Assay for lipid peroxides in animal tissues by thiobarbituric acid reaction

http://faculty.wwu.edu/~shulld/ESCI%20101/Andrady2011Plastics.pdf

Microplastics in the marine environment

介绍了Kirk—Othmer Encyclopedia of Chemical Technology（化工技术百科全书）（第五版）电子图书网络版数据库，并对该数据库使用方法和检索途径作出了说明，且结合实例简单地介绍了该数据库的检索方法。

Kirk-Othmer Encyclopedia of Chemical Technology数据库介绍及实例

The recent advances in nanotechnology and the corresponding increase in the use of nanomaterials in products in every sector of society have resulted in uncertainties regarding environmental impacts. The objectives of this review are to introduce the key aspects pertaining to nanomaterials in the environment and to discuss what is known concerning their fate, behavior, disposition, and toxicity, with a particular focus on those that make up manufactured nanomaterials. This review critiques existing nanomaterial research in freshwater, marine, and soil environments. It illustrates the paucity of existing research and demonstrates the need for additional research. Environmental scientists are encouraged to base this research on existing studies on colloidal behavior and toxicology. The need for standard reference and testing materials as well as methodology for suspension preparation and testing is also discussed.

Nanomaterials in the environment: Behavior, fate, bioavailability, and effects

Titanium dioxide (TiO2) nanoparticles (NPs) are manufactured worldwide in large quantities for use in a wide range of applications. TiO2 NPs possess different physicochemical properties compared to their fine particle (FP) analogs, which might alter their bioactivity. Most of the literature cited here has focused on the respiratory system, showing the importance of inhalation as the primary route for TiO2 NP exposure in the workplace. TiO2 NPs may translocate to systemic organs from the lung and gastrointestinal tract (GIT) although the rate of translocation appears low. There have also been studies focusing on other potential routes of human exposure. Oral exposure mainly occurs through food products containing TiO2 NP-additives. Most dermal exposure studies, whether in vivo or in vitro, report that TiO2 NPs do not penetrate the stratum corneum (SC). In the field of nanomedicine, intravenous injection can deliver TiO2 nanoparticulate carriers directly into the human body. Upon intravenous exposure, TiO2 NPs can induce pathological lesions of the liver, spleen, kidneys, and brain. We have also shown here that most of these effects may be due to the use of very high doses of TiO2 NPs. There is also an enormous lack of epidemiological data regarding TiO2 NPs in spite of its increased production and use. However, long-term inhalation studies in rats have reported lung tumors. This review summarizes the current knowledge on the toxicology of TiO2 NPs and points out areas where further information is needed.

/pdf/titanium-dioxide-nanoparticles-a-review-of-current-1qh7o5i0ft.pdf

Titanium dioxide nanoparticles: a review of current toxicological data

With the emergence of manufactured nanomaterials, it is urgent to carry out researches on their potential environmental impacts and biological effects To better understand the potential ecotoxicological impacts of metal oxide nanoparticles released to aquatic environments, the zebrafish 96-h embryo-larval bioassay was used to assess and compare the developmental toxicities of nanoscale zinc oxide (nZnO), titanium dioxide (nTiO(2)) and alumina (nAl(2)O(3)) aqueous suspensions Toxicological endpoints such as zebrafish embryos or larvae survival, hatching rate and malformation were noted and described within 96 h of exposure Meanwhile, a comparative experiment with their bulk counterparts (ie, ZnO/bulk, TiO(2)/bulk and Al(2)O(3)/bulk) was conducted to understand the effect of particle size on their toxicities The results showed that: (i) both nZnO and ZnO/bulk aqueous suspensions delayed zebrafish embryo and larva development, decreased their survival and hatching rates, and caused tissue damage The 96-h LC(50) of nZnO and ZnO/bulk aqueous suspensions on the zebrafish survival are 1793 mg/L and 1550 mg/L respectively; and the 84-h EC(50) on the zebrafish embryo hatching rate are 2065 mg/L and 2066 mg/L respectively Serious tissue ulceration was found on zebrafish larvae exposed to nZnO and ZnO/bulk aqueous suspensions (ii) In contrast, neither nTiO(2) and TiO(2)/bulk nor nAl(2)O(3) and Al(2)O(3)/bulk showed any toxicity to zebrafish embryos and larvae under the same experimental condition It revealed that the metal oxide nanoparticles with different chemical composition have different zebrafish developmental toxicities (iii) Exposures of nTiO(2), nZnO and nAl(2)O(3) produced toxic effects on zebrafish embryos and larvae, which was not different from the effects caused by exposing to their bulk counterparts This is the first study about the developmental toxicity of metal oxide nanoparticles, and the results demonstrate that nZnO is very toxic to zebrafish embryos and larvae, which highlights the need to evaluate the potential eco-toxicity of these manufactured nanomaterials (MNMs)

Comparative toxicity of several metal oxide nanoparticle aqueous suspensions to Zebrafish (Danio rerio) early developmental stage

Toxicity and bioaccumulation of TiO2 nanoparticle aggregates in Daphnia magna.

The rapid growth of nanotechnology is stimulating research on the potential environmental impacts of manufactured nanomaterials (MNMs). This paper summarizes a comprehensive study on the 48-h acute toxicity of water suspensions of six MNMs (i.e., ZnO, TiO2, Al2O3, C60, SWCNTs, and MWCNTs) to Daphnia magna, using immobilization and mortality as toxicological endpoints. The results show that the acute toxicities of all MNMs tested are dose dependent. The EC50 values for immobilization ranged from 0.622 mg/L (ZnO NPs) to 114.357 mg/L (Al2O3 NPs), while the LC50 values for mortality ranged from 1.511 mg/L (ZnO NPs) to 162.392 mg/L (Al2O3 NPs). In these tests, TiO2, Al2O3, and carbon-based nanomaterials were more toxic than their bulk counterparts. Moreover, D. magna were found to ingest nanomaterials from the test solutions through feeding behaviors, which indicates that the potential ecotoxicities and environmental health effects of these MNMs cannot be neglected.

Acute toxicities of six manufactured nanomaterial suspensions to Daphnia magna

Trophic transfer of TiO2 nanoparticles from daphnia to zebrafish in a simplified freshwater food chain

With extensive use of metal oxide nanoparticles (NPs) in a variety of applications comes a higher potential of release into aquatic environments. NPs tend to form much larger aggregates in water, which are expected to settle down to the bottom of the water column and possibly get mixed with the sediments. However, little is known about the environmental impacts and biological effects of these aggregated NPs in the sediment column. In this study, we examined the sedimentation of nanoscale ZnO particles (nZnO) in zebrafish culture medium, and assessed the toxicity of settled nZnO aggregates on developing zebrafish embryos and larvae. Given the known dissolution of nZnO particles to release Zn(2+), we also assessed the toxic effect of soluble Zn(2+) in this organism. We demonstrated that within 48 h, micron-sized nZnO aggregates were formed and settled out of the culture medium. These aggregates were found to exert dose-dependent toxicity to zebrafish embryos and larvae, reducing the hatching rate and causing pericardial edema. The observed toxicity of the nZnO aggregates was not likely a result solely of particle dissolution, as soluble Zn(2+) alone caused much less toxicity to zebrafish embryos than nZnO. Instead, the combination of both nZnO and Zn(2+) may contribute to the embryonic toxicity, possibly by increasing reactive oxidative species (ROS) and/or compromising the cellular oxidative stress response. Interestingly, we demonstrated that one type of formulated sediments could mitigate the toxicity of nZnO aggregates, highlighting a possible countermeasure to reduce the adverse impact of nZnO aggregates on the environment.

https://iopscience.iop.org/article/10.1088/0957-4484/20/19/195103/pdf

Xiaoshan Zhu

Papers

Comparative toxicity of several metal oxide nanoparticle aqueous suspensions to Zebrafish (Danio rerio) early developmental stage

Toxicity and bioaccumulation of TiO2 nanoparticle aggregates in Daphnia magna.

Acute toxicities of six manufactured nanomaterial suspensions to Daphnia magna

Trophic transfer of TiO2 nanoparticles from daphnia to zebrafish in a simplified freshwater food chain

The impact of ZnO nanoparticle aggregates on the embryonic development of zebrafish(Danio rerio)