http://faculty.wwu.edu/~shulld/ESCI%20101/Andrady2011Plastics.pdf

Microplastics in the marine environment

Sustainable Development Goals

The recent advances in nanotechnology and the corresponding increase in the use of nanomaterials in products in every sector of society have resulted in uncertainties regarding environmental impacts. The objectives of this review are to introduce the key aspects pertaining to nanomaterials in the environment and to discuss what is known concerning their fate, behavior, disposition, and toxicity, with a particular focus on those that make up manufactured nanomaterials. This review critiques existing nanomaterial research in freshwater, marine, and soil environments. It illustrates the paucity of existing research and demonstrates the need for additional research. Environmental scientists are encouraged to base this research on existing studies on colloidal behavior and toxicology. The need for standard reference and testing materials as well as methodology for suspension preparation and testing is also discussed.

Nanomaterials in the environment: Behavior, fate, bioavailability, and effects

We present the science and technology roadmap for graphene, related two-dimensional crystals, and hybrid systems, targeting an evolution in technology, that might lead to impacts and benefits reaching into most areas of society. This roadmap was developed within the framework of the European Graphene Flagship and outlines the main targets and research areas as best understood at the start of this ambitious project. We provide an overview of the key aspects of graphene and related materials (GRMs), ranging from fundamental research challenges to a variety of applications in a large number of sectors, highlighting the steps necessary to take GRMs from a state of raw potential to a point where they might revolutionize multiple industries. We also define an extensive list of acronyms in an effort to standardize the nomenclature in this emerging field.

/pdf/science-and-technology-roadmap-for-graphene-related-two-4q9m7czlkc.pdf

Science and technology roadmap for graphene, related two-dimensional crystals, and hybrid systems

For decades, studies of endocrine-disrupting chemicals (EDCs) have challenged traditional concepts in toxicology, in particular the dogma of “the dose makes the poison,” because EDCs can have effects at low doses that are not predicted by effects at higher doses. Here, we review two major concepts in EDC studies: low dose and nonmonotonicity. Low-dose effects were defined by the National Toxicology Program as those that occur in the range of human exposures or effects observed at doses below those used for traditional toxicological studies. We review the mechanistic data for low-dose effects and use a weight-of-evidence approach to analyze five examples from the EDC literature. Additionally, we explore nonmonotonic dose-response curves, defined as a nonlinear relationship between dose and effect where the slope of the curve changes sign somewhere within the range of doses examined. We provide a detailed discussion of the mechanisms responsible for generating these phenomena, plus hundreds of examples from...

/pdf/hormones-and-endocrine-disrupting-chemicals-low-dose-effects-2vn32zoqc8.pdf

Hormones and endocrine-disrupting chemicals: Low-dose effects and nonmonotonic dose responses

Development of a flow-through system for sediment toxicity testing has been difficult in part because of problems associated with the precision, and subsequent expense, necessary to create a pump that accurately delivers small amounts of overlying water. This article describes a novel continuous flow-through apparatus designed to quantitatively and continuously deliver small amounts of overlying water to individual test chambers. This system uses a series of motor-driven pistons, similar to bicycle pumps, to accurately (∼5% variability) deliver small amounts of overlying water ( 70% of saturation), but an average daily range of 0.685 and 1.67 mg/L dissolved oxygen in continuous and intermittent renewal systems, respectively, was observed. No differences were observed in midge survival between continuous and intermittent renewal, but there was a 33% decrease in growth (dry weight) of C. riparius in test chambers subjected to intermittent renewal.

Development of a continuous-flow renewal system for sediment toxicity testing†

Copper is a common pollutant found in watersheds that exerts toxic effects on both invertebrates and vertebrates. Layer double hydroxide (LDH) clays are able to adsorb a wide range of contaminants through ion-exchange mechanisms. Coating LDH clays with various materials alters the aggregation of clay particles into the nano-size range, thus increasing relative surface area and offering great potential for contaminant remediation. The goal of this study was to determine if treatment with coated LDH clays decreases the toxicity of copper-containing solutions to Daphnia magna. Four LDH clays with different coatings used to alter hydrophobicity were as follows: used: Na+ montmorillonite, Zn–Al LDH-nitrate, Zn–Al LDH-stearate, and Zn–Al LDH-carbonate. It was determined that coated LDH clays decreased copper toxicity by decreasing bioavailability and that smaller aggregate sizes decreased bioavailability the most. 96 h LC50 values increased by as much as 4.2 times with the treatment of the solutions with 100 mg/L LDH clay. Copper analysis of the clay and solutions indicated that the clays work by decreasing copper bioavailability by way of a binding mechanism. Coated LDH clays hold promise as a small-scale remediation tool or as an innovative tool for toxicity identification and evaluation characterization of metals.

Treatment with Coated Layer Double Hydroxide Clays Decreases the Toxicity of Copper-Contaminated Water

/pdf/408-potential-use-of-typha-latifolia-for-bioremediation-of-2xeds42wli.pdf

408 Potential Use of Typha latifolia for Bioremediation of Metalaxyl and Simazine

The success of a population is dependent upon the fitness of the individuals. Fitness is defined as the contribution of a genotype to the next generation, thus, referring to the success of a reproductive organism (Campbell, 1996). However, reproduction by an individual is dependent upon growth. Surplus energy not used for maintenance or metabolism is invested in growth (Lawrence, et al., 2003). Eventually, as the organism ages, energy invested in growth will be allocated for reproduction. Although, when exposed to an environmental pollutant, such as copper, the energy allocated for growth and reproduction maybe assigned to maintenance and repair in an effort to restore homeostasis (Heath, 1987; Lawrence, et al., 2003; Brafield and Llewllyn). This has consequences on energy balance in an organism and depending upon the intensity and duration of the copper exposure, growth and reproduction may be affected. Population level effects have been documented at metal contaminated sites, noting reduced growth and development in fish and invertebrates (Peplow and Edmonds, 2005). Previous work has shown that acute pulsed exposures to copper results in a loss of sodium in larval fish, which may lead to mortality (Zahner, et al., 2006). Further, these organisms have demonstrated an ability to regain sodium homeostasis when given an adequate period of recovery in copper free water (~96-h). However, these organisms may be allocating energy to recovering ion homeostasis rather than growth and reproduction. Thus, chronic episodic exposures to copper over an organisms life-span may have significant consequences on organism growth and reproduction. Researchers have shown that chronic exposures to copper affect growth in larval and juvenile fish (DeBoeck, et al., 1997; Marr, et al., 1996; Woltering, 1984). But growth alone is not a reliable indicator of reproductive success (McCahon and Pascoe, 1990; Handy 1994). Organisms exposed to low levels of pollution may have no notable adverse effects at the larval age; however, reproductive effects may become apparent in later life stages. This may affect the survival of the population. The current NPDES methodology for assessing the risk of an effluent to the in-stream community does not account for long-term reproductive consequences, or the impacts of episodic exposures occurring over the duration of the organism’s life cycle. Effects from pulsed exposures may result in sub-lethal responses to the aquatic community, such as reduced feeding rate, impairment of growth, or reduced reproductive success, which may cause decreased population survival resulting in ecosystem perturbation or degradation (McCahon and Pascoe, 1990; Handy 1994). These latent post-exposure population level responses cannot be assessed using current NPDES testing and this may result in an underestimation or an overestimation of risk to the biological community. However, little research has been completed on the effects of episodic exposures on a population. Thus, the goal of this research is to characterize population responses to episodic copper exposures throughout the life-span of the fathead minnow (Pimephales promelas).

/pdf/effects-of-episodic-copper-exposures-on-population-fitness-srbs30z7km.pdf

Stephen J. Klaine

Papers

Development of a continuous-flow renewal system for sediment toxicity testing†

Treatment with Coated Layer Double Hydroxide Clays Decreases the Toxicity of Copper-Contaminated Water

408 Potential Use of Typha latifolia for Bioremediation of Metalaxyl and Simazine

Effects of Episodic Copper Exposures on Population Fitness