Contaminant Types

Organic (carbon based) Pathogens PAHs Halogenated Hydrocarbons DDD, DDE, DDT, 2,4-D and 2,4,5-T PCBs Persistent Organic Pollutants (POPs) PCBs, aldrin, chlordane, DDT, dieldrin, endrin, mirex, toxaphane, and heptachlor as well as dioxins, hexachlorobenzene, and furans Inorganic Nutrients P, N, C Metals/Metalloids Pb, Zn, Cd, Cu, Hg, Cr, Ni As, Sb Radionuclides Alpha, Beta, Gamma U/Th Series Contaminant Types

Contaminant Types • PAHs – Polycyclic Aromatic Hydrocarbons • PCBs - Polychorinated biphenyl compound • POPs – Persistent Organic Pollutants • Dioxins/Furans -

Persistent Organic Pollutants (POPs) Other characteristics that make them particularly hazardous include • (1) their propensity to accumulate in biota, • (2) a strong tendency for concentrations to increase up the food chain (i.e., biomagnify), • (3) their ability to be transported over long distances, and • (4) their potential to be toxic to both humans and other animals at very low concentrations. More specifically, POPs have been linked to disruptions of the immune system, cancer, reproductive problems, and nervous system dysfunction. • POPs were recently addressed by the Stockholm Convention, a United Nations Treaty that seeks to reduce or completely eliminate the production, use, and/or release of the 12 most important POPs (sometimes referred to as the dirty dozen).

Nutrients • N, P, C, K • Eutrophication (Cultural/natural) • P – control in freshwater • N – control in marine waters • Nitrate – methylmeglobenemia (blue baby disease.

Their physical properties generally include: They are good conductors of heat and electricity. They are malleable and ductile in their solid state. They show metallic luster. They are opaque. They have high density. They are solids (except mercury) They have crystal structure in which each atom is surrounded by eight to twelve near neighbors Their chemical properties generally are: They have one to four valence electrons. They have low ionization potentials; they readily lose electrons. They are good reducing agents. They are electopositive. Metals defined by an electrolysis test – test consists of dissolving the element in acid and running an electric current through the solution. If the element is metallic, the atoms of the element will show a positive charge. That is they will seek the negative pole. Metals and Metalloids

Heavy Metals • Includes: Pb, Hg, Zn and others, most of which are transition elements • These elements are often considered as the most harmful to aquatic ecosystems, and are of particular concern to site assessments because they can be extremely toxic to humans at high concentrations. • Heavy metals are often defined according the density of the metal; densities that have been cited in the literature range from >3.5 g/cm3 to >7 g/cm3. • Hodson (2004) has argued that investigators should avoid using the term.

Radionuclides • Produced by the fission of relatively heavy elements such as uranium, thorium, and plutonium. • Alpha particles • Beta particles • Gamma rays • Measured in terms of picocurie (pCi): • 3.7 x 10-2 disintegrations per second

National Assessments of Riverine Ecosystems • The National Water Quality Inventory (USEPA) • The National Sediment Quality Survey (USEPA) • The National Water-Quality Assessment Program (USGS)

Problems with National Assessments • data is typically collected by multiple people, using different protocols, and analyzed by different labs. Hard to determine if delineated trends are real or simply represent differences in the methods of sample collection and analysis. • samplings sites are not randomly selected, but represent geochemical records collected to address a specific question. So, most large scale assessments are biased by the geographical distribution of the sampling locations.

Important Aspects of the National Water Quality Inventory • Required by Section 305b of Clean Water Act • Assessments conducted by states & other jurisdictions, but USEPA must approve standards • Findings reported to USEPA very other year

Water Quality StandardsConsist of Three Components • Designated uses of water • A set of criteria that are intended to protect human and aquatic life • Some form of anti-degradation policy that attempts to prevent degraded waters from getting worse, and high quality waters from becoming degraded.

River Reaches are Reported As: • Good – Fully supporting of their uses, or fully supporting of all uses but are threatened for one or more • Impaired – partially or not supporting of one or more uses • Not attainable – not able to support one or more use

Leading Pollutants in Rivers and Streams 19%

Guidelines Provided for Designated Uses to be Fully Supporting Aquatic Life Support: Water quality is good enough to support a healthy, balanced community of aquatic organisms including fish, plants, insects, and algae. Fish Consumption: People can safely eat fish caught in the river or stream. Primary Contact Recreation(swimming): People can make full body contact with water without risk to their health. Secondary Contact Recreation: No risk to public health from recreational activities on the water, such as boating, that expose the public to minimal contact with the water. Drinking Water Supply: The river provides a safe supply of water with standard treatment. Agricultural Uses: The water can be used for Irrigating fields and watering livestock.

The National Sediment Quality Survey(Important Aspects) • In response to 1992 Water Resources Development Act • Based on National Sediment Inventory • Contains 2 million records of sediment chemistry and biological data from 21,000 monitoring stations • Primary goal: to assess probable risk of contaminated channel bed sediments to benthic organisms and human populations who consume aquatic organisms that have been exposed to contaminated materials. • Also, aimed at identifying regions where additional studies are warranted.

Categorization of Monitoring Stations • Tier 1 – associated adverse effects on aquatic life or human health are probable. • Tier 2 – associated adverse effects on aquatic life or human health are possible, but infrequently expected • Tier 3 – no indication of associated adverse effects on aquatic or human health

National AssessmentRiver Reach Categories • Of 21,000 Sites • 26 % Tier 1 • 49 % Tier 2 • Data not Uniformly • Collected • ~ 5% of sediment in • rivers is polluted • enough to cause adverse effects Based on a total of 6,774 river reaches

Measurements Above Detection Limit (586,994) Measurements Indicating Potential Risk (Tier 1 & 2) (142,004) Sediment & Fish Tissue Measurements (1,565,103)

Areas of Probable Concern • Watershed must contain: • 10 or more Tier 1 stations • And/or 75 % classified as Tier 1 or Tier 2 • Of the 2,110 watersheds in assessment, only 488 have 10 or more sampling stations • Of these, ~20 % qualify as areas of probable concern.

Chemical Classes(National Sediment Quality Survey) • PCBs • Pesticides • PAHs • Other Organics (including dioxin & furans) • Mercury • Other Metals

Significance of Chemical Classes

Tier 1 Tier 2 Tier 3 yes What was the result of comparing [SEM] to [AVS]? Was AVS measured for the sample no [SEM] – [AVS] > 5 Did Chemical concentration Exceed any metal screening values? [SEM] – [AVS] < 0 yes [SEM] – [AVS] = 0 to 5 no

Sources of Contamination • Point source: refers to the discharge of contaminants from a specific location, such as the end of a pipe or canal • Nonpoint source: refers to the delivery of pollutants to a river from a diffuse area, such as an agricultural field or an urban center

Sources associated with selected classes of contaminants

National Water-Quality Assessment Program • Established in 1991 in response to National Academy of Science Report; • Primary Difference of Other Assessments • Watershed based • Sampling and Analysis Protocols are Consistent • 50 Watersheds included in analysis

Guiding Questions for NAWQA • What is the current conditions of the water resources in U.S.? • How is water quality changing over time? • What are the natural and human controls on stream and groundwater quality?

Some NAWQA Conclusions • Agricultural Areas • 95 % of stream samples had measurable pesticides • 66 % exhibited 5 or more, including DDT • Urban Areas • 80 % of samples contained 5 or more pesticides • 70 % of river samples from both areas exceeded nutrient levels for preventing eutrophication in rivers

A Significant NAWQA Conclusion • vulnerability of water resources to contamination differs from region to region depending on the underlying geology, soils, hydrology, and land-management practices.

Contaminant Types