Nakata Hokuto, Nakayama Shouta M M, Oroszlany Balazs, Ikenaka Yoshinori, Mizukawa Hazuki, Tanaka Kazuyuki, Harunari Tsunehito, Tanikawa Tsutomu, Darwish Wageh Sobhy, Yohannes Yared B, Saengtienchai Aksorn, Ishizuka Mayumi
Laboratory of Toxicology, Department of Environmental Veterinary Sciences, Graduate School of Veterinary Medicine, Hokkaido University, Kita 18 Nishi 9, Kita-ku, Sapporo 060-0818, Japan.
Water Research Group, Unit for Environmental Sciences and Management, North-West University, Potchefstroom 2520, South Africa.
Int J Environ Res Public Health. 2017 Jan 10;14(1):56. doi: 10.3390/ijerph14010056.
Although Japan has been considered to have little lead (Pb) pollution in modern times, the actual pollution situation is unclear. The present study aims to investigate the extent of Pb pollution and to identify the pollution sources in Japan using stable Pb isotope analysis with kidneys of wild rats. Wild brown (, n = 43) and black (, n = 98) rats were trapped from various sites in Japan. Mean Pb concentrations in the kidneys of rats from Okinawa (15.58 mg/kg, dry weight), Aichi (10.83), Niigata (10.62), Fukuoka (8.09), Ibaraki (5.06), Kyoto (4.58), Osaka (4.57), Kanagawa (3.42), and Tokyo (3.40) were above the threshold (2.50) for histological kidney changes. Similarly, compared with the previous report, it was regarded that even structural and functional kidney damage as well as neurotoxicity have spread among rats in Japan. Additionally, the possibility of human exposure to a high level of Pb was assumed. In regard to stable Pb isotope analysis, distinctive values of stable Pb isotope ratios (Pb-IRs) were detected in some kidney samples with Pb levels above 5.0 mg/kg. This result indicated that composite factors are involved in Pb pollution. However, the identification of a concrete pollution source has not been accomplished due to limited differences among previously reported values of Pb isotope composition in circulating Pb products. Namely, the current study established the limit of Pb isotope analysis for source identification. Further detailed research about monitoring Pb pollution in Japan and the demonstration of a novel method to identify Pb sources are needed.
尽管近代以来日本一直被认为几乎没有铅（Pb）污染，但实际污染情况尚不清楚。本研究旨在通过对野生大鼠肾脏进行稳定铅同位素分析，调查日本铅污染的程度并确定污染源。从日本各地捕获了野生褐家鼠（，n = 43）和黑家鼠（，n = 98）。冲绳（干重15.58毫克/千克）、爱知（10.83）、新潟（10.62）、福冈（8.09）、茨城（5.06）、京都（4.58）、大阪（4.57）、神奈川（3.42）和东京（3.40）的大鼠肾脏中铅的平均浓度高于肾脏组织学变化的阈值（2.50）。同样，与之前的报告相比，认为日本大鼠中肾脏的结构和功能损伤以及神经毒性甚至也已蔓延。此外，假定了人类接触高浓度铅的可能性。关于稳定铅同位素分析，在一些铅含量高于5.0毫克/千克的肾脏样本中检测到了稳定铅同位素比值（Pb-IRs）的独特值。这一结果表明铅污染涉及多种复合因素。然而，由于先前报道的循环铅产品中铅同位素组成的值之间差异有限，尚未确定具体的污染源。也就是说，本研究确定了用于源识别的铅同位素分析的局限性。需要对日本铅污染监测进行更详细的研究，并证明一种识别铅源的新方法。
