Prevalence of selected UV filter compounds in Biscayne National Park.

This research was carried out in order to assess a baseline occurrence in Biscayne National Park, Florida, of four organic contaminants: the UV filters oxybenzone, dioxybenzone, and benzophenone, as well as the topical pain reliever benzocaine. A total of 35 samples were taken from five locations within the park, four near barrier islands, and one at a coral reef. Analyses were carried out using liquid chromatography coupled to high-resolution mass spectrometry. Oxybenzone was detected in 26% of samples from the park at concentrations up to 31 ng/L. Benzophenone was detected in 49% of samples from the park at concentrations up to 131 ng/L. Benzocaine and dioxybenzone were not detected in any of the samples.

Nontargeted Analysis Study Reporting Tool: A Framework to Improve Research Transparency and Reproducibility.

Non-targeted analysis (NTA) workflows using mass spectrometry are gaining popularity in many disciplines, but universally accepted reporting standards are nonexistent. Current guidance addresses limited elements of NTA reporting-most notably, identification confidence-and is insufficient to ensure scientific transparency and reproducibility given the complexity of these methods. This lack of reporting standards hinders researchers' development of thorough study protocols and reviewers' ability to efficiently assess grant and manuscript submissions. To overcome these challenges, we developed the NTA Study Reporting Tool (SRT), an easy-to-use, interdisciplinary framework for comprehensive NTA methods and results reporting. Eleven NTA practitioners reviewed eight published articles covering environmental, food, and health-based exposomic applications with the SRT. Overall, our analysis demonstrated that the SRT provides a valid structure to guide study design and manuscript writing, as well as to evaluate NTA reporting quality. Scores self-assigned by authors fell within the range of peer-reviewer scores, indicating that SRT use for self-evaluation will strengthen reporting practices. The results also highlighted NTA reporting areas that need immediate improvement, such as analytical sequence and quality assurance/quality control information. Although scores intentionally do not correspond to data/results quality, widespread implementation of the SRT could improve study design and standardize reporting practices, ultimately leading to broader use and acceptance of NTA data.

An Introduction to the Benchmarking and Publications for Non-Targeted Analysis Working Group.

Non-targeted analysis (NTA) encompasses a rapidly evolving set of mass spectrometry techniques aimed at characterizing the chemical composition of complex samples, identifying unknown compounds, and/or classifying samples, without prior knowledge regarding the chemical content of the samples. Recent advances in NTA are the result of improved and more accessible instrumentation for data generation and analysis tools for data evaluation and interpretation. As researchers continue to develop NTA approaches in various scientific fields, there is a growing need to identify, disseminate, and adopt community-wide method reporting guidelines. In 2018, NTA researchers formed the Benchmarking and Publications for Non-Targeted Analysis Working Group (BP4NTA) to address this need. Consisting of participants from around the world and representing fields ranging from environmental science and food chemistry to 'omics and toxicology, BP4NTA provides resources addressing a variety of challenges associated with NTA. Thus far, BP4NTA group members have aimed to establish a consensus on NTA-related terms and concepts and to create consistency in reporting practices by providing resources on a public Web site, including consensus definitions, reference content, and lists of available tools. Moving forward, BP4NTA will provide a setting for NTA researchers to continue discussing emerging challenges and contribute to additional harmonization efforts.

Application of an Improved Chloroform-Free Lipid Extraction Method to Staghorn Coral (Acropora cervicornis) Lipidomics Assessments.

Lipids are excellent biomarkers for assessing coral stress, although staghorn coral data (Acropora cervicornis) is lacking. Lipid extraction is the most critical step in lipidomic assessments, usually performed using carcinogenic solvents. Efficient alternative using less toxic methods, such as the BUME method using butanol and methanol as extraction solvents, have not been applied to coral lipidomics evaluations. Thus, we aimed to develop a lipidomic approach to identify important coral health biomarkers by comparing different solvent mixtures in staghorn corals. Total lipid extraction was equivalent for both tested methods, but due to its efficiency in extracting polar lipids, the BUME method was chosen. It was then applied to different coral masses (0.33-1.00 g), resulting in non-significant differences concerning number of lipid classes and compounds. Therefore, this method can be successfully applied to coral assessments in a climate change context, with the added benefit of low sample masses, lessening coral sampling impacts.

Simulation of Deepwater Horizon oil plume reveals substrate specialization within a complex community of hydrocarbon degraders.

The Deepwater Horizon (DWH) accident released an estimated 4.1 million barrels of oil and 1010 mol of natural gas into the Gulf of Mexico, forming deep-sea plumes of dispersed oil droplets and dissolved gases that were largely degraded by bacteria. During the course of this 3-mo disaster a series of different bacterial taxa were enriched in succession within deep plumes, but the metabolic capabilities of the different populations that controlled degradation rates of crude oil components are poorly understood. We experimentally reproduced dispersed plumes of fine oil droplets in Gulf of Mexico seawater and successfully replicated the enrichment and succession of the principal oil-degrading bacteria observed during the DWH event. We recovered near-complete genomes, whose phylogeny matched those of the principal biodegrading taxa observed in the field, including the DWH Oceanospirillales (now identified as a Bermanella species), multiple species of Colwellia, Cycloclasticus, and other members of Gammaproteobacteria, Flavobacteria, and Rhodobacteria. Metabolic pathway analysis, combined with hydrocarbon compositional analysis and species abundance data, revealed substrate specialization that explained the successional pattern of oil-degrading bacteria. The fastest-growing bacteria used short-chain alkanes. The analyses also uncovered potential cooperative and competitive relationships, even among close relatives. We conclude that patterns of microbial succession following deep ocean hydrocarbon blowouts are predictable and primarily driven by the availability of liquid petroleum hydrocarbons rather than natural gases.

Assessment of Sucralose, Caffeine and Acetaminophen as Anthropogenic Tracers in Aquatic Systems Across Florida.

Sucralose is one of the most popular artificial sweeteners worldwide. Due to its high stability, persistence and low removal efficiency in wastewater treatment plants, sucralose has been used as an indicator of wastewater intrusion into aquatic systems. However, its stability has also been a reason for discussion whether sucralose's presence in surface water could indicate a recent anthropogenic input. Caffeine and acetaminophen have been considered as tracers in human impacted aquatic ecosystems and potentially good indicators of recent anthropogenic inputs into the environment due to their short half-lives in water. Here, a novel, high throughput and sensitive method based on online SPE-LC-HRMS for the determination of caffeine, sucralose and acetaminophen was developed and validated for both fresh and seawater samples and applied to environmental water samples to evaluate the efficiency of these compounds as tracers of aquatic pollution. Caffeine and sucralose were detected in > 70% of samples, while acetaminophen was only detected in 3% of samples above the MDL, demonstrating its limited environmental applicability.

Partitioning of PAHs between Crude Oil Microdroplets, Water, and Copepod Biomass in Oil-in-Seawater Dispersions of Different Crude Oils.

The impact of oil microdroplets on the partitioning of polycyclic aromatic hydrocarbons (PAHs) between water and marine zooplankton was evaluated. The experimental approach allowed direct comparison of crude oil dispersions (containing both micro-oil droplets and water-soluble fraction; WSF) with the corresponding WSF (without oil droplets). Dispersion concentration and oil type have an impact on the PAH composition of WSFs and therefore affect dispersion bioavailability. Higher T-PAH body residues were observed in copepods treated with dispersions compared to the corresponding WSFs. PAHs with log Kow 3-4.5 displayed comparable accumulation factors between treatments; however, accumulation factors for less soluble PAHs (log Kow = 4.5-6) were higher for the WSF than for the dispersions, suggesting low bioavailability for components contained in oil droplets. The higher PAH body residue in dispersion exposures is assumed to result mainly from copepods grazing on oil droplets, which offers an alternative uptake route to passive diffusion. To a large degree this route is controlled by the filtration rates of the copepods, which may be inversely related to droplet concentration.

Using Polydimethylsiloxane (PDMS) Pellets to Create an Absorption Model for the Determination of Equilibrium Concentrations of Dissolved Contaminants in the Aquatic Environment.

Polydimethylsiloxane (PDMS) is a polymer material with high absorptive properties increasingly used as a passive environmental sampler for persistent organic compounds. However, the partitioning behavior of hydrophobic chemicals to PDMS remains largely unknown. Organochlorines (OCs) and polycyclic aromatic hydrocarbons (PAHs) are ubiquitous environmental pollutants of great concern due to their persistence and potential toxic effects on humans and animals. In this study, the affinity of 20 OCs and 25 PAHs for commercially available PDMS pellets was determined to assess their effectiveness as passive samplers. Experiments were conducted to estimate the absorption rates (k) and equilibrium concentrations, demonstrating that 16 OCs and 21 PAHs were efficiently absorbed by PDMS, while others remained dissolved in water. A model has been proposed to predict dissolved concentrations in water based on the Kow of the compound, suggesting that PDMS is a suitable passive sampler for these compounds.

Analysis of Photoirradiated Water Accommodated Fractions of Crude Oils Using Tandem TIMS and FT-ICR MS.

For the first time, trapped ion mobility spectrometry (TIMS) in tandem with Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) is applied to the analysis of the low energy water accommodated fraction (WAF) of a crude oil as a function of the exposure to light. The TIMS-FT-ICR MS analysis provided, in addition to the heteroatom series identification, new insights into the WAF isomeric complexity (e.g., [m/z; chemical formula; collision cross section] data sets) for a better evaluation of the degree of chemical and structural photoinduced transformations. Inspection of the [m/z; chemical formula; collision cross section] data sets shows that the WAF composition changes as a function of the exposure to light in the first 115 h by initial photosolubilization of HC components and their photo-oxidation up to O4-5 of mainly high double bond equivalence species (DBE > 9). The addition of high resolution TIMS (resolving power of 90-220) to ultrahigh resolution FT-ICR MS (resolving power over 400k) permitted the identification of a larger number of molecular components in a single analysis (e.g., over 47k using TIMS-MS compared to 12k by MS alone), with instances of over 6-fold increase in the number of molecular features per nominal mass due to the WAF isomeric complexity. This work represents a stepping stone toward a better understanding of the WAF components and highlights the need for better experimental and theoretical approaches to characterize the WAF structural diversity.

Rapid ultra-trace analysis of sucralose in multiple-origin aqueous samples by online solid-phase extraction coupled to high-resolution mass spectrometry.

Because of its widespread consumption and its persistence during wastewater treatment, the artificial sweetener sucralose has gained considerable interest as a proxy to detect wastewater intrusion into usable water resources. The molecular resilience of this compound dictates that coastal and oceanic waters are the final recipient of this compound with unknown effects on ecosystems. Furthermore, no suitable methodologies have been reported for routine, ultra-trace detection of sucralose in seawater as the sensitivity of traditional liquid chromatography-tandem mass spectrometry (LC-MS/MS) analysis is limited by a low yield of product ions upon collision-induced dissociation (CID). In this work, we report the development and field test of an alternative analysis tool for sucralose in environmental waters, with enough sensitivity for the proper quantitation and confirmation of this analyte in seawater. The methodology is based on automated online solid-phase extraction (SPE) and high-resolving-power orbitrap MS detection. Operating in full scan (no CID), detection of the unique isotopic pattern (100:96:31 for [M-H](-), [M-H+2](-), and [M-H+4](-), respectively) was used for ultra-trace quantitation and analyte identification. The method offers fast analysis (14 min per run) and low sample consumption (10 mL per sample) with method detection and confirmation limits (MDLs and MCLs) of 1.4 and 5.7 ng/L in seawater, respectively. The methodology involves low operating costs due to virtually no sample preparation steps or consumables. As an application example, samples were collected from 17 oceanic and estuarine sites in Broward County, FL, with varying salinity (6-40 PSU). Samples included the ocean outfall of the Southern Regional Wastewater Treatment Plant (WWTP) that serves Hollywood, FL. Sucralose was detected above MCL in 78% of the samples at concentrations ranging from 8 to 148 ng/L, with the exception of the WWTP ocean outfall (at pipe end, 28 m below the surface) where the measured concentration was 8418 ± 3813 ng/L. These results demonstrate the applicability of this monitoring tool for the trace-level detection of this wastewater marker in very dilute environmental waters.

Oxidation of microcystin-LR by ferrate(VI): kinetics, degradation pathways, and toxicity assessments.

The presence of the potent cyanotoxin, microcystin-LR (MC-LR), in drinking water sources poses a serious risk to public health. The kinetics of the reactivity of ferrate(VI) (Fe(VI)O4(2-), Fe(VI)) with MC-LR and model compounds (sorbic acid, sorbic alcohol, and glycine anhydride) are reported over a range of solution pH. The degradation of MC-LR followed second-order kinetics with the bimolecular rate constant (kMCLR+Fe(VI)) decreasing from 1.3 ± 0.1 × 10(2) M(-1) s(-1) at pH 7.5 to 8.1 ± 0.08 M(-1) s(-1) at pH 10.0. The specific rate constants for the individual ferrate species were determined and compared with a number of common chemical oxidants employed for water treatment. Detailed product studies using liquid chromatography-mass spectrometry/mass spectrometry (LC-MS/MS) indicated the oxidized products (OPs) were primarily the result of hydroxylation of the aromatic ring, double bond of the methyldehydroalanine (Mdha) amino acid residue, and diene functionality. Products studies also indicate fragmentation of the cyclic MC-LR structure occurs under the reaction conditions. The analysis of protein phosphatase (PP1) activity suggested that the degradation byproducts of MC-LR did not possess significant biological toxicity. Fe(VI) was effective for the degradation MC-LR in water containing carbonate ions and fulvic acid (FA) and in lake water samples, but higher Fe(VI) dosages would be needed to completely remove MC-LR in lake water compared to deionized water.

Fully automated trace level determination of parent and alkylated PAHs in environmental waters by online SPE-LC-APPI-MS/MS.

Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous compounds that enter the environment from natural and anthropogenic sources, often used as markers to determine the extent, fate, and potential effects on natural resources after a crude oil accidental release. Gas chromatography-mass spectrometry (GC-MS) after liquid-liquid extraction (LLE+GC-MS) has been extensively used to isolate and quantify both parent and alkylated PAHs. However, it requires labor-intensive extraction and cleanup steps and generates large amounts of toxic solvent waste. Therefore, there is a clear need for greener, faster techniques with enough reproducibility and sensitivity to quantify many PAHs in large numbers of water samples in a short period of time. This study combines online solid-phase extraction followed by liquid chromatography (LC) separation with dopant-assisted atmospheric pressure photoionization (APPI) and tandem MS detection, to provide a one-step protocol that detects PAHs at low nanograms per liter with almost no sample preparation and with a significantly lower consumption of toxic halogenated solvents. Water samples were amended with methanol, fortified with isotopically labeled PAHs, and loaded onto an online SPE column, using a large-volume sample loop with an auxiliary LC pump for sample preconcentration and salt removal. The loaded SPE column was connected to an UPLC pump and analytes were backflushed to a Thermo Hypersil Green PAH analytical column where a 20-min gradient separation was performed at a variable flow rate. Detection was performed by a triple-quadrupole MS equipped with a gas-phase dopant delivery system, using 1.50 mL of chlorobenzene dopant per run. In contrast, LLE+GC-MS typically use 150 mL of organic solvents per sample, and methylene chloride is preferred because of its low boiling point. However, this solvent has a higher environmental persistence than chlorobenzene and is considered a carcinogen. The automated system is capable of performing injection, online SPE, inorganic species removal, LC separation, and MS/MS detection in 28 min. Selective reaction monitoring was used to detect 28 parent PAHs and 15 families of alkylated PAHs. The methodology is comparable to traditional GC-MS and was tested with surface seawater, rainwater runoff, and a wastewater treatment plant effluent. Positive detections above reporting limits are described. The virtual absence of sample preparation could be particularly advantageous for real-time monitoring of discharge events that introduce PAHs into environmental compartments, such as accidental releases of petroleum derivates and other human-related events. This work covers optimization of APPI detection and SPE extraction efficiency, a comparison with LLE+GC-MS in terms of sensitivity and chromatographic resolution, and examples of environmental applications.

Photodegradation of sulfonamide antibiotics in simulated and natural sunlight: implications for their environmental fate.

The photochemical fate of seven sulfonamides was investigated in matrices representative of natural water bodies under various light sources. Fundamental photolysis parameters such as molar absorption coefficient, quantum yield (QY) and first-order rate constants were determined. The photolysis decay rate was dependent on the protonation state of the molecule, pH of the water sample and dissolved organic matter. Natural organic matter was the most significant factor in the indirect photolysis of sulfonamides. Half-lives were in the range of minutes at 254 nm to days under natural sunlight. Under natural sunlight, all sulfonamides showed higher removal rates in natural waters implying that indirect photolysis is the predominant mechanism.

Unraveling the chemical fingerprint of the Miami River sources: Insights from high-resolution mass spectrometry and nontarget analysis.

This study investigated the chemical composition of waters in the heavily urbanized and historically polluted Miami River, Florida. The goal was to assess the different water sources and anthropogenic influence in this managed area using nontarget analysis (NTA) combined with high-resolution mass spectrometry (HRMS). Surface water samples were collected from 10 sites during five sampling events in the wet season of 2021 and 2022. The HRMS data was processed using Compound Discoverer™ version 3.3, and the results were analyzed using techniques including Principal Component Analysis and Kendrick Mass Defect plots. Results showed a gradient change in the chemical composition from the Everglades to Biscayne Bay endmembers. The Seybold Canal, an adjacent canal, was consistently identified as a unique source of contaminants, contributing its own specific set of tracers. Increased presence and intensity of organic contaminants along the waterway was observed, indicating significant anthropogenic influence in the area. The NTA and post-processing were evaluated for reproducibility, demonstrating robustness with a 71.2% average reproducibility for compounds detected in 3 out of 5 sampling trips. A detection frequency of 80% (4 out of 5) was the set criterion for detected compounds suggested as tracers. To prioritize samples, hierarchical cluster analysis was employed, and potential tracers for each water source were determined. Tracers included natural products and agricultural herbicides and insecticides for the Everglades, anthropogenic contaminants for the Seybold Canal, and a lack of unique tracers for Biscayne Bay. Additionally, urban-influenced contaminants such as flame retardants, insect repellents, pharmaceuticals, and non-agricultural herbicides were identified along the river. This study highlights the impact of human activities on the Miami River and demonstrates the effectiveness of NTA in differentiating and tracking water sources. The results emphasize the importance of reproducibility in NTA and provide guidance on implementing monitoring strategies by prioritizing samples based on chemical compositions.

Innovative non-targeted screening approach using High-resolution mass spectrometry for the screening of organic chemicals and identification of specific tracers of soil and dust exposure in children.

Environmental contamination through direct contact, ingestion and inhalation are common routes of children's exposure to chemicals, in which through indoor and outdoor activities associated with common hand-to-mouth, touching objects, and behavioral tendencies, children can be susceptible and vulnerable to organic contaminants in the environment. The objectives of this study were the screening and identification of a wide range of organic contaminants in indoor dust, soil, food, drinking water, and urine matrices (N = 439), prioritizing chemicals to assess children's environmental exposure, and selection of unique tracers of soil and dust ingestion in young children by non-targeted analysis (NTA) using Q-Exactive Orbitrap followed data processing by the Compound Discoverer (v3.3, SP2). Chemical features were first prioritized based on their predominant abundance (peak area>500,000), detection frequency (in >50% of the samples), available information on their uses and potential toxicological effects. Specific tracers of soil and dust exposure in children were selected in this study including Tripropyl citrate and 4-Dodecylbenzenesulfonic acid. The criteria for selection of the tracers were based on their higher abundance, detection frequency, unique functional uses, measurable amounts in urine (suitable biomarker), and with information on gastrointestinal absorption, metabolism, and excretion, and were further confirmed by authentic standards. We are proposing for the first time suitable unique tracers for dust ingestion by children.

Detection and occurrence of microconstituents in reclaimed water used for irrigation--a potentially overlooked source.

An online SPE-HPLC-HESI-MS/MS method and an online SPE-HPLC-APPI-MS/MS method were developed to analyze 72 microconstituents in reclaimed water. In this study, 55 reclaimed water samples were collected from the sprinkler system for a year-long period at Florida International University Biscayne Bay Campus, where reclaimed water was reused for daily irrigation. Analysis results showed that several analytes were continuously detected in all reclaimed water samples and others will show rather transient signal increases. Coprostanol, bisphenol A, and DEET's maximum concentration exceeded 10,000 ng/L. The four most frequently detected compounds were diphenhydramine (100%), DEET (98%), atenolol (98%) and carbamazepine (96%).

Online solid-phase extraction-liquid chromatography-electrospray-tandem mass spectrometry determination of multiple classes of antibiotics in environmental and treated waters.

An online solid-phase extraction and liquid chromatography in combination with tandem mass spectrometry method was developed for the simultaneous determination of 31 antibiotics in drinking water, surface water and reclaimed waters. The developed methodology requires small sample volume (10 mL), very little sample preparation and total sample run time was 20 min. An Ion Max API heated electrospray ionization source operated in the positive mode with two selected reaction monitoring transitions was used per antibiotic for positive identity and quantification performed by the internal standard approach, to correct for matrix effects and any losses in the online extraction step. Method detection limits were in the range of 1.2-9.7, 2.2-15, 5.5-63 ng/L in drinking water, surface water and reclaimed waters, respectively. The method accuracy in matrix spiked samples ranged from 50-150% for the studied antibiotics. The applicability of the method was demonstrated using various environmental and reclaimed water matrices. Erythromycin was detected in more than 85% of the samples in all matrices (28-414, n.d.-199, n.d.-66 ng/L in reclaimed, river and drinking waters respectively). The other frequently detected antibiotics in reclaimed waters were nalidixic acid, clarithromycin, azithromycin, trimethoprim, and sulfamethoxazole.

High sensitivity liquid chromatography tandem mass spectrometric methods for the analysis of dioctyl sulfosuccinate in different stages of an oil spill response monitoring effort.

After the incident on the Deepwater Horizon platform, around 1.8 million gallons of dispersants were used in the field as part of the response cleanup efforts. This study describes an online solid phase extraction-liquid chromatography (LC)-tandem mass spectrometry (MS/MS) method and a direct-injection LC-MS/MS method for the analysis of dioctyl sulfosuccinate (DOSS; a component in Corexit® EC9500A) in seawater at trace levels, with method detection limits (MDLs) of 7.0 and 440 ng/L and run times of 7 and 17 min, respectively. Stability and preservation studies demonstrated that samples at 4.7 µg/L could be preserved for up to 150 days without loss of analyte when stored with 33 % acetonitrile in glass containers. Data acquisition was performed by heated electrospray ionization (ESI) MS/MS operating in negative mode. Methods were validated in terms of percent recovery in fortified blank and matrix samples and to evaluate carryover. A simple modification of the direct-injection method allowed quantitation of 2-butoxyethanol, a dispersant component specific to the Corexit® EC9527A formulation. This method was used to simultaneously quantify DOSS and 2-butoxyethanol in two Corexit® formulations and extracts from an MC-252 source oil standard. MDLs in crude oil were 0.723 and 4.46 mg/kg, respectively, with recoveries of (92 ± 9)% for DOSS and (104 ± 8)% for 2-butoxyethanol. Detection of both indicators was achieved in a single chromatographic run by ESI-MS/MS operating sequentially in positive and negative mode. Corexit® EC9500A and Corexit® EC9527A were found to contain (21 ± 2)% and (22 ± 5)% w/w DOSS and 0 and (37 ± 2)% w/w 2-butoxyethanol, respectively.

Outcompeting GC for the detection of legacy chlorinated pesticides: online-SPE UPLC APCI/MSMS detection of endosulfans at part per trillion levels.

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 ß-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 ß-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.

Concentration of trace metals in sediments and soils from protected lands in south Florida: background levels and risk evaluation.

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.