South Dakota s Statewide Ground Water Quality Monitoring Network

Transcription

1 South Dakota s Statewide Ground Water Quality Monitoring Network Derric L. Iles State Geologist Geological Survey Program Department of Environment and Natural Resources 2014 Eastern South Dakota Water Conference University Student Union, South Dakota State University October 29, 2014

2 A typical monitoring site in eastern South Dakota

3 Site selection criteria Aquifer is at land surface or very near surface, and is unconfined. Not near known or suspected point-source pollution. Representative of typical land use. Aquifer is thick enough to accommodate nested wells, if possible. Accessible to the drilling equipment of the Geological Survey.

4 Site selection criteria Aquifer is at land surface or very near surface, and is unconfined. Not near known or suspected point-source pollution. Representative of typical land use. Aquifer is thick enough to accommodate nested wells, if possible. Accessible to the drilling equipment of the Geological Survey. Drilling and well/pump installation Well casing and screen steam cleaned and wrapped at factory. Back of drilling rig and down-hole tools steam cleaned prior to drilling of each hole. No fluid added to hole during drilling; hollowstem auger method. Pumps, well seals, and tubing steam cleaned and wrapped at factory; manufactured to fit well depth. Down-hole tools and materials handled with clean gloves.

5 Geological Survey Program s Mobile B-61 Drilling Rig

6 1981; Hamlin County >200 mg/l NO 3 -N Well house Why not use existing wells instead of installing our own? Unknown or poor well construction Poor location Minimal control over access to the well Well may draw water from multiple horizons in the aquifer Etc.

7 Aquifers and Monitoring Sites in the Statewide Ground Water Quality Monitoring Network R , 23 R , 48 R , 25 R , 53 R R R R R R R , 15 (replaced R , 104) R R , 31 R , 32 (replaced R , 35) R , 27 R , 09 R , 37 R , 37 R R , 10 R , 30 R , 39 R , 39 R , 20 R , 16 R R R , 07 R R , 37 R R , 18 R , 35 R , 15 R , 53 R , 55 R , 33 R & R R R , 18 R , 02 R , 48 R & TU-80C R & CO R & CO R , 45 R , 16 R , 18 R , 42 R , 44 R (replaced R ) R & R (replaced R ) R , 24 R , 09 R , 07 R , 02 (replaced R , 22) R , 50 R , 05 R , 27 R , 64 R , 20 R , 55 R , 02 R , 57 R , 10 R , 13 R , 60 R , 33 Monitoring site. Water quality monitoring wells for each site are labeled. For example, a label of R , 29 indicates that wells R and R exist at that site. R , 29 R , 33 R , 35 Number of aquifers monitored = 26 Number of monitoring sites = 85 Number of monitoring wells = 150 R , 41 R R , 14 R , 05 R , 07 R R R , 15 R R , 67 R , 12 R R R , 09

8 A typical well Most are 4-inch diameter Some are 2-inch diameter Cross section of a nested monitoring site

9 Clean work space in a modified van Gasoline powered generator (220v, 110v, 12v) Stainless steel Grundfos Redi-Flo2 pumps are dedicated to each well thereby eliminating most concerns of cross contamination and decontamination. (11½ long x 1¾ dia.) Well seal Grundfos Redi-Flo2 controller

10 Timing of sampling: Each site was sampled about the same time every year to eliminate concerns of seasonal variability. Sampling & The network has been monitored for: Common inorganics (includes nitrate/ammonia) once per year Pesticides once per year Trace metals once every 5 years Radionuclides once every 5 years Volatile organic compounds 25% of an aquifer s wells every 5 years Additional monitoring for pesticides and/or nitrate and ammonia: 3 additional times during the growing season at sites

11 Timing of sampling: Whenever a site is sampled, it is still sampled about the same time as in pervious years to eliminate concerns of seasonal variability. Sampling The network is presently monitored for: Common inorganics (includes nitrate/ammonia) once every other year Pesticides once every other year

12 Common Inorganics Alkalinity - M Alkalinity - P Ammonia Calcium Chloride Conductivity Fluoride Iron Magnesium Manganese Nitrate + nitrite ph Phosphorous, total Potassium Sodium Solids, dissolved Sulfate Metals Antimony Arsenic Barium Beryllium Cadmium Chromium Copper Lead Mercury Nickel Selenium Thallium Pesticides 2,4-D Acetochlor Alachlor Atrazine desethyl atrazine desisopropyl atrazine Bentazon Carbofuran Cyanazine Dicamba Glyphosate Malathion MCPA Metolachlor Metribuzin Picloram Simazine Trifluralin Radionuclides Gross Alpha Radium 226 Radium 228 Uranium Cyanide Volatile Organic Compounds Benzene Bromobenzene Bromochloromethane Bromodichloromethane Bromoform Bromomethane N-Butylbenzene sec-butylbenzene tert-butylbenzene Carbon tetrachloride Chlorobenzene Chloroethane Chloroform Chloromethane 2-Chlorotoluene 4-Chlorotoluene Dibromochloromethane 1,2-Dibromo-3-Chloropropane 1,2-Dibromoethane Dibromomethane 1,3-Dichlorobenzene o-dichlorobenzene para-dichlorobenzene Dichlorodifluoromethane 1,1-Dichloroethane 1,2-Dichloroethane 1,1-Dichloroethylene trans-1,2-dichloroethylene 1,2-Dichloropropane 1,3-Dichloropropane 2,2-Dichloropropane 1,1-Dichloropropene cis-1,3-dichloropropene trans-1,3-dichloropropene Ethylbenzene Hexachlorobutadiene Isopropylbenzene Isopropyltoluene Methylene Chloride Naphthalene N-Propylbenzene Styrene 1,1,1,2-Tetrachloroethane 1,1,2,2-Tetrachloroethane Tetrachloroethylene Toluene 1,2,3-Trichlorobenzene 1,2,4-Trichlorobenzene 1,1,1-Trichloroethane 1,1,2-Trichloroethane Trichloroethylene Trichlorofluoromethane 1,2,3-Trichloropropane Trihalomethanes, total 1,2,4-Trimethylbenzene 1,3,5-Trimethylbenzene Vinyl Chloride m,p-xylene o-xylene Xylenes, total

13 Data from 1996 through 2014 Statewide Ground Water Quality Monitoring Network Percent of sites monitored Percent of sites with nitrate 10 mg/l Date Percent of sites with detectable pesticide

14 Monitoring sites at which nitrate+nitrite as nitrogen was 10 mg/l in 2010

15 Monitoring sites at which a pesticide was detected in 2010 Atrazine, 2.63, 1.7, 0.8, 0.71, 0.25, 0.11, 0.18 µg/l Desethyl atrazine, 0.5, 0.74, 0.34, 0.32, 0.1 µg/l Desisopropyl atrazine, 0.6 µg/l Atrazine, 0.65µg/L Atrazine, 0.17 µg/l Desethyl atrazine, 0.1 µg/l Atrazine, 0.13, 0.11, 0.11 µg/l Atrazine, 0.14 µg/l Desethyl atrazine, 0.11 µg/l 2,4-D, 9.27 µg/l Atrazine, 0.18 µg/l Atrazine, 0.21 µg/l Site at which a pesticide was detected Atrazine, 0.34 µg/l Desethyl atrazine, 0.11 µg/l Site at which a pesticide was detected and which also had nitrate 10 mg/l Atrazine: standard = 3 µg/l Desethyl atrazine: no standard or health advisory level Desisopropyl atrazine: no standard or health advisory level 2,4-D: standard = 70 µg/l

16 Questions?