Copper Drinking Water Pipes as a Previously Undocumented Source of Silver-Based Nanoparticles

Nanoparticles in drinking water: Assessing health risks and regulatory challenges

Nanoparticles (NPs) pose a significant concern in drinking water due to their potential health risks and environmental impact. This review provides a comprehensive analysis of the current understanding of NP sources and contamination in drinking water, focusing on health concerns, mitigation strategies, regulatory frameworks, and future perspectives. This review highlights the importance of nano-specific pathways, fate processes, health risks & toxicity, and the need for realistic toxicity assessments. Different NPs like titanium dioxide, silver, nanoplastics, nanoscale liquid crystal monomers, copper oxide, and others pose potential health risks through ingestion, inhalation, or dermal exposure, impacting organs and potentially leading to oxidative stress, inflammatory responses, DNA damage, cytotoxicity, disrupt intracellular energetic mechanisms, reactive oxygen species generation, respiratory and immune toxicity, and genotoxicity in humans. Utilizing case studies and literature reviews, we investigate the health risks associated with NPs in freshwater environments, emphasizing their relevance to drinking water quality. Various mitigation and treatment strategies, including filtration systems (e.g., reverse osmosis, and ultra/nano-filtration), adsorption processes, coagulation/flocculation, electrocoagulation, advanced oxidation processes, membrane distillation, and ultraviolet treatment, all of which demonstrate high removal efficiencies for NPs from drinking water. Regulatory frameworks and challenges for the production, applications, and disposal of NPs at both national and international levels are discussed, emphasizing the need for tailored regulations to address NP contamination and standardize safety testing and risk assessment practices. Looking ahead, this review underscores the necessity of advancing detection methods and nanomaterial-based treatment technologies while stressing the pivotal role of public awareness and tailored regulatory guidelines in upholding drinking water quality standards. This review emphasizes the urgency of addressing NP contamination in drinking water and provides insights into potential solutions and future research directions. Lastly, this review worth concluded with future recommendations on advanced analytical techniques and sensitive sensors for NP detection for safeguarding public health and policy implementations.

Characterization of Fe-Containing and Pb-Containing Nanoparticles Resulting from Corrosion of Plumbing Materials in Tap Water Using a Hyphenated ATM-DMA-spICP-MS System

Single-particle inductively coupled plasma mass spectrometry (spICP-MS) has been used to characterize metallic nanoparticles (NPs) assuming that all NPs are spherical and composed of pure element. However, environmental NPs generally do not meet these criteria, suggesting that spICP-MS may underestimate their true sizes. This study employed a system hyphenating the atomizer (ATM), differential mobility analyzer (DMA), and spICP-MS to characterize metallic NPs in tap water. Its performance was validated by using reference Au nanoparticles (AuNPs) and Ag-shelled AuNPs. The hyphenated system can determine the actual size and metal composition of both NPs with additional heating after ATM, while stand-alone spICP-MS misidentified the Ag-shelled AuNPs as smaller individual AgNPs and AuNPs. Dissolved metal ions could introduce artifact NPs after heating but could be eliminated by centrifugation. The hyphenated system was applied to characterize Fe-containing and Pb-containing NPs resulting from the corrosion of plumbing materials in tap water. The mode sizes of Fe-containing and Pb-containing NPs were determined to be 110 and 100 nm and the particle number concentrations were determined to be 4.99 × 107 and 1.40 × 106 #/mL, respectively. Cautions should be paid to potential changes in particle size induced by heating for metallic NPs with a low melting point or a high organic content.

Evaluation of Maghemite Nanoparticles-Induced Developmental Toxicity and Oxidative Stress in Zebrafish Embryos/Larvae

Maghemite nanoparticles ([Formula: see text] NPs) have a wide array of applications in various industries including biomedical field. There is an absence of legislation globally for the regulation of the production, use, and disposal of such NPs as they are eventually dumped into the environment where these NPs might affect the living systems. This study evaluates the effect of the [Formula: see text] NP-induced developmental toxicity in zebrafish embryos/larvae. The commercially available Fe₂O₃ NPs were purchased, and zebrafish embryos toxicity test was done by exposing embryos to various concentrations of [Formula: see text] NPs at 1 hpf and analyzed at 96 hpf. Based on the LC₅₀ value (60.17 ppm), the sub-lethal concentrations of 40 and 60 ppm were used for further experiments. Hatching, lethality, developmental malformations, and heartbeat rate were measured in the control and treated embryos/larvae. The ionic Fe content in the media, and the larvae was quantified using ICP-MS and AAS. The biomolecular alterations in the control and treated groups were analyzed using FT-IR. The Fe ions present in the larvae were visualized using SEM-EDXS. In situ detection of AChE and apoptotic bodies was done using staining techniques. Biochemical markers (total protein content, AChE, and Na⁺ K⁺-ATPase) along with oxidants and antioxidants were assessed. A significant decrease in the heartbeat rate and hatching delay was observed in the treated groups affecting the developmental processes. Teratogenic analysis showed increased developmental deformity incidence in treated groups in a dose-dependent manner. The accumulation of Fe was evidenced from the ICP-MS, AAS, and SEM-EDXS. Alterations in AChE and Na⁺ K⁺-ATPase activity were observed along with an increment in the oxidants level with a concomitant decrease in antioxidant enzymes. These results show [Formula: see text] NP exposure leads to developmental malformation and results in the alteration of redox homeostasis.

Nanobionics in Crop Production: An Emerging Approach to Modulate Plant Functionalities

The "Zero Hunger" goal is one of the key Sustainable Development Goals (SDGs) of the United Nations. Therefore, improvements in crop production have always been a prime objective to meet the demands of an ever-growing population. In the last decade, studies have acknowledged the role of photosynthesis augmentation and enhancing nutrient use efficiency (NUE) in improving crop production. Recently, the applications of nanobionics in crop production have given hope with their lucrative properties to interact with the biological system. Nanobionics have significantly been effective in modulating the photosynthesis capacity of plants. It is documented that nanobionics could assist plants by acting as an artificial photosynthetic system to improve photosynthetic capacity, electron transfer in the photosystems, and pigment content, and enhance the absorption of light across the UV-visible spectrum. Smart nanocarriers, such as nanobionics, are capable of delivering the active ingredient nanocarrier upon receiving external stimuli. This can markedly improve NUE, reduce wastage, and improve cost effectiveness. Thus, this review emphasizes the application of nanobionics for improving crop yield by the two above-mentioned approaches. Major concerns and future prospects associated with the use of nanobionics are also deliberated concisely.

Insights into the lower trophic transfer of silver ions than silver containing nanoparticles along an aquatic food chain

Silver nanoparticles (AgNPs) released into the environment are subject to environmental transformation processes before accumulating in aquatic organisms and transferring along the food chain. Lack of understanding on how environmental transformation affects trophic transfer of AgNPs hinders accurate prediction of the environmental risks of these widely present nanomaterials. Here we discover that pristine AgNPs as well as their sulfidation products (Ag₂S-NPs) and dissolution products (Ag⁺) tend to be accumulated in Daphnia magna and subsequently transferred to zebrafish. In D. magna, Ag⁺ exhibits the highest bioaccumulation potential whereas Ag₂S-NPs show the lowest bioaccumulation. Surprisingly, the biomagnification factor of Ag⁺ along the D. magna-zebrafish food chain appears to be significantly lower relative to AgNPs and Ag₂S-NPs, likely due to the limited release of Ag from D. magna to zebrafish during digestion. Moreover, AgNPs and their transformation products mainly accumulate in the internal organs, particularly intestine, of zebrafish. Adsorption of AgNPs on the surface of the intestinal cell membrane mitigates depuration of AgNPs and, at least in part, leads to the larger biomagnification factor of AgNPs, relative to their transformation products. This research highlights the necessity of considering environmental transformation processes of nanomaterials in assessing their bioavailability and risk.

Potential concerns in fullerene application to water treatment related to transformation, cellular uptake and intracellular catalysis

Fullerene (C₆₀) exhibits versatile properties that shows great potential for improving water treatment technologies. However, the probable transformation of C₆₀ during water treatment, which consequently changes the physicochemical properties and toxicity of the parent compound, may introduce doubt concerning its application. Our results demonstrated that the C₆₀ aggregate (nC₆₀) was transformed to a more oxidized form under common water disinfection processes (i.e., ultraviolet irradiation and photochlorination). The light-irradiated product (UV_nC₆₀) exhibited lower cytotoxicity toward macrophage J774A.1 cells relative to nC₆₀, whereas the photochlorinated product (UV/Cl_nC₆₀) increased the toxic effect. Particularly, the internalization of nanoparticles and the mimetic superoxide dismutase (SOD) activity resulted in the selective accumulation of intracellular hydrogen peroxide. Thus, sequential exposure to a nonlethal dose of nanoparticles followed by 5 μM copper ions (which is a much lower level than the EPA-regulated level of 20 μM in drinking water) led to the significant production of hydroxyl radicals inside cells. The uptake and SOD-like activity were highly structure-related, with the most noteworthy activity obtained for UV/Cl_nC₆₀. These results emphasize that environmental transformation-induced property changes should be given adequate consideration in the risk assessment of C₆₀.