Table 1: Sediment bioassay summary for Georgia Pacific Corporation

Bellingham, Washington (sampled September 1993)

Grabs/ Reps/ Site site site		Bioassay	DOE Type 1 t-test p Sig* error p			Dunnett's ANOVA p F calc power test **
A-1	5 2 5 5	Rhepoxynius Echinoderm Neanthes	0.0101 0.0131 0.0990	_ _	0.1426 0.1855 0.3017	0.0793 0.0311 0.0020	(F 3, 15 = 2.75) (F 4, 20 = 3.31) (F 7, 32 = 4.26)	0.35 0.55 0.90	Different Not different
A-2	1	Rhepoxynius Echinoderm Neanthes
A-3	4 1 5 5	Rhepoxynius Echinoderm Neanthes	0.0379 0.0035 0.0845	_ _	0.1426 0.1855 0.3017	0.0793 0.0311 0.0020	(F 3, 15 = 2.75) (F 4, 20 = 3.31) (F 7, 32 = 4.26)	0.35 0.55 0.90	Different Not different
B-1	2 5 5	Rhepoxynius Echinoderm Neanthes	0.0124 0.0028	_ _	0.1855 0.3017	0.0311 0.0020	(F 4, 20 = 3.31) (F 7, 32 = 4.26)	0.55 0.90	Different Different
B-2	2 5	Rhepoxynius Echinoderm Neanthes	0.0020	_	0.3017	0.0020	(F 7, 32 = 4.26)	0.90	Different
B-3	2 5	Rhepoxynius Echinoderm Neanthes	0.0536		0.3017	0.0020	(F 7, 32 = 4.26)	0.90	Not different
C-1	5 3 5	Rhepoxynius Echinoderm Neanthes	0.0762 0.0010	_	0.1426 0.3017	0.0793 0.0020	(F 3, 15 = 2.75) (F 7, 32 = 4.26)	0.35 0.90	Different
C-2	2	Rhepoxynius Echinoderm Neanthes
C-3	2 5 5	Rhepoxynius Echinoderm Neanthes	0.0256 0.0278	_ _	0.1855 0.3017	0.0311 0.0020	(F 4, 20 = 3.31) (F 7, 32 = 4.26)	0.55 0.90	Different Not different
Total statistically significant			10 of 14			7 of 14

* Sig means difference based on results of t-tests. An x means a statistically significant difference was found

** Dunnett's test evaluates statistical differences between bioassays for test and reference sediments.

Different means a statistically significant difference exists between test and reference sediments.

Not different means a statistical difference does not exist.

Model: o = l + P _i + D _j + PD _{i j} + r _{( ij ) k}

P = Position (upcurrent or downcurrent) ( i = 1..2, fixed)

D = Distance (from start of diffuser) ( j = 1..5, fixed)

r = replicates ( k = 1..4, random)

Source df EMS F

P _i 1 u ²_r + 20 l _P MS_P / MSr (1, 30)

D _j 4 u ²_r + 8 l _D MS_D / MSr (4, 30)

PD _ij 4 u ²_r + 4 l _{P D} MD_PD / MSr (4, 30)

r _{( ij ) k} 30 u ²_r

total 39

The guidelines for all of the sediment bioassays included in this document recommend that all field-collected sediments be homogenized before subsamples are removed for bioassay and chemical analyses. This technique is the one used for most studies in Puget Sound, and it ensures that the bioassay and chemical results are related as closely as possible. The replicate analyses that are subsequently conducted on the bioassay subsample assess the variability encountered in laboratory testing, rather than the variability of sediment toxicity that exists in the field. To assess field variability, an alternate sampling design could be specified that requires each bioassay replicate to be run on a separate replicate grab sample from each station. The primary drawback to this technique is that the single set of chemical concentrations usually measured at each station (i.e., primarily because of cost constraints) would not relate directly to the sediment toxicity measured in each replicate grab sample. This lack of a direct relationship between bioassay and chemical results can sometimes make data interpretation difficult for individual replicate samples. However, the mean bioassay response could be compared directly with chemical concentrations if the chemical measurements are made on a composite of equal amounts of sediment subsampled from each of the replicate samples used for bioassay analysis. (emphasis added)

WAC 173 - 204 - 320 Marine sediment quality standards

WAC 173 - 204 - 420 Sediment impact zone maximum criteria

WAC 173 - 204 - 520 Cleanup screening levels criteria

Example from WAC 173 - 204 - 320 (3) Biological effects criteria

(3) Biological effects criteria. For designation of sediments pursuant to WAC 173-204-310(2), sediments are determined to have adverse effects on biological resources when any one of the confirmatory marine sediment biological tests of WAC 173-204-315(1) demonstrate the following results:

(a) Amphipod: The test sediment has a higher (statistically significant, t test, p£0.05) mean mortality than the reference sediment and the test sediment mean mortality exceeds twenty-five percent, on an absolute basis.

(b) Larval: The test sediment has a mean survivorship of normal larvae that is less (statistically significant, t test, p£0.05) than the mean normal survivorship in the reference sediment and the test sediment mean normal survivorhsip is less than eighty-five percent of the mean normal survivorship in the reference sediment (i.e. the test sediment has a mean combined abnormality and mortality that is greater than fifteen percent relative to time final in the reference sediment).

(d) Juvenile polychaete: The test sediment has a mean biomass of less than seventy percent of the reference sediment mean biomass and the test sediment biomass is statistically different (t test, p£0.05) from the reference sediment biomass.

(emphasis added)