The effects of engineered natural organic amendments on two measures of the environmental “availability” of polycyclic aromatic hydrocarbons (PAHs) associated with soil and sediment samples are ...assessed. Two soils spiked with pyrene alone and a sediment spiked with a mixture of 4 PAH compounds were amended with raw or superheated-water processed peat or soybean stalks, then aged for periods of either 62 or 105 days. The aged soils were then examined with respect to bioaccumulation of spiked pyrene by earthworms (Eisenia foetida), and to its human bioaccessibility as measured by extraction with simulated gastrointestinal fluid. Additions of processed amendments reduced both measures of availability by factors ranging from 7.6 to 27.0 for earthworm bioaccumulation and from 2.3 to 8.8 for gastrointestinal extractability. All PAH compounds spiked to the sediment were reduced to varying extents in their availabilities to E. foetida and leachabilities by water by both processed and raw organic amendments.
Commons are public lands that are often used for recreational activities and are generally assumed to be free of soil contamination. However, in old industrial cities, urban commons may have ...accumulated heavy metal burdens from airborne contamination. This paper examines the heavy metal burdens and risk analysis results for 50 commons in the greater Cleveland, Ohio area. The U.S. Environmental Protection Agency Method 3050B and 1N HCl soil extraction results are presented for Cd, Cr, Cu, Ni, Pb, and Zn mass burdens, and are interpreted relative to Ohio residential soil guidance and “typical” values from the remediation guidance of 30 states. Results demonstrate that most of these soils have heavy metal burdens that are well above naturally occurring levels, and several (at least 8 of the 50 sites tested) have heavy metal burdens that exceed Ohio’s residential soil contamination guidance. Lead and cadmium were found to be the most significant contributors to site hazard index values.
Developing methods to measure interactions of carbon nanotubes (CNTs) with soils and sediments and understanding the impact of soil and sediment properties on CNT deposition are essential for ...assessing CNT environmental risks. In this study, we utilized functionalized carbon-14 labeled nanotubes to systematically investigate retention of multiwall CNTs (MWCNTs) by 3 humic acids, 3 natural biopolymers, and 10 model solid-phase polymers, collectively termed macromolecules. Surface properties, rather than bulk properties of macromolecules, greatly influenced MWCNT retention. As shown via multiple linear regression analysis and path analysis, aromaticity and surface polarity were the two most positive factors for retention, suggesting retention was regulated by pi-pi stacking and hydrogen bonding interactions. Moreover, MWCNT deposition was irreversible. These observations may explain the high retention of MWCNT in natural soils. Moreover, our findings on the relative contribution of each macromolecule property on CNT retention provide information on macromolecule selection for removal of MWCNTs from wastewater and provide a method for measuring CNT interactions with organic macromolecules. Published by Elsevier Ltd.
The results esults of a survey of heavy metal contamination at Cleveland area brownfields and public spaces are presented. Soils were analyzed using a 24 h, 1N HCl extraction procedure. The study was ...conducted to seek brownfield soils that manifest properties of “old” sequestered contamination and to develop a better understanding of the nature and extent of heavy metal burdens at brownfield sites in the Greater Cleveland area. The results indicated that Cleveland brownfields commonly yield soil burdens well above remediation triggers for residential soils and often yield values above industrial remediation triggers. It was also discovered that public areas in the vicinity of brownfields commonly have heavy metal contamination significantly above background levels and occasionally above residential remediation triggers. These results indicate that brownfields redevelopment initiatives should proceed with caution. The appropriate remediation goals or restrictions must be imposed to control urban exposure to heavy metal contamination.
The US-EU Community of Research (CoR) was established in 2012 to provide a platform for scientists to develop a ‘shared repertoire of protocols and methods to overcome nanotechnology environmental ...health and safety (nanoEHS) research gaps and barriers’ (
www.us-eu.org/
). Based on work within the Ecotoxicology CoR (2012–2015) we provide here an overview of the state-of-the-art of nanomaterials (NMs) in the aquatic environment by addressing different research questions with a focus on ecotoxicological test systems and the challenges faced when assessing nanomaterial (NM) hazards (e.g., uptake routes, bioaccumulation, toxicity, test protocols and model organisms). Our recommendation is to place particular importance on studying the ecological effects of aged/weathered NMs, as-manufactured NMs, as well as NMs released from consumer products in addressing the following overarching research topics: i) NM characterization and quantification in environmental and biological matrices, ii) NM transformation in the environment and consequences for bioavailability and toxicity, iii) alternative methods to assess exposure, iv) influence of exposure scenarios on bioavailability and toxicity, v) development of more environmentally realistic bioassays and vi) uptake, internal distribution, and depuration of NMs. Research addressing these key topics will reduce uncertainty in ecological risk assessment and support the sustainable development of nanotechnology.
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