Ref. No. [UMCES]CBL 2013-018
ACT VS12-04
molecules the filtered 254 nm light fraction is used. A photodiode with 360 nm interference filter
measures the intensity of the fluorescence light (emission) sent out by the dissolved PAH
molecules. The detected emission intensity is directly proportional to the PAH/oil concentration
in water. Lamp intensity fluctuations and ambient light influence are compensated by a reference
photodiode. Excitation and emission lights pass through a stain-resistant, nano-material coated
measuring window. Two range versions are available (not limited to the listed high oil range): 0
to 500 ppb PAH or 0.1 to 15 ppm oil, and 0 to 5000 ppb PAH or 0.1 to 150 ppm oil. All range
specifications are referred to calibration standards. Customer calibration by using factors or a
multi-point curve allow for higher oil concentration ranges. T
90
response time is 10s, though 1 Hz
rate readings are possible. The probe is powered and operated by direct connection to a HACH
sc controller. It can be immersed into the water by a suspension pin and a chain. An optional
automatic compressed air cleaning system operated by the same HACH sc controller allows
extending manual cleaning intervals of the measuring window. The 3MPa (435 PSI) pressure
rating of the Stainless Steel or Titanium housing allows for up to 300 m (980 ft) submersed
operation with appropriate accessories. Turbidity (TSS) values below 200 ppm are
recommended, though higher values are possible when the probe is used for oil spill detection.
The FP 360 sc is designed for use in environmental monitoring, water treatment plant
inlet protection, waste water treatment and process/produced water monitoring.
SUMMARY of VERIFICATION PROTOCOLS
The protocols used for this performance verification were developed in conference with
ACT personnel, the participating instrument manufacturers and a technical advisory committee.
The protocols were refined through direct discussions between all parties during a Hydrocarbon
Sensor Performance Verification Protocol Workshop held on 2-4 February, 2011 in Moss
Landing, CA. All ACT personnel involved in this Verification were trained on use of
instruments by manufacturer representatives and on standardized water sampling, storage,
analysis and shipping methods during a training workshop held on 18-20 May 2011 in Moss
Landing, CA. The manufacturer representative and the ACT Chief Scientist verified that all staff
were trained in both instrument and sample collection protocols.
This performance verification report presents instrument output voltage, relative
florescence units or derived hydrocarbon values reported over time, position, or depth as directly
downloaded from the test instruments or captured through independent dataloggers. The report
includes means, standard deviations, and number of replicates of laboratory determined Diesel
Range Organics, Volatile Hydrocarbons, EEMS, Absorbance, CDOM and Chlorophyll values for
corresponding reference samples at the same time, position, or depth of the instrument
measurements. The report also includes turbidity values for each sample measured on site using
a Hach Turbidimeter which was used for all laboratory and field tests. Instruments were tested
under four different applications, including: (1) laboratory tests with known additions of variance
hydrocarbons; (2) a wave tank test with known additions of crude oil with and without
dispersant; (3) a moored deployment in Baltimore Harbor; and (4) vertical profiling deployments
in the Gulf of Mexico at a site with known leaking bunker oil. A summary of the testing
protocols is provided below. A complete description of the testing protocols is available in the
report,
Protocols for the ACT Verification of In Situ Hydrocarbon Sensors
(ACT PV11-01) and
can be downloaded from the ACT website
.
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