S.C. Code Regs. § § 61-58.5.E
Current through Register Vol. 48, 12, December 27, 2024
Section 61-58.5.E - Organic Chemicals Other Than Total Trihalomethanes, Sampling and Analytical Requirements(1) The monitoring requirements for organic contaminants specified in R.61-58.5(D)(2)(a)(D)(2)(a)shall apply to all community water systems. The monitoring requirements for organic contaminants specified in 61-58.5(D)(2)(b)shall apply to community water systems and non-transient non-community water systems.(7) Analytical methods used to comply with Section D(2)(b) above, shall be made using EPA-approved methods listed in 40 CFR 141. Analysis of the contaminants listed in Section D(2)(b) above, for the purposes of determining compliance with the maximum contaminant level shall be conducted as follows: (a) Groundwater systems shall take a minimum of one sample at every entry point to the distribution system which is representative of each well after treatment (hereafter called a sampling point). Each sample must be taken at the same sampling point unless conditions make another sampling point more representative of each source or treatment plant.(b) Surface water systems shall take a minimum of one sample at points in the distribution system that are representative of each source or at each entry point to the distribution system after treatment (hereafter called a sampling point). Each sample must be taken at the same sampling point unless conditions make another sampling point more representative of each source or treatment plant. [Note: For purposes of this paragraph, surface water systems include systems with a combination of surface and ground sources.](c) If the system draws water from more than one source and the sources are combined before distribution, the system must sample at an entry point to the distribution system during periods of normal operating conditions (i.e., when water representative of all sources is being used).(d) Monitoring frequency: (i) Each community and non-transient non-community water system shall take four consecutive quarterly samples for each contaminant listed in Section D(2)(b) above, during each compliance period beginning with the initial compliance period.(ii) Systems serving more than 3,300 persons which do not detect a contaminant in the initial compliance period, may reduce the sampling frequency to a minimum of two quarterly samples in one year during each repeat compliance period.(iii) Systems serving 3,300 persons or less which do not detect a contaminant in the initial compliance period may reduce the sampling frequency to a minimum of one sample during each repeat compliance period.(e) Each community and non-transient water system may apply to the Department for a waiver from the requirement of paragraph (7)(d) of this section. A system must reapply for a waiver for each compliance period.(f) The Department may grant a waiver after evaluating the following factor(s): Knowledge of previous use (including transport, storage, or disposal) of the contaminant within the watershed or zone of influence of the system. If a determination by the Department reveals no previous use of the contaminant within the watershed or zone of influence, a waiver may be granted. If previous use of the contaminant is unknown or it has been used previously, then the following factors shall be used to determine whether a waiver is granted. (i) Previous analytical results.(ii) The proximity of the system to a potential point or non-point source of contamination. Point sources include spills and leaks of chemicals at or near a water treatment facility or at manufacturing, distribution, or storage facilities, or from hazardous and municipal waste landfills and other waste handling or treatment facilities. Non-point sources include the use of pesticides to control insect and weed pests on agricultural areas, forest lands, home and gardens, and other land application uses.(iii) The environmental persistence and transport of the pesticide or PCBs.(iv) How well the water source is protected against contamination due to such factors as depth of the well and the type of soil and the integrity of the well casing.(v) Elevated nitrate levels at the water supply source.(vi) Use of PCBs in equipment used in the production, storage, or distribution of water (i.e., PCBs used in pumps, transformers, etc.).(g) If an organic contaminant listed in Section D(2)(b) above, is detected (as defined by paragraph (7)(r) of this section) in any sample, then: (i) Each system must monitor quarterly at each sampling point which resulted in a detection.(ii) The Department may decrease the quarterly monitoring requirement specified in paragraph (7)(g)(i) of this section provided it has determined that the system is reliably and consistently below the maximum contaminant level. In no case shall the Department make this determination unless a groundwater system takes a minimum of two quarterly samples and a surface water system takes a minimum of four quarterly samples.(iii) After the Department determines the system is reliably and consistently below the maximum contaminant level the Department may allow the system to monitor annually. Systems which monitor annually must monitor during the quarter that previously yielded the highest analytical result.(iv) Systems which have 3 consecutive annual samples with no detection of a contaminant may apply to the Department for a waiver as specified in paragraph (7)(f) of this section.(v) Groundwater systems which have detected one or more of the following two-carbon organic compounds: trichloroethylene, tetrachloroethylene, 1,2,-dichloroethane, 1,1,1-trichloroethane, cis-1,2-dichloroethylene, trans-1,2-dichloroethylene, or 1,1-dichloroethylene shall monitor quarterly for vinyl chloride. A vinyl chloride sample shall be taken at each sampling point at which one or more of the two-carbon organic compounds was detected. If the results of the first analysis do not detect vinyl chloride, the Department may reduce the quarterly monitoring frequency of vinyl chloride monitoring to one sample during each compliance period. Surface water systems are required to monitor for vinyl chloride as specified by the Department.(h) Systems which violate the requirements of Section D(2)(b) above, as determined by paragraph (7)(k) of this section must monitor quarterly. After a minimum of four quarterly samples show the system is in compliance and the Department determines the system is reliably and consistently below the MCL, as specified in paragraph (7)(k) of this section, the system shall monitor at the frequency specified in paragraph (7)(g)(iii) of this section.(i) The Department may require a confirmation sample for positive or negative results. If a confirmation sample is required by the Department, the result must be averaged with the first sampling result and the average used for the compliance determination as specified by paragraph (7)(k) of this section. The Department has the discretion to delete results of obvious sampling errors from this calculation.(j) The Department may reduce the total number of samples a system must analyze by allowing the use of compositing. Composite samples from a maximum of five sampling points are allowed, provided that the detection limit of the method used for analysis is less than one-fifth of the MCL. Compositing of samples must be done in the laboratory and analyzed within 14 days of sample collection. (i) If the concentration in the composite sample detects one or more contaminants listed in Section D(2)(b) above, then a follow-up sample must be taken within 14 days at each sampling point included in the composite, and be analyzed for that contaminant.(ii) If duplicates of the original sample taken from each sampling point used in the composite are available, the system may use these duplicates instead of resampling. The duplicate must be analyzed and the results reported to the Department within 14 days of collection.(iii) If the population served by the system is more than 3,300 persons, then compositing may only be permitted by the Department at sampling points within a single system. In systems serving 3,300 persons or less, the Department may permit compositing among different systems provided the 5-sample limit is maintained.(k) Compliance with Section D(2)(b) above, shall be determined based on the analytical results obtained at each sampling point. If one sampling point is in violation of an MCL, the system is in violation of the MCL. (i) For systems monitoring more than once per year, compliance with the MCL is determined by a running annual average at each sampling point.(ii) Systems monitoring annually or less frequently whose sample result exceeds the regulatory detection level as defined by paragraph (7)(r) of this section must begin quarterly sampling. The system will not be considered in violation of the MCL until it has completed one year of quarterly sampling.(iii) If any sample result will cause the running annual average to exceed the MCL at any sampling point, the system is out of compliance with the MCL immediately.(iv) If a system fails to collect the required number of samples, compliance will be based on the total number of samples collected.(v) If a sample result is less than the detection limit, zero will be used to calculate the annual average.(m) Analysis for PCBs shall be conducted using EPA-approved methods listed in 40 CFR 141. (iii) Compliance with the PCB MCL shall be determined based upon the quantitative results of analyses using EPA-approved methods listed in 40 CFR 141.(n) If monitoring data collected after January 1, 1990, are generally consistent with the requirements of this section, then the Department may allow systems to use that data to satisfy the monitoring requirement for the initial compliance period beginning January 1, 1993.(o) The Department may increase the required monitoring frequency, where necessary, to detect variations within the system (e.g., fluctuations in concentration due to seasonal use, changes in water source).(p) The Department has the authority to determine compliance or initiate enforcement action based upon analytical results and other information compiled by the Department.(q) Each public water system shall monitor at the time designated by the Department within each compliance period.(r) Detection as used in this paragraph shall be defined as greater than or equal to the following concentrations for each contaminant. Contaminant | Detection Limit |
Atrazine | 0.0001 mg/l |
Benzo[a]pyrene | 0.00002 mg/l |
Carbofuran | 0.0009 mg/l |
Chlordane | 0.0002 mg/l |
Dalapon | 0.001 mg/l |
Dibromochloropropane (DBCP) | 0.00002 mg/l |
Di (2-ethylhexly) adipate | 0.0006 mg/l |
Di (2-ethylhexly) phthalate | 0.0006 mg/l |
Dinoseb | 0.0002 mg/l |
Diquat | 00004 mg/l |
2,4-D | 00001 mg/l |
Endothall | 0.009 mg/l |
Endrin | 0.00001 mg/l |
Ethylene dibromide (EDB) | 0.00001 mg/l |
Glyphosate | 0.006 mg/l |
Heptachlor | 0.00004 mg/l |
Heptachlor epoxide | 0.00002 mg/l |
Hexachlorobenzene | 0.0001 mg/l |
Hexachlorocyclopentadiene | 0.0001 mg/l |
Lindane | 0.00002 mg/l |
Methoxychlor | 0.0001 mg/l |
Oxamyl | 0.002 mg/l |
Picloram | 0.0001 mg/l |
Polychlorinated biphenyls (PCBs) (as decachlorobiphenyl) | 0.0001 mg/l |
Pentachlorophenol | 0.00004 mg/l |
Simazine | 0.00007 mg/l |
Toxaphene | 0.001 mg/l |
2,3,7,8-TCDD (Dioxin) | 0.000000005 mg/l |
2,4,5-TP (Silvex) | 0.0002 mg/l |
(s) All new systems or systems that used a new source of water that begin operation after January 22, 2004 must demonstrate compliance with the MCL within a period of time specified by the Department. The system must also comply with the initial sampling frequencies specified by the Department to ensure a system can demonstrate compliance with the MCL. Routine and increased monitoring frequencies shall be conducted in accordance with the requirements in this section.S.C. Code Regs. § 61-58.5.E