EFFECTS OF THREE PHOSPHATE INDUSTRIAL SITES ON GROUND-WATER QUALITY IN CENTRAL FLORIDA, 1979 TO 1980 By Ronald L. Miller and Horace Sutcliffe, Jr. U.S. GEOLOGICAL SURVEY Water-Resources Investigations Report 83-4256 Prepared in cooperation with the FLORIDA DEPARTMENT OF ENVIRONMENTAL REGULATION on behalf of the U.S. ENVIRONMENTAL PROTECTION AGENCY Tallahassee, Florida 1984 UNITED STATES DEPARTMENT OF THE INTERIOR WILLIAM P. CLARK, Secretary GEOLOGICAL SURVEY Dallas L. Peck, Director For additional information Copies of this report can be write to: purchased from: District Chief Open-File Services Section U.S. Geological Survey Western Distribution Branch Suite 3015 U.S. Geological Survey '227 North Bronough Street Box 25425, Federal Center Tallahassee, Florida 32301 Denver, Colorado 80225 (Telephone: (303) 234-5888) CONTENTS Page Definitions ------------------------------------------------ ____________ ix Abstract ----------------------------------------------------------------- i Introduction -------------------- ----------------_--__----------_-_----- 3 Purpose and scope ----------------------------- ____--_-_______-_ _ 5 Acknowledgments ------------------------------------------- -------- 6 Description of the area --------------------------------------- ---- g Previous studies ---------------------------------------------------- 8 Hydrogeologic framework -------------------------- ________ __________ JQ Surficial aquifer ------------------------------------- ------------ 13 Intermediate aquifer system ------------------- ----------- -_____- 14 Floridan aquifer ---------------------------------------------------- 14 Methods of investigation --------------------------- -------------------- 15 Site selection and description -------------------------------------- 15 Well placement ------------------------------------------------------ 16 Well construction ----------- --_-------_-__-__-__-__-_---------- - \~j Water-level measurements -------------------------------------------- 19 Water-quality sampling ---------------------------------------------- 19 Data interpretation ---------------------------------- ------------- 20 Principles and processes ------------------ ----------------------------- £1 Dissolution -------------------------- ----------------------------- 22 Neutralization ------------------------------------------ ---------- 24 Mineral precipitation ----------------------------------------------- 25 Adsorption ----- ---------------- -- _____________________________ 25 Ion exchange ------------------------------------------- ----------- 26 Dilution ------- 27 Radioactive decay --------------------------------------------------- 28 Ion indices --------------------------------------------------------- 32 Chemical reactions with aquifers ------------------------------------ 37 AMAX Phosphate, Inc., chemical plant ------------------------------------- 40 Hydrogeology --- ----------- --_-__-_--______ _ _________________ 42 Surficial aquifer - ------------------------------------------- 49 First artesian aquifer ----------- ---___-_-_____-_--_--------- 51 Second artesian aquifer ---------------------------------------- 53 Water quality -- - -------- _______________________________ _-___ 56 Process water ---------------------- ____-___--_----_ ____---_ 56 Background water quality in the surficial aquifer -------------- 59 Background water quality in the first artesian aquifer ------- 60 Background water quality in the second artesian aquifer -------- 62 Soil resistivity ---------------------------------------------------- 65 Water quality in the surficial aquifer ------------------------------ 67 Specific conductance ----------------------- ------------------ 67 Major constituents ---------------------------------- --------- 69 Nitrogen and phosphorus ----------- _-____--___________-_--_- 73 Radiochemicals ------------------- ____-_____------------------ 74 Trace elements --------------------------------- ------- _-___ 73 Organic compounds ------ ------------------------------- - - gi 111 CONTENTS--Continued Page Water quality in the first artesian aquifer - - 81 Major constituents - -- ------------------------- _______ _ 31 Nitrogen and phosphorus _____ _____ _______ _______ _ 33 Radiochemicals ------- --- -- __________________________ _ 33 Trace elements --------------------------- _---___ ___________ 34 Organic compounds --------------- _________ ____________ 35 Water quality in the second artesian aquifer ---------------- _ - 35 Major constituents -- ___________ _ _ ______ _ _ _ 35 Nitrogen and phosphorus --------------- -- ---- - - --- -- 33 Radiochemicals ------ ---------- ______________ __________ 33 Trace elements --------- - ___________ ____ _____________ go Organic compounds ----------------------- ----- - _______ _ go Quality of water from wells tapping more than one aquifer --------- 90 Quality of water from a drainage ditch --- - - --------- ----- - 92 Summary --------------- - ------- -- ______________ _____ __ _ g2 USS Agri-Chemicals plant 93 Hydrogeology - --- -------- - ______________________ _-_-____ 95 Surficial aquifer ----- ------ _________ ______ _ _____ _ IQQ First artesian aquifer - ______--------------- ____________ _ 102 Second artesian aquifer ----------------- ___--______--- -_ _ iQ2 Water quality -- - - - 106 Process water ----___- --- ___________ ________ ______ 106 Background water quality in the surficial aquifer -- ------- - 109 Background water quality in the first artesian aquifer ------ - 109 Background water quality in the second artesian aquifer -------- 112 Soil resistivity -------------------- --__-______--____- ____ ____ 112 Water quality in the surficial aquifer ------------------ ------- 115 Specific conductance ------------------ -- - ---- __________ 115 Major constituents --------------------------------------------- 117 Nitrogen and phosphorus ---------------- __________ ____ _ _ 123 Radiochemicals --------- __-------___--- _________ -_ _ 124 Trace elements ------- - _____________ ___-_ ___________ 125 Organic compounds ---------------------- _________________ _ 126 Water quality in the first artesian aquifer ____-_______-----_-__ 127 Specific conductance ------------ ------- - -_________-- ___ 127 Major constituents -------- -------- _- _____________________ 123 Nitrogen and phosphorus -- ___-___----- _________ _ _- __ 129 Radiochemicals ----------------------- ---------------------- 129 Trace elements --------- ----------------------- _____________ 130 Organic compounds ---------- ____________ ___________ _______ 131 Water quality in the second artesian aquifer ------------ ---------- 131 Specific conductance --- -------------------------------------- 131 Major constituents ----------------- ____________ ___________ 132 Nitrogen and phosphorus __________________ _________________ 133 Radiochemicals -------------------- -------- -____ _______ _ 134 Trace elements --------- --------------- ____________ ____ _ 134 Organic compounds ------------------------- ------------------- 135 Summary ----------- ----------- __-- _______ ___ _______________ 135 IV CONTENTS--Continued Page International Minerals and Chemical Corporation Clear Springs mine 136 Hydrogeology 137 Water quality - - - - -- - - 145 Pond water - - - - - 145 Background water quality in the surficial aquifer -- - 150 Background water quality in the first artesian aquifer - - 150 Water quality in the surficial aquifer - - 151 Specific conductance - ----- - - - - - - 151 Major constituents - - - --- - - - --- 151 Nitrogen and phosphorus -- - --- - -- 153 Radiochemicals -- - ---- - - - - - - - - 155 Trace elements ---- - - ---- - -- _-___ 155 Organic compounds - - -- -- --- - 158 Water quality in the first artesian aquifer -- - --- 158 Specific conductance - - --- - - 158 Major constituents -- - - - - - - 159 Nitrogen and phosphorus - - - - --- 160 Radiochemicals - -- -- - --- - --- - 160 Trace elements -- - - - - - - - 162 Organic compounds - ---- - - - - --- - - 162 Summary - - 163 Water quality of rainfall _____ ___ _ _ _ - 154 Results and conclusions --- - -- - - -- - -- - 169 AMAX chemical plant - - _--_ ----- -- 171 USSAC chemical plant - 174 IMC mine 176 Selected references -- - -- - - 178 ILLUSTRATIONS Page Figure 1. Map showing locations of study sites in west-central Florida 7 2. Map showing plant layout and locations of data-collection sites at the AMAX plant - - - - - 41 3. Hydrographs of monthly precipitation at the AMAX plant and at Bradenton, 1977-80 43 4. Geophysical logs for well 2 at the AMAX plant -- -- 46 5. Generalized geologic section underlying the AMAX plant - - 47 6. Graph showing relation of water-bearing zones penetrated by cluster wells at the AMAX plant -- - 48 7. Map showing generalized water table of the surficial aquifer at the AMAX plant, July 18, 1980 50 8. Map showing potentiometric surface of the first artesian aquifer at the AMAX plant, July 18, 1980 52 9. Map showing potentiometric surface of the second artesian aquifer at the AMAX plant, July 18, 1980 54 10. Hydrographs of water levels in wells at the AMAX plant ----- 55 IILUSTRATIONS--Continued Page Figure 11. Modified Stiff diagram showing concentrations of principal ions in process water from the AMAX plant ------------------ 57 12. Modified Stiff diagram showing concentrations of principal ions in water from surficial aquifer wells adjacent to the AMAX gypsum stack and a background well -------------------- 61 13. Modified Stiff diagram showing concentrations of principal ions in water from first artesian aquifer wells adjacent