Chemical Considerations in Stream Restoration

Paul CapelResearch Team Leader

National Water Quality Assessment Program

U.S. Geological Survey

Adjunct Associate ProfessorDepartment of Civil Engineering

University of Minnesota

capel001@umn.edu

Photo: www.ctpurcellinc.com/gallery.htm

“Big Picture” Perspective of Chemicals in Streams

Cl-

Photos: http://www.sharnoffphotos.com, http://www.evsc.virginia.edu

Questions for You !

1.What do chemicals have to do with stream restoration?

2.What chemicals are of importance to stream restoration? Why?

3.What questions would you like addressed during this class?

THE “OLIVE THEORY” OF THE BEHAVIOR AND TRANSPORT OF CHEMICALS IN THE ENVIRONMENT

Properties of the Environment

- temperature- pH- salinity- kind of solids- amount of solids- amount of water- bacteria....

Properties of the Chemical

- water solubility- vapor pressure- Henry’s Law- acid / base- charge- size- reactivity.....

Chemical-based Concerns

-- Toxicity, health effects (human, ecosystem)

-- Accumulation in biota (human, ecosystem)

-- Accumulation in hydrologic system (volume loss, disposal, legacy, …)

-- Ecosystem / habitat change

Energy and Carbon Flow in Streams

Source: http://www.mrothery.co.uk/ecology

“Needs” for a Healthy Stream Ecosystem

-- Light

-- Heat (relatively stable temperature)

-- Habitat

-- Dissolved oxygen

-- Carbon

-- Nutrients (N, P)

-- Lack of toxic chemicals

-- Biotic diversity

-- ….

Chemical Distribution among Environmental Phases

liquid (water), air, solid

Solids-Water Distribution

concentration of the chemical on solid (mg/kg)

concentration of the chemical in water (mg/L)

Air-Water Distribution

concentration of the chemical in air (mg/m3)

concentration of the chemical in water (mg/L)

Kd =

Kaw =

Chemical Distribution among Environmental Phases

Holistic Perspectives of Chemicals in Streams

Capel et al., USGS, in review

EQUILIBRIUM DISTRIBUTIONS OF CHEMICALS AMOUNG SOLIDS, WATER, AND AIR

Chemical Transformations

Induced by (external energy): - light - biota - chemical - hydrolysis - oxidation - reduction- heat

“Half-life”: time for 50% to be transformed

“Environmental lifetime” of a chemical = 6 half-lives (~1% remains)

Holistic Perspectives of Chemicals in Streams

Capel et al., USGS, in review

Legacy Chemicals

Legacy Chemicals

“Chemicals” of Particular Interest

-- Carbon

-- Nutrients (N, P)

-- Salts

-- Sediment

-- Trace Elements

-- Organic chemicals

-- Pathogens

Important Redox Elements

-- Oxygen

-- Nitrogen

-- Manganese

-- Iron

-- Sulfur

-- Carbon

“Chemicals” of Particular Interest: Carbon

-- Natural Organic Matter (NOM, DOC, ...)

-- Anthropogenic Organic Chemicals

Source: http://www.acadiau.ca/~jmurimbo

“Chemicals” of Particular Interest: Nutrients (N, P)

-- necessary for growth (limiting nutrient)

“Chemicals” of Particular Interest: Salts

-- major ions (Na+, K+, Ca++, Mg++, Cl-, SO4

--, HCO3-)

-- Sources: -- road salt -- irrigation return -- natural -- seawater intrusion

“Chemicals” of Particular Interest: Sediment

-- as particles themselves turbidity, erosion, sedimentation, ...

-- as carriers of chemicals

“Chemicals” of Particular Interest: Trace Elements

-- low-abundance cations copper, zinc, mercury, chromium, arsenic, ... iron, manganese, aluminum, ...-- Sources: -- anthropogenic -- natural -- mobilized by redox changes (As, Se)

Kesterson Reservoir, CACopper sulfate

“Chemicals” of Particular Interest: Organics

Anthropogenic Organic Chemicals

PCBs, PAHs, dioxins, PBDE, PFOS, pesticides, detergents, disinfectants, pharmaceuticals, plastics, personal care products, ...

“Chemicals” of Particular Interest: Pathogens

-- microorganisms that cause disease bacteria, fungi, parasites, and viruses

Staphylococcus E. coli

Source: http://www.soils.wisc.edu/courses/SS325

-- Oxygen

-- Nitrogen-- Manganese

-- Iron

-- Sulfur-- Carbon

Important Redox Elements

Mineral surfaces

Organic matter

Air

WaterChemical

SOIL-CHEMICAL INTERACTIONS

Photo: Karnok, 2003, Australian Turfgrass Management

CHEMICAL CONTROLS ONSOIL-CHEMICAL INTERACTIONS

WaterSolubility (S)

Charge andreactivity

Henry’s Lawconstant (~V/S)

Vapor pressure (V)

EQUATIONS – FOR THE ENGINNERS !

Solids-Water Distribution

concentration of the chemical on solid (mg/kg)

concentration of the chemical in water (mg/L)

Air-Water Distribution

concentration of the chemical in air (mg/m3)

concentration of the chemical in water (mg/L)

Kd =

Kaw =

Capel et al., USGS, in review

EQUILIBRIUM DISTRIBUTIONS OF CHEMICALS AMOUNG SOLIDS, WATER, AND AIR

Capel et al., USGS, in review

EQUILIBRIUM DISTRIBUTIONS OF CHEMICALS AMOUNG SOLIDS, WATER, AND AIR

Capel et al., USGS, in review

Legacy Chemicals

Legacy Chemicals

Nitrate as a Legacy Chemical

Sediment as a Legacy “Chemical”

Source: http://www.fws.gov/digitalmedia

Source: Gilliom et al., USGS Circular 1291

DDT and Friends as Legacy Chemicals

Dredging sediments!

Many trace elements, too!

Landscape Changes: Improved Irrigation

Furrow / Flood to Sprinkler

Central Washington

<1980s present

Landscape Changes: Improved Irrigation

Granger Drain

Yakima River

Landscape Changes: Improved Irrigation

Unfortunate result ...

Excess Irrigation: “Delta” Region (Mississippi)

Excess Irrigation: “Delta” Region (Mississippi)

Excess Irrigation: “Delta” Region (Mississippi)

Big Sunflower River (kind of ....)

Influence of Water Flowpaths to the Stream

Influence of Water

Flowpaths

Influence of Water Flowpaths to the Stream

Nitrate concentrations and watershed yields for agricultural streams with various types of

dominant water flowpaths

Agricultural DitchesSouthfork of the Iowa River

Source: http://www.southforkwatershed.org

Starts in three tile drains, emerges from a culvert, …

and turns into a very beautiful stream.