Publications by authors named "Margaret Opazo"
Article Synopsis
- Elevated levels of total aluminum (Al) in natural waters often stem from acid extraction of Al from suspended solids, creating a need for methods to measure bioavailable Al specifically.
- In a study involving Ceriodaphnia dubia, high total suspended solids (TSS) from natural waters were found to inhibit reproduction by up to 40% due to nutritional deficiencies, rather than total Al levels.
- A new extraction method at pH 4 was developed to better differentiate bioavailable Al's chronic toxicity effects from non-toxic mineral forms, suggesting its use for assessing Al toxicity in natural surface waters.
The complex chemistry of iron (Fe) at circumneutral pH in oxygenated waters and the poor correlation between ecotoxicity results in laboratory and natural waters have led to regulatory approaches for iron based on field studies (US Environmental Protection Agency Water Quality Criteria and European Union Water Framework Directive proposal for Fe). The results of the present study account for the observed differences between laboratory and field observations for Fe toxicity to algae (Pseudokirchneriella subcapitata). Results from standard 72-h assays with Fe at pH 6.
View Article and Find Full Text PDFBackground: Low blood lead levels previously thought to pose no health risks may have an adverse impact on the cognitive development of children. This concern has given rise to new regulatory restrictions upon lead metal containing products intended for child use. However few reliable experimental testing methods to estimate exposure levels from these materials are available.
View Article and Find Full Text PDF