USGS
Lake Pontchartrain Basin:  Bottom Sediments and Related Environmental Resources

Table 8.  Alert range table.

[This table provides ranges of contaminant concentrations (in µg/g) that have been used to predict adverse biological effects on estuarine bottom organisms. "ERL" and "ERM" are two guideline values which delineate three concentration ranges for each chemical. Adverse effects on organisms are rarely observed when concentrations fall below the ERL value. Concentrations between the ERL and ERM values represent a range within which effects will occasionally occur. And toxic effects are frequently observed in the range of concentrations above the ERM (Long and others, 1995). This table also provides other reference ranges as stated in the notes.]

Element Natural
Soil 1		 SQG 2
ERL 3		 SQG 2
ERM 4		 Low alert
level 5		 High alert
level 5, 6

 
Notes

  1. Natural soils are taken as the earth materials most closely resembling uncontaminated estuarine sediments (from Bowen, 1979).
  2. Sediment Quality Guidelines (SQG) for bulk sediment elemental concentrations.
  3. ERL refers to Toxic Effects-Range Low, from Long and others (1995, 1998). Below this level is not considered toxic, since adverse effects to organisms occurred in less than 10% of studies in which concentrations fell below the respective ERL values.
  4. ERM refers to Toxic Effects-Range Medium, from Long and others, (1995, 1998). Above this level is considered toxic, since adverse effects to organisms occurred in more than 75% of studies in which concentrations exceeded the respective ERM values.
  5. Refers to concentration range limits normally found in natural, uncontaminated sediments, based on standard geochemical reference publications (Wedepohl, 1978, and Bowen, 1979), and range found in Atlantic continental shelf drill cores (Manheim and Commeau, 1981, and Commeau and Manheim, 1981).
  6. Estimated sediment screening values from USEPA (1996), Table A-2. Many of these values are the same as ERM values. Approximate screening values for elements not given in USEPA (1996) are estimated from upper 10 percentile of NOAA NS&T national sediment monitoring data set (Cantillo, A., NOAA NS&T Program Sediment Chemistry Data, ASCII files, unpub. data).
  7. Does not include carbonate-rich environments in south Florida.
  8. Value for uncontaminated Mississippi Delta sediments (Presley and others, 1998).
  9. Does not include sediment from phosphorite rich areas.
  10. NA = these elements are not toxic even at high concentrations
Ag 0.05 1 3.7 0.02 3.7
Al 71000 NA10 NA 7000 100000
As 6 8.2 70 0.5 70
B 20     5 150
Ba 500 NA NA 50 1000
Be 0.4     0.1 6
Ca 7 15000 NA NA 2000 100000
Cd 8 0.1 1.2 9.6 0.04 9.6
Co 8 NA NA 0.5 120
Cr 70 81 370 4 370
Cu 30 34 270 2 270
Fe 40000 NA NA 2000 100000
Hg 0.06 0.15 0.71 0.01 0.71
K 14000 NA NA 1000 40000
Mg 5000 NA NA 2000 40000
Mo 1.2     0.5 18
Na 5000 NA NA 3000 50000
Ni 50 20.9 51.6 3 50
P 9 800 NA NA 200 25000
Pb 14 46.7 218 2 218
S 700     300 30000
Sb 1     0.2 15
Se 0.4     0.05 6
Sn 2.2     0.2 25
Si 330000 NA NA 10000 480000
Tl 0.2     0.05 3
U 2     0.5 10
V 90     5 350
Zn 90 150 410 5 410
Corg 20000     1000 50000
Norg 2000     200 5000

 

  Back to Analytical Methods

[an error occurred while processing this directive]