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Posted: Dec 27, 2010
California chemical information call-in: Nanometals, nanometal oxides, and quantum dots
(Nanowerk News) Pursuant to Health and Safety Code section 57019(d), the Department of Toxic Substances Control (DTSC) formally announces this request for information regarding analytical test methods, and other relevant information, from manufacturers of the following nanomaterials:
Health and Safety Code section 57018(a)(4) defines a "manufacturer" as a "person who produces a chemical in this state or imports a chemical into this state for sale in this state." Accordingly, persons and businesses who produce or import one or more of the above chemicals, in any quantity, must comply with the statute and this request.
The Type of Information Requested
DTSC seeks information about analytical test methods - which are laboratory procedures for sampling, preparing, and analyzing a specific matrix to determine the identity and concentration of the specified chemical. For this call-in, DTSC requests information about the analytical test methods to detect and measure these six nanomaterials in the environment. Specifically, we seek relevant information about analytical test methods which identify and quantify these nanomaterials, their metabolites, and their degradation products in water, air, soil, sediment, sludge, chemical waste, fish, blood, adipose tissue, and urine.
Reasons for Requesting This Information
DTSC has conducted a search of known public sources for analytical test methods for these six nanomaterials. We have compiled our research in this bibliography. DTSC has also contacted and consulted with manufacturers, researchers, environmental laboratory experts, other governments, and stakeholders regarding analytical test methods for these nanomaterials in these matrices. We convened public workshops and symposia on nanotechnology and, in particular, these six nanomaterials.
From our research, consultations, and workshops, we have determined that little or no information on analytical test methods for these nanomaterials in the human body or the environment now exists. To better understand the behavior, fate and transport of the se six nanomaterials, appropriate analytical test methods are needed for manufacturers, for contract and reference laboratories, and for regulatory agencies. Manufacturers may be required to develop information consistent with the requirements of Health and Safety Code section 57019(c) and (d).
Nano silver is used increasingly in many consumer products. These include food contact materials (storage containers, cups, bowls and cutting boards), children's toys and infant products, disinfectants, cosmetics, cleaning agents and machines, textiles, athletic apparel, dyes/paints, varnishes, polymers, and in medical products and applications. Given these diverse applications, nano silver is likely entering the environment. Several scientific studies describe potential adverse effects of nano silver on publicly owned treatment works (wastewater collection, treatment, and disposal systems).
Silver has been known historically as a potent antibacterial, antifungal, and antiviral agent. In recent years, silver is used as a biocide in solution, suspension, and in nano-particulate form. The strong antimicrobial activity is a major reason for the development of products that contain nano silver. Nano silver may also have applications in agricultural, vector, and urban pest control. However, little or no information about detecting and measuring the effect of nano silver in the environment exists. Recent published papers point out difficulties in quantifying the existence of nano particles in environmental and biological contexts, which presents challenges in estimating and assessing the hazards and risks of nano silver.
Nano Zero Valent Iron (nZVI)
Nano zero valent iron (nZVI, or nano iron) particles, powder or slurry and bimetallic (iron and palladium) particles are increasingly used for environmental remediation of contaminated groundwater and soil and for the treatment of water and wastewater. Nano iron powder is used in magnetic materials for coatings, sensors, memory and storage; electrodes for batteries, fuel cells, water electrolysis, capacitors, integrated circuits; and chemical catalysts. Nano iron in aqueous dispersion is used for adsorption of bio-molecules for labeled probe synthesis, drug carriers, catalyst, ferrofluids, molecular delivery and heating, high density magnetic recording, magnetic pastes, and other applications. Federal agencies (USEPA, USNIST) and others have expressed concerns about the fate and transport of nano zero valent iron in the environment and its potential effects on ecosystems and human health.
Nano Titanium Dioxide
Nano titanium dioxide is used widely, from cosmetics and consumer products to construction materials. The photocatalytic property of nano titanium dioxide produces oxidative stress which can adversely affect mammalian cells. Scientific studies report that nano titanium dioxide causes oxidative stress-mediated toxicity in human colon cells.
Nano Zinc Oxide
Unique chemical, electrical, optical, and physical properties of nano zinc oxide enable many applications, including cosmetics, pigments, paints and coatings, automobile tires, food pathogen inhibitors, and antimicrobial wound dressings. As production and uses of nano zinc oxide increases, releases to the environment - particularly waste, wastewater, sludge, and soils - are likely increasing. Numerous published scientific studies on crustaceans, bacteria, algae, fish, ciliates, nematodes, yeast, rodent and human cells have observed toxicity associated with nano zinc oxide.
Nano Cerium Oxide
Nano cerium oxide is used as a combustion catalyst in the automotive industry and as a polishing agent in the optics and semiconductor industries. Scientific studies report aquatic toxicity, cytotoxicity by oxidative stress, and uptake in the human lung as potential harms from nano cerium oxide.
Quantum dots (QDs) are being produced in increasingly larger numbers for a wide array of uses in consumer products (cell phone cameras, products with LEDs), medicine, and green products such as solar cells. Production of quantum dot-enabled solar cells is estimated to increase at least five-fold over 2007 levels by 2012. While they may produce brighter pictures on our television screens at lower cost, provide better detection systems for early cancer detection, and produce clearer pictures in cell phones, the environmental, health and safety aspects of quantum dots are generally unknown. Results of the relatively few studies in lab animals have ranged from no effects while others have shown some toxicity. Results from more numerous in-vitro ("test tube") studies have been similar as well as have provided some information on how toxicity may occur. However, overall there is a lack information about the human health and environmental effects of quantum dots.