Urban Stormwater Runoff Contamination Associated with Gutter and Pipe Material Use

Transcription

1 Urban Stormwater Runoff Contamination Associated with Gutter and Pipe Material Use Olga Ogburn and Robert Pitt 2 Graduate Student; Civil, Construction, and Environmental Engineering Department; The University of Alabama 2 Ph.D., P.E., BCEE, D.WRE Cudworth Professor of Urban Water Systems; The University of Alabama

2 The Goal To determine how stormwater quality is affected by the type of gutter and pipe materials, environmental parameters causing degradation of the material, time of contact, and interactions of those factors.

3 Prior Research Contribution of rooftop material to runoff water quality, for example: Zinc concentrations from uncoated galvanized metal ranged between 3.5 and 9.8 mg/l (Clark, Long et al., 28). Zinc concentrations from coated galvanized metal were below.5 mg/l (Clark, Long et al., 28). Effect of pipe material and environmental parameters on drinking water quality, for example: Iron concentration from PVC pipes reached.58 mg/l after 3 days of exposure (Lasheen M.R., Sharaby, C.M., et. al, 28).

4 Experimental Design A series of long-term static leaching tests Eight roof and pipe materials Low and high ph condition Natural storm water was collected in the city of Tuscaloosa from downspouts and from storm drain inlets.

5 Materials: Gutter Materials: vinyl, aluminum, copper, and galvanized steel. Pipe Materials: concrete, HDPE, PVC, and galvanized steel. New materials Concrete pipes - 5 cm long The rest of pipes - 3 cm long

6 Experimental Design Containers with ph values of 5 and 8 (using Na 2 HPO 4 * 2H 2 O and KH 2 PO 4 to create buffers) Sampling times: time zero,.5 hr, hr, 27 hr, mo, 2 mo, 3 mo Measured Parameters: Metals (cadmium, chromium, lead, copper, zinc, aluminum, and iron) Toxicity (Microtox) ph Nutrients (ammonia nitrogen, total nitrogen, nitrate) and COD

7 Mass Release per Surface Area, mg/m 2 Lead Mass Release per Surface Area of a Pipe/Gutter in Containers with ph 5 and ph 8... Time, day Lead release was observed only for galvanized steel materials during both short and long exposure times. The loss of lead was higher for containers with ph 8 compared to containers with ph 5. The highest lead release was noted for galvanized steel pipe at ph 8 and was between mg/l (corresponds to 25-3 mg/m 2 ). P. Steel ph 5 G. Steel ph 5 P. Steel ph 8 G. Steel ph 8

8 Mass Release per Surface Area, Copper Mass Release per Surface Area of a Pipe/Gutter for Containers with ph 5, mg/m 2... P. PVC ph 5 P. HDPE ph 5 P. Steel ph 5 G. Vinyl ph 5 G. Aluminum ph 5 G. Copper ph 5 Time, day The highest copper release was observed from copper materials. After 27 hr of exposure copper release was more than 6 mg/l (up to 97 mg/m 2 ). Copper release was also found in containers with other materials but in much lower concentrations.

9 Mass Release per Surface Area, mg/m 2 Copper Mass Release per Surface Area of a Pipe/Gutter for Containers with ph 8,... Time, day P. PVC ph 8 P. HDPE ph 8 P. Steel ph 8 G. Vinyl ph 8 G. Aluminum ph 8 G. Copper ph 8 G. Steel ph 8 Lower and slower copper release was observed at higher ph

10 Zinc Mass Release per Surface Area of a Pipe/Gutter in the Containers with ph 5 Mass per Surface Area, mg/m 2... Time, day Zinc losses were the highest for galvanized steel materials Copper materials were the second highest source of Zinc release -Reached.3 mg/l (6 mg/m 2 ) after long time exposure -Higher losses at ph 5 Concrete and Plastic materials were the lowest source of zinc P. PVC ph 5 P. HDPE ph 5 P. Steel ph 5 G. Vinyl ph 5 G. Aluminum ph 5 G. Steel ph 5 G. Copper ph 5

11 Mass Release per Surface Area, Zinc Mass Release per Surface Area of a Pipe/Gutter in the Containers with ph 8 mg/m 2... Time, day P. PVC ph 8 P. HDPE ph 8 P. Steel ph 8 G. Vinyl ph 8 G. Aluminum ph 8 G. Steel ph 8 G. Copper ph 8 P. Con ph 8 For galvanized steel materials zinc release was greater and faster at higher ph conditions during long exposure After long-time exposure (9 mg/l; 42 mg/m 2 at ph 8)

12 Total Metal Concentration, mg/l Concrete and Galvanized Steel Materials Total Metal Concentration, mg/l Total Metal Concentration, mg/l No metals were detected with concrete pipes until 2 months.2..8 Concrete Pipes at 3 mo.6.4 ph 5 ph 8.2. Lead Copper Zinc Aluminum Iron Steel Gutters at 27 hrs Steel Gutters at 3 mo ph 5 8 ph 5 6 ph 8 6 ph Lead Copper Zinc Lead Copper Zinc Aluminum Iron

13 Total Metal Concentration, mg/l Total Metal Concentration, mg/l Total Metal Concentration, mg/l Total Metal Concentration, mg/l Aluminum and Copper Materials Aluminum Gutters at 27 hrs Aluminum Gutters at 3 mo ph 5 ph ph 5 ph Lead Copper Zinc. Lead Copper Zinc Aluminum Iron Copper Gutters at 27 hrs Copper Gutters at 3 mo ph 5 3 ph ph 8 2 ph 8 Lead Copper Zinc Lead Copper Zinc Aluminum Iron

14 ph, unitless % Effect % Effect Toxicity At higher ph conditions Concrete and Vinyl materials least toxic Copper and PVC most toxic ph measurements for containers with ph Time, hr P. PVC P. HDPE P. Steel G. Vinyl G. Aluminum G. Steel G. Copper P. Concrete Gutters ph 5 min Time, hr Pipes ph 5 min Time, hr G. Aluminum ph 8 G. Aluminum ph 8 G. Copper ph 8 G. Copper ph 8 G. Steel ph 8 G. Steel ph 8 G. Vinyl ph 8 G. Vinyl ph 8 P. Concrete ph 8 P. Concrete ph 8 P. HDPE ph 8 P. HDPE ph 8 P. PVC ph 8 P. PVC ph 8 P. Steel ph 8 P. Steel ph 8

15 Conclusions The greatest source of lead, zinc, and iron were galvanized steel materials, while copper materials were the highest source of copper. Lead and Zinc release was detected during both short and long exposure. During short exposure time copper releases were detected only for copper materials at both low and high ph Copper and aluminum materials had the highest toxicity, while concrete materials were least toxic.

16 References Clark, Shirley E., Long Brett V., Siu Christina Y.S., Spicher Julia, Steele Kelly A., 28 Runoff Quality from Roofing during Early Life. Water Environment Federation. Lasheen M.R., C.M. Sharaby, N.G. El-Kholy, I. Y. Elsherif, S. T. El-Wakeel, 28. Factors influencing lead and iron release from some Egyptian drinking water pipes. Journal of Hazardous Materials. 6 (28) ery/copper/copper_gutters.jpg _964.jpg NSF EPSCoR Acknowledgements

17 Thank you!