Overview of Lake Apopka North Shore Pesticide Research by SJRWMD

Overview of Lake Apopka North Shore Pesticide Research by Michael F. Coveney, PhD SJRWMD Harris Chain of Lakes Restoration Council 6 February 2015 Bureau of Environmental Sciences St. Johns River Water Management District Palatka, Florida, USA mcoveney@sjrwmd.com

Overview of NSRA Pesticide Research by SJRWMD Overview of NSRA extent of farming, land elevations, subsidence, current flooding Bird mortality in 1998/99 Ensuing research program by SJRWMD and NRCS Remediation and continued restoration

Lake Apopka Lake Apopka Development of Farms on the North Shore of Lake Apopka 1941-1985 Lake Apopka Lake Apopka Shallow marsh Shrub swamp Hardwood swamp Wet prairie Farm in prep Farm

Reduce phosphorus loading through wetland restoration on former farms In 2000 3,480 Acres (22%) In 2005 6,730 Acres (43%) In 2011 11,170 Acres (71%) In 2013 15,660 Acres (100%)

Lake Apopka North Shore Restoration Area Christmas 1998 bird count 176 species Bird mortality winter 1998/99 (despite environmental site assessments, remediation, ecological risk assessments) Drained the fields Organochlorine pesticide residues responsible in part Research program on distribution, bioaccumulation, and fate in organic soils

Bird Mortality on Site 9/98 3/99 White pelicans 441 Herons and egrets 135 Wood storks 43 Other species 57 Total 676.

NSRA 1998-99 Bird Mortality Questions for SJRWMD/NRCS 1. How did lethal OCP levels accumulate in birds? 2. How to proceed with restoration of wetlands with acceptable risk? Availability of weathered soil OCPs to biota Transfer of OCPs from soil fish and fish birds Roles of soil TOC and OCP levels in determining exposure Distribution of OCPs among bird tissues

SJRWMD/NRCS Research Program Formation of Technical Advisory Group and Expert Review Group Large-scale sampling of soils Contract with Exponent for forensic analyses Pesticide bioaccumulation studies Soil Fish and Fish Birds

Cooperators with SJRWMD/NRCS U.S. Fish & Wildlife Service U.S. Environmental Protection Agency Fl. Fish and Wildlife Conservation Commission Fl. Dept of Health Fl. Dept of Agriculture and Consumer Services Fl. Dept. of Environmental Protection University of Florida U. S. Geological Survey Lake County Lake Co. Water Authority Orange County Audubon Society Friends of Lake Apopka

Lake Apopka Pesticide Study Expert Review Group Michael Fry, Ph.D. University of California at Davis Ecological toxicology Michael Hooper, Ph.D. Texas Tech University Avian toxicology Thomas W. La Point, Ph.D. University of North Texas Avian toxicology P. Suresh C. Rao, Ph.D. Purdue University Soil biogeochemistry Gary Rand, Ph.D. Florida International University Ecological toxicology James Sikarskie, D.V.M. Michigan State University Wildlife veterinarian

Pesticide Residues of Interest 4,4'-DDD, 4,4'-DDE; 4,4'-DDT alpha-chlordane; cis-nonachlor; gamma-chlordane; heptachlor; heptachlor epoxide; oxychlordane; trans-nonachlor Dieldrin Toxaphene

Distribution of Toxaphene

Distribution of DDE

DDE Concentrations in Bird Brains Analyzed at En Chem 250 140 120 0.3 0.2 0.1 Control birds Concentration (mg/kg) 100 80 60 40 20 0 0 Black- crowned Night Heron Great Blue Heron White Ibis White Pelican Wood Stork = brain concentrations considered hazardous (Stickel 1980)

Dieldrin Concentrations in Bird Brains Analyzed at En Chem Concentration (mg/kg) 16 14 12 10 8 6 4 2 0 0.12 0.08 0.04 0 Control birds Black- crowned Night Heron Great Blue Heron White Ibis White Pelican Wood Stork Range of brain concentrations considered hazardous (Ohlendorf et al. 1981)

Toxaphene Concentrations in Bird Brains Analyzed at En Chem 6 4 Control birds Concentration (mg/kg) 80 70 60 50 40 30 20 10 0 2 0 Black- crowned Night Heron Great Blue Heron White Ibis White Pelican Wood Stork Range of concentrations considered hazardous (4 mg/kg in pigs)

Exponent s Conclusions Page 6-4. Overall, application of epidemiological criteria to the mortality event does not produce strong evidence either supporting or refuting the hypothesis that mortality was a result of exposure to organochlorine pesticides. In other words, Exponent could not reach a conclusion on the cause of the mortality.

District s Conclusions Weight of Evidence OCP toxicosis caused, or contributed to, the deaths of many of the birds Primary agents of toxicosis were toxaphene and dieldrin Primary route of exposure was soils to fish to birds

Bioaccumulation Studies Soil fish Birds Laboratory microcosms Field mesocosms Great egret feeding study Fish sausages measured, controlled dose

Microcosm Study Bioaccumulation soil fish Tank experiment (~700 L, 1.2 m diam.) Soils with a range of TOC and OCPs 10 soil types +3 controls in triplicate (total 39 tanks) Measured OCP accumulation and lipids in stocked mosquitofish and crayfish Run for 16 weeks

Biota Sediment Accumulation Factor (BSAF) BSAF is one way to calculate the bioaccumulation of lipophilic ( fat-loving ) compounds in the environment BSAF = OCP in fish lipid OCP in soil C BSAF = (OCP fish µg/kg wet wt) / (lipid fish µg/kg wet wt) (OCP sed µg/kg dry wt) / (TOC sed µg/kg dry wt)

a b c On-site collection of soil f g

Toxaphene Uptake by Gambusia 2.0 Ratio of OCP in Fish to OCP in Soil 1.5 Ratio 1.0 0.5 0.0 2% 9% 10% 17% 23% 40% 44% 48% Treatment Soil TOC

Toxaphene Uptake by Gambusia BSAF: Ratio of OCP in fish Lipid to OCP in Soil TOC 2.5 2.0 Treatment g o mitted M edian 1.63 M ean 1.73 BSAF 1.5 1.0 0.5 0.0 2% 9% 10% 17% 23% 40% 44% 48% Treatment Soil TOC

Toxaphene Uptake by Gambusia 2.5 2.0 BSAF: Ratio of OCP in fish Lipid to OCP in Soil TOC Treatment g o mitted M edian 1.63 M ean 1.73 BSAF 1.5 1.0 0.5 0.0 782 1015 1255 5300 10083 13000 42500 44500 Treatment Soil Toxaphene ug/kg

Field Mesocosm Study Bioaccumulation soil fish Mesocosms constructed within berms on NSRA. Natural soils. Covered with netting 3 shallow ponds (0.75 acre, 0.3 ha) at low medium high soil OCP levels 2 deeper ponds (0.25 acre, 0.1 ha) at high soil OCP levels Stocked with tilapia, mosquitofish, crayfish, sunfish, bullhead catfish Operated approx. 6 yr

Changes in Toxaphene in Soil

Changes in DDE in Soil

Changes in Toxaphene in Fish

Changes in DDE in Fish

Results - Reduction in OCPs in Soil and Fish First-order rate constants calculated for 1.9 to 6.1 yr for open water soils, 1.9 to 5.3 yr for marsh soils, and 2.0 to 6.1 yr for open water fish.

Results - BSAFs n = 229 or 314 fish samples for marsh and 114 samples for open water. Chlordanes not shown. Flooding times 1.1 to 2.7 yr for marsh and 1.1 to 3.5 for open water mesocosms.

Median Parcel Soil Contam Risk (HQ) 2.0 1.5 1.0 0.5 0.0 NSRA, Units 1 & 2 (orig data set) DDE Toxaphene Dieldrin Safe Level Emergent Marsh Open Water

Bird Feeding Study Bioaccumulation fish birds Raise fish in two 0.25-acre ponds on high OCP soils on the NSRA Feed fish to captive great egrets Measure bioaccumulation of weathered OCPs from NSRA fish Kinetics of accumulation Distribution of OCPs among tissues Possible remobilization of OCPs from fat to brain

Fish sausages measured, controlled dose

Results Bird Feeding Study Found long half-lives for OCPs in birds OCP concentrations in birds showed constant ratios among organs Evidence that OCPs were mobilized from fat to brain upon fasting Birds did not die but may have sickened on 100% contaminated fish diet

Results Bioaccumulation Studies BSAF bioaccumulation model works despite varying organic content of soils, varying fat content of fish, and varying OCP levels in soils. BSAFs 2 to 4 times higher in open water vs emergent marsh OCPs move from fat to critical tissues when birds metabolize fat reserves Half-life of weathered toxaphene in birds much longer than earlier believed OCPs degrade under flooded conditions

Results Toxicity Reference Values (TRVs) Pesticide TRV (ug/kg wet wt) Fasting Factor Adjusted TRV 4,4'-DDE 1,500 none 1,500 DDTr** 3,000 2 1,500 Dieldrin 280 2 140 Toxaphene 10,000 2 5,000 cis-nonachlor 1,100 2 550 gamma-chlordane 2,000 2 1,000 Heptachlor 800 2 400 Heptachlor epoxide 200 2 100 Oxychlordane 100 2 50 trans-nonachlor 900 2 450 alpha-chlordane 2,000 2 1,000 ** DDTr indicates a calculated DDT equivalent which considers toxic effects of DDT, DDD, and DDE (Stickel et al., 1970)

Risk Assessment Soil OCP levels BSAFs Predict fish OCP levels in a flooded field + TRVs Calculate Hazard Quotient (HQ) for each OCP Add HQs to calc Hazard Index for mortality (DDE Use HQ for reproductive effects) Remediation and Management

OCPs (Toxaphene) Concentrated in upper 12 inches of soil Mean values, all field samples

Remediation Pilot Projects Summary Project % Reduction DDE Rate: Acre/Day Cost: $/Acre Total Time (Days) 8,000 acres Total Cost Inversion 79 15 $2,500 533 $20,000,000 Blending 58 1 $2,700 8000 $21,600,000 Bioremediation 50 NA $31,839 NA $254,712,000 Excavation & disposal 100 0.25 $100,000 32,000 $800,000,000

Re-Sampling Sites for OCP and TOC

Remediation Plan FY 06/07-300 acres FY 07/08-1490 acres FY 08/09 2175 acres Total: 3,965 acres

Steps in Soil Inversion Equipment used dependent on field condition 10 12 passes needed: Soil Packer / Roller Offset Disc Ripper / chisel plow Chopper

4 or 5 bottom Baker reversible disc plow Custom 52-in blades 2.5 3.5 ft furrow Top 10 in soil buried in furrow 600 horsepower quad-track. Specially built.

Remediation of Soil Pesticides by Deep Plowing 2007-2009 Total 1620 hectares (3965 acres) Cost USD 9.6 million Median 67% reduction in surface (30 cm) DDE concentration (d wt)

Questions?