Toxicity of Per- and polyfluoroalkyl substances in elutriates prepared with estuarine and freshwater sediments.

PFAS has a ubiquitous environmental occurrence, posing challenges to sediment management. To address data gaps concerning release of PFAS from sediment to the water column during dredged material aquatic placement or other sediment resuspension activity, we generated elutriates from PFAS-contaminated sediments. Sediments were obtained from both freshwater and estuarine environments, with a field-collected sediment representative of contaminated areas and a spiked sediment with concentrations exceeding levels frequently measured at contaminated sites.

Bioaccumulation in fish (Cyprinodon variegatus) during rejuvenations of a thin active cap over field-aged PCB contaminated sediment: The effect of clean versus contaminated ongoing influx.

Repeated addition of activated carbon (AC) via the water column was applied to rejuvenate sorption capacity of thin AC-amended sand caps placed over polychlorinated biphenyl- (PCB) contaminated marine bed sediment receiving ongoing input of sediment (contaminated or clean) in mesocosms. Bioaccumulation of PCBs in sheepshead minnows (Cyprinodon variegatus) from bed sediment was reduced by repeated application of rejuvenating AC when the ongoing input was contaminated. However, when the input sediment was clean, the novel AC addition increased fish uptake of bedded PCBs in the first 60-days of the 90-day experiments.

Quantitative thermodynamic exposure assessment of PCBs available to sandworms () in activated carbon remediated sediment during ongoing sediment deposition.

Marine mesoscale studies with sandworms () were conducted to isolate important processes governing the exposure and bioaccumulation of polychlorinated biphenyls (PCBs) at contaminated sediment sites. equilibrium sampling with silicone-coated jars, and passive sampling with low-density polyethylene (LDPE) were used to determine the performance of an activated carbon (AC) amendment remedy applied to the bed sediment. A quantitative thermodynamic exposure assessment ('QTEA') was performed, showing that PCB concentrations in polymers at equilibrium with the surficial sediment were suited to measure and assess the remedy effectiveness with regard to PCB bioaccumulation in worms.

Interlaboratory Study of Polyethylene and Polydimethylsiloxane Polymeric Samplers for Ex Situ Measurement of Freely Dissolved Hydrophobic Organic Compounds in Sediment Porewater.

We evaluated the precision and accuracy of multilaboratory measurements for determining freely dissolved concentrations (C ) of polycyclic aromatic hydrocarbons (PAHs) and polychlorinated biphenyls (PCBs) in sediment porewater using polydimethylsiloxane (PDMS) and low-density polyethylene (LDPE) polymeric samplers. Four laboratories exposed performance reference compound (PRC) preloaded polymers to actively mixed and static ex situ sediment for approximately 1 month; two laboratories had longer exposures (2 and 3 months). For C results, intralaboratory precision was high for single compounds (coefficient of variation 50% or less), and for most PAHs and PCBs interlaboratory variability was low (magnitude of difference was a factor of 2 or less) across polymers and exposure methods.

Acute Toxicity of Eight Aqueous Film-Forming Foams to 14 Aquatic Species.

Researchers have developed numerous per- and polyfluoroalkyl substances (PFAS)-free aqueous film-forming foam (AFFF) formulations to replace PFAS-containing AFFF used for fire suppression. As part of the Department of Defense's Strategic Environmental Research and Development Program (SERDP), we examined the direct lethal effects of seven PFAS-free AFFF and a PFAS-containing AFFF on 14 aquatic species using a series of lethal concentration (LC50) tests. We assessed the LC10, LC50, and LC90 values using log-logistic and logit analyses.

Interlaboratory Comparison of Three Sediment Bioaccumulation Tests.

Standard bioaccumulation tests are commonly conducted using Macoma nasuta (clam), and Alitta virens (polychaete) for marine tests, and Lumbriculus variegatus (an oligochaete) for freshwater tests. Because the interlaboratory variability associated with these tests is unknown, four experienced laboratories conducted standard 28-day bioaccumulation tests with the above species using sediments contaminated with polychlorinated biphenyls (PCBs) and polycyclic aromatic hydrocarbons (PAHs). Chemical analysis of tissue samples was performed by a single laboratory.

Passive-Sampler-Based Bioavailability Assessment of PCB Congeners Associated with Aroclor-Containing Paint Chips in the Presence of Sediment.

This is the first investigation of the bioavailability of PCBs associated with paint chips (PC) dispersed in sediment. Bioavailability of PCB-containing PC in sediment was measured using ex situ polyethylene passive samplers (PS) and compared to that of PCBs from field-collected sediments. PC were mixed in freshwater sediment from a relatively uncontaminated site with no known PCB contamination sources and from a contaminated site with non-paint PCB sources.

Effect of Activated Carbon in Thin Sand Caps Challenged with Ongoing PCB Inputs from Sediment Deposition: PCB Uptake in Clams (Mercenaria mercenaria) and Passive Samplers.

Ongoing inputs, in the form of sediment deposition along with associated dissolved contaminants, have challenged the assessment of cap performance at contaminated sediment sites. To address this issue, thin 2-3 cm layer sand caps amended with activated carbon (AC) were investigated for the remediation of polychlorinated biphenyl (PCB) contaminated marine sediments using 90-day mesocosms. All treatments were challenged with (1) ongoing clean or marker-PCB-spiked sediment inputs and (2) bioturbation.

Leaching Rate of Polychlorinated Biphenyls (PCBs) from Marine Paint Chips.

Polychlorinated biphenyls (PCBs) were added to certain marine vessel bottom paints as a plasticizer to improve the adhesion and durability of the paint. The most common PCB formulation used to amend such paints was Aroclor 1254. Fugitive Aroclor-containing paint chips generated from vessel maintenance and repair operations represent a potential source of PCB contamination to sediments.

Mode of action evaluation for reduced reproduction in Daphnia pulex exposed to the insensitive munition, 1-methyl-3-nitro-1-nitroguanidine (MeNQ).

The US Department of Defense (DOD) is developing insensitive munitions (IMs) that are resistant to unintended detonation to protect warfighters. To enable material life-cycle analysis for the IM, 1-methyl-3-nitro-1-nitroguanidine (MeNQ), ecotoxicological impacts assessment was required. A previous investigation of MeNQ exposures in Daphnia pulex revealed concentration-responsive decreases in reproduction relative to controls (0 mg/L) across a 174, 346, 709, 1385, and 2286 mg/L exposure range.

Environmental Characterization of Underwater Munitions Constituents at a Former Military Training Range.

As a result of military activities, unexploded ordnance and discarded military munitions are present in underwater environments, which has resulted in the release of munitions constituents including the high explosives 2,4,6-trinitrotoluene (TNT) and hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX), along with their primary degradation products, to the water column and adjacent sediments. The present study focused on the characterization of underwater exposure and concentrations of energetics such as TNT and RDX at the former Vieques Naval Training Range at Bahia Salina del Sur (Vieques, Puerto Rico, USA), a bay with documented high incidence of munitions. In situ passive sampling using polar organic chemical integrative samplers (POCIS) was used for the detection and quantification of constituents in water at target locations approximately 15 to 30 cm from 15 individual potentially leaking munitions, and also at 15 unbiased locations approximately evenly spaced across the Bay.

Streamlining Freshwater Bioaccumulation Bioassays: Letting the Worms Do the Hard Work.

When terminating sediment bioaccumulation tests with the oligochaete Lumbriculus variegatus, varying amounts of detrital material are retained along with the recovered worms after sieving, necessitating time-consuming, labor-intensive manual separation of worms from detritus prior to tissue residue analysis. A method to facilitate the worms self-extracting out of the detrital material into a column of gravel was developed, resulting in approximately 90% recovery test organisms (on a mass basis) at test termination. Following exposure to contaminated sediment, polychlorinated biphenyl tissue residues and residual sediment in the gut of self-extracted animals were not significantly different compared to worms recovered by manual separation followed by purging of gut contents.

Multi-species Aquatic Toxicity Assessment of 1-Methyl-3-Nitroguanidine (MeNQ).

The Army is replacing traditional munitions with insensitive munitions (IM) resistant to accidental detonation. The aquatic toxicity of 1-methyl-3-nitroguanidine (MeNQ), which is being assessed for potential use in IM formulations, remains largely untested. The present study fills a number of critical data gaps for MeNQ aquatic toxicity by evaluating effects across two vertebrate and five invertebrate species.

Methods for simultaneous determination of legacy and insensitive munition (IM) constituents in aqueous, soil/sediment, and tissue matrices.

Currently, no standard method exists for analyzing insensitive munition (IM) compounds in environmental matrices, with or without concurrent legacy munition compounds, resulting in potentially inaccurate determinations. The primary objective of this work was to develop new methods of extraction, pre-concentration, and analytical separation/quantitation of 17 legacy munition compounds along with several additional IM compounds, IM breakdown products, and other munition compounds that are not currently included in U. S.

Evaluation of dredged sediment for aquatic placement: interpreting contaminant bioaccumulation.

The potential bioaccumulation of sediment-associated contaminants is one of the primary concerns associated with the aquatic placement of dredged sediment. Laboratory bioaccumulation tests with representative infaunal organisms exposed to dredged sediment and reference sediment are used to assess the potential for contaminant-related bioaccumulation impacts. Dredged sediment testing and evaluation guidance provides statistical inferences and numerous assessment factors (e.

Comparative Toxicological Evaluation of UV-Degraded versus Parent-Insensitive Munition Compound 1-Methyl-3-Nitroguanidine in Fathead Minnow.

The US Army is replacing traditional munitions with insensitive munitions resistant to accidental detonation. Although the parent insensitive munition compound nitroguanidine (NQ) is generally not acutely toxic at concentrations >1000 mg/L in aquatic exposures, products formed by intensive ultraviolet (UV) degradation resulted in multiple-order of magnitude increases in toxicity. A methylated congener of NQ, 1-methyl-3-nitroguanidine (MeNQ), is also being assessed for potential use in insensitive munition explosive formulations; therefore, the present study investigated the hazard of parent versus UV-degraded MeNQ using fathead minnows (Pimephales promelas).

Release of Munitions Constituents in Aquatic Environments Under Realistic Scenarios and Validation of Polar Organic Chemical Integrative Samplers for Monitoring.

Munitions constituents (MC) may be released into aquatic environments as a result of underwater military munitions (UWMM) corrosion and breach. The present study investigated the release of 2,4,6-trinitrotoluene (TNT) and hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) from Composition B fragments under 2 realistic exposure scenarios in a large flume with flow set at 15 cm/s: the first represented the release of MC from fully exposed Composition B, and the second represented release through a small hole, simulating a breached munition. Release of MC through a small hole was approximately 10 times lower than from exposed Composition B, demonstrating the strong influence of exposure to flow on release.

Bioaccumulation in Functionally Different Species: Ongoing Input of PCBs with Sediment Deposition to Activated Carbon Remediated Bed Sediments.

Activated carbon-amended bed sediments reduced total polychlorinated biphenyl (PCB) accumulation in 3 functionally different marine species, sandworms (Alitta virens), hard clams (Mercenaria mercenaria), and sheepshead minnows (Cyprinodon variegatus), during both clean and contaminated ongoing sediment inputs. Mesocosm experiments were conducted for 90 d to evaluate native, field-aged bed sediment PCBs, and ongoing input PCBs added 3 times a week. Simulated in situ remediation applied an activated carbon dose equal to the native organic carbon content that was premixed into the bed sediment for 1 mo.

Molecular Evaluation of Impacted Reproductive Physiology in Fathead Minnow Testes Provides Mechanistic Insights into Insensitive Munitions Toxicology.

Previous toxicological investigations of the insensitive munition (IM), 3-nitro-1,2,4-triazol-5-one (NTO), demonstrated histopathological and physiological impacts in mammalian testes. The implications of these findings for fish was unknown, therefore we investigated the effects of chronic (21 day) exposures to NTO and an NTO-containing IM formulation called IMX-101 (composed of 2,4-dinitroanisole (DNAN), nitroguanidine (NQ), and NTO) in adult male fathead minnows to assess if impacts on testes were conserved. The NTO exposure caused no significant mortality through the maximum exposure concentration (720 mg/L, measured), however NTO elicited testicular impacts causing significant asynchrony in spermatogenesis and necrosis in secondary spermatocytes at the two highest exposure concentrations (383 mg/L and 720 mg/L) and testicular degeneration at the highest exposure.

Can Tenax Extraction Be Used as a Surrogate Exposure Metric for Laboratory-Based Bioaccumulation Tests Using Marine Sediments?

The Tenax technique was used as an alternative exposure metric to assess the bioavailability of polychlorinated biphenyls (PCBs) from contaminated marine sediments. The sediments used were collected from 2 Superfund sites, New Bedford Harbor (MA, USA) and Gould Island (RI, USA). No sieving was conducted for either sediment after arrival, and sediments were stored in stainless steel drums at 2.

Sensitivity of the Marine Calanoid Copepod Pseudodiaptomus pelagicus to Copper, Phenanthrene, and Ammonia.

There are limited acute toxicity test methods for native North American marine species that are considered zooplankton for their entire life cycle. Examples of standardized marine zooplankton methods include mussel, bivalve, and echinoderm development tests that use a relatively short-lived planktonic larval stage, chronic life-cycle toxicity tests using epibenthic copepods, and a 24-h Acartia tonsa copepod test method. The objectives of the present study were to: 1) develop and evaluate a novel, 48-h acute toxicity test method using the marine North American copepod Pseudodiaptomus pelagicus that is planktonic for its entire life cycle, and 2) determine the sensitivity of P.

Subchronic, chronic, lethal and sublethal toxicity of insensitive munitions mixture formulations relative to individual constituents in Hyalella azteca.

Insensitive munitions (IMs) are replacing conventional munitions, improving safety from unintended detonation. IMs are deployed in mixture formulations but little is known about their mixture toxicology. We characterized mixture effects of the IM formulations IMX-101 (mixture of 2,4-dinitroanisole [DNAN], 3-nitro-1,2,4-triazol-5-one [NTO], and nitroguanidine [NQ]) and IMX-104 (DNAN, NTO, and hexahydro-1,3,5-trinitro-1,3,5-triazine [RDX]) in subchronic (10 d) and chronic (35 d) water-only tests in Hyalella azteca assessing impacts on survival, growth and reproduction.

Field validation of POCIS for monitoring at underwater munitions sites.

The present study evaluated polar organic chemical integrative samplers (POCIS) for quantification of conventional munitions constituents, including trinitrotoluene (TNT), aminodinitrotoluenes, diaminonitrotoluenes, dinitrotoluene, and hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) in a field setting. The POCIS were deployed at varying distances from the commonly used explosive formulation composition B (39.5% TNT, 59.