Shibo Wang Outline • What’s in the Water? • Chemical Properties – Physical Properties – Biological Properties • Testing Methods & Equipment – Test Strips – Colorimeters and Reagents – Electronic Sensors – Microbial Testing 2 Chemical Properties and Testing Methods 3 Chemical Properties Fluorine Atomic number 9 Highly reactive - with other elements to form fluorides Sources Erosion of Natural Deposits Fertilizer Factories Aluminum Factories Health Effects Tooth benefits at low levels (0.1 mg/L) Dental Fluorosis at higher levels Crippling Skeletal Fluorosis http://www.theodoregray.com/periodictable/Tiles/009/s7.JPG 4 Chemical Properties Nitrates and Nitrites Nitrate NO3- – Fertilizers and explosives Relatively non-toxic except when converted to nitrites through the digestive system – especially in infants Nitrite NO2- - Food preservatives http://www.nicolayvette. com/wpcontent/uploads/2011/10/ post_full_1283472073nit rate.jpg 5 TESTING METHODS AND EQUIPMENT • Test Strips • Colorimeters and Reagents • Electronic Sensors • Microbial Testing http://www.lamotte.com/ 6 TEST STRIPS • Testing Parameters: Total Chlorine, Free Chlorine Hardness pH Nitrates and Nitrites Phosphorous 7 TEST STRIPS • Advantages Cheap and Widely Available Easily Stored and Transported Convenient to Use and Quick Result Easy Cleanup • Disadvantages Sometimes Inaccurate - Inconsistent Results 8 Colorimeters and Reagents • The device that measures absorbance of particular wavelength of light by a specific solution • Change Colors When Mixed With Reagents • Measures Multiple Parameters pH Total and Free Chlorine Hardness Nitrates and Nitrites Phosphorous Dissolved Oxygen and Chemical Oxygen Demand 9 Colorimeters and Reagents • Advantages Accurate Relatively Easy to Manipulate • Disadvantages Expensive Time Consuming Lots of Garbage and Chemicals 10 Electronic Sensors • Multiple Parameter Testing pH Conductivity Salinity Temperature http://www.geotechenv .com/usb_sensors_test _strips.html 11 Electronic Sensors • Advantages Accurate Easily Stored and Transported Easy to Use • Disadvantages Expensive Requires Calibration 12 Physical Properties • Salinity • Electrical Conductivity • pH • Turbidity • Hardness • Temperature 13 Physical Properties Salinity and Conductivity Salinity – the saltiness or dissolved salt content. Not a big health concern. Conductivity Ability of water to pass electrical current. Indicates presence of inorganic dissolved elements Higher values may indicate more contaminants http://upload.wikimedia.org/wikipedia/commons/thumb/9/98/W ater_salinity_diagram.png/300px-Water_salinity_diagram.png 14 Physical Properties pH pH = a measure of the activity of the hydrogen ion Measures the acidity or basicity of an aqueous solution <7 = Acidic 7 = Neutral >7 = Basic 6.5 to 8.5 is ideal, but natural waters have pH levels of 5.0 to 8.5. Below 6.5 can be corrosive Above 8.5 can inhibit effectiveness of chlorine and other disinfectants. No health impacts at normal ranges, but very important parameter in water treatment http://www.phionbalance.com/images/site/pHion/common/c olor_chart_products.jpg 15 pH levels for household items 1.0 - battery acid 1.8 - 2.0 - limes 2.2. - 2.4 lemon juice 2.2 Vinegar (acetic acid) 2.8 - 3.4 - fruit jellies 2.9 - 3.3 - apple juice, cola 3.0 - 3.5 - strawberries 3.7 - orange juice 4.0 - 4.5 - tomatoes 5.6 - unpolluted rain 5.8 - 6.4 - peas 6.0 - 6.5 - corn 6.1 - 6.4 - butter 6.4 - cow's milk 6.5 - 7.5 - human saliva 6.5 - 7.0 - maple syrup 7.0 - distilled water 7.3 - 7.5 - human blood 7.6 - 8.0 - egg whites 8.3 - baking soda 9.2 - borax 10.5 - milk of magnesia 11.0 - laundry ammonia 12.0 - lime water 13.0 - lye 14.0 - 16 Physical Properties Turbidity Turbidity – the cloudiness of a fluid caused by individual particles. Can be measured in nephelometric turbidity units (NTU) Should be no more than 1 NTU for drinking water Humans can start to see turbidity around 8 NTU Turbid water is from clay, silt, and microscopic organisms, and can be caused by boat activity (not here, obviously…) and bottom feeders. Darkly colored water can still be clear and not turbid. We will measure the turbidity in JTU (Jackson Turbidity Unit) http://www.learnnc.org/lp/media/uploads/2010/05/turbidit y_chart_2_500.png 17 Biological Properties • Bacteria • Viruses • Protozoa • Parasitic worms 18 Viral Pathogens • Adenoviruses • Enteroviruses • Hepatitis A virus • Hepatitis E virus • Rotavirus 19 Helminth Pathogens • Guinea Worm Disease - Dracunculus medinensis – These worms are really super gross • Intestinal Flukes - Fasciolopsis • Blood Flukes - Schistosoma http://www.parasitesinh umans.org/schistosomablood-flukes.html IT’S A CYCLE! 20 http://www.dpd.cdc.gov/dpdx/HTML/Metagonimiasis.htm Biological Properties Indicator Organisms Coliform Bacteria Commonly used bacterial indicator of sanitary quality of foods and water Include a wide range of aerobic and anaerobic bacteria Relatively not difficult to test for Health standard is 0 coliform per 100 ml sample E. coli A subset of coliforms Presence is indication of human fecal contamination Present in Bowman Creek! 21 Microbial Testing 22 Microbial Testing • Presence Tests • Membrane Filtration • Coliscan Easy Gel http://www.thermofisher.com.au/content/Scientific/MicrobiologyProducts/Microbial-Safety-Testing/Environmental-WaterTesting/Environmental-Water-Testing.jpg 23 Microbial Testing P/A Pillows • Tests for Presence of Harmful Bacteria • Requires Just a Pillow and Sample Bag • Associate with fetal contamination and the presence of coliforms http://www.usabluebook.com/images /Product/medium/309779.jpg 24 Microbial Testing P/A Pillows • Advantages Quick and Easy to Use Accurate Results Within 24 Hours No Incubator Required Easily Transported Simple Yes/No Results • Disadvantages No Differentiation of Harmful Bacteria 25 Microbial Testing Membrane Filtration • Tests for Coliform Bacteria and E. Coli • Uses Membrane Filter and Agar in Petri Dishes • Bacteria Counts Within 24 Hours Coliforms are Red and Blue E. Coli are Blue • Requires an Incubator at 35° C 26 Microbial Testing Membrane Filtration http://academic.pgcc.edu/~kroberts/Lecture/Chapter%2 06/06-22_MembraneFilter_L.jpg 27 Microbial Testing Membrane Filtration • Advantages Accurate Results Within 24 Hours Identifies and Counts Coliform and E. Coli • Disadvantages Requires an Incubator Preserving Agar needed Plenty of Garbage Time Consuming Expensive 28 Microbial Testing Coliscan Easy Gel • Tests for Coliform Bacteria and E. Coli • Uses Agar in Petri Dishes • Bacteria Counts Within 24 to 48 Hours Coliforms are Red and Blue E. Coli are Blue • Works with or without and Incubator 29 Microbial Testing Coliscan Easy Gel http://hatch.cehd.umn.edu/1112/Mod10_C oliLab_files/image001.jpg 30 Microbial Testing Coliscan Easy Gel • Advantages Accurate Results Within 24 Hours (Incubator) to 48 Hours (Room Temperature) Incubator not necessary Moderate Turbidity is fine Identifies and Counts Coliform and E. Coli Relatively Easy to Transport Easy to Use Inexpensive Disadvantages Agar Must be Kept Refrigerated. It will only last one to two weeks without refrigerator. 31 Thanks ! 32