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Fungi and substrates undergoing fungal decomposition were collected from forests in northern and southernSweden and analyzed for chlorinated dimethoxybenzenes (DMBs). Specimens were fungi fruiting bodies, rottingwood, forest litter and underlying humus. Targeted compounds were DAME (1,2,4,5-tetrachloro-3,6-DMB) andrelated fungal secondary metabolites. A screening procedure was developed which involved soaking the speci-mens in ethyl acetate followed by analysis by capillary gas chromatography – mass spectrometry with mass selec-tive detection (GC-MSD). DAME was the most frequently found (62% of 47 specimens) and often the most abun-dant target compound, with range and mean ± SD concentrations of <0.0017–3.81 and 0.21 ± 0.63 mg kg−1ww. Based on log-log correlations of partition coefficients of hydrophobic compounds between fungal biomass/water (KD) and octanol/water (KOW), five species of fungi are suggested to produce DAME de novo versus bioaccu-mulation from forest runoff water. Full-scan mass spectra of some high-concentration specimens indicated thepresence of a Cl2DMB and a Cl3DMB, which could not be identified further due to lack of standards, anddrosophilin A (DA = 2,3,5,6-tetrachloro-4-methoxyphenol), the precursor to DAME. Tetrachloroveratrole(TeCV = 1,2,3,4-tetrachloro-5,6-DMB) was found in only a few specimens. This study supports our hypothesis offungi as a source of DAME in terrestrial runoff and indicates that other chlorinated secondary metabolites arepresent. DAME is widely distributed globally, and it would be good to have a better understanding of its sourcesand pathways as a marker of terrestrial organochlorines and their availability for bioaccumulation, EcoChange

EcoChange

Hexachlorobenzene (HCB) was used in the United States from 1945 to 1966 as a fungicide on wheat, while octachlorostyrene (OCS) was never marketed. However, both HCB and OCS continue to be emitted into the atmosphere as byproducts of several industrial processes. We have measured the atmospheric concentrations of HCB and OCS in samples collected every 12 days at five sites on the shores of the North American Great Lakes since 1991. The geometric mean concentrations of HCB and OCS are ∼60 and 0.7 pg/m3, respectively, at all sites regardless of the local population, and these concentrations have not changed significantly over time. The concentrations of HCB measured here are similar to those reported by other studies of the northern troposphere and are ∼3 times those reported in the southern troposphere, suggesting that HCB sources are largely in the Northern Hemisphere. It is apparent that direct and recycled emissions of HCB and OCS into the northern troposphere are widespread in scope and, despite the elimination of HCB as a fungicide, have not changed in a meaningful way in the past 20–30 years. This is unlike the case for other legacy chemicals, for which global restrictions on their use have been more effective., EcoChange

The time trend of α- and γ-hexachlorocyclohexane (HCH) isomers in Lake Superior water was followed from 1986 to 2016, the longest record for any persistent organic pollutant (POP) in Great Lakes water. Dissipation of α-HCH and γ-HCHs was first order, with halving times (t1/2) of 5.7 and 8.5 y, respectively. Loss rates were not significantly different starting a decade later (1996−2016). Concentrations of β-HCH were followed from 1996−2016 and dissipated more slowly (t1/2 = 16 y). In 1986, the lake contained an estimated 98.8 tonnes of α-HCH and 13.2 tonnes of γ-HCH; by 2016, only 2.7% and 7.9% of 1986 quantities remained. Halving times of both isomers in water were longer than those reported in air, and for γ-HCH, they were longer in water than those reported in lake trout. Microbial degradation was evident by enantioselective depletion of (+)α-HCH, which increased from 1996 to 2011. Volatilization was the main removal process for both isomers, followed by degradation (hydrolytic and microbial) and outflow through the St. Mary’s River. Sedimentation was minor. Major uncertainties in quantifying removal processes were in the two-film model for predicting volatilization and in microbial degradation rates. The study highlights the value of long-term monitoring of chemicals in water to interpreting removal processes and trends in biota., EcoChange

Accurate values of physicochemical properties are essential for screening semivolatile organic compounds for human and environmental hazard and risk. In silico approaches for estimation are widely used, but the accuracy of these and measured values can be difficult to ascertain. Final adjusted values (FAVs) harmonize literature-reported measurements to ensure consistency and minimize uncertainty. We propose a workflow, including a novel Bayesian approach, for estimating FAVs that combines measurements using direct and indirect methods and in silico values. The workflow was applied to 74 compounds across nine classes to generate recommended FAVs (FAVRs). Estimates generated by in silico methods (OPERA, COSMOtherm, EPI Suite, SPARC, and polyparameter linear free energy relationships (pp-LFER) models) differed by orders of magnitude for some properties and compounds and performed systematically worse for larger, more polar compounds. COSMOtherm and OPERA generally performed well with low bias although no single in silico method performed best across all compound classes and properties. Indirect measurement methods produced highly accurate and precise estimates compared with direct measurement methods. Our Bayesian method harmonized measured and in silico estimated physicochemical properties without introducing observable biases. We thus recommend use of the FAVRs presented here and that the proposed Bayesian workflow be used to generate FAVRs for SVOCs beyond those in this study., EcoChange

The subcooled liquid-phase vapor pressures (pL298/Pa) and octanol–air partition coefficients (KOA298) at T/K = 298, enthalpies of vaporization (ΔVAPH/kJ·mol–1), and internal energies of phase transfer from octanol to air (ΔOAU/kJ·mol–1) were estimated for synthetic musks, novel brominated flame retardants (N-BFR), organophosphate esters, and ultraviolet filters using the capillary gas chromatographic retention time (GC-RT) method. These compounds, which spanned approximately six and three orders of magnitude for pL298/Pa and KOA298, respectively, were co-chromatographed with one of three reference compounds to give initial estimates of properties at T/K = 298. The initial GC-RT property estimates were subsequently calibrated using 18 compounds that spanned 6 log units for pL298/Pa and 13 compounds covering 4 log units for KOA298. The calibrated log10pL298/Pa values estimated here ranged from 0.14 ± 0.19 to −9.19 ± 0.29 for cyclopentadecanone to syn-dechlorane plus (syn-DDC-CO), respectively, while the range of log10KOA298 values was 6.59 ± 0.26 to 11.40 ± 0.23 for cyclopentadecanone to 2,2′,4,4′,5-pentabromodiphenyl ether (BDE-99), respectively. The calibrated GC-RT-derived values were highly correlated with, and were within an average of 0.70 log units of, the literature data for compounds with well-established pL298/Pa and KOA298 measured or derived using non-GC-RT methods. Nonpolar compounds were used in this study to estimate the target polar compound data, which may introduce systematic errors. However, the comparison of our GC-RT results against the literature non-GC-RT values shows that the GC-RT methods performed similarly well for estimating both polar and nonpolar target compounds studied in this work., ecochange

Thousands of halogenated natural products (HNPs) pervade the terrestrial and marine environment. HNPs are generated by biotic and abiotic processes and range in complexity from low molecular mass natural halocarbons (nHCs, mostly halomethanes and haloethanes) to compounds of higher molecular mass which often contain oxygen and/or nitrogen atoms in addition to halogens (hHNPs). nHCs have a key role in regulating tropospheric and stratospheric ozone, while some hHNPs bioaccumulate and have toxic properties similar those of anthropogenic-persistent organic pollutants (POPs). Both chemical classes have common sources: biosynthesis by marine bacteria, phytoplankton, macroalgae, and some invertebrate animals, and both may be similarly impacted by alteration of production and transport pathways in a changing climate. The nHCs scientific community is advanced in investigating sources, atmospheric and oceanic transport, and forecasting climate change impacts through modeling. By contrast, these activities are nascent or nonexistent for hHNPs. The goals of this paper are to (1) review production, sources, distribution, and transport pathways of nHCs and hHNPs through water and air, pointing out areas of commonality, (2) by analogy to nHCs, argue that climate change may alter these factors for hHNPs, and (3) suggest steps to improve linkage between nHCs and hHNPs science to better understand and predict climate change impacts., EcoChange

Marine macroalgae are used worldwide for human consumption, animal feed, cosmetics and agriculture. In addition to beneficial nutrients, macroalgae contain halogenated natural products (HNPs), some of which have toxic properties similar to those of well-known anthropogenic contaminants. Sixteen species of red, green and brown macroalgae were collected in 2017–2018 from coastal waters of the northern Baltic Sea, Sweden Atlantic and Norway Atlantic, and analyzed for bromoanisoles (BAs) and methoxylated bromodiphenyl ethers (MeO-BDEs). Target compounds were quantified by gas chromatography-low resolution mass spectrometry (GC-LRMS), with qualitative confirmation in selected species by GC-high resolution mass spectrometry (GC-HRMS). Quantified compounds were 2,4-diBA, 2,4,6-triBA, 2′-MeO-BDE68, 6-MeO-BDE47, and two tribromo-MeO-BDEs and one tetrabromo-MeO-BDE with unknown bromine substituent positions. Semiquantitative results for pentabromo-MeO-BDEs were also obtained for a few species by GC-HRMS. Three extraction methods were compared; soaking in methanol, soaking in methanol–dichloromethane, and blending with mixed solvents. Extraction yields of BAs did not differ significantly (p > 0.05) with the three methods and the two soaking methods gave equivalent yields of MeO-BDEs. Extraction efficiencies of MeO-BDEs were significantly lower using the blend method (p < 0.05). For reasons of simplicity and efficiency, the soaking methods are preferred. Concentrations varied by orders of magnitude among species: ∑2BAs 57 to 57 700 and ∑5MeO-BDEs < 10 to 476 pg g−1 wet weight (ww). Macroalgae standing out with ∑2BAs >1000 pg g−1 ww were Ascophyllum nodosum, Ceramium tenuicorne, Ceramium virgatum, Fucus radicans, Fucus serratus, Fucus vesiculosus, Saccharina latissima, Laminaria digitata, and Acrosiphonia/Spongomorpha sp. Species A. nodosum, C. tenuicorne, Chara virgata, F. radicans and F. vesiculosus (Sweden Atlantic only) had ∑5MeO-BDEs >100 pg g−1ww. Profiles o, EcoChange

We report concentrations of polychlorinated biphenyls, polybrominated diphenyl ethers, novel flame retardants, and naturally occurring bromoanisoles in water and filter-feeding black fly (Simuliidae) larvae in 3 tundra streams in northern Sweden. The results demonstrate that black fly larvae accumulate a wide range of organic contaminants and can be used as bioindicators of water pollution in Arctic streams.