•

•

PART 8 GROUND WATER MONITORING

This part of the checklist/questionnaire is applicable to any person who owns or

operates a surface impoundment, landfill, land treatment or water pile (final status)

facility which is used to manage hazardous waste and therefore is required to 'maintain

a ground water monitoring network. The ground water monitoring checklist/questionnaire

consists of five subparts listed as follows:

1. Hydrogeologic Characterization

2. Ground Water Monitoring Network

3. Monitoring Well Installation and Construction

4. Field Inspection

5. Water Quality Results

All five subparts apply to interim status facilities and detection monitoring programs

under final status. The technical information requirements to assess the adequacy of

a ground water monitoring program are the same for an interim status facility and a

detection monitoring program under final status. Therefore, even though many of the

questions in these subparts reference, final status regulations, they are also required,

on a technical basis, to assess interim status ground water monitoring programs. A

ground water assessment checklist (for interim status facilities where ground water

contamination has been detected) and additional subparts for final status ground water

monitoring requirements will be added later.

Note that in many instances more than one of each subpart may be required for a

facility inspection. For example, a facility may have three different kinds of

well constructions, thus, three monitoring well installation and construction

checklist/questionnaires may be appropriate. Subpart 4, Field Inspection is filled

out at the facility during the compliance inspection.

Whenever possible copies of drawings and figures listed in the checklist/questionnaire

should be obtained and attached. These may include but are not limited to:

1. . An as-built drawing and geologic log (on one figure) for each

monitoring well.

2. Water table and potentiometric maps

3. Hydrogeologic profiles

4. Site maps such as topographic maps, well location maps, surface water

and drainage maps, etc.

5. Tabulated water quality data.

Note that the federal regulations are referenced in the checklist/questionnaire for

interim status facilities and state regulations are referenced for final status

facilities.

• Space for additional remarks is available at the end of the checklist.

-k ~k i~ * "k "k * ~k ;'\ 7, * "k "k * * * * * * "I, * "k * ",/, * * * * * * * * * * * * * * i'( * * * *
1. HYDROGEOLOGIC CHARACTERIZATION

A. Regional Hydrogeology (WAC -806(4) (xx) (B)) •

Yes No o

a. Is the regional hydrogeology and its relationship.

to the facility characterized?

If yes, what data sources have been used to

characterize the regional hydrogeology?

(i) Published and other technical reports?

Specify the reports used:

(ii) Water well logs?

(iii) Geotechnical borings?

(iv) Climatic records?

(v) Surface water records?

(vi) On-site geologic mapping?

(vii) Other (specify)?

b. Is the on-site and off-site ground w~ter use

characterized?

If yes, does the chara~terization include the

following:

(i) A map showing ground water production wells

and other wells (e.g. neighboring monitoring

wells) relative to the site? (WAC -806(4)(a)

(xviii) (1)

(ii) Well logs for all wells (if available)?

(iii) Use and use rates for all production wells?

- 2 -

o
•

•

(iv) Pumping and static water levels?

(v) Effect of on-site and off-site pumping on

the ground water flow direction?

c. Does the regional hydrogeologic characterization

include the following:

(i) Identification of the principal aquifers

(i.e. aquifers being used or which have

potential use) that may be potentially

affected by the site? (WAC -806(4)(x)(B)

Remarks:

(ii) Hydrogeologic profiles showing the relationship

of the facility to the principle aquifers?

Remarks:

(iii) Water table contour and/or potentiometric maps

for the principle aquifers?

Remarks:

B. Site Hydrogeology

a. List the pertinent hydrologic and geologic

investigations ongoing or completed at the

facility:

•

Month/Year

Description of Work Ongoing

or Completed (Obtain copies of all reports)

- 3 -
b. Is a site map (or site maps) available that shows

the following: (WAC -806(4)(a)(xviii)

(i) Waste management areas?

(ii) Monitoring well locations?

(iii) Site topography?

(iv) Surface water features and drainage?

(v) On-site water supply wells?

(vi) Pertinent engineered structures and operational

units?

(vii) Is the scale of the map appropriate?

Scale used:

(viii) North arrow?

(ix) Legal boundaries?

(x) Access controls (e.g. roads, fences)

(xi) Surface and buried utilities?

(xii) Barriers to drainage?

c. Are the following characteristics of the uppermost

aquifer (uppermost monitorable saturated zone)

defined: (WAC 806(4)(x)(B)

(i) Aquifer materials (sand, sandy [ravel, sandstone, etc.)

Specify

(ii) Thickness and lateral extent?

Remarks:

- 4 -

G

()
..

•

•

•

(iii) Continuity beneath and adjacent to the site?

Remarks:

(iv) Water-table contour maps and potentiometric

maps that show ground water flow directions?

Remarks:

(v) Seasonal variation of ground water flow

directions?

Remarks:

(vi) Effect of ground water use on the ground

water flow directions?

Remarks:

(vii) Hydraulic conductivity/transmissivity

including lateral and vertical variations?

Which of the following methods were used

to determine hydraulic conductivity/

transmissivity

a) Es~imates from grain size analyses

Describe

- 5 -
b) Laboratory tests (permeameter tests)

Describe

c

c) Slug tests

Describe

d) Pumping tests

Describe

e) Other

Describe ----------------

(viii) Methods used to evaluate slug tests, pumping

tests, etc.

Remarks:

(ix) Effective porosity?

(x) Storage coefficie~t including lateral and

vertical variations?

(xi) Interaction with surface water?

c

e. Has the relationship of the uppermost aquifer to

underlying aquifers been characterized? (WAC

-806(4)(xx)(B))

- 6 -
'.'

•

•

•

If not, explain

If yes, does the characterization include the

following:

(i) Thickness and extent of low permeability

layers separating the aquifers?

Remarks:

(ii) Hydraulic conductivity of the low permeability

layers?

Remarks:

(iii) Relative hydraulic heads of the uppermost

aquifer and the underlying aquifers?

Remarks:

f. Have the underlying aquifers been characterized?

(WAC -806(4)(xx)(B)

If yes, does the characterization of the underlying

aquifers include the following:

(i) Description of aquifer materials (e.g. sandy

gravel, fractured sandstone, etc.)?

Describe:

- 7 -
(ii) Thickness and lateral extent?

(iii) Continuity beneath and adjacent to the site?

(iv) Water-table contour maps and potentiometric

maps that show ground water flow directions?

(v) Seasonal variation of ground water flow

directions?

(vi) Effect of ground water use on ground water

flow directions?

(vii) Hydraulic conductivity/transmissivity

including lateral and vertical variations?

Which of the following methods were used to

determine the hydraulic conductivity/

transmissivity.

a) Estimates from grain size analyses

Describe:

b) Laboratory tests (permeameter tests)

Describe:

c) Slug tests

Describe:

d) Pump tests

Describe:

- 8 -

'.

..
• e) Other

Describe:

•

•

(viii) Methods used to evaluate slug tests, pumping

tests, etc.?

(ix) Effective porosity?

(x) Storage coefficient or specific yield including

lateral and vertical variations?

(xi) Interaction with surface water?

- 9 -
2. GROUND WATER MONITORING NETWORK (265.91. WAC -806(4)(xx)E.

-645(8)

A. Is a site map available that shows the location of

the monitoring wells relative to the waste management

areas?

B: Upgradient/background monitoring wells. (265. 91(a)( 1).

WAC -645(8)(a)(i»

a. Are upgradient/background monitoring wells

designated to determine background water

quality?

How many background wells?

b. Are these wells hydraulically upgradient from

the facility?

If not. how were the well locations

determined?

c. Are the wells screened over the appropriate

saturated zone?

Describe:

d. Are the wells placed so they are not affected

by the active portion?

Des cri.be.:

e. If ground water mounding is known to occur

beneath the facility. could this influence the

water quality of upgradient/background wells?

Describe:

Yes No c

C)

f. Are wells downgradient.of other activities

(i.e. non DW) that are known to have

affected ground water quality?

- 10 -

()
•

C. Downgradient monitoring wells. (265.91(a)(2),

WAC -645(8)(a)(ii))

a. Specify the number of downgradient wells installed

at each management unit? . -------------

b. Are the downgradient wells screened in the same

zone as the upgradient wells?

Remarks:

c. Are all downgradient mori t.or i ng wells screened

over the appropriate saturated intervals?

(e.g. at the appropriate depth within the uppermost monitorable zone)

Describe:

• d. Is the well spacing adequate to detect contaminant

migration? .

If not, where should add1tional wells be

installed?

•

e. Is the ground water flow direction verified at

least annually to ensure that the wells are

adequately placed? (265.93(f), WAC -645(9)(e))

f. Do the monitoring wells show water level

variations due to seasonal or hydraulic (e.g.

tidal) fluctuations?

Remarks:

- 11 -
3. MONITORING WELL INSTALLATION AND CONSTRUCTION

(WAC -645(8)(a) and (c), 265.91(c))

A. Are separate as-built drawings and geologic logs

available for each monitoring well?

Remarks:

B. Were all monitoring wells installed and constructed

similarly? .

If not, a separate well installation and

construction checklist should be filled out

for each type of installation and construction method.

Remarks:

Yes No c

C. Well installations for wells through

a. Circle the drilling method used to install the

monitoring wells: 1) hollow-stem auger, 2) cable

tool, 3) top-drive air rotary, 4) duwnhole air

rotary, 5) mud rotary, 6) solid-stem auger,

7) jetting, 8) driving, 9) other (sp~cify)

If mud rotary was used specify the kind of

drilling fluid used.

If air rotary was used, were in-line filters

installed to remove oil from the compressed air?

- 12 -

()
• Remarks:

For other drilling methods, were any fluids added

to the hole at any time during drilling or

installation?

If yes, explain.

b. Circle the soil sampling methods used during drilling.

1) grab, 2) split-spoon sampler, 3) shelby tube,

4) D&M sampler, 5) other, explain

•

c . Describe the soil sampling interval.

•

d. Was the well logged by an experienced geologist,

hydrogeologist, or soils engineer?

Who?

e. Was the drilling equipment decontaminated prior

to arriving on-site?

Describe the decon method.

f. Were the drill, drilling equipment, and temporary

casing decontaminated between borings?

- 13 -
Describe the decon method.

g. Was the sampling equipment decontaminated between

samples?

Describe the decon method.

D. Monitoring Well Construction for Wells through ___

(WAC -400(3)(c)(v), -645(8)(c), 265.91(c))

a. Wa~ the well construction.supervised by an

experienced hydrogeologist, geologist, or soils

engineer?

Who?

c

b. Circle the type of completion: 1) single well

2) nests (or clusters) of wells in separate

boreholes, 3) multiple wells in a single borehole, 4) multiportsampler, 5) other (specify)

()

c. Circle the casing materials used: 1) teflon,

2) stainless steel 304, 3) SCH 40 PVC, 4) SCH 80

PVC, 5) ABS, 6) carbon steel, 7) other (specify)

d. Circle the type of cour1ing used: 1) flush-threaded

2) bell, 3) regular pipe, 4) other (specify)

- 14 -

()
•

e. Circle the screen material used: 1) teflon,

2) stainless steel 304, 3) SCH 40 PVC, 4) SCH 80

PVC, 5) ABS, 6) carbon steel, 7) other (specify)

•

•

f. Describe the type of bottom plug used.

g. Were any glues or solvents used in the well

construction?

If yes, specify _

h. Was a gravel pack installed?

If yes,

(i) Describe the material, its source, and

the method of installation.

(ii) Is a grain size distribution of the gravel

pack available?

(iii) Was the top of the gravel pack measured

before the backfilling or the well seals were

installed?

Remarks:

i. Were well seals installed?

If yes, describe the type of seal and the method of

installation. (For cement grouts specify the

water/cement ratio, bentonite/cement ratio, etc.)

- 15 -
j. Were bentonite pellets placed in the unsaturated

zone?

If yes, were the pellets hydrated (wetted) after

they were installed?

k. Was the well seal installation method appropriate?

Remarks:

1. Are the wells properly constructed to prevent

contamination of the samples, the sampled waterbearing zones, and between aquifers and waterbearing zones? (WAC -400(3)(c)(v), -645(8)(c)

Remarks:

m. Were samples taken of all materials used in well

installation (grout, sand pack, bentonite, well

material, etc.)?

Remarks:

C)

E. Well Development for Wells through

a. Were the monitoring wells developed?

b. Circle the well development method: 1) Air lift,

2) pumping, 3) overpumping, 4) bailing, 5) surge

block, 6) raw hiding, 7) other (~~_cify)

c. Describe the equipment used for development.

- 16 -
•

d. Describe the duration of development.

•

•

e. What was the volume of water and sediment removed

during development?

f. Was the development continued until the purged

water at all wells was sediment free?

If not, explain

g. Was the well development adequate?

If not, explain

h. Were well yields measured?

If yes, for which wells

i. Were drawdowns and recovery measured during water

yield determinations?

If yes, specify:

- 17 -
4. FIELD INSPECTION

A. Sampling and Analysis Plan (265.92(a), WAC -645(8)

(d) and (e))

a. Are all wells to be sampled identified in the

plan?

Remarks:

b. Are all the appropriate parameters to be sampled

and tested identified in the plan?

Remarks:

c. Are procedures for purging the wells prior to sample

collection specified?

Remarks:

Yes No

d. Do these procedures adequately identify:

(i) The equipment that will be used for evacuation?

Remarks:

(ii) Method of decontaminating equipment between wells?

Remarks:

(iii) Depth(s) in well or borehole from which water will

be evacuated?

Remarks:

(iv) Pumping rate and duration (or amount as

appropriate)?

Remarks:

- 18 -

(\
• (v) Special procedures as necessary for evacuation

" prior to sampling separate phases of immiscible

contaminants?

Specify:

e. Are these procedures identified for well

evacuation appropriate?

If not, what aspects of the specified procedures are

not appropriate and require correction?

•

f . Do the procedures specified for actual collection

of ground water samples from the well adequately

identify:

(i) Equipment that will be used to collect the

sample from the well?

(ii) Method of decontaminating equipment between

wells?

(iii) Depth(s) in the well from which the sample

will be taken?

(iv) Time between"well evacuation and sample

collection?

(v) Special procedures as necessary for collecting

samples from separate phases of immiscible

contaminants?

•

g. Are appropriate procedures and equipment identified

for the collection of samples?

- 19 -
If not, what aspects of the identified procedures

are not appropriate and require correction?

h. Do the sampling procedures clearly identify:

(i) Sample containers?

(ii) Filtering procedures?

(iii) Preservation procedures?

(iv) Chain of Custody?

(v) Transfer and transport blanks?

(vi) Other

i. Are these procedures adequate?

If not, what aspects of these procedures are

not adequate and require correction?

j. Do the sampling and analysis procedures identify

analytical procedures?

k. Do these analytical procedures specify analytical

methods for each parameter?

- 20 -

c

()
•

1. Are these procedures appropriate? If not, what

aspect of the procedures are not adequate and

require correction?

m. Are QA and QC procedures described?

n. Are these procedures adequate?

If not, what aspect of the procedures are not

adequate and require co:rection?

B. Field Inspection - Well Appearance

• a. Are the wells adequately protected?

Describe: .

---------------------

•

b. Are the wells locked?

c. Are the wells vented?

d. Are the surface seals sloped away from the well?

e. Does the integrity of the surface seal appear

adequate?

f. Are the wells clearly labeled?

Remarks:

- 21 -
c. Field Inspection - Well Purging

a. Specify the method of purging: 1) air lift,

2) centrifugal pump, 3) peristaltic pump,

4) gas-contact positive displacement pumps,

5) non-gas-contact positive displacement

pumps 6) bailer, 7) electric submersible pump,

8) other

b. Is this method of purg1ng suitable for the

parameters to be tested?

Remarks:

c. Describe the make and model of the purging

-equipment.

d. Is the depth of the intake measured to verify

that it is properly positioned in the well?

Remarks:

e. Is the volume of water removed mpa~ured?

Specify the volume of wat.e r removed -------

- 22 -

()

()
•• f.

g.

Is the pumping/removal rate measured?

If yes, what is the pumping rate?

Is the purging equipment adequately decontaminated

between wells?

(i) Describe decon methods

(ii) Describe decon mett~ds that require correction

•

•

D. Field Inspection-Sampling Procedures (WAC -645(8)(d) and (3))

a. Are the samples obtained immediately after purging?

If "No," specify the time that elapses between

purging and sampling ~----~--~----___ Is this elapsed time appropriate for the parameters being tested?

Remarks:

b. Are the samples obtained by the same personnel

during each sampling episode?

Remarks:

- 23 -
c. Circle the sampling method used: 1) air lift,

2) centrifugal pump, 3) peristaltic pump,

4) electric submersible pump, 5) gas-contact

positive displacement pump, 6) non-gas-contact

positive displacement pump, 7) bailer, 8) other

(specify)

(j

d. Describe the make and model of the sampling

equipment.

e. Is the sampling procedure consistent with the

parameters to be tested? Remarks

f. Is the sampling equipment dedicated to the well?

(i) If not, describe the decontamination procedures

between wells.

(ii) Are the decontamination procedures adequate?

Remarks: . _

f. Are water levels measured:

(265.92(3), WAC -645(8 1 ( £) )

(i) prior to sampling?

(ii) during sampling?

Describe the method

- 24 -

(;

(
• g. Is the depth of the sampling intake measured to

verify that it is properly positioned in the well?

•

•

h. Describe the sampling materials that the sample

water comes in contact with. (e.g. PVC, teflon,

stainless, etc.)

(i) Suction tubing/piping

(ii) Discharge tubing/piping -----------

(iii) Pump/baler

Remarks

1. Are special methods used to prevent sample aeration?

Remarks ----------------------

j. Are the samples field filtered for:

(i) metals?

(ii) others (specify)

If yes, what is the filter pore size and which

brand of filters are used?

- 25 -
() k. Are all samples sediment free?

If not, specify the wells with sediment

()

f)

1.. Are the types of bottles used consistent with

the parameters to be tested (see Table I)?

Remarks

m. What parameters are tested in the field:

(i) pH?

Specify meter make and model

(ii) Specific conductance?

Specify meter make and model

(iii) Temperature?

Specify thermometer make and model

(iv) Eh (Redox potential)?

Specify meter make and model

n. Are the field instruments calibrated?

Describe the calibration methods.

o. Are the field sampling procedures consistent with

the sampling and analysis plan?

- 26 -
•

•

Describe inconsistencies

p. Are the current sampling procedures consistent

with past sampling procedures?

q. Are differences significant?

Explain _

•

r. Has the same laboratory been used for all sampling

episodes?

If not, list the laboratories as follows:

•

Sampling

Episode

(Month/Year)

Remarks

Testing

Laboratory

- 27 -
E. Field Inspection - QA/QC Procedures (WAC -645(8)(d)(iv))

•

o

a. Are the sample bottles properly cleaned prior to

sampling?

Remarks

b. What kinds of QA/QC samples are used:

(i) Duplicates? - -

How many?

(ii) Sample preservative blanks? - -

How many?

(iii) Transport blanks? - -

How many?

(iv) Spikes? - -

How many? C)

(v) Transfer blanks? - -

How many

(vi) Other - -

Describe

c. Are the appropriate sample holdin6 times observed?

(See Table 1)

Remarks

()

- 28 -
•

•

•

•

d. Are the samples labeled with the following:

(i) Sample number

(Lt ) Well number

(iii) Data and time sampled

(iv) Name of sample collector

(v) Preservatives

Remarks

e. Is a bound field notebook maintained to record

pertinent sampling events and procedur.es?

Remarks

f. Does the field notebook record the following:

(i) Well number?

(ii) Sample number?

(iii) Names of sample collectors?

(iv) Signature of sampler?

(v) Sampling method?

(vi) Presampling purging data (e.g. volume and

rate of purging)?

(vii) Field measured parameters (pH, specific

conductance, Eh, temperature)?

(viii) Water level measurements?

g. Is a chain-of-custody record maintained?

If "Yes," does it record the following:

(i) Well number?

(ii) Sample number?

(iii) Date and time collected?

(iv) Signature of sampler?

- 29 -
(v) Signature of witness?

(vi) Tests to be conducted?

(vii) Signatures of all intermediate handlers and

time and date of handling?

(viii) Signature of receiving laboratory representative

and time and date received?

h. Are the chain-of-custodyprocedures adequate to

maintain sample integrity?

Remarks

- 30 -

•

C)

(j

()
•

•

•

5 . WATER QUALITY RESULTS (INTERIM STATUS) (265.92(b))

A. Does the water quality data obtained to date include:

a. Drinking water parameters (Table 1), one year of

quarterly samples?

Remarks

b. Ground water quality parameters (Table 1),

(i) One year of quarterly samples?

(ii) Annual samples aft0r the first year?

Remarks

c. Indicator parameters (Table 1)

(i) One year of quarterly samples, four replicates

each sampling episode?

(ii) Semiannual samples thereafter, four replicates

for each sampling episode?

Remarks

B. Have initial background concentrations been determined

for the following parameters (Table I)?

a. Drinking water parameters?

b. Water quality parameters?

Remarks

- 31 -

Yes No
c. For upgradient/background wells have the following

been determined for the indicator parameters:

a. Initial background arithmetic mean?

b. Initial background variance?

Remarks

C)

D. Have initial background concentrations been determined

for the following parameters (Table 1).

a. Drinking water parameters?

b. Water quality parameters?

Remarks

E. For upgradient/background wells have the following

been determined for the indicator parameters:

a. Initial background arithmetic' mean?

b. Initial background variance?

Remarks

c

F. For each of the downgradient wells after the first year

of quarterly samples were the following dct.e rmi ned for

the indicator parameters:

a. Arithmetic mean based nn at least four replicates

per sampling episode?

b. Variance based on at least four replicates per

sampling episode?

Remarks

- 32 -

()
•• G. Were the initial background values for the indicator

parameters statistically compared to the semiannual

samples after the first year for:

a. The upgradient/background wells?

b. The downgradient wells?

Remarks

H. Was the student t-test at the .01 level of significance

used for the statistical comparison?

Remarks

I. Have the comparisons shown a statistical increase (or

decrease of pH) over initial background for:

•

a . The upgradient wells?

If yes, was this information submitted with the

annual reported data?

Remarks

•

b. The downgradient wells?

If yes, were the following completed?

(i) Were wells showing increase (or pH decrease)

resampled and tested?

i

(ii) Ecology was notified within seven days after

the increase (or pH decrease) was confirmed?

(iii) A ground water assessment plan was submitted

to Ecology within 15 days after the notification?

Remarks

- 33 -
Additional Remarks:

- 34 -

..

()
,\

,.

Table 1

SAMPLING AND PRESERVATION PROCEDURES INTERIM STATUS PARAMETERS

T,P,G 4°C 28 days 50 ml

T,P Field Acidified* 6 months 1000 ml

to pH <2 with

HN03

G 4°C/H2SO4 to 28 days 500 ml

pH <2

T,P,G Cool, 4°C 28 days 50 ml

T,P,G None-Field 2 hours 25 ml

Determined

P,G None-Field None 100 ml

Determined

G, Teflon lined Cool 4°C, H SO (2) 28 days' 40 ml(2)

cap, no head space to pH <2 2 4

G, Amber,. Cool 4°C, add 7 days 500 ml(2)

Teflon lined cap, 1 ml of 0.1 M

no head space sodium sulfite

•

Parameter

Drinking Water

Arsenic

Barium

Cadmium

Chromium

Lead

Selenium

Silver

Mercury

Fluoride

Nitrate

Endrin

Lindane

Methoxychlor

Toxaphene

2,4 D

2,4,5 TP Sil vex

Radium

Gross Alpha

Gross Beta

Coliform

bacteria

Ground Water Quality

Chloride

Iron

~langanese

Sodium

Phenols

Sulfate

Ground Water Contamination

pH

Speci fi c conductance

TOC

TOX

Container

T,P

G p(2) ,

T,Pro

T,P,G

T,G

P,G

Pro,G (sterilized)

Preservation

Field Acidified . to pH <2 with

HN03

Field Acidified

to pH<2 with

HN03

Field Acidified

to pH <2 with

HN03

4°C**

Field Acidified

to pH <2 with

HN03

Field Acidified

to pH <2 with

HN03

Cool 4°C

Maximum Holding

Time

6 months

(1 ) P = 13 days(2) G - 28 days

28 days

24 hours

24 hours

6 months

30 hours(2)(3)

Minimum Volume

1000 ml

200 ml(2)

300 ml

100 ml

1000 ml

1 gallon

200 ml

P Polyeth1ene

G - Glass

Pro - Polypropylene

T - Teflon

*In the event that HNO cannot be used because of shipping restrictions the

sample should be refr~gerated to 4°C, shipped immediately and acidified on receipt at the laboratory. The container should be ringed with HN03•

'. (1 )

(2 )

(3)

**For samples from nonchlorinated drinking water supplies concentrated H,S04

should be added to lower sample pH to less than 2. Analyze sample witnin 14 days.

SW 846

Ecology Sample requirements (Rev.. 12/84)

Standard Methods, 16th Ed., 1985