Co-exposure of polystyrene microplastics influence cadmium trophic transfer along the "lettuce-snail" food chain: Focus on leaf age and the chemical fractionations of Cd in lettuce.

Cadmium (Cd) and polystyrene microplastics (PS) co-contamination always occurs in environment; however, the trophic transfer of Cd and PS is still poorly understood. A hydroponic experiment was conducted to investigate the behavior of Cd in lettuce, together with the root or foliar exposure of different sized PS. Accumulation and chemical form distributions of Cd in leaves were distinguished into young and mature leaves. Subsequently, a 14-day snail feeding experiment was performed. Data showed that Cd accumulation in roots, rather than in leaves, are significantly affected by PS coexistence. However, mature leaves had a higher Cd content than young leaves under the root exposure of PS, while a reverse effect was observed in the foliar exposure. There existed a positive correlation between the food-chain transfer associated Cd (CdFi+Fii+Fiii) in mature leaves and Cd content in snail soft tissue (r = 0.705, p < 0.001), but not in young leaves. Though no bio-amplification of Cd in food chain was observed, an increase of Cd transfer factor (TF) from lettuce to snail was noted in the root exposure of 5 µm PS and the foliar exposure of 0.2 µm PS. Moreover, we observed a highest increase rate of 36.8 % in TF values from lettuce to snail viscera, and a chronic inflammatory response in snail stomach tissue. Therefore, more attentions should be paid to study the ecological risks of heavy metals and microplastics co-contamination in environment.

The environmental fate of phenanthrene in paddy field system and microbial responses in rhizosphere interface: Effect of water-saving patterns.

The effects of water-saving patterns (Semi-dry water-saving, B; Shallow-wet control irrigation, Q; Traditional flooding irrigation, C; and Moistening irrigation, S) on the environmental fate of phenanthrene (Phe) and microbial responses in rhizosphere were investigated in paddy field system. Results showed the rice grain in Q treatment was more high production and safety with less Phe residue (up to 18%-49%) than other treatments, and the residual Phe in soil declined in the order: C (14.17%) > S (13.36%) > B (5.86%)>Q (2.70%), which proves the existence of optimal water conditions for PAHs degradation and rhizosphere effect during rice cultivation. Laccase (LAC) and dioxygenase (C23O) played important roles in Phe degradation, which were significantly positively correlated with Phe dissipation rate in soil (p < 0.01). Moreover, their activities in Q treatment, rhizosphere and subsoil were higher than those in C treatment, non-rhizoshere and upper layer soil. The introduction of Phe and rice into paddy field system decreased the microorganism diversity, and promoted the activities of enzymes and some PAHs degrading bacteria, such as Delftia, Serratia, Enterobacter, Pseudomonas, norank_f_Rhodospirillaceae, norank_f_Nitrosomonadaceae and so on. According to the cluster analysis, redundancy analysis and correlation analysis between bacterial community composition and environmental factors, water-saving patterns markedly impacted the relative abundance and bacterial community structure by the regulating and controlling on environmental conditions of paddy field. The dioxygenase activity, laccase activity, oxidation-reduction potential and conductivity were the main affecting factors on Phe dissipation during growth stage of rice.

Author Correction: 150,000-year palaeoclimate record from northern Ethiopia supports early, multiple dispersals of modern humans from Africa.

A correction to this article has been published and is linked from the HTML and PDF versions of this paper. The error has been fixed in the paper.

150,000-year palaeoclimate record from northern Ethiopia supports early, multiple dispersals of modern humans from Africa.

Climatic change is widely acknowledged to have played a role in the dispersal of modern humans out of Africa, but the timing is contentious. Genetic evidence links dispersal to climatic change ~60,000 years ago, despite increasing evidence for earlier modern human presence in Asia. We report a deep seismic and near-continuous core record of the last 150,000 years from Lake Tana, Ethiopia, close to early modern human fossil sites and to postulated dispersal routes. The record shows varied climate towards the end of the penultimate glacial, followed by an abrupt change to relatively stable moist climate during the last interglacial. These conditions could have favoured selection for behavioural versatility, population growth and range expansion, supporting models of early, multiple dispersals of modern humans from Africa.

'Death ... more desirable than life'? The human skeletal record and toxicological implications of ancient copper mining and smelting in Wadi Faynan, southwestern Jordan.

Skeletal material from 36 people, dating from the early Christian era, who lived by or worked in the notorious Roman copper mines of Phaeno, were analysed to determine their exposure to copper and lead. We demonstrate that many of the bones analysed had a substantially higher concentration of these cations than modern individuals exposed to metals through industrial processes. Health, toxicological and environmental implications of these data are reviewed.