Ecotoxicology (2008) 17:660–679 DOI 10.1007/s10646-008-0230-0 Aquatic risk assessment of pesticides in surface waters in and adjacent to the Everglades and Biscayne National Parks: I. Hazard assessment and problem formulation John F. Carriger Æ Gary M. Rand Accepted: 3 June 2008 / Published online: 19 July 2008 Ó Springer Science+Business Media, LLC 2008 Abstract An aquatic risk assessment under the U.S. Introduction Environment Protection Agency (EPA) ecological risk framework was conducted for atrazine, metolachlor, mal- In 1996, the Department of the Interior (DOI) prepared a athion, chlorpyrifos, and endosulfan in the C-111 report entitled ‘‘A Comprehensive Plan for the Restoration of freshwater basin (eastern boundary of the Everglades the Everglades,’’comprising four main elements: (1) federal National Park), northeast Florida Bay, and south Biscayne legislative authority for restoration activities; (2) accelerated Bay in South Florida. Based on the use of the hazard state and federal land acquisition; (3) increased scien- quotient approach, measured concentrations of chlorpyrifos tific research to guide restoration; and (4) federal, state, and endosulfan in surface waters suggest potential hazards and private sector cost sharing (http://www.sfrestore.org/tf/ to aquatic organisms and were, therefore, considered as otherres/comp.html). In 2000, Congress passed the Com- chemicals of potential ecological concern (COPECs). The prehensive Everglades Restoration Plan (CERP) as a part of problem formulation included an overview of the physical/ the Water Resources Development Act (1996). The goal of chemical and environmental fate characteristics and aqua- the CERP is to restore and preserve the hydrology of the pre- tic toxicology of the COPECs. Background surface water drainage Everglades ecosystem, to protect the quality of the exposure concentrations of endosulfan and toxicity data remaining habitat, to promote the return of populations of from laboratory and field studies indicate that fish and plants and animals, and to foster human development com- invertebrate mortality may be a concern when endosulfan patible with sustaining a healthy ecosystem. is applied in agricultural areas near aquatic ecosystems. Biological changes in the Everglades have been linked to levels of phosphorus and mercury and to changes in the Keywords Endosulfan Á Chlorpyrifos Á Atrazine Á complex hydrological patterns of the natural system Malathion Á Metolachlor Á Ecological risk assessment Á resulting from water management projects to control floods Everglades National Park Á Biscayne National Park Á and water distribution (Science Subgroup 1996). In fact, C-111 canal Á Florida Bay Á Biscayne Bay Á alterations in the hydrologic system are thought to be the Everglades restoration main cause of dramatic declines of fish and wildlife pop- ulations because of habitat changes. Therefore, the basic premise behind all restoration activities identified by the Interagency Restoration Task Force for South Florida is that hydrologic restoration is a prerequisite to achieve ecosystem restoration and a sustainable South Florida Ecosystem. The restoration plan was, thus, formulated to J. F. Carriger Á G. M. Rand (&) reconstruct some key features of the natural hydrologic Department of Environmental Studies, Ecotoxicology & Risk system in order to restore conditions that support landscape Assessment Laboratory, Southeast Environmental Research patterns, biodiversity, wildlife abundance, and clean and Center, Florida International University, Biscayne Bay Campus, 3000 NE 151st Street, North Miami, FL 33181, USA abundant water. In the past, little consideration, however, e-mail: randg@fiu.edu was given in the restoration effort to the role that organic 123 Hazard assessment and problem formulation 661 pesticides and other contaminants play in the structure 1995, and occasionally exceeded the Florida Department of and function of ecosystems, although this was clearly Environmental Protection (FDEP) and U.S. Environment recommended by the Science Subgroup (1996) in all Protection Agency (EPA) water quality criteria (Miles and physiographic regions that comprise South Florida. This Pfeuffer 1997). Surface water samples collected indepen- was further supported at a workshop entitled ‘‘Linking dently by the NOAA from the southern SFWMD sampling Ecotoxicity and Risk Management to Sustainable Resto- sites confirmed these findings (Scott et al. 1994). Residues ration of South Florida Ecosystems,’’ which recommended of endosulfan sulfate were also consistently found by the screening-level ecological risk assessments with retro- SFWMD in sediment samples at S-178 in the C-111, while spective and prospective diagnostic studies (LaPoint et al. the a and b isomers were occasionally found. All three 1998). endosulfan residues were also found in sediment samples It is evident that water quantity rather than water quality from structures S-177 and S-18C in the C-111. The issues have dominated the South Florida restoration plan- SFWMD summarized endosulfan sulfate residues in S-178 ning (Scott et al. 2002). However, it is also evident that water and found that the FDEP water quality criteria were agriculture represents a major land use in South Florida exceeded 11 times from 1996 to 2000 (two samples were and pesticide use presents a potential risk, especially to from NOAA; R. Pfeuffer, personal communication). In a aquatic organisms. Based on a hazard ranking of pesticides SFWMD monitoring program of South Florida canals from by the National Oceanic and Atmospheric Administration 1992 to 2001, the most common pesticides in surface water (NOAA), the top three estuarine drainage areas at risk in were the herbicides atrazine and ametryn, while DDE and the U.S. were in Florida-Rookery Bay, Biscayne Bay, and DDD were the most frequently detected pesticides in sed- Tampa Bay (Pait et al. 1992). The subtropical climate, long iment samples (Pfeuffer and Rand 2004). The U.S.EPA, in crop-growing season, application frequency, and multitude 1995, also monitored contaminants in surface water, sedi- of uses (e.g., mosquito and termite control, golf courses, ment, and biota in the C-111 and creeks of northeast and landscape management) renders pesticides particularly Florida Bay (Goodman et al. 1999). Endosulfan residues hazardous in South Florida ecosystems. were detected in sediments of the C-111, and in sediments The Canal 111 (Aerojet Canal or C-111) freshwater of Shell and Trout Creeks (in northeast Florida Bay). basin (Fig. 1) is a buffer zone that separates the wetlands of Organochlorine contaminants occurred at low concentra- the Everglades National Park (ENP) from highly produc- tions in sediments of canals and creeks, and PCBs and tive subtropical agricultural lands and urban development PAHs were also at low concentrations but higher in the to the east, and while considerable attention and resources C-111 than in creeks. At most sampling sites for water and have been allocated to altering the hydrology of this sediment, more than one pesticide was detected in each landscape, little effort has focused on understanding water sample. quality issues that may arise from land use practices. Thus The NOAA conducted sediment toxicity tests and a far, analytical monitoring programs have detected the contaminant monitoring study of the C-111 and Florida presence of organic pesticides in the surface water of either Bay from 1993 to 1997, but it did not evaluate cause the lower C-111 freshwater canal basin and/or its confluent (exposure)–effect (toxicity) relationships for contaminants estuaries/saltwater systems. For example, the South Florida (Scott et al. 2002). It did however; indicate the presence of Water Management District (SFWMD) began monitoring low levels of endosulfan (total), atrazine, chlorpyrifos, and pesticides in the water and sediment of South Florida chlorothalonil in surface waters of canals adjacent to canals in the mid-1980s (Pfeuffer 1985, 1991). Sediment agricultural areas that drain into the C-111 and in northeast and water analyses by SFWMD indicates that atrazine, Florida Bay waters. Florida Bay waters occasionally ametryn, bromacil, simazine, diuron, alpha (a)-endosulfan, exceeded the U.S.EPA marine water quality criterion beta (b)-endosulfan, endosulfan sulfate, ethion, hexazi- (WQC) for endosulfan. Waters from canal sites also con- none, and norflurazon were the most frequently detected tained detectable concentrations of endosulfan that pesticides in surface water and DDE, DDD, ametryn, sporadically exceeded U.S.EPA fresh WQC. Detectable atrazine, dicofol, diquat, and endosulfan sulfate were the endosulfan (total) residues were also found in sediment and most frequently detected pesticides in sediment samples oysters, while chlorpyrifos was detected in fish tissue. between 1991 and 1995 (Miles and Pfeuffer 1997). Several Toxicity tests with in-place sediment and copepods and of the sampling sites were located in the Everglades bivalves indicated potential adverse effects, but the caus- Agricultural Area (EAA) and others in the Homestead ative agent(s) was not determined. The highest concen- Agricultural Area (HAA) adjacent to the Everglades tration of endosulfan (total) reached 477 ng/l, and 10% of National Park. Detectable endosulfan residues (a and b the samples from canal sites exceeded the U.S.EPA chronic isomers, and sulfate metabolite) in the C-111 (at S-178) freshwater WQC (56 ng/l) (47% of the canal sites had were consistently present in the surface water from