Influence of Al2O3 Nanoparticles on the Soil Elements

Impact on Some Soil Physical and Chemical Properties Caused by Metal and Metallic Oxide Engineered Nanoparticles: A Review

In recent years, the release of metal and metallic oxide engineered nanoparticles (ENPs) into the environment has generated an increase in their accumulation in agricultural soils, which is a serious risk to the ecosystem and soil health. Here, we show the impact of ENPs on the physical and chemical properties of soils. A literature search was performed in the Scopus database using the keywords ENPs, plus soil physical properties or soil chemical properties, and elements availability. In general, we found that the presence of metal and metallic oxide ENPs in soils can increase hydraulic conductivity and soil porosity and reduce the distance between soil particles, as well as causing a variation in pH, cation exchange capacity (CEC), electrical conductivity (EC), redox potential (Eh), and soil organic matter (SOM) content. Furthermore, ENPs or the metal cations released from them in soils can interact with nutrients like phosphorus (P) forming complexes or precipitates, decreasing their bioavailability in the soil solution. The results depend on the soil properties and the doses, exposure duration, concentrations, and type of ENPs. Therefore, we suggest that particular attention should be paid to every kind of metal and metallic oxide ENPs deposited into the soil.

Risks of graphene nanomaterial contamination in the soil: evaluation of major ions

Soils are facing new environmental contaminants, such as nanomaterials. While these emerging contaminants are increasingly being released into soil, their potential impact on this medium and their effect on soil's major chemical components (e.g., sulfate, nitrate, ammonia, and phosphate) have yet to be examined, as well as their relation with microbial toxicity. Herein, column experiments were conducted to investigate the behavior of major ions under 10 and 200 mg/L multiple contaminations of graphene nanomaterials in agricultural and undisturbed soils, as well as the retention of the graphene nanomaterials in the soil and their effect on soil zeta potentials throughout the column. Moreover, to evaluate the impact of the risks of graphene nanomaterial contamination on soil major ions, the present study also examines the bacterial toxicity. The results showed that graphene retention was influenced the soil zeta potentials. Graphene also influenced the concentrations of the major ions in soil and the order of the influence degree was sulfate > phosphate > ammonia > nitrate. The changes of the major ions in soil by the exposure of graphene nanomaterials have also affected the response of selected bacteria.

Effects of Zn and ZnO Nanoparticles on Artemia salina and Daphnia magna Organisms: Toxicity, Accumulation and Elimination

In the study, Zn in the size of 40-60 nm and 80-100 nm and ZnO in the size of 10-30 nm were applied to A. salina and D. magna individuals in 7 groups with 3 repetitions. Measurements were made at 24^th, 48^th and 72^nd hours and elimination values were examined at +24 h. LC₅₀ values of NPs were determined and chemical analysis (metal accumulation and elimination), ion quantities which were given to the environment and the survival rates of organisms were determined after the exposure. According to the results of phase contrast microscopy, it was found that both experimental organisms absorbed the NPs in the medium level. In the toxicity results of D. magna, it can be said that Zn NP (40-60 nm) has a highly toxic effect only at 50 ppm concentration for 48 h and lethal dose can be accepted as of 5 ppm at the end of 72 h. In A. salina individuals, it is clearly seen that there is an increase in mortality in organisms parallel to the dose increase. Although all NPs were applied to organisms in low doses corresponding to environmental values, it was observed that toxic effect was in parallel with the increase in time. It is clearly known that there is the inverse proportion between the size of NPs and the toxic effect. The smaller the size of NPs is, the higher the toxic effect becomes When the results of Zn accumulation and elimination of A. salina and D. magna individuals exposed to the Zn and ZnO NPs were examined; it was found that accumulation and elimination occurred in parallel with the increase in concentration at each application hour and elimination. Intensive and possible misuse of nanoscale materials is one of the biggest threats to the environment and all living things worldwide.