Assessment of the toxicity of a mixture of five rare earth elements found in aquatic ecosystems in Hydra vulgaris.

Rare earth elements (REEs) are considered critical elements for technology and their extraction through mining activities is expected to increase in the future. Due to their chemical similarities, they often co-occur in minerals and thus their ecotoxicity should be assessed as a group/family. However, the available ecotoxicological studies focused mainly on the evaluation of the potential toxicological impacts of individual REEs rather than their mixtures. The aim of this study was therefore to evaluate the toxicity of a representative mixture of five REEs (La, Ce, Pr, Nd and Sm) spanning environmentally relevant concentrations ranging from 0.05X (29 µg REEs L-1) to 5X (2926 µg REEs L-1) to the test organism, Hydra vulgaris, at the morphological, reproductive and regenerative levels. The data showed that lethality occurred at concentrations near (2.5 fold) to those inducing sublethal effects after chronic exposure of 7 days. The mixture affected reproduction and head regeneration and even lethality at concentrations even below those reported at environmental concentration (0.5X = 293 µg REEs L-1) in lakes. This suggests that REEs concentrations found in lakes near mining activities could disrupt regeneration and impair embryonic development. Our data also revealed that combining the 5 REEs results in an antagonistic effect, suggesting that those elements share the same receptor and that low molecular weight and high radius elements (approaching iron) were less toxic. Taken together, hydra could be used as a sensitive model organism for the assessment of aquatic ecotoxicological risks of REE mixtures but further analyses of biochemical and gene expressions should improve our understanding of the long-term effects of REEs mixtures.

Attachment states of mind in late adolescence and the quality and course of romantic relationships in adulthood.

The purpose of this study was to examine the longitudinal relations between attachment state of mind in late adolescence and romantic relationships in adulthood. Participants were drawn from two independent studies that were conducted respectively in 1992 and 1996 and that involved the administration of the Adult Attachment Interview (AAI) to 167 college students. They were followed-up in 2007 (N = 99) to investigate different aspects of their romantic relationships since college. Those who had shown greater preoccupation with attachment in the AAI were more likely to be single in adulthood and to report romantic relationships of shorter length. In addition, they reported lower levels of intimacy, commitment, and passion in their current or recent romantic relationships. Dismissing tendencies were associated with higher levels of perceived passion in romantic relationships. Most of these associations remained significant after controlling for intervening life events, different dimensions of individual adjustment, socio-economic status, as well as probable life events derived from the AAI.