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Biomedical subjects

Peter M Chapman

Publications and source records attributed to Peter M Chapman.

7 recordsLinked to original sources
PubMed2002

Ecological risk assessment (ERA) and hormesis.

Based on our current state of knowledge, the significance and importance of hormesis is likely to be greater for ecotoxicology, a component of ecological risk assessment (ERA), than for the overall process of ERA. Appropriately determining the role of hormesis in ERA will require extension of hormesis beyond chemical stressors to abiotic (e.g. habitat) and biotic stressors (e.g. species introductions, organism interactions). It will also require determining for all stressors whether at both individual and higher levels of organization, hormesis has positive, neutral or adverse effects. This determination must be made for model organisms, populations and communities. Adverse effects are the least likely, however, neutral effects cannot be ruled out. Presently, consideration of hormetic effects in ERA is most appropriate in a detailed level ecological risk assessment (DLERA), the most complex form of ERA. It is not appropriate in either problem formulation or a screening level ERA (SLERA). Further, for hormetic effects to be recognized and accepted fully into ERA may require a paradigm shift. Three on-going paradigm shifts to which hormesis could be linked are: recognition of the low utility of no-observed effects concentrations (NOECs); recognition of the need for special treatment of essential element dose/concentration-responses, which are similar to hormetic responses; and, the replacement of environmental toxicology with ecological toxicology (ecotoxicology).

Adaptation, Physiological↗
PubMed2002

Pore water testing and analysis: the good, the bad, and the ugly.

The increasingly common practice of collecting and assessing sediment pore water as a primary measure of sediment quality is reviewed. Good features of this practice include: pore water is a key exposure route for some organisms associated with sediments; pore water testing eliminates particle size effects; pore water analyses and tests can provide useful information regarding contamination and pollution. Bad features include: pore water is not the only exposure route; pore water tests lack chemical or biological realism: their "sensitivity" relative to other tests may be meaningless due to manipulation and laboratory artifacts; many sediment and surface dwelling organisms are not directly influenced by pore water. Bad features can become ugly if: other exposure pathways are not considered (for toxicity or bioaccumulation); manipulation techniques are not appropriate; pore water tests are inappropriately linked to population-level effects. Pore water testing and analyses can be effective tools provided their limitations are well understood by researchers and managers.

Animals↗
PubMed2002

Integrating toxicology and ecology: putting the "eco" into ecotoxicology.

Environmental toxicology has been and continues to be an important discipline (e.g., single-species testing for screening purposes). However, ecological toxicology (ecotoxicology--more realism in tests, test species and exposures) is required for predicting real world effects and for site-specific assessments. Ecotoxicology and ecology have shown similar developmental patterns over time; closer cooperation between ecologists and toxicologists would benefit both disciplines. Ecology can be incorporated into toxicology either extrinsically (separately, e.g., providing information on pre-selected test species) or intrinsically (e.g., as part of test species selection)--the latter is preferable. General guidelines for acute and chronic testing and criteria for species selection differ for ecotoxicology and environmental toxicology, and are outlined. An overall framework is proposed based on ecological risk assessment (ERA), for combining ecology and toxicology (environmental and ecological) for decision-making. Increased emphasis on ecotoxicology represents a shift from reductionist to holistic approaches.

Animals↗
PubMed2002

Toxicity of 1,4-dichlorobenzene in sediments to juvenile polychaete worms.

Investigation of sediment contamination associated with a marine sewage outfall in Victoria (BC, Canada) found elevated concentrations of 1,4-dichlorobenzene (1,4-DCB). Juvenile polychaete worm (Neanthes) growth was significantly reduced at or near the outfall, roughly corresponding to elevated 1,4-DCB concentrations. There are few data on 1,4-DCB toxicity to marine organisms and no published literature on its toxicity to benthic marine organisms. To determine whether reduced polychaete growth (measured as dry weight) was due to 1,4-DCB exposure, a laboratory investigation was conducted. Uncontaminated marine sediment was spiked with 1,4-DCB and juvenile Neanthes were exposed in 20-d sublethal toxicity tests. There were no adverse effects on survival at any test concentration; mean survival was 80-100%. Statistically significant decreases in average dry weight only occurred at the highest 1,4-DCB concentration (19,900 microg/kg, dry weight); this represented a 1,4-DCB concentration more than 10 times higher than previously measured at the outfall (1,710 microg/kg, dry weight). There were no adverse effects on survival or dry weight at the range of concentrations previously measured in sediments from the vicinity of the outfall.

Animals↗
PubMed2002

PAH phototoxicity--an ecologically irrelevant phenomenon?

Photoenhanced toxicity of polycyclic aromatic hydrocarbons (PAH) is well demonstrated in laboratory and in a few in situ studies. Effects have been observed for multiple taxa and toxicological endpoints, and the mechanism of toxic action has been described. However, this phenomenon is ameliorated by physical, chemical and biotic factors. The ecological relevance of PAH phototoxicity remains uncertain; it should not be used for environmental management decisions unless its ecological relevance is firmly established, and then only as part of a weight of evidence determination.

Ecology↗