A re-assessment of the safety of silver in household water treatment: rapid systematic review of mammalian in vivo genotoxicity studies

Abstract

BackgroundDespite poor evidence of their effectiveness, colloidal silver and silver nanoparticles are increasingly being promoted for treating potentially contaminated drinking water in low income countries. Recently, however, concerns have been raised about the possible genotoxicity of particulate silver.ObjectivesThe goal of this paper was to review the published mammalian in vivo genotoxicity studies using silver micro and nanoparticles.MethodsSCOPUS and Medline were searched using the following search string: (“DNA damage” OR genotox* OR Cytotox* OR Embryotox*) AND (silver OR AgNP). Included papers were any mammalian in vivo experimental studies investigating genotoxicity of silver particles. Studies were quality assessed using the ToxRTool.Results16 relevant papers were identified. There were substantial variations in study design including the size of silver particles, animal species, target organs, silver dose, route of administration and the method used to detect genotoxicity. Thus, it was not possible to produce a definitive pooled result. Nevertheless, most studies showed evidence of genotoxicity unless using very low doses. We also identified one human study reporting evidence of “severe DNA damage” in silver jewellery workers occupationally exposed to silver particles.ConclusionsWith the available evidence it is not possible to be definitive about risks to human health from oral exposure to silver particulates. However, the balance of evidence suggests that there should be concerns especially when considering the evidence from jewellery workers. There is an urgent need to determine whether people exposed to particulate silver as part of drinking water treatment have evidence of DNA damage.

Silver and zinc oxide nanoparticle disinfection in water treatment applications: synergy and water quality influences

“…Concerns, however, remain regarding silver's health, economic, and technical impacts, hindering its applicability to POUWTS. Specifically, over-consumption of silver can lead to negative health outcomes such as Argyria or even DNA damage (Fewtrell et al 2017), leading the World Health Organization (WHO) to recommend a 0.1 mg/L limit on silver concentration in drinking water; this concentration ensures less than 10 g of silver be consumed over a 70-year lifespan (WHO 2011). Silver is also a notably expensive material, with a cost of approximately $3 USD per gram (Argenol Laboratories, personal communication, 2017).…”

Silver Nanoparticles in the Lung: Toxic Effects and Focal Accumulation of Silver in Remote Organs

“…The inflammatory, DNA-damaging and cytokine-inductive properties of Ag-NP have been well known for several years and have been reviewed along with innovative detection methods [ 4 ]. Consequently, many studies addressing safety aspects of Ag-NP have focused on the effects of Ag-NP secondary to oral, intravenous or intraperitoneal application [ 5 , 6 , 7 ]. However, as Ag-NP can also occur as airborne dust, e.g., during nanoparticle (NP) fabrication processes, well-adapted occupational exposure levels are necessary, as well, and have been recently suggested [ 2 ].…”

Mechanisms and efficacy of disinfection in ceramic water filters: A critical review

“…Silver elution is a significant feature of CWF performance, as it is necessary to ensure the concentration in the effluent remains below the WHO's recommended limit of 0.1 mg/L (World Health Organization, 2006). Daily ingestion of silver above this concentration may lead a lifetime accumulation greater than 10 g (WHO, 2011), which can lead to negative health outcomes such as Argyria or even DNA damage (Fewtrell et al, 2017). Guidelines developed by The Canadian Council of Ministers of the Environment (CCME) also stipulate total silver directly released into freshwater and marine environments should be in quantities no greater than 0.25 and 7.5 mg/L, respectively, to ensure the protection of aquatic life (CCME, 2015).…”