7 research outputs found
Developmental toxicity study of sodium molybdate dihydrate administered in the diet to Sprague Dawley rats
AbstractMolybdenum is an essential nutrient for humans and animals and is a constituent of several important oxidase enzymes. It is normally absorbed from the diet and to a lesser extent from drinking water and the typical human intake is around 2ÎŒg/kg bodyweight per day. No developmental toxicity studies to contemporary standards have been published and regulatory decisions have been based primarily on older studies where the nature of the test material, or the actual dose levels consumed is uncertain.In the current study the developmental toxicity of sodium molybdate dihydrate as a representative of a broad class of soluble molybdenum(VI) compounds, was given in the diet to Sprague Dawley rats in accordance with OECD Test Guideline 414. Dose levels of 0, 3, 10, 20 and 40mgMo/kgbw/day were administered from GD6 to GD20. No adverse effects were observed at any dose level on the dams, or on embryofetal survival, fetal bodyweight, or development, with no increase in malformations or variations. Significant increases in serum and tissue copper levels were observed but no toxicity related to these was observed. The NOAEL observed in this study was 40mgMo/kgbw/day, the highest dose tested
Non-Targeted Analysis of Petroleum Metabolites in Groundwater Using GCĂGCâTOFMS
Groundwater at fuel
release sites often contains nonpolar hydrocarbons
that originate from both the fuel release and other environmental
sources, as well as polar metabolites of petroleum biodegradation.
These compounds, along with other polar artifacts, can be quantified
as âtotal petroleum hydrocarbonsâ using USEPA Methods
3510/8015B, unless a silica gel cleanup step is used to separate nonpolar
hydrocarbons from polar compounds prior to analysis. Only a limited
number of these metabolites have been identified by traditional GCâMS
methods, because they are difficult to resolve using single-column
configurations. Additionally, the targeted use of derivatization limits
the detection of many potential metabolites of interest. The objective
of this research was to develop a nontargeted GCĂGCâTOFMS
approach to characterize petroleum metabolites in environmental samples
gathered from fuel release sites. The method tentatively identified
more than 760 unique polar compounds, including acids/esters, alcohols,
phenols, ketones, and aldehydes, from 22 groundwater samples collected
at five sites. Standards for 28 polar compounds indicate that effective
limits of quantitation for most of these compounds in the groundwater
samples range from 1 to 11 ÎŒg/L