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SUMMARY OF COMPOUND DETECTIONS AND CONCENTRATIONS

 

VOCs and Nutrients


| Contents | Summary of Compound Detections and ConcentrationsSVOCs |

Concentrations of herbicides, insecticides, volatile organic compounds, and nutrients detected in ground and surface waters of the Trinity River Basin Study Unit

[
mg/L, micrograms per liter; %, percent; <, less than; --, not measured; mg/L, milligrams per liter; trade names might vary]

EXPLANATION explanation graph for detections

Freshwater-chronic criterion for the protection of aquatic life
a


Drinking-water standard or guideline
a

Range of surface-water detections in all 20 Study Units

Range of ground-water detections in all 20 Study Units

Detection in the Trinity River Basin Study Unit

Volatile organic compound 
(Trade or common name)

Rate 
of 
detec-
tion b

 Concentration, in mg/L

explanation graph


1,1-Dichloroethene (Vinylidene chloride)

--

1%

graph showing detections

1,2,4-Trimethylbenzene (Pseudocumene)

--

1%

graph showing detections

Benzene

--

1%

graph showing detections

Chlorobenzene (Monochlorobenzene)

--

1%

graph showing detections

Chloroethene (Vinyl Chloride)

--

1%

graph showing detections

Dimethylbenzenes (Xylenes (total))

--

1%

graph showing detections

total Trihalomethanes

--

3%

graph showing detections

Trichloroethene (TCE)

--

3%

graph showing detections

Trichlorofluo-
romethane (CFC 11)

--

1%

graph showing detections

cis-1,2-Dichloro (ethene)

--

1%

graph showing detections

trans-1,2-Dichloro (ethene)

--

1%

graph showing detections


 

 


Volatile organic compound 
(Trade or common name)

Rate 
of 
detec-
tion b

 Concentration, in mg/L

explanation graph


Methyl tert-butyl etherd (MTBE)

--

4%

graph showing detections

Tetrachloroethene (Perchloroethene)

--

1%

graph showing detections


 

Nutrient

Rate 
of 
detec-
tion b

 Concentration, in mg/L

explanation graph


Dissolved ammonia

90%

92%

graph showing detections

Dissolved ammonia plus organic nitrogen as nitrogen

 91%

41%

graph showing detections

Dissolved phosphorus as phosphorus

77%

66%

graph showing detections

Dissolved nitrite plus nitrate

87%

50%

graph showing detections


a Selected water-quality standards and guidelines (Gilliom and others, in press). 

b Rates of detection are based on the number of analyses and detections in the Study Unit, not on national data. Rates of detection for herbicides and insecticides were computed by counting only detections equal to or greater than 0.01 mg/L to facilitate equal comparisons among compounds, which had widely varying detection limits. For herbicides and insecticides, a detection rate of "<1%" means that all detections are less than 0.01 mg/L, or the detection rate rounds to less than 1%. For other compound groups, all detections were counted and minimum detection limits for most compounds were similar to the lower end of the national ranges shown. Method detection limits for all compounds in these tables are summarized in (Gilliom and others, in press). 

c Detections of these compounds are reliable, but concentrations are determined with greater uncertainty than for the other compounds and are reported as estimated values (Zaugg and others, 1995). 

d The guideline for methyl tert-butyl ether is between 20 and 40 mg/L; if the tentative cancer classification C is accepted, the lifetime health advisory will be 20 mg/L (Gilliom and others, in press). 

e Selected sediment-quality guidelines (Gilliom and others, in press). 

 



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