The stable isotopes composition of chemolithoautotrophic cave ecosystems is known to differ from epigenic caves. Here we show that in addition, dead carbon (devoid 14 C), utilized and transferred throughout this ecosystem, rendering it unsuitable for radiocarbon dating. connectivity the Ayyalon Cave ecosystem with surface studied, along its sources energy carbon, as well interconnections betwee...

Deuterium to hydrogen ratios of 14 plant species from a salt marsh and lagoon were 55 per thousand depleted in deuterium relative to the environmental water. Carbon tetrachloride-extractable material from these plants was another 92 per thousand depleted in deuterium. This gave a fractionation factor from water to CCl(4) extract of 1.147. This over-all fractionation was remarkably constant for ...

Nitrogen sources in the Mississippi River basin have been linked to degradation of stream ecology and to Gulf of Mexico hypoxia. In 2013, the USGS and the USEPA characterized water quality stressors and ecological conditions in 100 wadeable streams across the midwestern United States. Wet conditions in 2013 followed a severe drought in 2012, a weather pattern associated with elevated nitrogen c...

Soil is an integral part of terrestrial ecosystems. Many soil ecologists interested in soil ecosystem functioning rely, to some degree, on stable isotope methodologies. The study of the natural abundance of carbon isotopes, especially (13)C but also (14)C, in the environment and the use of stable carbon isotope tracers have proved very useful in investigating the soil carbon cycle and soil trop...

Naturally occurring radioactive materials (NORM) found in liquid wastes from hydraulic fracturing are an emerging environmental health concern. The heavily drilled Marcellus Shale, for example, contains isotopes of radium, polonium, and lead. However, the few studies that have focused on NORM in fracking wastewater (produced fluids) have reported on a single element—radium. In this issue of EHP...

The synthesis of various volatile and thermally stable derivatives of metals ions has permitted the use of conventional mass spectrometry for trace metal analysis. This paper reviews the development of the field using electron impact and chemical ionization mass spectrometry. This latter methodology produces simple mass spectra that enable complex mixtures to be analyzed. In addition the use of...

[1] Products of nuclear reactions between primary radiation belt protons and constituents of the tenuous upper atmosphere form a collocated secondary radiation belt. A calculation of the time-dependent secondary intensity provides a model specification of this environmental component for lowand medium-altitude satellite orbits. It is based on an earlier model of the radiation belt protons, the ...

Researchers at a commercial environmental laboratory have developed an effective method for validating high throughput multi-element data from high matrix waste water samples. The method used an Agilent 7700x ICP-MS with High Matrix Introduction (HMI)1 capability and third generation Collision Reaction Cell (CRC) operating in helium (He) mode. This simultaneously removes the polyatomic interfer...

We develop a general equation for converting laboratory-reported tritium levels, expressed either as concentrations (tritium isotope number fractions) or mass-based specific activities, to mass fractions in aqueous systems. Assuming that all tritium is in the form of monotritiated water simplifies the derivation and is shown to be reasonable for most environmental settings encountered in practi...

Mercury (Hg) is a pervasive contaminant that can adversely affect predatory wildlife. Bird eggs provide insights into breeding females' Hg burdens, and are easily collected and archived. We present data on Hg trends in herring gull (Larus argentatus) eggs from five sites in Atlantic Canada from 1972 to 2008. We found a significant decrease in Hg at Manawagonish Island, New Brunswick and Île du ...