Ohio Water Microbiology Lab
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OWML: QA/QC
Quality Assurance/Quality Control Manual: Ohio Water Microbiology
Laboratory
Laboratory water
The Ohio Water Microbiology Laboratory (OWML) has two
types of laboratory water:
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Type III deionized water (“deionized
water”) produced from City of Columbus tap water for general laboratory
use. The deionized water unit and tap are stored in the warehouse. The
system is described in Francy and Shaffer (2008). The vendor changes the
cation and anion columns, moves forward the standby mixed-bed column,
installs a new standby tank, and changes the carbon filter when the red
service light illuminates. Maintenance checks are recorded in the LIMS.
-
Reagent-grade water produced using a
Millipore MilliQ system (“MilliQ water”). Deionized water is used as source
water for the MilliQ system. Reagent water is used for cultivation media
and additives (mTEC, MI, mEI, antibiotic stocks, and others) as well as for
preparation of reagents for sensitive procedures (elutions, PCR,
hybridization, and others). The MilliQ cartridges are changed by OWML
laboratory personnel when the service light blinks and the display message
reads “EXCH. CARTRIDGES.” Indicate the date of
cartridge change in the LIMS.
A variety of quality-control checks are
routinely done on the two types of water and may differ depending on the type of
water. Acceptance criteria are listed in table 2. For deionized water, two
levels of acceptance criteria are listed—(1) a warning level wherein the system
is inspected and constituents are retested and (2) a shut-down level. For
MilliQ water, only a shut-down level is listed in table 2.
-
Quarterly checks of specific
conductance and turbidity are done on both types of water and recorded in
the LIMS. Instructions for performing this check
are in Appendix BB.
-
Quarterly checks of bacterial growth are done on the MilliQ
water and recorded in the LIMS. Instructions for
performing this check are in
Appendix BB.
-
A blank of deionized water is
submitted to the National Water Quality Laboratory (NWQL) annually and
analyzed for low level nutrients (Schedule 1217), and total-organic carbon (Labcode
114), and the results are recorded in the LIMS. We
no longer analyze a blank for trace elements and low-level major ions
because the need for these low-level analyses is project specific.
Table 2. Acceptance criteria for
laboratory water quality-assurance checks. [Adopted from USEPA (1978), APHA
(1998), and ASTM (1999); NA is not applicable; constituents highlighted in gray
are no longer required tests]
|
DEIONIZED |
MILLIQ |
ACTION |
warning |
shut down |
shut down |
Specific conductance (ms/cm) |
3 |
5 |
2 |
Turbidity |
1 |
5 |
1 |
Heterotrophic plate count
(colonies/mL) |
NA |
NA |
<1 |
Total organic carbon (mg/L) |
0.5 |
10 |
NA |
Sodium (mg/L) |
0.1 |
1 |
NA |
Nutrients individual (mg/L) |
0.1 |
1 |
NA |
Heavy metals, individual (Cd,
Cr, Cu, Ni, Pb, Zn) (mg/L) |
1 |
10 |
NA |
Other trace elements (mg/L) |
3 |
50 |
NA |
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