Measures of Water Quality

Introduction  The United States Geographical Survey monitors waterways all over the country, tracking all of the most important factors that have an impact on water quality.water quality

Temperature  Taken and recorded every time a sample is gathered.  Important indicator of changes in water quality  All aquatic organisms have a preferred temperature range  Influences water chemistry – higher temperatures allow for more dissolved minerals, less dissolved gases (like Oxygen)  USGS data for streams and rivers in Maryland USGS data for streams and rivers in Maryland

Color and Odor Color & Odor Observations If: Then: Water smells moldy or musty Test for Iron or bacteria Water smells like rotten eggs Test for hydrogen sulfide or methane Water causes red stains Test for dissolved Iron Water causes black/brown stains Test for dissolved Manganese Water has milky/gray appearance Test for e. coli/bacteria Water has green appearance Test for excess nutrients (nitrates/phosp hates)  Can indicate other measurements/tests needed  Should be continually monitored & logged for changes  Should be described with every sample taken

Turbidity  Measure of clarity  High turbidity causes lakes to fill in faster, places for pollution to attach, reduced plant productivity, habitat destruction (from sedimentation)  Measured with a “turbidity tube” (at right)  USGS Data for Maryland USGS Data for Maryland

pH  Measured on a scale of 0-14, 7 is neutral.  pH reading of 5 is 10X more acidic than pH of 6  Determines the solubility of water, and the availability of nutrients to organisms  USGS Data for Maryland Streams & Rivers USGS Data for Maryland Streams & Rivers

Alkalinity  Measure of water’s ability to neutralize acid  Important because it indicates how healthy a stream is, how it resists changes  Higher readings are better  Measured in PPM of Calcium Carbonate CaCO 3

Nutrient Balance  Nitrates  Critical for plants & animals  Denitrification (getting Nitrogen gas from nitrates) = important task in ecosystems  Nitrate load being too high causes algae blooms  Phosphorus  Also critical for plants and animals  Often the “limiting factor” in streams  Too much phosphorus can also cause algae blooms

Dissolved Oxygen (DO)  Cooler water can hold more dissolved Oxygen gas (O 2 )  10 PPM is optimal, but not necessary for life  DO readings should be taken every few days, at the same time each day.  USGS Data for Maryland Streams USGS Data for Maryland Streams

Fecal Bacteria  Presence indicates animal/human pollution  Not always an indicator of an unhealthy stream, just of poor drinking quality  Testing generally indicates presence, not levels

Works cited    ll.asp?program=WaterTre#problems ll.asp?program=WaterTre#problems   etail.viewInd&lv=list.listbyalpha&r=216594&subtop= etail.viewInd&lv=list.listbyalpha&r=216594&subtop=20 0   cfm cfm