Measuring Water Pollution A Quick Overview

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

Two Basic Approaches: n TECHNOLOGY- BASED LIMITS: Use a certain treatment technology (BPT, BAT, MACT, BPJ) to achieve a given quality of effluent (work backward from effluent chemistry) n WATER QUALITY- BASED LIMITS: Quantitative relationship between inputs and quality (LD 50, NOEL)-- dose/response risk assessment, hydrology, mass balance

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

Oxidizing (Oxygen-Using) Reactions n Fire n Metabolism of humans and animals n Fate of pollutants in water n C in fuel combines with atmospheric O 2 n carbon-bearing organic compounds oxidized to CO 2,water, energy n pollutants are oxidized, depleting O 2 in water

“Assimilative capacity”: ability of a waterbody to convert a pollutant into something harmless (to whom or what?)

Measures of oxygen in water: n Dissolved oxygen (DO)--time and space variables, dilution n Biological oxygen demand, five days (BOD 5 ) n Chemical oxygen demand (COD) n Sediment oxygen demand (SOD)

Oxygen and other pollutants may vary according to: n Fluctuations in inputs (lagged) n Time of day (day-night) n Time of year (summer-winter) n Water temperature (thermal stratification) n Stream flow –Which in turn varies with land clearing/impervious cover, storm events, seasonal variations, channel structure, etc.

Sediments

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

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

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

Toxics and Bioaccumulation

Impacts of toxics n Acute mortality (instant death) n Chronic illnesses (e.g., cancer) n Toxicity at low doses (e.g., dioxin) n Reproductive and developmental toxicity (“hormone mimics”) n Persistence over space (toxaphene) and time (PCBs); or transformation (DDT to DDE, PCB dechlorination, methyl mercury) n Storage in reservoirs (sediment sinks)

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

Traditional sampling: “grab samples”

Automated Measurements: Sondes (Hydrolab or YSI) n Automated sampling of basic conventional parameters n Fine-grained (e.g., every 15 minutes) n Download to laptop for analysis

Indices Bring diverse measurements together into a single-number value

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

Institutional Context: Remedial Action Plan n Great Lakes Water Quality Agreements n “Areas of Concern” n Plan to restore “beneficial uses”

Beneficial Uses n Restrictions on Fish Consumption n Restrictions on Dredging n Added costs to agriculture or industry n Tainting of fish flavor n Restrictions on drinking water consumption n Degraded fish or wildlife populations n Degraded benthos n Eutrophication or undesirable algae n Loss of fish or wildlife habitat n Fish tumors or deformities