Management of Non-Point Source Pollution CE 296B

1. Management of Non-Point Source PollutionCE 296B Department of Civil Engineering California State University, Sacramento Lecture #5, February 12, 1998 Sources of Pollutants - Part I

2. I. In the world of non-point source pollution, what are the pollutants and how will be organize our knowledge about them? • A. Recall the six categories of pollutants: • 1. Toxic inorganics - e.g. metals • 2. Synthetic organics - e.g. solvents • 3. Biostimulants - BOD, nutrients • 4. Sediment - clay, silt, sand, gravel • 5. Pathogenic organisms - viruses, bacteria, protozoa • 6. Trash - use your imagination

3. I. In the world of non-point source pollution, what are the pollutants and how will be organize our knowledge about them? (cont.) • B. Select members of each category will be analyzed to provide a organized framework of knowledge as follows: • 1. What are the sub-categories in each category and what are representative members? • 2. What are the origins of pollutants? • 3. How pollutants are introduced to the flow stream? • 4. How pollutants behave in water?

4. II. The first category of pollutant to examine is toxic inorganics. A. Toxic inorganics may be divided into the following categories: • Metals (examples include) • Lead (Pb) • Zinc (Zn) • Copper (Cu) • Selenium (Se) • Ions associated with acids (examples) • Sulfate (SO4-2) • Nitrate (NO3-)

5. II. The first category of pollutant to examine is toxic inorganics. (cont.) • A. Toxic inorganics can be divided into the following categories: (cont.) • Cations (examples) • Sodium (Na+) • Magnesium (Mg+2) • Calcium (Ca+2) • Members of the halogen family (examples) • Chloride (Cl-) • Chlorine (Cl2, OCl-) • Fluoride (Fl-)

6. II. The first category of pollutant to examine is toxic inorganics. (cont.) B. Let us focus on metals, starting with the origins of lead, zinc, and copper (the big three). 1. From “Urban storm water quality: summary of contaminant data,” Critical Reviews in Environmental Science and Technology, (1995) Makepeace et al. Lead: Oil and gas combustion, gasoline-powered vehicles and gasoline additives, tires, paint, storage batteries, and lead arsenate.

7. II. The first category of pollutant to examine is toxic inorganics. (cont.) • B. Let us focus on metals, starting with the origins of lead, zinc, and copper • (the big three). • 1. From “Urban storm water quality: summary of contaminant data,” Critical Reviews in Environmental Science and Technology, (1995) Makepeace et al. Zinc: Wear from tires (filler material), brake pads, oil and gas consumption, corrosion of building materials (roofs, pipes, etc.), corrosion of metal objects (galvanized steel)

8. II. The first category of pollutant to examine is toxic inorganics. (cont.) • B. Let us focus on metals, starting with the origins of lead, zinc, and copper • (the big three). • 1. From “Urban storm water quality: summary of contaminant data,” Critical Reviews in Environmental Science and Technology, (1995) Makepeace et al. Copper: Tire & brake wear, oil and gas combustion, paint, electrical, corrosion of building materials, wear of bearings and bushings in engines, industrial emissions, fungicides, and insecticides.

9. II. The first category of pollutant to examine is toxic inorganics. (cont.) • B. Let us focus on metals, starting with the origins of lead, zinc, and copper • (the big three). 2. From the text, focusing on airborne emissions, pages 191-194 (Global) Lead: Source Emissions (103 kg/yr) Coal combustion ~10,000 Oil combustion ~2,000 Mining and processing ~50,000 Refuse incineration ~2,000 Wood combustion ~2,000

10. II. The first category of pollutant to examine is toxic inorganics. (cont.) • B. Let us focus on metals, starting with the origins of lead, zinc, and copper • (the big three). 2. From the text, focusing on airborne emissions, pages 191-194 (Global) Zinc (sampling of estimates): Source Emissions (103 kg/yr) Coal combustion ~15,000 Oil combustion ~2,500 Mining and processing ~80,000 Refuse incineration ~6,000 Wood combustion ~3,000

11. II. The first category of pollutant to examine is toxic inorganics. (cont.) • B. Let us focus on metals, starting with the origins of lead, zinc, and copper • (the big three). 2. From the text, focusing on airborne emissions, pages 191-194 (Global) Copper (sampling of estimates): Source Emissions (103 kg/yr) Coal combustion ~5,000 Oil combustion ~2,000 Mining and processing ~25,000 Refuse incineration ~1,500 Wood combustion ~1,000

12. II. The first category of pollutant to examine is toxic inorganics. (cont.) • B. Let us focus on metals, starting with the origins of lead, zinc, and copper • (the big three). 2. From the text, focusing on the airborne component, pages 191-194 (Global) Median Total Estimate for Each Metal Emissions (103 kg/yr) Lead ~332,350 Zinc ~131,880 Copper ~35,370

13. Discussion Break How diffuse are the sources of lead, zinc, and copper? Does the nature of these sources help explain why some advocate “end-of-pipe” solutions?

14. II. The first category of pollutant to examine is toxic inorganics. (cont.) • B. Let us focus on metals, starting with the origins of lead, zinc, and copper • (the big three). 3. Some interesting observations about lead, zinc and copper with respect to urban non-point source pollution. • Concentrations of lead in mussels in California coastal areas have been declining since 1980. Discussion item Does unleaded gas work?

15. II. The first category of pollutant to examine is toxic inorganics. (cont.) • B. Let us focus on metals, starting with the origins of lead, zinc, and copper • (the big three). • 3. Some interesting observations about lead, zinc and copper with respect to urban non-point source pollution. (cont.) • Airborne samples taken both upwind and downwind from a busy intersection in Sacramento showed similar concentrations of lead and zinc. Discussion item How widespread are lead, zinc, and copper?

16. Discussion Break Most monitoring efforts in urban areas indicate that everywhere one looks, one will find significant amounts of lead, zinc, and copper. What kind of time frames are involved in source control solutions?

17. II. The first category of pollutant to examine is toxic inorganics. (cont.) • B. Let us focus on metals, starting with the origins of lead, zinc, and copper • (the big three). • 3. Some interesting observations about lead, zinc and copper with respect to urban non-point source pollution. (cont.) • In urban run-off, there is substantially more zinc than lead or copper. Recall that for airborne emissions, Pb was emitted than Zn. Discussion item What about the hypothesis that tire wear contributes much of urban zinc?

18. Discussion Break How disruptive would true source control be for metals such as lead, zinc, and copper to the economy and society? Any ideas on how to approach meaningful source control? How about looking for truly negative receiving water impacts before pursuing drastic solutions?

19. II. The first category of pollutant to examine is toxic inorganics. (cont.) C.What can we generalize about the sources of metals in non-point source pollution? 1. A wide variety of materials, useful in everyday life contain metals that are constituents of concern. Use of these items can liberate those metals in particulate or soluble form. Emphasis on wide variety! 2. A major source is from industrial combustion.

20. II. The first category of pollutant to examine is toxic inorganics. (cont.) • C.What can we generalize about the sources of metals in non-point source pollution? (cont.) 3. Results from different types of sampling indicate a ubiquitous presence of metals in urban environments. 4. Some source control measures have been successful in achieving meaningful reductions.

21. II. The first category of pollutant to examine is toxic inorganics. (cont.) D. How do metals find their way into the flow stream that is the carrier for non-point source pollution? 1. Atmospheric scrubbing of airborne metals. In Los Angeles, the concentration of dissolved copper was one-third that of the concentration of dissolved copper coming of a nearby stretch of Freeway. This is wetfall.

22. II. The first category of pollutant to examine is toxic inorganics. (cont.) • D. How do metals find their way into the flow stream that is the carrier for non-point source pollution? 2. Airborne particulates striking the ground and staying put. Overland flow during storms then picks up those particulates. This is dryfall. 3. Mechanical wear directly deposits material on the ground where it can be picked up by overland flow. Tire wear would fit this description.

23. II. The first category of pollutant to examine is toxic inorganics. (cont.) • D. How do metals find their way into the flow stream that is the carrier for non-point source pollution? 4. Uses that have the metal already in solution are disposed of improperly. (The copper sulfate down the drain example.) Improper disposal of paint and used paint thinner are another example.

24. II. The first category of pollutant to examine is toxic inorganics. (cont.) • D. How do metals find their way into the flow stream that is the carrier for non-point source pollution? 5. Metals become sequestered within the soil matrix. Two mechanisms are at work: • Adsorption to soil surface particles • Complexation with organic compounds present in soil. When the soil is eroded, the metals are transported with the eroded soil.

25. II. The first category of pollutant to examine is toxic inorganics. (cont.) • D. How do metals find their way into the flow stream that is the carrier for non-point source pollution? 5. (cont.) In soils within about 5 meters of heavily traveled roadways during pre-unleaded gasoline days substantial concentrations of lead can be found. The elevated lead levels are usually within the top 200 centimeters of soil. However, much of that lead has weathered to inert forms

26. Discussion Break In general terms how would you establish a source control program of BMP’s to minimize metals in urban run-off? • Material substitution • Better control of industrial emissions • Public education programs

27. Filtered Dissolved Conc. Measure Conc. in aqueous phase using AA Acidify and Heat Split Initial Sample Total Conc. Unfiltered II. The first category of pollutant to examine is toxic inorganics. (cont.) D. How do metals behave in water? 1. Start with how metals are analyzed for in environmental water samples.

28. Discussion Break What is the dissolved concentration a measure of? What is the total concentration a measure of? Preferences?

29. II. The first category of pollutant to examine is toxic inorganics. (cont.) D. How do metals behave in water? 2. What general chemical forms do metals take in water? • Metallic, i.e. Pbo, Zno, Cuo • Free ion, i.e. Pb+2, Zn+2, Cu+2 • Inorganic complex, portion in the inorganic complexed form is a function of dissolved metal concentration, pH, alkalinity, and hardness.

30. II. The first category of pollutant to examine is toxic inorganics. (cont.) D. How do metals behave in water? 2. What general chemical forms do metals take in water? • Organic complex, portion in the organic complex is a function of the total metal concentration, the nature of the solids present, the amount and nature of the organic material present, the amount inorganic complexed metal (the inorganic complex is more stable), and the “age” of the metal. (Certainly other factors as well.)

31. Discussion Break Currently, the USEPA is spending substantial resources to develop easy methods to differentiate between different species (free ion, inorganic complex, organic complex). Why?

32. Toxicity Toxicity Free Ion Conc. Environmental Samples Conc. Discussion Break Consider some toxicity tests: How urgent is the need to get a better handle on what forms metals take in water?