Combined Assessment of Preschool Childrens’ Exposure to Substances in Household Products

Understanding how indoor-air contaminants affect human health is of critical importance in our developed society. We assessed the combined exposure by inhalation of preschool children and children to household products. A total of 1175 families with 72 infants, 158 toddlers, 230 children, and 239 youths were surveyed to determine the combined respiratory exposure concentrations and amounts associated with 21 substances in eight household product groups. We determined the mean concentrations of these substances in each product, and derived reference toxicity values based on the information gathered in order to identify respiratory health risks. On average, cleaners were used at a rate of 1.0 × 103 g/month, while coating agents and other substances were used at 43 g/month. The combined inhalation exposure concentrations of methanol to infants and toddlers were 5.1 and 4.2 mg/m3 per month, respectively, with values of 2.1 and 1.7 mg/m3 for isopropanol, respectively. Risks to preschool children and children should be assessed on the basis of the toxicity values of combined exposed hazardous substances, as well as their combined concentrations and amounts. This exposure assessment approach can be used to establish improved guidelines for products that may pose inhalation hazards to preschool children and children

Potential Health Risks of Chemicals in Car Colorant Products

Public concern regarding the use of products with chemicals has increased in Korea, following reports indicating that hazardous chemicals in products, such as disinfectants, can cause fatal lung disease. Despite the widespread use of car colorant products, little is known regarding their potential health risks. The purpose of this study was to determine the potential health risks of substances that exist in car colorant products. Thirteen car colorant products were purchased from the Korean market and 15 commonly used chemicals were analyzed. Exposure and risk assessments were conducted in two assessment stages (screening and refined). The analysis showed that all of the examined products contained toluene, ethylbenzene, and xylene. The maximum concentration of toluene was 52.5%, with a median concentration of 10.8%. Tier 1 (screening) assessment showed that four chemicals (toluene, ethylbenzene, xylene, and 2-butoxyethanol) may pose health risks, but tier 2 (refined) assessment showed that these chemicals do not pose any risk. However, these chemicals were present in all of the examined products, and government regulations did not control their concentrations in these products. Therefore, we suggest that levels of toluene, ethylbenzene, and xylene in car colorant products should be regulated to protect public health

Close Association between Stream Water Quality and Fluorescence Properties of Dissolved Organic Matter in Agriculture-Dominated Watersheds

The characteristics of dissolved organic matter (DOM) and its relationships with other environmental factors are beneficial for comprehending water pollution in watersheds. This study aimed to improve our understanding of the association of DOM with water quality by connecting the spectroscopic characteristics of DOM with land cover and land use (LCLU). Clustering the tributaries of the Miho upstream watershed according to LCLU resulted in Clusters 1 and 2 having a large proportion of farmland and a large forest area, respectively. Various fluorescence indices derived from fluorescence excitation-emission matrix spectra revealed that livestock effluent resulted in the enrichment of autochthonous organic matter of algal or microbial origin in catchment areas with a high proportion of farmland. Furthermore, to analyze water quality changes according to the land-use characteristics, the water quality and spectroscopic characteristics of DOM were utilized based on the period of farmland use. Further correlation analysis indicated a high correlation between the fluorescence index (FI) in Cluster 1 and organic matter parameters and nitrogenous pollution (Total nitrogen (TN), Dissolved total nitrogen (DTN) and Nitrate nitrogen (NO3-N)) (planting season, r = 0.991, post-planting season, r = 0.971). This suggests that the FI can be used as a surrogate to estimate the degree of water pollution in watersheds largely affected by land uses related to agricultural activity and the livestock industries

Close Association between Stream Water Quality and Fluorescence Properties of Dissolved Organic Matter in Agriculture-Dominated Watersheds

The characteristics of dissolved organic matter (DOM) and its relationships with other environmental factors are beneficial for comprehending water pollution in watersheds. This study aimed to improve our understanding of the association of DOM with water quality by connecting the spectroscopic characteristics of DOM with land cover and land use (LCLU). Clustering the tributaries of the Miho upstream watershed according to LCLU resulted in Clusters 1 and 2 having a large proportion of farmland and a large forest area, respectively. Various fluorescence indices derived from fluorescence excitation-emission matrix spectra revealed that livestock effluent resulted in the enrichment of autochthonous organic matter of algal or microbial origin in catchment areas with a high proportion of farmland. Furthermore, to analyze water quality changes according to the land-use characteristics, the water quality and spectroscopic characteristics of DOM were utilized based on the period of farmland use. Further correlation analysis indicated a high correlation between the fluorescence index (FI) in Cluster 1 and organic matter parameters and nitrogenous pollution (Total nitrogen (TN), Dissolved total nitrogen (DTN) and Nitrate nitrogen (NO3-N)) (planting season, r = 0.991, post-planting season, r = 0.971). This suggests that the FI can be used as a surrogate to estimate the degree of water pollution in watersheds largely affected by land uses related to agricultural activity and the livestock industries