Influence of soil properties on the effect of silver nanomaterials on microbial activity in five soils

Abstract

We investigated the effects of silver nanomaterials (AgNMs) on five well-characterized soils with distinct physicochemical properties using two standardized test systems. The carbon transformation test (OECD217) showed minimal sensitivity whereas the ammonia oxidizing bacteria test (ISO 15685) showed extreme sensitivity over 28 days of exposure. AgNM toxicity was compared with the physicochemical properties of the soils, revealing that toxicity declined with increasing clay content and increasing pH. AgNM toxicity did not appear to be affected by the organic carbon content of the soil. Our results showed that AgNM toxicity cannot be attributed to any single soil property but depends on the same parameters that determine the toxicity of conventional chemicals. Recommendations in the test guidelines for soil ecotoxicity studies are therefore applicable to AgNMs as well as conventional chemicals.

Silver nanoparticles (AgNPs) biosynthesized using pod extract of Cola nitida enhances antioxidant activity and phytochemical composition of Amaranthus caudatus Linn

“…Epidemiological studies have also strongly shown that consumption of vegetables positively correlated to prevention of degenerative diseases (Li et al 2015), while studies have established high correlation between antioxidant activity and phytochemicals of vegetables (Olajire and Azeez 2011). However, the composition and concentration of phytochemicals in vegetables are influenced by many factors, such as soil condition (chemical form, bioavailability and mobility), photosynthesis pigment contents and climatic conditions (Chandra et al 2014;Leonov et al 2015;Li et al 2015;Schlich and Hund-Rinke 2015). A novel way to improve the quantity and quality of phytochemicals in vegetables is through the intervention of nanobiotechnology, which was undertaken in this study.…”

“…Nanosilvers either chemically or biologically synthesized have unequalled properties, and have gained prominence because of their anticancer, antimicrobial, antibacterial, larvicidal, antioxidant antiparasitic, anticoagulant, thrombolytic and antifungal properties Jayaseelan et al 2011;Sukirtha et al 2012;Zahir and Rahuman 2012;Raliya et al 2015;Azeez et al 2016;Lateef et al 2016a, b, c, d;Ojo et al 2016). Due to these properties nanosilvers have been used in therapeutics, and applied in manufacturing of plastics, textile, healthcare products and electrical appliances (Gengan et al 2013;Schlich and Hund-Rinke 2015;Lateef et al 2016e).…”

Considerations of Environmentally Relevant Test Conditions for Improved Evaluation of Ecological Hazards of Engineered Nanomaterials

“…122-134 ENMs can acquire coatings 135, 136 such as natural organic matter (NOM), 137, 138 and age with varying pH and sunlight. 139, 140 Assessment outcomes are affected by media chemistry, physical characteristics, and additives (e.g., soil pH, 141 temperature, 142 or organic matter content, 108, 143 and dispersing agents in aqueous media 144 ). The exposure concentration at the receptor and consequent effects 145 depend on ENM dissolution 146 perhaps assisted by biotic ligands, 147 and speciation, 103 shed ions, 103 surface associations, 148 and heteroaggregation with colloids and particulate matter, 148-151 or agglomeration and settling.…”

Silver effect on the biodegradation process of styrene-ethylene/butylene-styrene based thermoplastic elastomers compounds upon weathering exposure

“…50, 5.32 and 5.42, respectively and between 5.16 -5.23 in soil with silver-loaded TPE. Given that the pH of the solution can affect the metabolism and membrane permeability of microorganisms or impact on the oxidation and toxic element release (Schlich & Hund-Rinke, 2015), it can be proposed that differences in pH between soils may have changed the availability of toxic elements or the sensitivity of microbes to silver.…”