水化學(xué)AnalysisofWaterChemistryppt課件

1、Analysis of Water ChemistryUrban Stream Restoration ProjectBy:Bob Smith &Shelly AliciaOutline Water Chemistry Background Chemistry in Urban Streams Methods 2019 Results Comparison to 2019 ConclusionsOutline Water Chemistry Background Chemistry in Urban Streams Methods 2019 Results Comparison to

2、2019 ConclusionsTemperature Most aquatic organisms are cold-blooded and have an ideal temperature range, specific to the organism: Diatoms 15-25 degrees C Green algae 25-35 degrees C Blue greens 30-40 degrees C Salmonids cold water fishTemperature, continued Affects development of invertebrates, met

3、abolism of organisms Affects dissolved oxygen (warm water holds less oxygen) Warm water makes some substances more toxic (cyanide, phenol, xylene, zinc) and, if combined with low DO, they become even more toxicDissolved Oxygen Oxygen that is dissolved in water DO increases with cooler water and mixi

4、ng of water through riffles, storms, wind Nutrient loading can lead to algal blooms which result in decreased DO 4-5 ppm DO is the minimum that will support large, diverse fish populations. Ideal DO is 9 ppm. Below 3 ppm, all fish die.Dissolved Oxygen, continued Dissolved oxygen can also be expresse

5、d as % saturation 80-124% = excellent 60-79% = ok 60% = poorConductivity Measures the ability of water to carry an electric current Measures the ions such as Na+, Cl- in the water Differences in conductivity are usually due to the concentration of charged ions in solution (and ionic composition, tem

6、p.) Reported as microsiemens per cmpH pH measures the degree of acidity or alkalinity of the water (each number is a 10-fold difference) 0-6 = acid; 7 = neutral; 8-14 = base Ideal for fish = 6.5 8.2 Ideal for algae = 7.5 8.4 Acid waters make toxic chemicals (Al, Pb, Hg) more toxic than normal, and a

7、lter trophic structure (few plants, algae)Turbidity Measures the cloudiness of the water Turbidity caused by plankton, chemicals, silt, etc. Most common causes of excess turbidity are plankton and soil erosion (due to logging, mining, farming, construction)Turbidity, continued Excess Turbidity can b

8、e a problem: Light cant penetrate through the water photosynthesis may be reduced or even stop algae can die Turbidity can clog gills of fish and shellfish can be fatal Fish cannot see to find food, but can hide better from predatorsPhosphorus (Reactive) Is necessary for plant and animal growth Natu

9、ral source = phosphate-containing rocks Anthropogenic source = fertilizer and pesticide runoff from farming Can stimulate algal growth/bloomNitrates Formed by the process of nitrification (addition of O2 to NH3 by bacteria) Used by plants and algae Is mildly toxic, fatal at high doses Large amounts

10、(leaking sewer pipes, fertilizer runoff, etc.) can lead to algal blooms, which can alter community structure, trophic interactions and DO regimes) Below 90 mg/L seems to have no effect on warm water fish, but cold water fish are sensitiveAlkalinity A measure of the substances in water that can neutr

11、alize acid and resist changes in pH Natural source = rocks Ideal water for fish and aquatic organisms has a total alkalinity of 100-120 mg/L Groundwater has higher alkalinity than surface waterHardness The amount of Calcium and Magnesium in the water (the two minerals mostly responsible) Natural sou

12、rce = rocks Limestone = hard water, granite = not hard waterHardness, continued Soft water can be a problem: in soft water, heavy metals are more poisonous, some chemicals are more toxic, drinking soft water over long periods can increase chance of heart attack 0 60 = soft water 61-120 = moderately

13、hard water 121-180 = hard water 181+ = very hard water Hardness and alkalinity are relatedOutline Water Chemistry Background Chemistry in Urban Streams Methods 2019 Results Comparison to 2019 ConclusionsPhysical Effects of Urbanization Related to Water Chemistry Riparian Vegetation Removal Decreased

14、 Groundwater Recharge Heat Island Effect Increased Surface Runoff / Impervious Surfaces Leaky Storm-water / Sewage Pipes Point Source PollutionTrends in Water Chemistry Temperature increases Nitrate increases Phosphorus increases Conductivity increases (Increased ion concentration) O2 demand increas

15、esOutline Water Chemistry Background Chemistry in Urban Streams Methods 2019 Results Comparison to 2019 ConclusionsField Measurements Dissolved Oxygen Temperature Conductivity pHWater Collection For Laboratory Analysis Grab Samples Three replicates (from multiple samples) Measured within 24 hours (f

16、ew exceptions)Picture Source: ci.gresham.or.us/ departments/des/stormwater/water_quality.htmLaboratory Analysis Nitrate Reactive Phosphorus Alkalinity Hardness TurbidityOutline Chemistry in Urban Streams Water Chemistry Measurements and Theory Methods 2019 Results Comparison to 2019 ConclusionsField

17、 Measurements 2019Temperature (oC)05101520123Dissolved Oxygen (mg/L)051015123Conductivity (us)0200400600800123pH55.566.577.5123 SAL PBTurbidity All values for 2019 5 jtu For 2019, all but one sampling date 5 was during a storm eventReactive Phosphorus 201900.050.10.150.20.25123Sampling Datemg/L PB S

18、ALNitrate 201900.511.522.5123Sampling Datemg/L* PB SALAlkalinity 2019051015202530354045123Sampling Datemg CaCO3/L* PB SALHardness 2019024681012123Sampling Dateg.d.h.* PB SALOutline Chemistry in Urban Streams Water Chemistry Measurements and Theory Methods 2019 Results Comparison to 2019 ConclusionsF

19、ield Measurement PBDissolved Oxygen (mg/L)051015123Conductivity (us)050100150123pH55.566.577.5123Temperature (oC)05101520123 2019 2019Field Measurement For SALDissolved Oxygen (mg/L)02468101214123Temperature (oC)05101520123Conductivity (us)0200400600800123pH6.66.76.86.977.17.2123 2019 2019Paint BranchReactive Phosphorus (mg/L)00.10.20.30.40.5123Nitrate (mg/L)00.511.522.5123Alkalinity (mg CaCO3/L)05101520123Hardness (g.d.h.)00.511.52123 2019 2019Stewart April LaneReactive Phosphorus (mg/L)00.20.40.60.811.2123Nitrate (mg/L)00.511.522.5123Alkalinity (mg CaCO3/L)0102030405060123H