The OECD test guidelines for animal experiments play an important role in evaluating the chemical hazards. Animal tests performed using OECD guidelines, especially when the good laboratory practice (GLP) principle is applied, reduce the duplication of toxicity testing and ensure the best mutual acceptance of data by the OECD’s Mutual Acceptance of Data (MAD). The OECD inhalation toxicity test guidelines 412 (28 days) and 413 (90 days) have been revised. These OECD guidelines now reflect the inclusion of nanomaterials and recent scientific and technological developments. In particular, these test guidelines aim to evaluate the bronchoalveolar lavage fluid in the lungs for objective toxicity evaluation, along with the existing subjective histopathological evaluation. For solid particles, the lung burden measurement of particles is required for toxicokinetic studies and, in order to properly perform a toxicokinetic study, two post-exposure observations are recommended. In light of the revised OECD guidelines, we propose a method to reduce the number of animals when testing is conducted for nanomaterials.

A lithium-ion battery is a rechargeable battery that uses the reversible reduction of lithium ions to store energy and is the predominant battery type in many industrial and consumer electronics. The lithium-ion batteries are essential to ensure they operate safely. We conducted an exposure assessment five days after a fire in a battery-testing facility. We assessed some of the potentially hazardous materials after a lithium-ion battery fire. We sampled total suspended particles, hydrogen fluoride, and lithium with real-time monitoring of particulate matter (PM) 1, 2.5, and 10 micrometers (μm). The area sampling results indicated that primary potential hazardous materials such as dust, hydrogen fluoride, and lithium were below the recommended limits suggested by the Korean Ministry of Labor and the American Conference of Governmental Industrial Hygienists Threshold Limit Values. Based on our assessment, workers were allowed to return to work.

Cellulose insulation (CI), a common building material, is a mixture of cellulose fibers and borates. Borates are approximately 20% of the product weight and act as a flame retardant. Given possible exposure to workers and consumers, an inhalation toxicity study was conducted following Organization for Economic Co-operation and Development (OECD) 414 for Prenatal Development Toxicity to evaluate if CI is a developmental toxicant. Pregnant female rats were exposed by nose-only inhalation to CI aerosols containing 20% boric acid for six h/day, from gestational day (GD) 6–19, and fetuses were evaluated for developmental parameters. Respirable CI was produced by grinding to produce respirable particles (MMAD 2.7–2.9 µm, geometric standard deviations (GSD) 1.9–2.6), which were then aerosolized. Target air concentrations were 15, 90, and 270 mg CI/m³. Controls were exposed to air only. Slight body weight reductions (average decrease <7% vs. control) were observed in male and female GD 20 fetuses in the mid and high dose groups. No embryo/fetal developmental toxicity or alterations in any other measured variable were reported at any dose. The no observed adverse effect level (NOAEL) for developmental outcomes was 270 mg/m³.

Increasing sensitivity of new analytical methods has enabled the detection of certain endocrine disrupting chemicals (EDCs) in drinking water systems. EDCs in raw water entering drinking water treatment plants can arise from many potential sources, including municipal wastewater treatment plant effluent, industrial discharges, agricultural activities, etc. Questions remain about the potential health effects of long-term, low-dose exposures to EDCs via potable water supplies. Of particular concern are potential consequences to sensitive population groups, such as pregnant women and children. We present preliminary data arising from our work on assessing the potential health risks of these chemicals and establishing target concentrations for water treatment. Specifically, we focus on the selection of chemicals of concern (COC) for this project. EDCs were selected as COC for this project on the basis of the following five criteria. (1) Status as an EDC. A literature review was conducted to collect evidence that certain chemicals can be classified as EDCs. Emphasis was placed on chemicals that have produced an adverse effect mediated through the endocrine system in at least one in vivo test system with a laboratory animal that serves as a surrogate for humans or that have been reported to produce an endocrine effect in humans. (2) Likelihood of exposure through drinking water. To assess occurrence in drinking water, monitoring for target chemicals is underway at several drinking water utilities nationwide. A literature search revealed additional occurrence data for source water, raw water, and drinking water, as well as information that can be used to predict the removal of EDCs through drinking water treatment processes. (3) Potential to cause adverse health effects. Severity of effects, potency, and pharmacokinetics (e.g., half-life, bioaccumulation) were considered. (4) Endocrine mode of action. Only those chemicals that act through the so-called "EAT" modes of action ( E strogenic (or anti-estrogenic), A ndrogenic (or anti-androgenic), and T hyroid-related) were considered. (5) Interest in specific contaminants. The Project Advisory Committee (PAC) and participating utilities were asked to identify EDCs that they believe are potential concerns. EDCs that appear to be the subject of interest among the public and the scientific community also were considered. For selected EDCs, animal and human clinical toxicity data are being examined to establish threshold exposure levels of concern, particularly focusing on the potential for reproductive and developmental effects and effects on endocrine function. The results of this project will provide information to determine whether consumption of EDCs in municipal drinking water poses a public health risk; which chemicals likely present the most significant risks, and which treatment systems most effectively reduce target chemical concentrations.