Investigation of polar organic chemical integrative sampler (POCIS) flow rate dependence for munition constituents in underwater environments

Comparison of chemical contaminant measurements using CLAM, POCIS, and silicone band samplers in estuarine mesocosms

Discrete water samples represent a snapshot of conditions at a particular moment in time and may not represent a true chemical exposure caused by changes in chemical input, tide, flow, and precipitation. Sampling technologies have been engineered to better estimate time-weighted concentrations. In this study, we consider the utility of three integrative sampling platforms: polar organic chemical integrative sampler (POCIS), silicone bands (SBs), and continuous, low-level aquatic monitoring (CLAM). This experiment used simulated southeastern salt marsh mesocosm systems to evaluate the response of passive (POCIS, SBs) and active sampling (CLAM) devices along with discrete sampling methodologies. Three systems were assigned to each passive sampler technology. Initially, all tanks were dosed at nominal (low) bifenthrin, pyrene, and triclosan concentrations of 0.02, 2.2, and 100 µg/L, respectively. After 28 days, the same treatment systems were dosed a second time (high) with bifenthrin, pyrene, and triclosan at 0.08, 8.8, and 200 µg/L, respectively. For passive samplers, estimated water concentrations were calculated using published or laboratory-derived sampling rate constants. Chemical residues measured from SBs resulted in high/low ratios of approximately 2x, approximately 3x, and 1x for bifenthrin, pyrene, and triclosan. A similar pattern was calculated using data from POCIS samples (~4x, ~3x, ~1x). Results from this study will help users of CLAM, POCIS, and SB data to better evaluate water concentrations from sampling events that are integrated across time. Integr Environ Assess Manag 2024;20:1384-1395. © 2024 The Authors. Integrated Environmental Assessment and Management published by Wiley Periodicals LLC on behalf of Society of Environmental Toxicology & Chemistry (SETAC).

Long-Term Trends for Blue Mussels from the German Environmental Specimen Bank Show First Evidence of Munition Contaminants Uptake

Submerged munitions are present in marine waters across the globe. They contain energetic compounds (ECs), such as TNT and metabolites thereof, which are considered carcinogenic, exhibit toxic effects in marine organisms, and may affect human health. The aim of this study was to investigate the occurrence of ECs and their trends in blue mussels from the annual collections of the German Environmental Specimen Bank sampled over the last 30 years at three different locations along the coastline of the Baltic and North Sea. Samples were analyzed by GC-MS/MS for 1,3-dinitrobenzene (1,3-DNB), 2,4-dinitrotoluene (2,4-DNT), 2,4,6-trinitrotoluene (TNT), 2-amino-4,6-dinitrotoluene (2-ADNT), and 4-amino-2,6-dinitrotoluene (4-ADNT). The first signals indicating trace levels of 1,3-DNB were observed in samples from 1999 and 2000. ECs were also found below the limit of detection (LoD) in subsequent years. From 2012 onwards, signals just above the LoD were detected. The highest signal intensities of 2-ADNT and 4-ADNT, just below the LoQ (0.14 ng/g d.w. and 0.17 ng/g d.w., respectively), were measured in 2019 and 2020. This study clearly shows that corroding submerged munitions are gradually releasing ECs into the waters that can be detected in randomly sampled blue mussels, even though the concentrations measured are still in the non-quantifiable trace 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. For comparison with POCIS-derived concentrations, grab samples were taken at the POCIS target locations. The POCIS-derived and averaged grab samples agreed within a factor of 3. When detected, munitions constituent concentrations (primarily TNT and RDX) were observed at ultratrace concentrations (as low as 4 ng/L for RDX), except 30 cm from one General Purpose bomb where the TNT concentration was 5.3 µg/L, indicating that low-level contamination exists at Bahia Salina del Sur on a very localized scale despite the relatively high density of munitions, similar to previously reported results for other munitions sites around the world. Sediment and porewater sampled at 4 stations where munitions constituents were detected in the water column had concentrations below detection (approximately 5 µg/kg and 5 ng/L, respectively), suggesting that the sediment was not a sink for these constituents at those locations. Environ Toxicol Chem 2022;41:275-286. © 2021 SETAC. This article has been contributed to by US Government employees and their work is in the public domain in the USA.

Experimental Estimation of 44 Pharmaceutical Polar Organic Chemical Integrative Sampler Sampling Rates in an Artificial River under Various Flow Conditions

The present study pertains to a polar organic chemical integrative sampler (POCIS) laboratory calibration to estimate the sampling rates for 44 pharmaceuticals featuring a wide range of polarity (-0.6 < octanol/water partition coefficient [log K_OW ] < 5.4). The calibration was performed at 16.0 ± 1.5 °C for 4 water flow velocities (0, 2-3, 6-7, and 20 cm/s) in both a tank (for calibration at 0 cm/s) and a laboratory-scale artificial river filled with 200 and 500 L of tap water spiked with 0.3 µg/L of each compound, respectively. Twelve new sampling rates and 26 sampling rates already available in the literature were determined, whereas the sampling rates for 6 pharmaceuticals could not be determined due to nonlinearity or poor accumulation in POCIS. An increase in the sampling rate value with flow velocity was observed, which is consistent with a decrease in the effective thickness of the water boundary layer at the POCIS membrane surface. Environ Toxicol Chem 2020;39:1186-1195. © 2020 SETAC.

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. The rate of release of MC into the flume was similar to that previously reported in a related field experiment, but a similar mass loss resulted in MC concentration in the field >300 times lower, likely by the dilution effect of hydrodynamic transport. The present study corroborates previous findings of release of MC at UWMM sites resulting in concentrations below the toxicity threshold to most species. In the flume water, MC was quantified using frequent grab sampling and polar organic chemical integrative samplers (POCIS). For TNT, POCIS-estimated time-weighted average concentrations were up to 40% higher than those derived from grab samples, whereas for RDX differences were 6% or less, demonstrating that POCIS provide reliable temporal integration of changing environmental concentrations for common MC. Environ Toxicol Chem 2019;38:2383-2391. Published 2019 Wiley Periodicals Inc. on behalf of SETAC. This article is a US government work and, as such, is in the public domain in the United States of America.

Monitoring of explosive residues in lake-bottom water using Polar Organic Chemical Integrative Sampler (POCIS) and chemcatcher: determination of transfer kinetics through Polyethersulfone (PES) membrane is crucial

Between 1920 and 1967, approximatively 8200 tons of ammunition waste were dumped into some Swiss lakes. This study is part of the extensive historical and technical investigations performed since 1995 by Swiss authorities to provide a risk assessment. It aims to assess whether explosive monitoring by passive sampling is feasible in lake-bottom waters. Polar organic chemical integrative sampler (POCIS) and Chemcatcher were first calibrated in a channel system supplied with continuously refreshed lake water spiked with two nitroamines (HMX and RDX), one nitrate ester (PETN), and six nitroaromatics (including TNT). Exposure parameters were kept as close as possible to the ones expected at the bottom of two affected lakes. Sixteen POCIS and Chemcatcher were simultaneously deployed in the channel system and removed in duplicates at 8 different intervals over 21 days. Sorbents and polyethersulfone (PES) membranes were separately extracted and analyzed by UPLC-MS/MS. When possible, a three-compartment model was used to describe the uptake of compounds from water, over the PES membrane into the sorbent. Uptake of target compounds by sorbents was shown not to approach equilibrium during 21 days. However, nitroaromatics strongly accumulated in PES, thus delaying the transfer of these compounds to sorbents (lag-phase up to 9 days). Whereas sampling rate (R_S) of nitroamines were in the range of 0.06-0.14 L day^-1, R_S of nitroaromatics were up to 10 times lower. As nitroaromatic accumulation in PES was integrative over 21 days, PES was used as receiving phase for these compounds. The samplers were then deployed at lake bottoms. To ensure that exposure conditions were similar between calibration and field experiments, low-density polyethylene strips spiked with performance reference compounds were co-deployed in both experiments and dissipation data were compared. Integrative concentrations of explosives measured in the lakes confirmed results obtained by previous studies based on grab sampling.