Title 18 . Environmental Conservation

Chapter 80 . Administrative Enforcement

Section 325. Volatile organic chemical sampling requirements

18 AAC 80.325. Volatile organic chemical sampling requirements

For purposes of this section, a GWUDISW source is considered a surface water source. The owner or operator of a Class A public water system shall monitor the system to determine compliance with the MCLs for the volatile organic chemicals (VOCs) listed in 18 AAC 80.300(b) (2)(B) as follows:

(1) the owner or operator of a groundwater system shall take a minimum of one sample at each entry point to the distribution system that is representative of each groundwater source or water treatment works; each of these points is a sampling point; samples must be collected after treatment; if the department determines that additional sampling points serve the interests of public health, the department will designate additional sampling points within the distribution system or at the consumer's tap that more accurately reflect consumer exposure; the owner or operator shall take each subsequent sample at the same sampling point unless conditions make another sampling point more representative of each source, water treatment works, or distribution system;

(2) the owner or operator of a surface water system or a combination-source system shall take a minimum of one sample at each entry point to the distribution system or at points in the distribution system that are representative of each surface water source or water treatment works; each of these points is a sampling point; samples must be collected after treatment; if the department determines that additional sampling points serve the interests of public health, the department will designate additional sampling points within the distribution system or at the consumer's tap that more accurately reflect consumer exposure; the owner or operator shall take each subsequent sample at the same sampling point unless conditions make another sampling point more representative of each source, water treatment works, or distribution system;

(3) if a system draws water from more than one source and the sources are combined before distribution, the owner or operator shall sample after treatment at an entry point to the distribution system during periods of typical operating conditions when the water is representative of all sources being used;

(4) the owner or operator shall take four consecutive quarterly samples for each VOC listed in 18 AAC 80.300(b) (2)(B) during each compliance period;

(5) the department will allow the use of monitoring data collected after January 1, 1988 under 42 U.S.C. 300j-4 (Safe Drinking Water Act) for purposes of monitoring compliance; if the data are generally consistent with (1) - (3) and (6) - (18) of this section, the department will allow the owner or operator to use that data from a single sample, rather than four quarterly samples, to satisfy the monitoring required by (4) of this section;

(6) subject to (7) of this section, the owner or operator of a system that does not detect one of the VOCs listed in 18 AAC 80.300(b) (2)(B) after conducting the initial round of monitoring required by (4) of this section shall take one sample annually;

(7) if the initial monitoring for VOCs listed in 18 AAC 80.300(b) (2)(B) as allowed in (5) of this section was completed by December 31, 1992 and the system did not detect a VOC, then the owner or operator shall take one sample annually;

(8) after a minimum of three years of annual sampling, the department will allow the owner or operator of a groundwater system with no previous detection of a VOC listed in 18 AAC 80.300(b) (2)(B) to take one sample during each compliance period;

(9) if the department determines that a waiver serves the interests of public health, and subject to (10) of this section, the department will waive the requirements of (6) and (7) of this section upon application by the owner or operator who has completed initial monitoring and who pays the fee required in 18 AAC 80.1910(b); the department will grant a waiver for up to two compliance periods in one compliance cycle for a system served by one or more groundwater sources; based upon new information received, the department will modify or revoke a waiver issued under this paragraph if the department determines that modification or revocation serves the interests of public health;

(10) the department will base its decision to grant or deny a waiver under (9) of this section upon an evaluation of information about previous uses within the system's waiver review area of each contaminant for which a waiver is sought; uses subject to evaluation include transport, storage, and disposal; the department will consider whether the system is vulnerable to contamination by VOCs; indicators of vulnerability include previous analytical results, proximity to a potential point source or nonpoint source of contamination, the number of individuals served by the system, the proximity of a smaller system to a larger system, how well the water source is protected against contamination, and environmental persistence and dispersal; the department will consider a system to be vulnerable until the owner or operator demonstrates that the system is not vulnerable;

(11) if a surface water system does not detect a contaminant listed in 18 AAC 80.300(b) (2)(B), the owner or operator may apply for a waiver from the requirement of (7) of this section after completing the initial monitoring; the department will allow composite samples if the detection limit of the method used for analysis is less than one-fifth of the MCL; each system receiving a waiver shall sample at a frequency determined by the department to serve the interests of public health;

(12) a waiver under (9) or (11) or this section is valid for a period that the department will determine based on the system's history of compliance with this chapter; the owner or operator of a surface water or groundwater system who receives a waiver under (9) or (11) of this section shall update the vulnerability assessment portion of the waiver application during the waiver period; based on the updated assessment and the indicators of vulnerability as described in (10) of this subsection, the department will determine whether the system is vulnerable; if the department does not make this determination within three years after granting the initial waiver, that waiver lapses, and the owner or operator shall sample annually as required by (6) of this section;

(13) the owner or operator of a public water system who receives a VOC monitoring waiver shall test for the waived VOC contaminants at least once at each sampling point during the waiver period set under (12) of this section;

(14) if a VOC listed in 18 AAC 80.300(b) (2)(B) is detected at a level exceeding 0.0005 mg/l in a sample,

(A) the owner or operator shall monitor quarterly for the detected VOC at each sampling point that resulted in a detection;

(B) the department will decrease the quarterly monitoring requirement specified in (A) of this paragraph if the department determines that the system is reliably and consistently below the MCL for the detected VOC; the department will not make this determination unless the owner or operator takes at least

(i) two quarterly samples for each groundwater source that resulted in detection of the VOC; and

(ii) four quarterly samples for each surface water source that resulted in detection of the VOC; and

(C) if the department determines that the system is reliably and consistently below the MCL for the detected VOC, the department will allow the system to monitor annually; the owner or operator of a system that monitors annually shall monitor during the quarter that previously yielded the highest analytical result;

(15) the owner or operator of a system that exceeds the MCL for a VOC in 18 AAC 80.300(b) (2)(B), as determined under 18 AAC 80.305(c) , shall monitor quarterly for each VOC that exceeded the MCL; after a minimum of four quarterly samples shows the system is in compliance as specified in 18 AAC 80.305(c) , and if the department determines that the system is reliably and consistently below the MCL, the owner or operator may monitor at the frequency and time specified in (14)(C) of this section;

(16) the department will require a confirmation sample for positive or negative results, if the department determines that a confirmation sample serves the interests of public health; if the department requires a confirmation sample, the department will average the sampling result with the first sampling result and use the average to determine compliance under 18 AAC 80.305(c) ; the department will delete results of obvious sampling errors from this calculation;

(17) if the detection limit of the method used or the results of an analysis is less than one-fifth of the MCL, the department will reduce the total number of samples that must be analyzed by allowing compositing; a composite of samples must be analyzed within 14 days after sample collection as follows:

(A) if the concentration in the composite sample is 0.0005 mg/l or more for a VOC listed in 18 AAC 80.300(b) (2)(B), then, within 14 days after receipt of notification of the analytic results of the composite sample, the owner or operator of the system shall take a follow-up sample from each sampling point included in the composite and ensure that each sample is analyzed for each contaminant detected;

(B) if duplicates of the original sample taken from each sampling point used in the composite are available, the owner or operator may use the duplicates instead of resampling; the duplicates must be analyzed and the results reported to the department within 14 days after collection, subject to the report certification requirements of 18 AAC 80.1900;

(C) if the system serves more than 3,300 individuals, the department will allow compositing only at sampling points within a single system; if the system serves 3,300 or fewer individuals, the department will allow compositing among different systems;

(D) if compositing samples before gas chromatograph analysis, the certified laboratory shall use the analytical procedures set out in 40 C.F.R. 141.24(f)(14)(iv) and (v), adopted by reference in 18 AAC 80.010(a) ;

(18) each certified laboratory shall determine the method detection limit (MDL) as defined in Appendix B to 40 C.F.R. 136, adopted by reference in 18 AAC 80.010(a) , at which the certified laboratory is capable of detecting VOCs; the acceptable MDL is 0.0005 mg/l; this concentration is the detection concentration for purposes of this section.

History: Eff. 10/1/99, Register 151

Authority: AS 46.03.020

AS 46.03.050

AS 46.03.070

AS 46.03.710

AS 46.03.720