2 How do you measure the quality of a moving, ever changing fluid medium?
3 Two Basic Approaches:TECHNOLOGY-BASED LIMITS: Use a certain treatment technology (BPT, BAT, MACT, BPJ) to achieve a given quality of effluentWATER QUALITY-BASED LIMITS: Quantitative relationship between inputs and quality (LD50, NOEL)--dose/response risk assessment, hydrology, mass balance
5 Oxidizing (Oxygen-Using) Reactions FireMetabolism of humans and animalsFate of pollutants in waterC in fuel combines with atmospheric O2carbon-bearing organic compounds oxidized to CO2,water, energypollutants are oxidized, depleting O2 in water
6 Measures of oxygen in water: Dissolved oxygen (DO)--time and space variables, dilutionBiological oxygen demand, five days (BOD5)Chemical oxygen demand (COD)Sediment oxygen demand (SOD)
7 Oxygen and other pollutants may vary according to: Fluctuations in inputs (lagged)Time of day (day-night)Time of year (summer-winter)Water temperature (thermal stratification)Stream flowWhich in turn varies with land clearance/impervious cover, storm events, seasonal variations, channel structure, etc.
8 Effects of sediment loading Destruction of spawning bedsAdsorption and transport of other pollutantsReduced light penetration, aquatic vegetationGreater nutrients loadings, oxygen demandInterference with navigation, flood control, recreation, industry
9 Effects of nutrient loadings (N, P measured by Chlorophyll a, Secchi, algal species) Algae bloomsDO changes, fish killsShift of trophic status toward eutrophicDrinking water impairment (direct and indirect)Aesthetics (color, clarity, smell)Uptake and release of toxics
10 Effects of acidification (measured in pH--log scale) Direct kill of living thingsShift toward acid-tolerant speciesMobilization (dilution, desorption) of metals and other toxics
12 Impacts of toxics Acute mortality (instant death) Chronic illnesses (e.g., cancer)Reproductive and developmental toxicity (“hormone mimics”)Persistence over space (toxaphene) and time (PCBs); or transformation (DDT to DDE, PCB dechlorination, methyl mercury)Storage in reservoirs (sediment sinks)
13 Some approaches to toxics parameters Chemical levels (water, sediment)Ability to support designated usesAbility to support beneficial usesFish advisoriesHistorical baselinesBackground levels“Narrative criteria” (no toxics in toxic amounts)
14 Bring diverse measurements together into a single-number value IndicesBring diverse measurements together into a single-number value
15 Ecosystem approachesLook at interactions of living and nonliving parts of the ecosystem (what’s an ecosystem?)Try to identify stresses and responsesHolistically integrate physical, biological, and social aspects of the area in question
16 “Social Indicators” Stewardship Sustainability Stakeholder Involvement Etc., etc. (what is the good society?)