“No instrument has yet been devised that can measure toxicity! Chemical concentrations can be measured with an instrument but only living material can measure toxicity.”

Cairns, John, Jr. and Mount, Don I

The reason this lecture was stimulated by this quote is that the concept expressed in the quote is the basis for the water quality based approach to toxics control that is reflected in the incorporation of WET tests in NPDES permits.

However, there remains an extrapolation and that extrapolation is from effluent toxicity to receiving system impacts. Stated simply it asks, Does effluent toxicity, as measured by WET tests, have any relationship to receiving system impact? It also stimulates the question, Why extrapolate at all? Why not just go to the receiving system and measure its health?

Diversity Indices and Standards

Ecology – study of the interrelationships between plants and animals and their abiotic environment.

Species – individuals that interbreed freely to produce fertile offspring.

Population – all the individuals of the same species in a defined area. All the Micropeterus salmoides in Lake Ray Roberts.

Community – all the populations in a defined area, or all the fish in Lake Ray Roberts.

Ecosystem – Lake Ray Roberts, the surrounding watershed and all the organisms there in.

Watershed – the area of land that catches precipitation that then if transported along the surface drains to a common point.

Historically pollution and organic enrichment problems were synonymous. Engineers and chemists used physical and chemical surveys to tell them about the “health” of a system.

Measured parameters like: pH, dissolved oxygen, BOD5, and suspended solids.

Why can’t you use physical/chemical measurements alone to tell you about the “health” of an ecosystem?

When biologists became significantly involved they tended to provide lists of species they found in a survey.

Species Lists…. Head of chironomid… dichotomous key

Indicator organisms

Diversity indices

Eventually developed a belief that organisms living in a system are probably the best indicator of their health.

http://images.google.com/imgres?imgurl=http://www.epa.gov/bioindicators/images/invertebrates/zavrelimyia_03040313web.JPG&imgrefurl=http://www.epa.gov/bioindicators/html/photos_invertebrates_midges.html&h=263&w=350&sz=19&hl=en&start=5&um=1&tbnid=D0mLoLyiiSKwaM:&tbnh=90&tbnw=120&prev=/images%3Fq%3DTanypodinae%26um%3D1%26hl%3Den%26rlz%3D1T4RNWE_en___US258%26sa%3DN

In the discussion that follows the letters used in the listing of organisms represent species A = a species, B = a species, etc.

The indices that are used in the following series of slides are examples of the kinds of indices that have been developed. There are many variations of these indices and each has its own inherent strengths and weaknesses.

If you are using diversity indices you would never

represent your data by a single index!

Reference Stream Stream of Concern

As i goes from A to J As i goes from A to J

.

For example replace J with LS=0.9

Notice this index tells us nothing about how theIndividuals are distributed among the species present

N is the total number of individuals present; while little n is the number in a given species. For example species A has 25 individuals so n for species A is 25.

Notice this index tells us nothing about which species are present.

Reference Stream

N

n

Study Stream

Study Stream

Study Stream

Study Stream

Reference Stream Study Stream

Bayou Chico

Green Book 1968, Blue Book 1972, Red Book 1976, Gold1986, Phantom Silver Book, acid soluble metals vs dissolved vs total

AF = Chronic value divided by the acute

CCC criteria continuous concentration

CMC criteria maximum concentration

Silver Book??? Acid soluble metals: That portion of the metal concentration that will pass through a 0.45 um membrane filter after the solution has been adjusted to within a pH 1.75 ± 0.1 for a period of 16 hours. Factor for adjusting WQC is 0.960 or 96% of the total metal is in the acid soluble form.

n = t2 x s2

d 2

n = 128

n = number of samples neededt for n-1 d.f. alpha = 0.05 based on number of samples used to determine variance n=10, 2.262s2 = varianced = difference you wish to detect In our example n = 10, variance = 100 d = 2

(0.960)(1.60)e(0.9422([ln hardness])-1.3844

For the chronic value for 100 mg/L hardness as CaCO3

Answer is: 29.5 ug/L copper; without the 0.960 and the 1.60 the standard would be 19.2 ug/L

The State criterion in Texas for a given river might look like the formula below where the 0.960 accounts for the acid soluble function and the 1.60 for the water effects ratio assigned to a particular receiving system.

Solve the equation above with and without the modifiers

Note the antidegradation policy for Outstanding National ResourceWaters

Segment Segment Name USES Criteria

Number Recreation Aquatic Domestic Other Cl-1 SO4-2 TDS D.O. pH Indicator Temp.

Life Water mg/L mg/L mg/L mg/L Range Bacteria (oF)Supply (SU) #/100mL

0202R.R. Below Lake Texoma CR H PS 375 250 1,100 5.0 6.5-9.0 126/200 93

0203Lake Texoma CR H PS 600 300 1,500 5.0 6.5-9.0 126/200 92

0204R.R. Above Lake Texoma CR H 2,000 1,200 6,000 5.0 6.5-9.0 126/200 93

0205R.R. Below Pease River CR H 5,000 2,000 10,000 5.0 6.5-9.0 126/200 93

0206R.R. Above Pease River CR H 12,000 4,000 25,000 5.0 6.5-9.0 126/200 93

0207Lower Prarie Dog Town Fork R.R. CR H 37,000 5,300 46,200 5.0 6.5-9.0 126/200 93

Texas Water Quality Standards for Red River and Major Tributaries