Investigating the Sorption of Pharmaceutical and Personal Care Products on High-Density Polyethylene and Polypropylene Microplastics

The term “microplastics” refers to plastic particles with a diameter of 5mm or less. Microplastics are capable of sorbing organic contaminants to concentrations magnitudes higher than the surrounding water. One such contaminants class is a group of pharmaceuticals and personal care products (PPCPs). As of now, very little information is known about the sorption behavior of PPCPs on microplastics; therefore, to better understand the interaction between PPCPs and microplastics, their sorption behavior must be studied. The goal of this project is to explore and evaluate the sorption behavior of polar and ionizable PPCPs onto microplastics. The PPCPs in this study were: diphenhydramine, an antihistamine, venlafaxine hydrochloride, an antidepressant, and N, N-diethylmeta-toluamide (DEET), which is an insect repellant.NSF, Sea Gran

Poultry Litter-Induced Endocrine Disruption: Laboratory and Field Investigations

Nearly 1.6 billion lbs. of poultry litter are generated annually as a by-product of the Delmarva poultry industry. Disposal via application to fields as fertilizer results in runoff of poultry litter-associated contaminants (PLACs) into receiving waters. Of particular concern are natural steroid hormones 17 ß-estradiol (E2) and testosterone (T), responsible for gender differentiation and development of reproductive structures. The objective of this research project was to assess the potential for endocrine disruption (ED) in fish populations on the Delmarva Peninsula as a result of agricultural litter application. The investigation included 5 laboratory and 2 controlled field exposures of fish (Pimephales promelas, Cyprinodon variegatus and Fundulus heteroclitus) to water-soluble PLAC. Laboratory assays involved 21-d exposures of adult male and mixed gender larval/juvenile fish to negative, positive (E2) and solvent (EtOH) control treatments, and to one or several environmentally relevant PLAC solutions. Effects on gonads were assessed histologically and plasma and whole-body homogenate vitellogenin (Vtg) levels were measured as a gauge of estrogenicity. Results were used to determine PLAC lower-effects thresholds. Litter application on research fields allowed comprehensive monitoring of runoff over entire planting seasons. Environmental persistence and transport were investigated by measuring PLAC in litter prior to field application and subsequently in runoff and receiving waters. Controlled field exposures involved caging of mature male P. promelas in surface waters receiving litter-amended runoff. Laboratory PLAC exposures routinely induced Vtg in male P. promelas with response generally dose-dependent. Induction in F. heteroclitus only occurred at the highest tested PLAC concentration while C. variegatus were unresponsive at any tested concentration. All three species produced considerable Vtg in response to the E2 positive control. Gonadosomatic index was unaffected in adult fish, but gamete maturity appeared inversely related to PLAC concentration. PLAC exposure caused a pronounced feminization in P. promelas exposed as larvae (3 - 24 dph) but not exposed as juveniles (36-57 dph). Steroid concentrations (E2 and T) in field runoff were substantial (up to 350 ng E2/L). E2 in receiving waters had an environmental persistence of weeks to months and in one instance exceeded lower effects thresholds identified in the laboratory. ED was not evident in P. promelas caged within receiving waters. However, exposure in the laboratory to agricultural runoff (frozen and renewed daily) induced substantial Vtg in adult male P. promelas

Effects-based spatial assessment of contaminated estuarine sediments from Bear Creek, Baltimore Harbor, MD, USA

The original publication of this paper contains an error. The correct image of figure 5 is shown in this paper

Microplastics in Four Estuarine Rivers in the Chesapeake Bay, U.S.A.

Once believed to degrade into simple compounds, increasing evidence suggests plastics entering the environment are mechanically, photochemically, and/or biologically degraded to the extent that they become imperceptible to the naked eye yet are not significantly reduced in total mass. Thus, more and smaller plastics particles, termed microplastics, reside in the environment and are now a contaminant category of concern. The current study tested the hypotheses that microplastics concentration would be higher in proximity to urban sources, and vary temporally in response to weather phenomena such as storm events. Triplicate surface water samples were collected approximately monthly between July and December 2011 from four estuarine tributaries within the Chesapeake Bay, U.S.A. using a manta net to capture appropriately sized microplastics (operationally defined as 0.3–5.0 mm). Selected sites have watersheds with broadly divergent land use characteristics (e.g., proportion urban/suburban, agricultural and/or forested) and wide ranging population densities. Microplastics were found in all but one of 60 samples, with concentrations ranging over 3 orders of magnitude (<1.0 to >560 g/km²). Concentrations demonstrated statistically significant positive correlations with population density and proportion of urban/suburban development within watersheds. The greatest microplastics concentrations also occurred at three of four sites shortly after major rain events