J-4 
Table J-1. Possible conclusions from application of the assessment protocol. 
n>=10 - sufficient sample size for assessment 
Impairment Analysis 
Stressor Diagnostic Analyses 
Scenario 
CL-L 
(P-P.) 
(Table 3 of 
VERSAR 
Technical 
Report) 
Impaired. 
Degraded Area 
method? 
(Table 3 of 
VERSAR 
Technical 
Report) 
Samples with 
contaminant 
Posterior Prob. 
p>= 0.90; % of 
Total (Table 5 of 
VERSAR Technical 
Report) 
Degraded Samples with 
excessive Abundance/Biomass; 
% of Total w/o Cont. (Table 5 of 
VERSAR Technical Report) 
Degraded Samples with 
Insufficient 
Abundance/Biomass; % of 
Total w/o Cont. (Table 5 of 
VERSAR Technical Report) 
1 
£0 
No 
review as 
supplemental Info 
review as supplemental info 
review as supplemental info 
A small, non-significant fraction of IBI scores are within or below the lower range of the reference distribution so water quality conditions in this 
segment support the benthic community (no Impairment) 
\Miere community samples are degraded, the stressor analyses may provide Information that supports other assessment data 
2 
>0 
Yes 
£ 25% of Total 
£ 25% of Total Samples 
£ 25% of Total Samples 
Samples 
A large significant fraction of IBI scores are within or below the lower range of the reference distribution, so water quality conditions in this 
segment do not support the benthic community (impaired condition) 
Stressor diagnostic analyses do not suggest dominant stressors affecting community composition Cause of degradation is “unknown" 
3 
>0 
Yes 
> 25% of Total 
£ 25% of Total Samples 
£ 25% of Total Samples 
Samples 
A large, significant fraction of IBI scores are within or below the lower range of the reference distribution, so water quality conditions in this 
segment do not support the benthic community (impaired condition) 
Stressor diagnostic analyses suggest sediment contaminants as a likely pollutant affecting benthic community structure 
4 
>0 
Yes 
> 25% of Total 
Samples 
> 25% of Total Samples 
£ 25% of Total Samples 
A large, significant fraction of IBI scores are within or below the lower range of the reference distribution, so water quality conditions in this 
segment do not support the benthic community (impaired condition) 
Stressor diagnostic analyses suggest sediment contaminants as a likely pollutant affecting benthic community structure Observation of high 
biomass or abundance is indicative of eutrophic conditions as an additional stressor affecting the benthic community 
5 
>0 
Yes 
> 25% of Total 
Samples 
£ 25% of Total Samples 
> 25% of Total Samples 
A large, significant fraction of IBI scores are within or below the lower range of the reference distribution, so water quality conditions in this 
segment do not support the benthic community (impaired condition) 
Stressor diagnostic analyses suggest sediment contaminants as a likely pollutant affecting benthic community structure Samples observed with 
low biomass or abundance are indicative of low dissolved oxygen as an additional stressor affecting the benthic community 
6 
>0 
Yes 
£ 25% of Total 
Samples 
> 25% of Total Samples 
£ 25% of Total Samples 
A large, significant fraction of IBI scores are within or below the lower range of the reference distribution, so water quality conditions in this 
segment do not support the benthic community (impaired condition) 
Stressor diagnostic analyses do not suggest sediment contaminants as a stressors affecting community composition Samples observed with 
7 
>0 
Yes 
£ 25% of Total 
Samples 
> 25% of Total Samples 
> 25% of Total Samples 
A large, significant fraction of IBI scores are within or below the lower range of the reference distribution, so water quality conditions in this 
segment do not support the benthic community (impaired condition) 
Stressor diagnostic analyses do not suggest sediment contaminants as stressor affecting community composition Samples observed with high 
biomass or abundance are indicative of eutrophic conditions within the segment while other samples observed with low biomass or abundance 
are indicative of low dissolved oxygen as another stressor within the segment 
8 
>0 
Yes 
£ 25% of Total 
Samples 
£ 25% of Total Samples 
> 25% of Total Samples 
A large, significant fraction of IBI scores are within or below the lower range of the reference distribution, so water quality conditions in this 
segment do not support the benthic community (impaired condition) 
Stressor diagnostic analyses do not suggest sediment contaminants as a stressor affecting community composition Samples observed with 
9 
>0 
Yes 
> 25% of Total 
Samples 
> 25% of Total Samples 
> 25% of Total Samples 
A large, significant fraction of IBI scores are within or below the lower range of the reference distribution, so water quality conditions in this 
segment do not support the benthic community (impaired condition) 
Stressor diagnostic analyses suggest sediment contaminants as a likely pollutant affecting benthic community structure Samples observed with 
high biomass or abundance are indicative of eutrophic conditions within the segment while other samples observed with low biomass or 
abundance are indicative of low dissolved oxygen as an additional stressor within the segment 
appendix j 
Bay Estuarine Benthic Communities Assessment Protocol for Maryland and Virginia 
