Bioavailability of biosolids- and consumer product-associated polybrominated diphenyl ether (PBDE) flame retardants to terrestrial invertebrates

The primary objectives of this research were therefore to evaluate polybrominated diphenyl ether (PBDE) bioavailability to ecologically distinct soil invertebrates exposed to Penta-BDE-treated consumer polyurethane foam (PUF) products and biosolid products with incurred PBDEs. In laboratory bioassays, earthworms (Eisenia fetida) bioaccumulated SigmaPBDEs (47+99+100+183) up to 11,000 mug/kg lipid after 28 days from a mixture of artificial soil and anaerobically-digested sludge biosolid (ADB). Earthworms also bioaccumulated SigmaPBDEs (47+99+100+153+154+183) up to 13,500 and 838,000 mug/kg lipid after 28 d from a mixture of artificial soil and composted sludge biosolid (CB) and Penta-BDE-spiked artificial soil (SAS), respectively. No previous lab studies on bioaccumulation of PBDEs from sludge or sludge-amended soils have been published. Two publications, done by the same research group on the same sites in Sweden, do exist documenting incidental levels of PBDEs in worms collected from historically sludge-amended agricultural fields. In the current research, biota-soil accumulation factors (BSAFs) were appreciably higher (dependent upon dose) than those reported in these Swedish field studies. PBDE usage in Sweden has been much less intense than in North America. Increasing BSAFs with decreasing biosolids-amended soil burdens may indicate that PBDE constituents within these biosolid products may impact earthworms at relatively low levels in soil. The potential for a terrestrial arthropod, the house cricket ( Acheta domesticus) to take up PBDEs directly from consumer PUF was also evaluated in a laboratory bioassay. These insects frequent indoor spaces and discarded materials and hence may have increased access (and thus exposure) to PBDE-treated polymers. Cricket nymphs were reared in proximity to a commercially manufactured Penta-BDE-treated PUF. They accumulated SigmaPBDEs (47+85+99+100+153+154) up to 14,200 mug/kg lipid after 28 days. Non-depurated crickets ingested SigmaPBDE burdens up to 80,600 mug/kg lipid. Owing to the high PBDE content of the PUF (9% by weight) and the fact that much of it likely remained within the polymer matrix, cricket/PUF bioaccumulation factors (BAFs) were on the order of 10-4 to 10-3 for all PBDE congeners. to evaluate real-world biosolid-associated PBDE bioavailability in the soil-associated terrestrial environment, a food web bioaccumulation study was conducted within a Mid-Atlantic US agricultural soil ecosystem receiving long-term (\u3e20 years) sludge amendments. Patterns of those with most intimate contact and reliance on the soil (e.g. earthworms) most closely reflected the soil/biosolid/commercial Penta-BDE fingerprint. PBDEs were BQL in the herbivorous grasshopper, in contrast to the closely related cricket, an omnivorous scavenger. Surprisingly, PBDEs were largely BQL in predaceous wolf spiders regardless of size or trophic level. Penta-BDE constituent biota-soil accumulation factors (BSAFs) ranged from 0.006 (crickets) to 1.2 (earthworms), while BDE-209 BSAFs ranged from 0.07 (earthworms) to 10.5 (millipedes). Lipid and TOC normalized PBDE burdens were strongly correlated for earthworms and ground beetles, perhaps indicative of attainment of steady state accumulation. In general, PBDE burdens decreased in the invertebrates with trophic level at the sludge-amended field. The pattern of carbon (delta13C) and nitrogen (delta 15N) stable isotopes in the taxa sampled suggests different trophic interactions at the non-sludge and sludge-applied fields. However, as only two sites were surveyed, a more exhaustive data set is needed in order to draw more definitive conclusions. Results of these studies provide unequivocal evidence that PBDEs accumulate in soils where biosolids are applied. They also demonstrate that PUF- and biosolid-associated PBDEs are bioavailable and are accumulated to varying degrees by ecologically diverse soil-associated invertebrates. as such, they may become available for uptake by higher order terrestrial consumers, including reptiles, mammals and birds. (Abstract shortened by UMI.)

The hetZ Gene Regulates Heterocyst Formation in Anabaena sp. strain PCC 7120

To form a complex multicellular organism, stem cells must differentiate into each cell/tissue type along proper spatiotemporal scales. The study of differentiation and organismal development has historically been conducted in prokaryotes due to their genetic and morphological simplicity. Anabaena sp. strain PCC 7120 is a multicellular filamentous cyanobacterium that differentiates a morphologically distinct secondary cell type, the heterocyst, in response to a lack of combined environmental nitrogen. Heterocysts are regularly spaced along filaments and fix atmospheric dinitrogen to maintain organismal viability in its absence. Previous work suggested that the hetZ gene is involved in heterocyst differentiation, but the insertional mutants created produced inconsistent phenotypes, so a specific role was not assigned. In this work, a clean hetZ mutant incapable of heterocyst differentiation was generated and the mutation was complemented with the reintroduction of hetZ alone. Overexpression of hetZ bypassed a mutation of hetR, the master regulator of heterocyst differentiation that controls biological pattern formation, but not a mutation of hetP, a regulator of commitment to a differentiated cell fate, which places hetZ roughly between these processes. A protein-protein interaction study showed that HetZ interacts with both HetR and itself. Assessment of transcriptional fusions between the hetZ, hetR, hetP, and patS (an inhibitor of HetR) promoter regions and GFP, and overexpression of HetR in a hetZ mutant resulted in the differentiation of heterocyst-like cells, together indicated that HetZ may act in concert with HetR as an early regulator of development. Taken together, these data describe a non-linear pathway of regulation leading to heterocyst development governed by both HetR and HetZ

Profiling Volatile Constituents of Homemade Preserved Foods Prepared in Early 1950s South Dakota (USA) Using Solid-Phase Microextraction (SPME) with Gas Chromatography–Mass Spectrometry (GC-MS) Determination

https://scholar.dsu.edu/research-symposium/1013/thumbnail.jp

Profiling Volatile Emissions from Sewage Sludge Land-Applied Across Washington State (USA) Using Headspace Sampling with Gas Chromatography-Mass Spectrometry (GC-MS) Determination

https://scholar.dsu.edu/research-symposium/1012/thumbnail.jp

Polybrominated Diphenyl Ether (PBDE) Accumulation by Earthworms (<i>Eisenia fetida</i>) Exposed to Biosolids‑, Polyurethane Foam Microparticle‑, and Penta-BDE-Amended Soils

Polybrominated diphenyl ether (PBDE) flame retardants have been used in consumer polymers at up to percent levels. While long viewed as biologically inaccessible therein, PBDEs may become bioaccessible following volatilization or polymer deterioration. PBDEs may then enter soils via polymer fragmentation or following land application of sewage sludge-derived biosolids. Studies of direct PBDE uptake from these materials by soil organisms are scarce. We thus exposed earthworms (Eisenia fetida) to artificial soil amended with a Class B anaerobically digested biosolid (ADB), an exceptional quality composted biosolid (CB), PBDE-containing polyurethane foam (PUF) microparticles, and Penta-BDE-spiked artificial soil (SAS). Worms accumulated mg/kg (lipid) ∑Penta-PBDE burdens from all substrates. Biota-soil accumulation factors (BSAFs) for worms exposed to ADB- and CB-amended soils were comparable after 28 d. BSAFs generally decreased with increasing congener <i>K</i>_OW and substrate dosage. Biosolids-associated PBDE bioavailability was lower than spiked PBDEs. BSAFs for worms exposed to PUF microparticles ranged from 3.9 to 33.4, with ∑Penta-PBDE tissue burdens reaching 3740 mg/kg lipid. Congener accumulation patterns were similar in worms and polyethylene passive sampling devices immersed in ADB-amended soil coincident with exposed worms. However, passive sampler accumulation factors were lower than BSAFs. Our results demonstrate that PBDEs may accumulate in organisms ingesting soils containing biosolids or waste plastics. Such organisms may then transfer their burdens to predators or translocate them from the site of application/disposal

Flame retardants: Persistent pollutants in land-applied sludges

Disposal of sewage sludge by application to agricultural and other land is widely practised and is presumed to be environmentally beneficial, but we have found high concentrations of an environmentally persistent class of organic pollutants, brominated diphenyl ethers (BDEs), in 'biosolids' from four different regions of the United States. These compounds are widely used as flame retardants, and their presence suggests that the environmental consequences of land application of biosolids need further investigation. We also frequently detected BDEs in wild-caught fish, indicating another pathway for human exposure

Profiling Volatile Constituents of Homemade Preserved Foods Prepared in Early 1950s South Dakota (USA) Using Solid-Phase Microextraction (SPME) with Gas Chromatography–Mass Spectrometry (GC-MS) Determination

An essential dimension of food tasting (i.e., flavor) is olfactory stimulation by volatile organic compounds (VOCs) emitted therefrom. Here, we developed a novel analytical method based on solid-phase microextraction (SPME) sampling in argon-filled gas sampling bags with direct gas chromatography&#8315;mass spectrometry (GC-MS) determination to profile the volatile constituents of 31 homemade preserves prepared in South Dakota (USA) during the period 1950&#8315;1953. Volatile profiles varied considerably, but generally decreased in detected compounds, complexity, and intensity over three successive 2-h SPME sampling periods. Volatile profiles were generally predominated by aldehydes, alcohols, esters, ketones, and organic acids, with terpenoids constituting much of the pickled cucumber volatiles. Bisphenol-A (BPA) was also serendipitously detected and then quantified in 29 samples, at levels ranging from 3.4 to 19.2 &#956;g/kg, within the range of levels known to induce endocrine disruption effects. Absence of BPA in two samples was attributed to their lids lacking plastic liners. As the timing of their preparation coincides with the beginning of BPA incorporation into consumer products, these jars may be some of the first BPA-containing products in the USA. To the best of our knowledge, this is the first effort to characterize BPA in and volatile profiles of rare historical foods with SPME

Assessment and verification of commercially available pressure cookers for laboratory sterilization.

Laboratory science requires careful maintenance of sterile reagents and tools as well as the sterilization of waste prior to disposal. However, steam autoclaves typically used for this purpose may not be readily accessible to everyone in the scientific community, such as K-12 teachers, researchers in the field, students in under-funded laboratories, or persons in the developing world who lack funding and resources. This work examines the use of commercial electric pressure cookers as an alternative method for the sterilization of media, instruments, and waste. Four commonly available brands of pressure cooker were tested for their ability to sterilize microbiological media, a variety of metal instruments, and high-titer microbial cultures. All four pressure cookers were able to sterilize these starting materials as well as a range of microbial types, including Gram-positive bacteria, Gram-negative bacteria, filamentous fungi, unicellular fungi, and mixed environmental samples. Only the Instant Pot, however, was able to sterilize autoclave tester ampoules of Geobacillus stearothermophilus spores. These results suggest that, depending on the nature of the work undertaken, store-bought pressure cookers can be an appropriate substitute for commercial autoclaves. Their adoption may also help increase the accessibility of science to a broader range of investigators