Dioxin and dioxin-like PCB impurities in some Japanese agrochemical formulations Shigeki Masunaga a,b, * , Takumi Takasuga c , Junko Nakanishi a,b a Institute of Environmental Science and Technology, Yokohama National University, 79-7 Tokiwadai, Hodogaya-ku, Yokohama, 240-8501, Japan b CREST, Japan Science and Technology Corporation, Kawaguchi, Kawaguchi 332-0012, Japan c Shimadzu Techno-Research Inc., 1 Nishinokyo-Shimoaicho, Nakagyo-ku, Kyoto 604-8436, Japan Received 22 November 1999; accepted 18 July 2000 Abstract The pro®le and amount of dioxin impurity in agrochemicals were studied through detailed analysis of historic Japaneseformulations.ThechemicalsanalyzedincludepentachlorophenolPCP),2,4,6-trichlorophenyl-4 0 -nitrophenyl ether chloronitrofen, CNP), 2,4-dichlorophenyl-4 0 -nitrophenyl ether nitrofen, NIP), tetrachloro-iso-phthalonitrile chlorothalonil, TPN), 2-methyl-4-chloro-phenoxyacetic acid MCP) and 2,4-dichlorophenoxyacetic acid 2,4-D). Among the six, two herbicides, PCP and CNP, produced during the 1960s and 1970s, contained very high concen- trations of PCDD/DFs and TEQ. Others contained relatively low concentrations of PCDD/DFs. Dioxin-like PCB concentrations in all chemicals studied were low and their contributions to TEQ were negligible. The total dioxin emissionsfromtheuseofagrochemicalsinJapanduringthepast40years1955±1995)wereestimatedtobeaboutafew hundredthousandkgofPCDD/DFsand250kgofWHO-TEQfromPCPand190 10 3 kgofPCDD/DFsand440kg of WHO-TEQ from CNP. The major dioxin congeners present in PCP formulations were highly chlorinated PCDD/ DFsthatcanbeformedbythecouplingofPCPand/or2,3,4,6-tetrachlorophenol,andthoseintheCNPformulations were tetra- to hexa-chlorinated PCDD/DFs that can be formed from 2,4,6-trichlorophenol and/or 2,3,4,6-tetra- chlorophenol. Ó 2001 Elsevier Science Ltd. All rights reserved. Keywords: Agrochemical; Dioxin; Dioxin-like PCB; Impurity 1. Introduction A signi®cant portion of dioxins accumulated in sed- iments in Japanese lakes and bays was shown to have originated from agrochemicals, especially pentachlor- ophenol PCP) and chloronitrofen CNP) Masunaga et al., 1998). However, little data are available con- cerning the amounts and characteristics of the dioxin impurities in these chemicals produced in Japan. Thus, the estimation of the amount of dioxin emission from them has been dicult. In this study, polychlorinated- dibenzo-p-dioxin PCDD), polychlorinated dibenzofu- ran PCDF) and dioxin-like polychlorinated biphenyl dioxin-likePCB)impuritiesin15agrochemicalsamples wereanalyzed.Thedataobtainedshowedthatrelatively high concentrations of dioxins were present in the old agrochemical formulations. The results also indicated that annual emissions of dioxins from agrochemicals were far greater than those from combustion sources during the 1960s and 1970s. www.elsevier.com/locate/chemosphere Chemosphere 44 2001) 873±885 * Correspondingauthor.Tel.:+81-45-339-4352;fax:+81-45- 339-4373. E-mail address: masunaga@kan.ynu.ac.jp S. Masunaga). 0045-6535/01/$ - see front matter Ó 2001 Elsevier Science Ltd. All rights reserved. PII:S0045-653500)00310-6