[Code of Federal Regulations]
[Title 40, Volume 22]
[Revised as of July 1, 2003]
From the U.S. Government Printing Office via GPO Access
[CITE: 40CFR258.53]

[Page 410-411]
 
                   TITLE 40--PROTECTION OF ENVIRONMENT
 
         CHAPTER I--ENVIRONMENTAL PROTECTION AGENCY (CONTINUED)
 
PART 258--CRITERIA FOR MUNICIPAL SOLID WASTE LANDFILLS--Table of Contents
 
        Subpart E--Ground-Water Monitoring and Corrective Action
 
Sec. 258.53  Ground-water sampling and analysis requirements.

    (a) The ground-water monitoring program must include consistent 
sampling and analysis procedures that are designed to ensure monitoring 
results that provide an accurate representation of ground-water quality 
at the background and downgradient wells installed in compliance with 
Sec. 258.51(a) of this part. The owner or operator must notify the State 
Director that the sampling and analysis program documentation has been 
placed in the operating record and the program must include procedures 
and techniques for:
    (1) Sample collection;
    (2) Sample preservation and shipment;
    (3) Analytical procedures;
    (4) Chain of custody control; and
    (5) Quality assurance and quality control.
    (b) The ground-water monitoring program must include sampling and 
analytical methods that are appropriate for ground-water sampling and 
that accurately measure hazardous constituents and other monitoring 
parameters in ground-water samples. Ground-water samples shall not be 
field-filtered prior to laboratory analysis.
    (c) The sampling procedures and frequency must be protective of 
human health and the environment.
    (d) Ground-water elevations must be measured in each well 
immediately prior to purging, each time ground water is sampled. The 
owner or operator must determine the rate and direction of ground-water 
flow each time ground water is sampled. Ground-water elevations in wells 
which monitor the same waste management area must be measured within a 
period of time short enough to avoid temporal variations in ground-water 
flow which could preclude accurate determination of ground-water flow 
rate and direction.
    (e) The owner or operator must establish background ground-water 
quality in a hydraulically upgradient or background well(s) for each of 
the monitoring parameters or constituents required in the particular 
ground-water monitoring program that applies to the MSWLF unit, as 
determined under Sec. 258.54(a) or Sec. 258.55(a) of this part. 
Background ground-water quality may be established at wells that are not 
located hydraulically upgradient from the MSWLF unit if it meets the 
requirements of Sec. 258.51(a)(1).
    (f) The number of samples collected to establish ground-water 
quality data must be consistent with the appropriate statistical 
procedures determined pursuant to paragraph (g) of this section. The 
sampling procedures shall be those specified under Sec. 258.54(b) for 
detection monitoring, Sec. 258.55 (b) and (d) for assessment monitoring, 
and Sec. 258.56(b) of corrective action.
    (g) The owner or operator must specify in the operating record one 
of the following statistical methods to be used in evaluating ground-
water monitoring data for each hazardous constituent. The statistical 
test chosen shall be conducted separately for each hazardous constituent 
in each well.
    (1) A parametric analysis of variance (ANOVA) followed by multiple 
comparisons procedures to identify statistically significant evidence of 
contamination. The method must include estimation and testing of the 
contrasts between each compliance well's mean and the background mean 
levels for each constituent.
    (2) An analysis of variance (ANOVA) based on ranks followed by 
multiple comparisons procedures to identify statistically significant 
evidence of contamination. The method must include estimation and 
testing of the contrasts between each compliance well's median and the 
background median levels for each constituent.
    (3) A tolerance or prediction interval procedure in which an 
interval for each constituent is established from the distribution of 
the background data, and the level of each constituent in each 
compliance well is compared to the upper tolerance or prediction limit.
    (4) A control chart approach that gives control limits for each 
constituent.
    (5) Another statistical test method that meets the performance 
standards of Sec. 258.53(h). The owner or operator must place a 
justification for this alternative in the operating record and notify 
the State Director of the use of this alternative test. The 
justification

[[Page 411]]

must demonstrate that the alternative method meets the performance 
standards of Sec. 258.53(h).
    (h) Any statistical method chosen under Sec. 258.53(g) shall comply 
with the following performance standards, as appropriate:
    (1) The statistical method used to evaluate ground-water monitoring 
data shall be appropriate for the distribution of chemical parameters or 
hazardous constituents. If the distribution of the chemical parameters 
or hazardous constituents is shown by the owner or operator to be 
inappropriate for a normal theory test, then the data should be 
transformed or a distribution-free theory test should be used. If the 
distributions for the constituents differ, more than one statistical 
method may be needed.
    (2) If an individual well comparison procedure is used to compare an 
individual compliance well constituent concentration with background 
constituent concentrations or a ground-water protection standard, the 
test shall be done at a Type I error level no less than 0.01 for each 
testing period. If a multiple comparisons procedure is used, the Type I 
experiment wise error rate for each testing period shall be no less than 
0.05; however, the Type I error of no less than 0.01 for individual well 
comparisons must be maintained. This performance standard does not apply 
to tolerance intervals, prediction intervals, or control charts.
    (3) If a control chart approach is used to evaluate ground-water 
monitoring data, the specific type of control chart and its associated 
parameter values shall be protective of human health and the 
environment. The parameters shall be determined after considering the 
number of samples in the background data base, the data distribution, 
and the range of the concentration values for each constituent of 
concern.
    (4) If a tolerance interval or a predictional interval is used to 
evaluate ground-water monitoring data, the levels of confidence and, for 
tolerance intervals, the percentage of the population that the interval 
must contain, shall be protective of human health and the environment. 
These parameters shall be determined after considering the number of 
samples in the background data base, the data distribution, and the 
range of the concentration values for each constituent of concern.
    (5) The statistical method shall account for data below the limit of 
detection with one or more statistical procedures that are protective of 
human health and the environment. Any practical quantitation limit (pql) 
that is used in the statistical method shall be the lowest concentration 
level that can be reliably achieved within specified limits of precision 
and accuracy during routine laboratory operating conditions that are 
available to the facility.
    (6) If necessary, the statistical method shall include procedures to 
control or correct for seasonal and spatial variability as well as 
temporal correlation in the data.
    (i) The owner or operator must determine whether or not there is a 
statistically significant increase over background values for each 
parameter or constituent required in the particular ground-water 
monitoring program that applies to the MSWLF unit, as determined under 
Secs. 258.54(a) or 258.55(a) of this part.
    (1) In determining whether a statistically significant increase has 
occurred, the owner or operator must compare the ground-water quality of 
each parameter or constituent at each monitoring well designated 
pursuant to Sec. 258.51(a)(2) to the background value of that 
constituent, according to the statistical procedures and performance 
standards specified under paragraphs (g) and (h) of this section.
    (2) Within a reasonable period of time after completing sampling and 
analysis, the owner or operator must determine whether there has been a 
statistically significant increase over background at each monitoring 
well.