Wet and dry deposition of phosphorus into Lake Huron

The deposition rates for wet, dry, and integrated fallout of P to the southern portion of Lake Huron were determined. Samples were analyzed for water-soluble, acid (pH =2) soluble, and insoluble (bound) P. The term ‘available P’ was used to indicate the sum of the water- and acid-soluble fractions of P in each type of input. Of the integrated fallout samples, approximately one-third was present as available P. The deposition rate for dry fallout of available P was determined to be 1.7 ng cm −2 day −1 . The wet deposition rate was estimated to be 2.2 ng cm −2 day −1 for available P. Total fallout of available P, determined from shore-based integrated fallout collectors, was calculated to occur at a rate of 6.5 ng cm −2 day −1 . The difference between the wet-plus-dry deposition and the integrated deposition rates has been ascribed to the contamination of integrated fallout collectors by local sources (roads, agricultural activity, etc.) though attempts were made to minimize this problem. The presence of large quantities of biological material (pollen, algae, insect larvae) accounted for a large fraction of the difference observed, especially in the spring months.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/43894/1/11270_2004_Article_BF00464714.pd

Ephemeris ofBrorsen's Comet

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Assessment of wet deposition monitoring in Atlantic Canada

The precipitation chemistry stations operating in the Atlantic Provinces during the period 1980–1982 were assessed by comparing their siting characteristics and sampling procedures with the criteria recommended by the Canadian Federal‐Provincial Research and Monitoring Coordinating Committee (RMCC). The data collected at these stations were also evaluated according to standards recommended by the Unified Deposition Data Base Committee. Only one quarter of the 32 stations satisfied all of these criteria. In addition, there is evidence to suggest that some of the laboratories experienced problems analysing for nitrate or pH. Therefore, producing a coherent region‐wide data set for the major ions in precipitation was not feasible. However, the qualifying measurements were adequate to indicate an excess sulphate deposition of slightly less than 20 kg ha−1 a−1 to most of the region, with less than 10 kg ha−1 a−1 to Labrador. Although this analysis was restricted to the monitoring in Atlantic Canada, the results are of broader relevance in illustrating the potential problems inherent in merging data from several networks