Estrogens and estrogen-like compounds are considered contaminants of emerging concern due to their endocrine disrupting capability and potential to build up in soil and aquatic environments, although little is known about the effects of estrogenic compounds on plant life. This research aims to understand the effect of the synthetic hormone 17-α ethynylestradiol (EE2) on Brassica rapa L. (field mustard) root and shoot vigor at the seedling stage. Endpoints considered included: plant height; root, shoot, and total dry biomass; number of leaves and inflorescences; leaf carbon and nitrogen; root growth traits (length, surface area, diameter, and volume); and root developmental parameters (tips, forks, and crossings). Tukey's method for multiple comparisons was used to determine the significance of pairwise differences between treatment means for each endpoint. 17-α Ethynylestradiol acted generally as a biostimulant at the concentrations considered (0, 0.5, 1, 5, 10, and 15 μg L −1 ), with the most pronounced differences occurring in seedlings treated with 1 μg L −1 EE2.Although number of leaves and biomass appeared to be inhibited at EE2 concentrations of ≥5 μg L −1 and ≥10 μg L −1 , respectively, all other traits in estrogen-treated plants were similar or improved compared with the control plants. Study results suggest that at certain concentrations, EE2 contributes to more structured root systems, triggering vigorous plant development that may potentially enhance a successful seedling establishment.

Radiological contamination of coastal habitats poses potential risk for native fauna, but the bioavailability of aqueous radium (Ra) and other dissolved metals to marine bivalves remains unclear. This study was the first to examine the tissue-specific disposition of aqueous 226 Ra in a coastal mussel, specifically the Atlantic ribbed mussel Geukensia demissa. Most organ groups reached steady-state concentrations within 7 days during experimental exposure, with an average uptake rate constant of 0.0013 mL g −1 d −1 . When moved to Ra-free synthetic seawater, mussels rapidly eliminated aqueous 226 Ra (average elimination rate constant 1.56 d −1 ). The biological half-life for aqueous 226 Ra ranged from 8.9 h for the gills and labial palps to 15.4 h for the muscle. Although previous field studies have demonstrated notable 226 Ra accumulation in the soft tissues of marine mussels and that, for freshwater mussels, tissue-incorporated 226 Ra derives primarily from the aqueous phase, our tissue-specific bioconcentration factors (BCFs) were on the order of (8.3 ± 1.5) × 10 −4 indicating low accumulation potential of aqueous 226 Ra in estuarine mussels. This suggests marine and estuarine mussels obtain 226 Ra from an alternate route, such as particulate-sorbed Ra ingested during filter-feeding or from a contaminated food source.

Perfluorooctanoic acid (PFOA), a surfactant, is a member of the perfluoroalkyl acids (PFAAs) family and is a contaminant of emerging concern for human and environmental health. Perfluorooctanoic acid is a persistent organic pollutant, but currently little is known about (a) the potential ecological and toxicological effects of PFOA and (b) how PFOA moves in the environment. This study uses a radiotracer (14C‐PFOA) to study the uptake and translocation of PFOA in hydroponically grown brown mustard [Brassica juncea (L.) Czern.], a representative crop species. Plants were exposed in quadruplicate over the course of 7 d (with plants sampled on Days 4 and 7) to PFOA concentrations of 0, 1, 5, 10, and 15 mg L−1. Uptake was quantified via liquid scintillation counting of samples from the nutrient solution, roots, stems, and leaves. Transfer factors (roots to shoots) ranged from 0.15 to 4.73 kg kg−1. Bioconcentration factors (solution to plant) ranged from 0.36 to 62.29 L kg−1. Factors were influenced by plant compartment, day sampled, and treatment level.

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A variety of processes, both natural and anthropogenic, can have a negative impact on surface waters, which in turn can be detrimental to human and environmental health. Few studies have considered the ecotoxicological impacts of concurrently occurring contaminants, and that is particularly true for mixtures that include contaminants of emerging concern (CEC). Motivated by this knowledge gap, our study considers the potential ecotoxicity of environmentally relevant contaminants in the representative aquatic plant, Lemna minor (common duckweed), a model organism. More specifically, biological effects associated with exposure of L. minor to a ubiquitous radionuclide (uranium, U) and a fluorinated organic compound (perfluorooctanoic acid, PFOA, considered a CEC), alone and in combination, were monitored under controlled laboratory conditions. L. minor was grown for 5 days in small, aerated containers. Each treatment consisted of four replicates with 7 plants each. Treatments were: 0, 0.3, and 3 ppb PFOA; 0, 0.5, and 5 ppb U; and combinations of these. Plants were observed daily for frond number and signs of chlorosis and necrosis. Other biological endpoints examined at the conclusion of the experiment were chlorophyll content and antioxidant capacity. In single‐exposure experiments, a slight stimulatory effect was observed on frond number at 0.3 ppb PFOA, whereas both concentrations of U had a detrimental effect on frond number. In the dual exposure experiment, the combinations with 5 ppb U also had a detrimental effect on frond number. Results for chlorophyll content and antioxidant capacity were less meaningful, suggesting that environmentally relevant concentrations of PFOA and U have only subtle effects on L. minor growth and health status.