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A hazard assessment was conducted of contaminants found at inflow and outflow monitoring stations of the Water Conservation Areas (WCAs) in South Florida. WCAs (1, 2A, 2B 3A, 3B) lie north of Everglades National Park (ENP) and southeast of Lake Okeechobee, span almost 1400 mi, and serve a number of water resource functions which include food control for three major counties, delivering water to ENP, and water storage during dry downs and for recharging groundwater. Measured concentrations of contaminants in sediment and water were evaluated at 13 monitoring stations in the WCAs using a screening benchmark approach. Chemicals of potential ecological concern (COPECs) included herbicides, organochlorine pesticides, organochlorine industrial chemicals, and heavy metals. Of the stations, total cadmium was a COPEC at nine of them. Most sites had maximum detected concentrations of cadmium that exceeded state of Florida (USA) water quality criteria standards. Beryllium, copper, mercury, methylmercury, and zinc (measured as total metal concentration) also exceeded surface water criteria at several sites. Several organochlorine chemicals in sediment were COPECs; chlordane, polychlorinated biphenyls, and p, p′-DDT with its metabolites ( p, p′-DDD and p, p′-DDE) had more than 200 sediment benchmark exceedences. Mercury in fish tissue was a COPEC at S5A when compared to a no-effect residue value for survival. Greater potential hazards were observed at northern monitoring sites than southern sites around the WCAs. The hazard assessment approach for screening water quality data described in this article can help focus higher tier risk assessment work, including laboratory, field, and data analysis studies, on contaminants with greater potential for adverse biological effects. [ABSTRACT FROM AUTHOR]

A comprehensive environmental evaluation was completed on 20 metals: two reference metals (Fe, Al) and several minor trace metals (As, Ba, Co, Cr, Cu, Mn, Ni, Pb, V, and Zn) for surface soils and sediments collected from 50 sites in Everglades National Park (ENP), the coastal fringes of Biscayne National Park (BNP), and Big Cypress National Preserve. Samples were prepared by acid digestion (EPA3050) and analyzed by ICP/MS detection (EPA6020). Although no widespread contamination was detected across the two parks and one preserve, there were some specific areas where metal concentrations exceeded Florida's ecological thresholds, suggesting that some metals were of concern. A screening-level evaluation based on a proposed effect index grouped trace metals by their potential for causing negligible, possible, and probable effects on the biota. For example, Cu in BNP and Cr and Pb in ENP were considered of concern because their adverse effect likelihood to biota was assessed as probable; consequently, these trace metals were selected for further risk characterization. Also, stations were ranked based on a proposed overall contamination index that showed that: site BB10 in BNP and sites E3 and E5 in ENP had the highest scores. The first site was located in a marina in BNP, and the other two sites were along the eastern boundary of ENP adjacent to current or former agricultural lands. An assessment tool for south Florida protected lands was developed for evaluating impacts from on-going Everglades restoration projects and to assist State and Federal agencies with resource management. The tool consists of enrichment plots and statistically derived background concentrations based on soil/sediment data collected from the two national parks and one preserve. Finally, an equally accurate but much simplified approach is offered for developing enrichment plots for other environmental settings. [ABSTRACT FROM AUTHOR]

Endosulfan, the last remaining organochlorine pesticide, has been the subject of a number of international regulations and restriction/banning action plans worldwide. Occurrence of endosulfan residues in South Florida environments has been widely described in the literature for more than two decades. This work describes a selective, sensitive, and fast online solid-phase extraction (SPE) method coupled with liquid chromatography separation and tandem mass spectrometry (LC-MS/MS) for the determination of endosulfan isomers and endosulfan sulfate in water samples at low part per trillion levels with very little sample preparation. A negative atmospheric pressure chemical ionization source was carefully optimized to produce reproducible spectra of the target compounds with no adduct ion formation. Selected reaction monitoring transitions were monitored and quantitation was performed against a per-deuterated internal standard β-endosulfan (d4). The automated online SPE clean-up was performed using only 20 mL of untreated water sample prior to LC-MS/MS analysis. The method was capable of separating and quantifying endosulfan within a 24-min run using acetonitrile and water as mobile phases and presenting statistically calculated method detection limits of 3, 10, and 7 ng/L for endosulfan sulfate, α-endosulfan, and β-endosulfan, respectively. In addition, a QuEChERS method was successfully developed and applied for endosulfan determination in sediments/soils, floating and submerged algal mats, and small fish. Minimal matrix effects were observed in all matrices analyzed and recoveries for all analytes ranged from 50-144 %. The developed methodology was applied to monitor the occurrence and to assess the potential transport of endosulfan in the Loveland Slough watershed, an area adjacent to Everglades National Park showing long-term contamination with endosulfans. [ABSTRACT FROM AUTHOR]

Endosulfan sulfate is a persistent environmental metabolite of endosulfan, an organochlorine insecticide-acaricide presently registered by the United States Environmental Protection Agency. There is, however, limited acute fish toxicity data for endosulfan sulfate. This study determines the acute toxicity (LCs and LCs) of endosulfan sulfate to three inland Florida native fish species (mosquitofish [ Gambusia affinis]; least killifish [ Heterandria formosa]; and sailfin mollies [ Poecilia latipinna]) as well as fathead minnows ( Pimephales promelas) . Ninety-six-h acute toxicity tests were conducted with each fish species under flow-through conditions. For all of the above-mentioned fish species, 96-h LC estimates ranged from 2.1 to 3.5 μg/L endosulfan sulfate. The 96-h LC estimates ranged from 0.8 to 2.1 μg/L endosulfan sulfate. Of all of the fish tested, the least killifish appeared to be the most sensitive to endosulfan sulfate exposure. The above-mentioned data were combined with previous acute toxicity data for endosulfan sulfate and freshwater fish for an effects analysis. The effects analysis estimated hazardous concentrations expected to exceed 5, 10, and 50% of the fish species' acute LC or LC values (HC, HC, and HC). The endosulfan sulfate freshwater-fish acute tests were also compared with the available freshwater-fish acute toxicity data for technical endosulfan. Technical endosulfan is a mixture of α- and β-endosulfan. The LCs had a wider range for technical endosulfan, and their distribution produced a lower HC than for endosulfan sulfate. The number of freshwater-fish LCs for endosulfan sulfate is much smaller than the number available for technical endosulfan, reflecting priorities in examining the toxicity of the parent compounds of pesticides. The toxicity test results and effects analyses provided acute effect values for endosulfan sulfate and freshwater fish that might be applied in future screening level ecologic risk assessments. The effects analyses also discussed several deficiencies in conventional methods for setting water-quality criteria and determining ecologic effects from acute toxicity tests. [ABSTRACT FROM AUTHOR]

Endosulfan is an insecticide–acaricide used in South Florida and is one of the remaining organochlorine insecticides registered under the Federal Insecticide Fungicide and Rodenticide Act by the U.S.EPA. The technical grade material consists of two isomers (α-, β-) and the main environmental metabolite in water, sediment and tissue is endosulfan sulfate through oxidation. A comprehensive probabilistic aquatic ecological risk assessment was conducted to determine the potential risks of existing exposures to endosulfan and endosulfan sulfate in freshwaters of South Florida based on historical data (1992–2007). The assessment included hazard assessment (Tier 1) followed by probabilistic risk assessment (Tier 2). Tier 1 compared actual measured concentrations in surface freshwaters of 47 sites in South Florida from historical data to U.S.EPA numerical water quality criteria. Based on results of Tier 1, Tier 2 focused on the acute and chronic risks of endosulfan at nine sites by comparing distributions of surface water exposure concentrations of endosulfan [i.e., for total endosulfan (summation of concentrations of α- and β-isomers plus the sulfate), α- plus β-endosulfan, and endosulfan sulfate (alone)] with distributions of species effects from laboratory toxicity data. In Tier 2 the distribution of total endosulfan in fish tissue (whole body) from South Florida freshwaters was also used to determine the probability of exceeding a distribution of whole body residues of endosulfan producing mortality (critical lethal residues). Tier 1 showed the majority of endosulfan water quality violations in South Florida were at locations S-178 followed by S-177 in the C-111 system (southeastern boundary of Everglades National Park (ENP)). Nine surface water sampling sites were chosen for Tier 2. Tier 2 showed the highest potentially affected fraction of toxicity values (>10%) by the estimated 90th centile exposure concentration (total endosulfan ) was at S-178. At all other freshwater sites there were <5% of the toxicity values exceeded. Potential chronic risk (9.2% for total endosulfan) was only found at S-178 and all other sites were <5%. Joint probability curves showed the higher probability of risk at S-178 than at S-177. The freshwater fish species which contain tissue concentrations of endosulfan (total) with the highest potential risk for lethal whole body tissue residues were marsh killifish, flagfish and mosquitofish. Based on existing surface water exposures and available aquatic toxicity data, there are potential risks of total endosulfan to freshwater organisms in South Florida. Although there are uncertainties, the presence of tissue concentrations of endosulfan in small demersal fish, is of ecological significance since these fish support higher trophic level species, such as wading birds. [ABSTRACT FROM AUTHOR]