Joe Thompson | PubMed Health

PubMed2006

Relationship between wetlands and mercury in brook trout.

The purpose of this study was to determine if wetlands influence mercury concentrations in brook trout (Salvelinus fontinalis), benthic macroinvertebrates, and stream water. On September 26, 2005, water samples, benthic macroinvertebrates, and brook trout were collected from four streams in western Maryland under low-flow conditions. Water samples were also collected in these four streams under high-flow conditions in January 2006. The watersheds of Blue Lick and Monroe Run did not contain wetlands, but the watersheds of the Upper Savage River (3% of upstream area) and Little Savage River (7% of upstream area) contained wetlands. We found significantly (p = 0.05) higher average total mercury concentration in brook trout from Little Savage River (129 +/- 54 ng g(-1)); intermediate concentrations (66 +/- 19 ng g(-1)) in brook trout from Upper Savage River; and lowest concentrations in brook trout from Blue Lick (28 +/- 11 ng g(-1)) and Monroe Run (23 +/- 19 ng g(-1)). Brook trout in all streams accumulated mercury at the same rate over their lifetimes, but the youngest fish had significantly different mercury concentrations (Little Savage > Upper Savage > Blue Lick = Monroe Run), which may be due to differences in mercury concentrations in the eggs or food for the fry. Mercury concentrations in brook trout were not consistent with mercury concentrations in stream water and benthic macroinvertebrates. The Little Savage River had significantly higher total and methylmercury concentrations in stream water, but mercury concentrations in the other streams and in the benthic macroinvertebrates were not significantly different among streams. The unusually high methylmercury concentrations (0.5 to 2.1 ng L(-1)) in the Little Savage River may have been caused by production of methylmercury in the pools. The relatively low methylmercury concentrations in the Upper Savage River may be caused by a mercury concentration gradient downstream of the wetland.

Animals↗

PubMed2004

Clinical practice guidelines and performance indicators as related--but often misunderstood--tools.

BACKGROUND: Widespread variation in medical practice indicates that existing scientific evidence is often not translated into appropriate clinical care. Two tools have evolved that try to address this variation: clinical practice guidelines (CPGs) and performance indicators (PIs). TENSIONS BETWEEN CPGS AND PIS: CPGs present available evidence that is subsequently reviewed and frequently adopted by professional organizations, so that clinicians may judge whether specific management recommendations are appropriate for each patient. PIs are devised to measure and document performance to motivate organizations to improve through the use of common metrics. IMPLICATIONS OF THESE TENSIONS: The increasingly widespread use of PIs with CPGs (and clinicians' confusion of them with CPGs) risks lowering the standards of clinical care. PIs are not intended to set optimal standards of care for any individual patient. Clinicians should not restrict their quality monitoring to a focus on PIs because they could miss important opportunities to learn and to improve the care they deliver to their individual patients. CONCLUSION: Tensions between CPGs and PIs do not mean that these tools should be abandoned but rather that they need to be refined. Recognition of the imperfections of CPGs and PIs should not blind clinicians to the ultimate goals of these tools--to promote quality (through changes in practice and/or selection) and ensure that medical care is based on scientific evidence.

Humans↗