pregnancies were not significant, the trends for AFP, uE₃, and hCG confirm earlier findings on first-trimester samples.     

Watershed-Based Survey Designs

Watershed-based sampling design and assessment tools help serve the multiple goals for water quality monitoring required under the Clean Water Act, including assessment of regional conditions to meet Section 305(b), identification of impaired water bodies or watersheds to meet Section 303(d), and development of empirical relationships between causes or sources of impairment and biological responses. Creation of GIS databases for hydrography, hydrologically corrected digital elevation models, and hydrologic derivatives such as watershed boundaries and upstream–downstream topology of subcatchments would provide a consistent seamless nationwide framework for these designs. The elements of a watershed-based sample framework can be represented either as a continuous infinite set defined by points along a linear stream network, or as a discrete set of watershed polygons. Watershed-based designs can be developed with existing probabilistic survey methods, including the use of unequal probability weighting, stratification, and two-stage frames for sampling. Case studies for monitoring of Atlantic Coastal Plain streams, West Virginia wadeable streams, and coastal Oregon streams illustrate three different approaches for selecting sites for watershed-based survey designs.     

The Composition of PM10 as collected by a Conventional TEOM, a Modified TEOM and a Partisol Gravimetric Monitor at a Kerbside Site in the North East of England

The composition of airborne particulate matter sampled by a conventional TEOM^®, an experimental modified TEOM, operated at a lower temperature but fitted with a drier to remove moisture and a Partisol^®, installed at a kerbside site in the North East of England, has been investigated. The results indicate that there is a seasonal variation in the composition of PM₁₀ as sampled by the three monitors, with chloride concentration being significantly higher in the winter. The Partisol was found to sample a higher mass of chloride and nitrate, however the differences between the monitors was only significant for chloride. Both TEOM's were found to sample a greater mass of sulphate, although the variability in the data collected meant that significance of the results was not proven statistically. The range of artifacts associated with PM₁₀ monitors is reviewed. Difficulties in the interpretation of results due to the variable nature of airborne particulate matter and the ability of filter based systems to accurately represent the composition of atmospheric particles are considered.     

Heavy metals and selenium in feathers of three shorebird species from Delaware bay

Concentrations of lead, cadmium, mercury, selenium, chromium and manganese were examined in breast feathers of shorebirds migrating north through Cape May, New Jersey in 1991 and 1992. Although we predicted that metal levels would be positively correlated with weight, this was only true for mercury in red knots (Calidris canutus). Selenium was negatively correlated with weight in red knots. No other significant correlation of metal concentrations with weight were found. Lead and mercury were highest in sanderlings (C. alba). Selenium and manganese were highest in red knots, while chromium and cadmium levels were highest in semipalmated sandpipers (C. pusilus). For 1991, interspecific metals differences were significant for all metals except lead. For semipalmated sandpipers, cadmium and chromium concentrations were significantly higher in 1991 while managese concentrations were significantly higher in 1992.     

Assessing the Relative Severity of Stressors at a Watershed Scale

Water quality monitoring data are usually used independently to report on the condition of streams and watersheds. For example, watersheds are often rated as good, fair, or poor with regard to a single stressor or with regard to an index of biotic integrity. The utility of monitoring data may be enhanced by integrating stressor-response information with the observed stressor data, and reporting stressor levels in terms of their relative effects upon valued ecological resources. We estimated stressor-response relationships at the regional scale using data collected in the Eastern Cornbelt Plains Ecoregion of Ohio. Generalized additive models were used to visualize stressor-response relationships. Piecewise linear functions and simple linear functions were then used to parameterize the observed responses. Parameters derived from the regional models were used to scale observations of stressors in the Big Darby Creek watershed, OH. After scaling, stressors were compared in terms of their spatial distribution and in terms of the severity with which they influenced the biological endpoint of interest. Stressors most strongly associated with the current ecological condition of the watershed were identified. In the Big Darby Creek watershed, decreases in substrate quality were associated with the most severe decrements in biological condition. At smaller decrements in biological condition, three stressors were important: substrate quality, riparian quality, and increased concentrations of NOx.     

Building consensus on divisive issues: a case study of the Yukon wolf management team

This article presents a case study of a successful effort to reach agreement on one of the most intractable environmental issues of our time: wolf management. This case is unusual in several ways. In this case, the members of the negotiating team were ordinary citizens rather than leaders of organized groups. This team was given an unusually high level of authority to write the plan as they saw fit; the agency pledged to implement “whatever they came up with.” The agency convened the process, but agency personnel were not members of the team and attended only when they were invited. The team members were able to reach agreement on this tough issue even though polar opposites were at the table—one who felt that wolves are a “spiritual essence” and another who felt that, as he put it, “wolves, coyotes, and cockroaches have a lot in common”. They produced a detailed plan that addressed all the issues in just 5 months. Another unusual aspect of this effort is that the final agreement does not list the team members. They explained that they wanted their plan to “stand alone” and be judged based on what it said, not on who was involved.However, just after their agreement was completed, a new, pro-wolf control government was elected that refused to endorse the plan. While the government gave various reasons for not ratifying the plan, more and more diverse interest groups came out in support for both the plan and the process that created it. Eventually, overwhelming public support forced the government to sign and implement the plan as written. This demonstrates that, while it is important for a team to seek the sanction of decision-makers, it is perhaps even more important for the general public to see the effort and the final agreement as fair. Strong support from a broad spectrum of the public can help win the necessary political support.In addition to discussing the unorthodox aspects of this consensus-building effort, this article also attempts to give the reader a front row seat to this process by using the informants' own words—words rich in detail, brimming with color and spoken straight from the heart. Certainly their experience dispels any notion that such efforts are simply a matter of following a recipe. During the process, members of the negotiating team experienced the entire gamut of emotions—anger, defeat, humor and, finally, a genuine sense of pride. As team member Patty Denison put it, “We showed that a random group of people could work together and do something truly monumental.”     

Spatial Convergence in Major Dissolved Ion Concentrations and Implications of Headwater Mining for Downstream Water Quality

Spatial patterns in major dissolved solute concentrations were examined to better understand impact of surface coal mining in headwaters on downstream water chemistry. Sixty sites were sampled seasonally from 2012 to 2014 in an eastern Kentucky watershed. Watershed areas (WA) ranged from 1.6 to 400.5 km² and were mostly forested (58%–95%), but some drained as much as 31% surface mining. Measures of total dissolved solutes and most component ions were positively correlated with mining. Analytes showed strong convergent spatial patterns with high variability in headwaters (<15 km² WA) that stabilized downstream (WA > 75 km²), indicating hydrologic mixing primarily controls downstream values. Mean headwater solute concentrations were a good predictor of downstream values, with % differences ranging from 0.55% (Na⁺) to 28.78% (Mg²⁺). In a mined scenario where all headwaters had impacts, downstream solute concentrations roughly doubled. Alternatively, if mining impacts to headwaters were minimized, downstream solute concentrations better approximated the 300 μS/cm conductivity criterion deemed protective of aquatic life. Temporal variability also had convergent spatial patterns and mined streams were less variable due to unnaturally stable hydrology. The highly conserved nature of dissolved solutes from mining activities and lack of viable treatment options suggest forested, unmined watersheds would provide dilution that would be protective of downstream aquatic life.     

A new technique helps to uncover unknown peptides and disinfection by-products in water

正Environmental water samples can be extremely complex,with potentially thousands of molecules that can derive from natural organic matter(NOM)and thousands that derive from anthropogenic contaminants.As complex as these samples are,drinking water can be even more complex.Due to disinfectants that are used to treat drinking water(e.g.,chlorine,chloramines,     

Risks to the stratospheric ozone shield in the Anthropocene: This article belongs to Ambio’s 50th Anniversary Collection. Theme: Ozone Layer

Crutzen (1974) and Crutzen and Ehhalt (1977) presented two key papers in Ambio that in Ambioexemplify how science first revealed to humankind the potential for damage to our ozone shield in the Anthropocene. Crutzen’s (1974) review is a sweeping summary of the risks to the ozone layer from supersonic aircraft, chlorofluorocarbons, as well as nuclear weapons testing and nuclear war. Crutzen and Ehhalt (1977) described how the nitrous oxide produced from fertilizers could pose another threat to the stability of the stratospheric ozone layer. The two papers are part of a body of influential scientific work that led to the pioneering Montreal Protocol to Protect the Earth’s Ozone Layer to phase out production of chlorofluorocarbons (in 1987), as well as national decisions that slowed or stopped production of supersonic planes (in the 1970s). They remain guideposts today for ongoing international negotiations regarding reducing emissions from fertilizer and limiting nuclear testing.