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Chironomids as Environmental Indicators:Heavy Metals and Deformities Chaleen Shephard May 6, 1999
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Pollutants Often manmade materials Excesses occur naturally
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Bioaccumulation Build-up of toxic materials in tissues Magnify in food chain
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Heavy Metals Chromium Copper Manganese Nickel
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Chironomids Non-biting Midges Aquatic Insect Larvae 1/2 Inch Two Small Prolegs Found In Sediment Detritivores
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a b c d e f g Chironomids
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Indicator Species Large distribution area Variety of habitats Primary food source for many organisms
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Morphological Testing Deformities in mouthparts, antennae, mandibles Effect of chemical contaminants
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Flow Line Division, New Castle, Pennsylvania Five sites, Five Subsamples at Each Site Sediment Sample: AA, ICP spectrometry Chironomid Samples Sampled on 10/28/98 and 1/30/99 Sampling
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Microwave Digester
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AAICP
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Mounting Head CapsuleCMCP-9/ CMCP-9AF Medium
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Classification Normal
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Classification Class I
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Classification Class II
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Classification Class III
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Statistical Analysis At each site the five subsamples were combined to produce a sufficient sample size
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Percent Deformity = chironomids at each site with deformed mouthparts divided by the total number of chironomids at that site
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Toxic Score [No. Class I+2(No. Class II)+3(No. Class III)] X 100 Total Number Of Larvae
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Concentration of Metals Kruskal-Wallis test (nonparametric alternative to Analysis of Variance) Followed by a distribution- free Multiple Comparisons Test
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Results p= 0.010
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Results p= 0.012
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Results p= 0.013
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Results p= 0.008
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Results Correlation
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Conclusions High concentrations of metals, especially at the outflow pipe No correlation between deformities and concentrations of heavy metals Low numbers of chironomids Lethal concentrations of heavy metals
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Future Studies Tissue Analysis Laboratory tests Identification of species More samples, more chironomids, quantitative sampling Similar locations
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