Measuring Water Pollution A Quick Overview

How do you measure the quality of a moving, ever changing fluid medium?

Two Basic Approaches: TECHNOLOGY-BASED LIMITS: Use a certain treatment technology (BPT, BAT, MACT, BPJ) to achieve a given quality of effluent WATER QUALITY-BASED LIMITS: Quantitative relationship between inputs and quality (LD50, NOEL)--dose/response risk assessment, hydrology, mass balance

The “Conventional” Pollutant Measures: Oxygen (BOD, COD, DO) Solids content (TSS, Conductivity, Secchi disk, settleable solids) Nutrients (phosphorus, nitrogen) /Algae/Eutrophication Acidity (pH) Bacteria (e.g., fecal coliform) Temperature

Oxidizing (Oxygen-Using) Reactions Fire Metabolism of humans and animals Fate of pollutants in water C in fuel combines with atmospheric O2 carbon-bearing organic compounds oxidized to CO2,water, energy pollutants are oxidized, depleting O2 in water

Measures of oxygen in water: Dissolved oxygen (DO)--time and space variables, dilution Biological oxygen demand, five days (BOD5) Chemical oxygen demand (COD) Sediment oxygen demand (SOD)

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 flow Which in turn varies with land clearance/impervious cover, storm events, seasonal variations, channel structure, etc.

Effects of sediment loading Destruction of spawning beds Adsorption and transport of other pollutants Reduced light penetration, aquatic vegetation Greater nutrients loadings, oxygen demand Interference with navigation, flood control, recreation, industry

Effects of nutrient loadings (N, P measured by Chlorophyll a, Secchi, algal species) Algae blooms DO changes, fish kills Shift of trophic status toward eutrophic Drinking water impairment (direct and indirect) Aesthetics (color, clarity, smell) Uptake and release of toxics

Effects of acidification (measured in pH--log scale) Direct kill of living things Shift toward acid-tolerant species Mobilization (dilution, desorption) of metals and other toxics

What about toxics?

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)

Some approaches to toxics parameters Chemical levels (water, sediment) Ability to support designated uses Ability to support beneficial uses Fish advisories Historical baselines Background levels “Narrative criteria” (no toxics in toxic amounts)

Bring diverse measurements together into a single-number value Indices Bring diverse measurements together into a single-number value

Ecosystem approaches Look at interactions of living and nonliving parts of the ecosystem (what’s an ecosystem?) Try to identify stresses and responses Holistically integrate physical, biological, and social aspects of the area in question

“Social Indicators” Stewardship Sustainability Stakeholder Involvement Etc., etc. (what is the good society?)