Arbuscular Mycorrhizae Occur in Common Spartina Species

We report the presence of arbuscular mycorrhizae (AM) in Spartina alterniflora Loisel roots. Roots were sampled for AM in field-collected and greenhouse-maintained Spartina patens (Aiton) Muhl. and S. alterniflora, the dominant species of Louisiana’s brackish and saline marshes, respectively. Previous reports of AM association in these Spartina sp. are limited and conflicting. Field-collected S. alterniflora had minimal AM (2.4%), whereas 39.5% of the S. patens roots examined were AM colonized. Greenhouse conditions of reduced salinity [3 parts per thousand (ppt)] appeared to increase AM association for S. patens compared with field samples. AM occurrence varied significantly among the three sample sites. Our results of low AM association in S. alterniflora differ from previous studies and confirm one previous report of AM in S. patens. Confirming AM association previously thought to be nonexistent in S. alterniflora marshes is a necessary first step in determining if AM influence zonation and competition

Exposure assessment of process-related contaminants in food by biomarker monitoring

Exposure assessment is a fundamental part of the risk assessment paradigm, but can often present a number of challenges and uncertainties. This is especially the case for process contaminants formed during the processing, e.g. heating of food, since they are in part highly reactive and/or volatile, thus making exposure assessment by analysing contents in food unreliable. New approaches are therefore required to accurately assess consumer exposure and thus better inform the risk assessment. Such novel approaches may include the use of biomarkers, physiologically based kinetic (PBK) modelling-facilitated reverse dosimetry, and/or duplicate diet studies. This review focuses on the state of the art with respect to the use of biomarkers of exposure for the process contaminants acrylamide, 3-MCPD esters, glycidyl esters, furan and acrolein. From the overview presented, it becomes clear that the field of assessing human exposure to process-related contaminants in food by biomarker monitoring is promising and strongly developing. The current state of the art as well as the existing data gaps and challenges for the future were defined. They include (1) using PBK modelling and duplicate diet studies to establish, preferably in humans, correlations between external exposure and biomarkers; (2) elucidation of the possible endogenous formation of the process-related contaminants and the resulting biomarker levels; (3) the influence of inter-individual variations and how to include that in the biomarker-based exposure predictions; (4) the correction for confounding factors; (5) the value of the different biomarkers in relation to exposure scenario’s and risk assessment, and (6) the possibilities of novel methodologies. In spite of these challenges it can be concluded that biomarker-based exposure assessment provides a unique opportunity to more accurately assess consumer exposure to process-related contaminants in food and thus to better inform risk assessment