ecotoxicological-effects-microplastics-on-bird-embryo-development

Ecotoxicological Effects of Microplastics on Bird Embryo Development by Hatching without Eggshell

Microplastics are an emerging global pollutant type that poses a great health threat to animals due to their uptake and translocation in animal tissues ...

Chinese Academy of Sciences

Following the development of nuclear science and technology, uranium contamination has been an ever increasing concern worldwide because of its potential for migration from the waste repositories and long-term contaminated environments. Physical and chemical techniques for uranium pollution are expensive and challenging. An alternative to these technologies is microbially mediated uranium bioremediation in contaminated water and soil environments due to its reduced cost and environmental friendliness. To date, four basic mechanisms of uranium bioremediation-uranium bioreduction, biosorption, biomineralization, and bioaccumulation-have been established, of which uranium bioreduction and biomineralization have been studied extensively. The objective of this review is to provide an understanding of recent developments in these two fields in relation to relevant microorganisms, mechanisms, influential factors, and obstacles.

Uranium Bioreduction and Biomineralization.

Recent reports have drawn attention to the uranium contamination arising from coal mining activities in the Yili region of Xinjiang, China due to the mixed distribution of uranium and coal mines, and some of the coal mines being associated with a high uranium content. In this study, we have collected water samples, solid samples such as soil, mud, coal, and coal ash, and hair and urine samples from local populations in order to evaluate the uranium level in this environment and its implications for humans in this high uranium coal mining area. Our results showed that uranium concentrations were 8.71-10.91 μg L in underground water, whereas lower levels of uranium occurred in river water. Among the solid samples, coal ash contained fairly high concentrations of uranium (33.1 μg g) due to enrichment from coal burning. In addition, uranium levels in the other solid samples were around 2.8 μg g (the Earth's average background value). Uranium concentrations in hair and urine samples were 22.2-634.5 ng g (mean: 156.2 ng g) and 8.44-761.6 ng L (mean: 202.6 ng L), respectively, which are significantly higher than reference values reported for unexposed subjects in other areas. Therefore, these results indicate that people living in this coal mining area have been subjected to uranium exposure for long periods of time.

A survey of uranium levels in urine and hair of people living in a coal mining area in Yili, Xinjiang, China.

Plastic film mulching has been extensively used in farmland, especially in arid regions, for over half-century. However, this has led to heavy pollution of soils by microplastics (MPs). Currently, efficient extraction of MPs from the organo-mineral soil matrix is a problem because microsize clay particles tightly adhere to MPs. It is therefore extremely challenging to investigate, identify, quantify, and characterize MP particles and their behavior in agricultural soils. In this study, we developed a simple and effective method of separating and extracting MPs from the soil matrix. Clean polyethylene (PE) MPs were obtained after a series of treatments including pressure leaching, flotation, electrostatic adsorption, and concentrated sulfuric acid (98% HSO) carbonization. The characteristics of MP pollutants, such as abundance, size, and morphology, in soils that have been continuously mulched with PE film for various periods of time were determined after extraction. The highest abundance of MPs (40.35 mg/kg) with sizes ranging from 0.9-2.0 mm was found in soil samples that had been continuously mulched with plastic film for 30 years. The sampled MP particles are in the microplastic size (0.8-0.3 mm) range, and the size of MPs decreases gradually as the period of mulching increased. Scanning electron microscopy analysis showed that the surface of the MP particles showed visible cracks, with round holes, and the particle surface roughened as the number of years of continuous mulching increased. Fourier-transform infrared spectroscopy results showed that the absorption peak area of hydrocarbyl (-CH) of PE MPs decreased significantly, and the typical oxidation characteristic peak area increased as the mulching period increased. The concentration of mesoplastics also increased, from 91.20 mg/kg to 308.50 mg/kg, when the mulching period increased from 5 to 30 years.

Rehemanjiang Wufuer

Xinjiang Key Laboratory of Environmental Pollution and Bioremediation,
Xinjiang Institute of Ecology and Geography,
Xinjiang Key Laboratory of Environmental Pollution and Bioremediation, Xinjiang Institute of Ecology and Geography

Chinese Academy of Sciences

Ecotoxicological Effects of Microplastics on Bird Embryo Development by Hatching without Eggshell