Abstract: Relatively few aquatic and terrestrial environments in the world are not impacted by human activities to some degree thus the ability to determine biological integrity becomes more difficult. Northeastern Minnesota's Northern Lakes and Forest Ecoregion is unique in offering a minimally impacted landscape. Water chemistry and habitat varied with both land use and stream modification. In watersheds where logging occurred, decreases in median values were observed for salinity, conductivity, pH, and QHEI while median stream width, depth and stream temperatures increased compared to least-impacted watersheds. Turbidity was 60% lower and dissolved oxygen was 11.4% higher in logged watersheds. Watersheds with beaver activity showed a reduction in median pH, turbidity and dissolved oxygen and an increase in QHEI scores, stream width, depth, and temperature when compared to non-beaver sites. The IBI median values for natural watersheds was 0, while the BCI median score was 23. Least impacted watersheds had 62.5% of the sites with scores of zero. Watersheds with logging had median IBI scores of 12 or "Very Poor". The BCI evaluated these sites similarly with a median score of 13 or "Poor". Benthic Community Index scores were higher in stream segments with beaver than those watersheds that did not. The IBI, however, showed lower scores for stream segments holding beaver. The BCI showed a highly significant positive correlation to the QHEI.

Keywords: Biological Integrity, Reference Conditions, Silviculture impacts, Beaver affects, fish assemblage, macro invertebrate community, United States.

Abstract: This paper reports results of characterization of haze particles collected during the 1997 haze episode in Malaysia. Haze samples were collected using a high volume sampler from 22 September to 7 November 1997 and February 1998 at Universiti Putra Malaysia (UPM) Station. The haze samples were subjected to scanning electron microscopy (SEM), particulate matter and trace metal analyses. Significant increase in particulate (PMIO) concentrations observed during haze period was mainly due to transboundary smoke-haze from biomass burning. The maximum PM10 concentration recorded at UPM station was 406.7 µg/m³ on 25 September 1997. Scanning electron microscopy showed that smoke-haze particles were spherical, uniform in size and have liquid droplet characteristics, typical of biomass burning. Analysis of trace metal showed the presence of high concentration of potassium (7.75 µg/m³) in sample collected on 24 September 1997. Other trace metals Na, Cu, Ca, Fe, Al, Mn, Cr, and Zn were attributed to both natural (soil dust) and industrial emissions. The level of lead was slightly increased (0.43 µg/m³) during the haze period.

Key words: Haze, trace metal, scanning electron microscopy, biomass burning.

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