Copper and zinc concentrations in human hair and popular foodstuffs in China

<p>Concentrations of copper (Cu) and zinc (Zn) were determined in 383 human hair samples and in 445 food samples purchased in 11 Chinese cities. The concentrations of Cu were 7.91, 5.39, 2.27 and 2.20 mg kg⁻¹ and those of Zn were 47.2, 24.8, 52.8 and 30.2 mg kg⁻¹ in vegetables, cereals, meat and fish, respectively. The overall mean concentrations of hair Cu and Zn were 8.97 and 128 mg kg⁻¹, respectively. Hair Cu and Zn concentrations were higher in females than in males, especially in the 13–19 and 20–50 year age groups. Hair Cu concentration increased with increasing age and these changes occurred mainly in males. In contrast, 51–65 years old females had the lowest hair Zn concentrations. Residents of rural areas had similar hair Cu or Zn concentrations to people in urban areas. There were no significant correlations between hair concentration and food intake in terms of Cu and Zn among the cities. The results indicate that hair Cu and Zn concentrations and their changes with biological and environmental factors cannot be explained satisfactorily by the estimated food intakes in the cities sampled.</p

Cytotoxicity of DnBP determined by flow cytometry assays.

<p>(a) coelomocyte apoptosis (a1,a2) stained with Annexin V-FITC and PI (Upper left quadrant, necrotic cells; upper right quadrant, late/secondary apoptotic cells; bottom left quadrant, live cells; and bottom right quadrant, early/primary apoptotic cells) in the 28th day and (b) lysosomal membrane stability characterized by NRR time in extruded coelomocyte of treated <i>E</i>. <i>fetida</i> in the 7th, 14th, 21st and 28th day after exposure in spiked natural soil CK, B-1, B-2, B-3, and B-4 for 28 days (n = 4; error bars, SEM). Refer other annotates to <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0151128#pone.0151128.g001" target="_blank">Fig 1</a>.</p

Genotoxicity of DnBP analyzed by comet assay.

<p>(a) length of tail; (b) tail DNA ratio; (c) tail moment and (d) olive tail moment of coelomocyte in treated <i>E</i>. <i>fetida</i> after treated for 7d, 14d, 21d and 28d in spiked natural soil CK, B-1, B-2, B-3, and B-4 (n = 4; error bars, SEM). Length of tail (TL) means tail length in arbitrary units; tail DNA ratio means relative ratio of DNA in the comet tail; tail moment (TM) means integrated value of DNA density multiplied by the migration distance; and Olive tail moment (OTM) means the product of the distance between the center of gravity of the head and the center of gravity of the tail and percent tail DNA. Refer other annotates to <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0151128#pone.0151128.g001" target="_blank">Fig 1</a>.</p

Toxicity effects of DnBP on biochemistry parameters of <i>E</i>. <i>fetida</i>.

<p>(a) Total protein content; (b) SOD activity; (c) POD activity; and (d) ROS activity were determined after treated for 7d, 14d, 21d and 28d in spiked natural soil CK, B-1, B-2, B-3, and B-4 (n = 4; error bars, SEM/mean values of standard errors). The spiked concentrations of DnBP were 0, 1, 2.5, 5, and 10 mg kg^-1 soil. Asterisk shows significant difference at <i>p</i><0.05 level compared to the control; double asterisks show significant difference at <i>p</i><0.01 level compared to the control.</p

Toxicity effects of di-(2-ethylhexyl) phthalate to <i>Eisenia fetida</i> at enzyme, cellular and genetic levels

<div><p>Di-(2-ethylhexyl) phthalate (DEHP) is a dominant phthalic acid ester (PAE) that has aroused public concern due to its resistance to degradation and its toxicity as an endocrine-disrupting compound. Effects of different concentrations of DEHP on <i>Eisenia fetida</i> in spiked natural soil have been studied in the body of the earthworm by means of soil cultivation tests 7, 14, 21 and 28 days after exposure. The results indicated that, in general, superoxide dismutase (SOD) activity, malondialdehyde (MDA) content, metallothionein (MT) content, the expression of heat shock protein 70 (HSP 70) and all the tested geno-toxicity parameters are promoted as time elapses and with increasing concentration of DEHP. However, peroxidase (POD) activity, neutral red retention time (NRRT) and mitochondrial membrane potential difference values were found to decrease even at a low concentration of DEHP of 1 mg kg^-1 soil (<i>p</i><0.05). Clear toxic effects of DEHP on <i>E</i>. <i>fetida</i> have been generally recognized by means of the disturbance of antioxidant enzyme activity/content and critical proteins, cell membrane and organelle disorder and DNA damage estimated by length of tail, tail DNA ratio, and tail moment parameters. A concentration of DEHP of 3 mg kg^-1 may be recommended as a precaution against the potential risk of PAEs in soils and for indicating suitable threshold values for other soil animals and soil micro-organisms.</p></div

Does phytoextraction with <i>Sedum plumbizincicola</i> increase cadmium leaching from polluted agricultural soil?

Sedum plumbizincicola is a cadmium (Cd) and zinc hyperaccumulator that can activate Cd by rhizosphere acidification. However, there is little understanding of the Cd leaching risk from polluted soil during phytoextraction process. Here, pot and column experiments were conducted to monitor soil Cd leaching characteristics under different rainfall simulation conditions during S. plumbizincicola phytoextraction. Soil Cd leaching increased significantly with increasing simulated rainfall intensity. Compared with normal rainfall (NR), weak rainfall (WR) resulted in a 34.3% decrease in Cd uptake by S. plumbizincicola and also led to a 68.7% decline in Cd leaching. In contrast, Cd leaching under heavy rainfall (HR) was 2.12 times that of NR in the presence of S. plumbizincicola. After two successive growing periods, phytoextraction resulted in a 53.5–66.4% decline in the amount of soil Cd leached compared with controls in which S. plumbizincicola was absent. Even compared with maize cropping as a control, S. plumbizincicola did not instigate a significant increase in Cd leaching. The contribution of Cd leaching loss to the decline in soil total Cd concentration was negligible after phytoextraction in the pot experiment. Overall, the results contribute to our understanding of soil Cd leaching risk by phytoextraction with S. plumbizincicola. Repeated phytoextraction by hyperaccumulator Sedum plumbizincicola is an important remediation technology to remove Cd from contaminated soils. At the same time, Sedum plumbizincicola can also activate soil Cd by rhizosphere acidification. However, studies on the leaching risk of soil activated Cd during the phytoextraction process are very few. This study looked at the effects of Sedum plumbizincicola growth on soil Cd leaching with the changes in rainfall simulation and plant type. Results showed that repeated phytoextraction with Sedum plumbizincicola did not increase Cd leaching from contaminated soil.</p

Influences of Temperature and Metal on Subcritical Hydrothermal Liquefaction of Hyperaccumulator: Implications for the Recycling of Hazardous Hyperaccumulators

Waste <i>Sedum plumbizincicola</i>, a zinc (Zn) hyperaccumulator during phytoremediation, was recycled via a subcritical hydrothermal liquefaction (HTL) reaction into multiple streams of products, including hydrochar, bio-oil, and carboxylic acids. Results show approximately 90% of Zn was released from the <i>S. plumbizincicola</i> biomass during HTL at an optimized temperature of 220 °C, and the release risk was mitigated via HTL reaction for hydrochar production. The low-Zn hydrochar (∼200 mg/kg compared to original plant of 1558 mg/kg) was further upgraded into porous carbon (PC) with high porosity (930 m²/g) and excellent capability of carbon dioxide (CO₂) capture (3 mmol/g). The porosity, micropore structure, and graphitization degree of PCs were manipulated by the thermal recalcitrance of hydrochar. More importantly, results showed that the released Zn²⁺ could effectively promote the production of acetic acid via the oxidation of furfural (FF) and 5-(hydroxymethyl)-furfural (HMF). Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) with negative electrospray ionization analysis confirmed the deoxygenation and depolymerization reactions and the production of long chain fatty acids during HTL reaction of <i>S. plumbizincicola</i>. This work provides a new path for the recycling of waste hyperaccumulator biomass into value-added products