Here are the chemical tracer and DNA marker test results by the Florida Department of Environmental Protection (FDEP) that WWALS has frequently mentioned, for example in Current Situation of Water Quality Testing, Suwannee River Basin 2020-08-02.

Below, please also find a summary of those results by WWALS Science Committee Chair Dr. Thomas Potter.

Human and Ruminant DNA markers

Thanks to Katrina Yancey of FDEP for sending the data, and for acknowledging that FDEP has no objection to WWALS publishing it. I asked FDEP for whatever they wanted to include, and this is what they sent:

“Thank you for asking, we recently set up our new site so it may be helpful to state that more information may be found at DEP’s webpage for the Suwannee River Basin Sampling Locations (https://floridadep.gov/dear/watershed-monitoring-section/content/suwannee-river-basin-sampling-locations).”

The actual data is on the WWALS website.

WWALS Summary of FDEP chemical and biological tracer measurements
on Withlacoochee and Suwannee River samples

Dr. Thomas Potter, WWALS Science Committee Chair

After Valdosta’s raw sewage spill in early December 2019, WWALS, the City of Valdosta, and several Florida agencies have tested for bacterial contamination in the Withlacoochee River and its tributaries. This testing continues and focuses on measuring bacteria that are indicators of human or animal waste.

The Florida Department of Environmental Protection (FDEP) has also tested for chemical tracers (drugs and artificial sweeteners such as sucralose) and DNA markers of bacterial contamination (human, canine, ruminant, bird, seabird), and selected pesticides. From December through February, FDEP collected and analyzed 89 water samples, including some samples from the Suwannee River. Currently FDEP continues this work on a small subset of the sample collection locations on a monthly basis.

WWALS requested a copy of all results to date from FDEP and received them. WWALS has summarized the FDEP Findings in the following five tables.

• Numbers of samples, locations, and the date range when samples were collected are shown in table 1.
• Table 2 provides results for all samples and tests based on the frequency of detection, i.e. when measurements were above the method detection limit (MDL).
• Tables 3, 4, and 5 show results for human and ruminant DNA biomarkers and the chemical marker, sucralose, by date, and sample location.

In the case of the human waste DNA marker, a total of 6 detections were reported. This represented approximately 7% of all samples. In all cases, measurements were near the reported limit of detection. On one sample date (1/22/20) a duplicate sample was collected and analyzed. In the duplicate the biomarker was not detected. Thus finding that the human waste biomarker was present remains uncertain. In summary there is some indication that human waste DNA was detected at selected locations on the Withlacoochee. But findings were sporadic and appear uncertain.

While detection of Human DNA biomarkers was infrequent, detection of Ruminant DNA markers at relatively high levels was common, especially in late December and early January. This supports the WWALS conclusion that continuing episodes of bacterial contamination in the Withlacoochee River starting at Knights Ferry Boat Ramp are most likely the result of cow manure washing off pastures within the Withlacoochee drainage basin, much of it coming down Okapilco Creek from Brooks and Colquitt Counties, Georgia. Stations with the highest levels of these biomarkers were at the GA state line (GA 31), and in Florida at CR 150 and FL 6. There were no discernable trends in levels of biomarkers detected suggesting that there are multiple sources of animal waste.

Chemical tracers that indicated the presence of sewage in samples was also common. The parameters sucralose, carbamazepine, and primidone were of particular note. The sweetener sucralose was detected in all samples. The most likely explanation of the presence of this compound in river samples is the discharge of treated wastewater into the river. This is for two reasons. The first is that human DNA biomarkers, an indicator of raw sewage were rarely detected. The second is that published studies that indicate that sucralose levels in wastewater are not reduced (except by dilution) when sewage passes through wastewater treatment facilities. The City of Valdosta’s Withlacoochee Wastewater Treatment Plant (WWTP) discharges into the Withlacoochee southwest of Valdosta.

Selected herbicides and insecticides were frequently detected, although in low concentrations. Potential for water quality impacts appear low.

Table 1. DNA bacterial biomarker and chemical sewage markers and pesticide tests conducted by the Florida Department of Environmental Protection (FDEP) following the Valdosta sewage spill on December 9. 2020.

Chemical sewage markers and pesticides tests
	# samples	date range
Withlacoochee River at GA 31	19	12/13/19 to 6/10/20
Withlacoochee River at CR 150	22	12/19/20 2/27/20
Withlacoochee River at FL 6	21	12/10/19 to 2/27/20
Withlacoochee River at CR 141	5	1/9/20 1/22/20
Suwanee River at US 90	18	12/10/19 to 2/27/20
Suwanee River at CR 250	3	1/9/20 to 2/27/20
Blank	1	1/22/2020
Duplicate	1	1/22/2020
DNA tests for bacteria source
	# samples	date range
Withlacoochee River at GA 31	19	12/16/19 to 6/10/20
Withlacoochee River at CR 150	22	12/10/19 to 6/10/20
Withlacoochee River at FL 6	22	12/10/19 to 6/10/20
Withlacoochee River at CR 141	5	1/9/20 to 1/22/20
Suwannee River at US 90	18	12/10/19 to 6/10/20
Suwannee River at CR 250	3	1/9/20 to 2/27/20
Blank	1	1/22/20
Duplicate	1	1/22/20

Table 2. Summary of the percentage of all FDEP samples with measurements above the reported limit of detection (MDL) of each analysis.

		# samples	# above method detection limit	% samples with detections
DNA test to detect bacteria source
BacR-qPCR	Ruminant DNA	79	32	41
DG3-qPCR	Dog DNA	79	0	0
GFD-purified-qPCR	Bird DNA	79	15	19
GULL2-qPCR	Gull DNA	79	0	0
HF183-qPCR	Human DNA	89	6	7
Chemical Sewage Markers
Acesulfame K	artificial sweetener	89	2	2
Acetaminophen	drug residue	89	2	2
Carbamazepine	drug residue	89	65	73
Hydrocodone	drug residue	89	6	7
Ibuprofen	drug residue	89	2	2
Naproxen	drug residue	89	2	2
Primidone	drug residue	89	59	66
Sucralose	artificial sweetener	89	89	100
Pesticides
2,4-D	herbicide	89	57	64
Acetamiprid	insecticide	89	12	13
Afidopyropen	insecticide	89	0	0
AMPA	herbicide breakdown product	89	34	38
Bentazon	herbicide	89	88	99
Benzovindiflupyr	fungicide	89	0	0
Clothianidin	insecticide	89	13	15
Dinotefuran	insecticide	89	88	99
Diuron	herbicide	89	48	54
Endothall	herbicide	89	0	0
Fenuron	herbicide	89	1	1
Fluridone	herbicide	89	15	17
Glufosinate	herbicide	89	0	0
Glyphosate	herbicide	89	9	10
Imazapyr	herbicide	89	88	99
Imidacloprid	insecticide	89	86	97
Linuron	herbicide	89	0	0
Mandestrobin	fungicide	89	0	0
MCPP	herbicide	89	57	64
Pyraclostrobin	fungicide	89	0	0
Thiamethoxam	insecticide	89	48	54
Tolfenpyrad	insecticide	89	0	0
Triclopyr	herbicide	89	1	1

Table 3. FDEP Human DNA Biomarker test results
for selected Withlacoochee and Suwannee River sample collection locations
(units are GEU/100 mL)

	Withlacoochee River			Suwannee River
	GA 31	CR 150	FL 6	US 90	CR 250
10-Dec-19		<MDL	<MDL
11-Dec-19		<MDL	<MDL
13-Dec-19		<MDL	<MDL
16-Dec-19	<MDL	<MDL	<MDL	<MDL
20-Dec-19	<MDL	<MDL	<MDL	<MDL
26-Dec-19	<MDL	<MDL	<MDL	<MDL
27-Dec-19	<MDL	<MDL	<MDL	<MDL
2-Jan-20	<MDL	<MDL	<MDL	<MDL
6-Jan-20	<MDL	<MDL	<MDL	<MDL
7-Jan-20	<MDL	<MDL	<MDL	<MDL
8-Jan-20	<MDL	<MDL	<MDL	<MDL
9-Jan-20	<MDL	<MDL	<MDL	<MDL	<MDL
13-Jan-20	<MDL	<MDL	<MDL
14-Jan-20	<MDL	<MDL	<MDL
15-Jan-20	<MDL	<MDL	<MDL
16-Jan-20	<MDL	<MDL	<MDL	<MDL
21-Jan-20	<MDL	<MDL	<MDL	<MDL
22-Jan-20	<MDL	170	<MDL	<MDL
23-Jan-20	<MDL	<MDL	<MDL	<MDL
25-Feb-20	<MDL	370	320	<MDL	<MDL
27-Feb-20	550	360	470	<MDL	<MDL
10-Jun-20	<MDL	<MDL	<MDL	<MDL

Table 4. FDEP Ruminant DNA Biomarker test results
for selected Withlacoochee and Suwannee River sample collection locations
(units are TSC/100 mL)

	Withlacoochee River			Suwannee River
	GA 31	CR 150	FL 6	US 90	CR 250
16-Dec-19	<MDL	<MDL	<MDL	<MDL
20-Dec-19	<MDL	<MDL	<MDL	<MDL
26-Dec-19	235000	30600	<MDL	2200
27-Dec-19	12000	24400	<MDL	<MDL
2-Jan-20	<MDL	<MDL	<MDL	<MDL
6-Jan-20	351000	<MDL	<MDL	<MDL
7-Jan-20	108000	636000	2300	3800
8-Jan-20	19000	31100	228000	<MDL
9-Jan-20	<MDL	5500	3100	4400	<MDL
13-Jan-20	3700	2100	<MDL
14-Jan-20	45300	136000	<MDL
15-Jan-20	1800	20700	19300
16-Jan-20	1800	<MDL	2000	<MDL
21-Jan-20	4000	<MDL	<MDL	<MDL
22-Jan-20	<MDL	<MDL	<MDL	<MDL
23-Jan-20	<MDL	<MDL	<MDL	<MDL
25-Feb-20	<MDL	<MDL	<MDL	<MDL	<MDL
27-Feb-20	37600	18100	21400	11000	99900
10-Jun-20	<MDL	<MDL	<MDL	<MDL

Table 5. FDEP chemical sewage marker test results
for the artificial sweetener sucralose
(Units are ug L-1)

	Withlacoochee River			Suwannee River
	GA 31	CR 150	FL 6	HWY90	CR 250
10-Dec-19		1.6	1.3	0.27
11-Dec-19		1.9	1.1	0.3
13-Dec-19	1.4	1.5	1.2	0.25
16-Dec-19	1.8	1	1.7	0.24
20-Dec-19	4.3	1.6	1	0.26
26-Dec-19	4.5	8.4	4.4	0.23
27-Dec-19	2.5	4.4	6.7	0.28
2-Jan-20	1.1	0.9	1.1	0.8
6-Jan-20	0.81	0.8	0.75	0.33
7-Jan-20	1.1	0.89	0.81	0.23
8-Jan-20	1.1	0.94	0.84	0.21
9-Jan-20	1.1	1.3	0.9	0.2	0.23
13-Jan-20	0.7	0.75	0.63
14-Jan-20	0.68	0.59	0.67
15-Jan-20	0.67	0.62	0.57
16-Jan-20	0.62	0.72	0.63	0.17
21-Jan-20	0.5	0.57	0.55	0.16
22-Jan-20	0.46	0.56	0.48	0.2
23-Jan-20	0.58	0.79	0.57	0.18
25-Feb-20	0.33	0.35	0.33	0.092	0.16
27-Feb-20	0.31	0.29	0.3	0.092	0.15

Editor’s note: to deal with the variant names found in the source spreadsheets, I normalized the roads to GA 31 (near State Line Boat Ramp), CR 150 (near Sullivan Launch), FL 6 (near Madison Blue Spring State Park), CR 141 (near Allen Ramp), US 90 (just below Suwannee River State Park and the Withlacoochee River Confluence with the Suwannee River), and CR 250 (near Dowling Park Ramp). Also, I normalized FL 145 and CR 145 to GA 31, because at Horn Bridge across the Withlacoochee River just north of the GA-FL line, the road is in Georgia and is actually GA 31 or Madison Highway (near State Line Boat Ramp). Dr. Potter’s tables are based on these normalizations, which also correspond to those used in the WWALS Composite Spreadsheet of Georgia and Florida bacterial water quality results and rainfall.

Thanks

Thanks to Merillee Malwitz-Jipson for helping persuade FDEP to collect and analyze this data (see Credit Where Credit Is Due. Thanks to Kristin Cathey for facilitating an appropriate path to FDEP to get the data. And thanks again to Katrina Yancey of FDEP for sending the data. Finally, thanks to WWALS Science Committee Chair Dr. Thomas Potter for the analysis.

 -jsq, John S. Quarterman, Suwannee RIVERKEEPER®

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