{"created":"2023-05-15T13:39:01.228857+00:00","id":3105,"links":{},"metadata":{"_buckets":{"deposit":"517335f0-243e-48f6-ba75-ccc39612a618"},"_deposit":{"created_by":12,"id":"3105","owners":[12],"pid":{"revision_id":0,"type":"depid","value":"3105"},"status":"published"},"_oai":{"id":"oai:repository.naro.go.jp:00003105","sets":["87:660:683:404:405"]},"author_link":["6587"],"item_10002_biblio_info_7":{"attribute_name":"書誌情報","attribute_value_mlt":[{"bibliographicIssueDates":{"bibliographicIssueDate":"2008-07","bibliographicIssueDateType":"Issued"},"bibliographicPageEnd":"92","bibliographicPageStart":"1","bibliographicVolumeNumber":"25","bibliographic_titles":[{"bibliographic_title":"農業環境技術研究所報告"},{"bibliographic_title":"Bulletin of National Institute for Agro-Environmental Sciences","bibliographic_titleLang":"en"}]}]},"item_10002_description_5":{"attribute_name":"抄録","attribute_value_mlt":[{"subitem_description":"Organochemicals Division, National Institute for Agro-Environmental Sciences / 3-1-3 Kannondai, Tsukuba, 305-8604, Japan (Present address:Physical and Chemical Properties Evaluation Division, Agricultural Chemicals Inspection Station/ 2-772, Suzuki-cho, Kodaira-shi, 187-0011, Japan) Algal communities are important for the maintenance of functioning ecosystems in fresh, brackish, and marine aquatic environments. Planktonic and periphytonic algae form the base of most food chains, produce oxygen, and are important in the nutrient cycle. Alterations of a phytoplankton community as a result of toxic stress may affect the structure and functioning of the whole ecosystem. In Japan more than half of agricultural land is paddy fields, and various herbicides are used for rice cultivation. The herbicides applied to paddy fields are apt to flow into water bodies such as rivers and lakes and those were detected in rivers at concentrations of several micrograms per liter for some months after the rice-planting season. Although it is important to understand the effects of herbicides on primary production in riverine ecosystems of Japan, only a few studies have examined the influence of rice herbicides on aquatic plants. Planktonic green algae are generally used test species for first tier aquatic risk assessment of pesticides. However, these species are not indicators suitable enough for assessing influence of pesticides to primary productivities at riverine ecosystems. In streams, attached diatoms(ADs) usually are dominant algal groups in terms of biodiversity and comprise major biomass, therefore, the phytotoxicity of chemicals to ADs or AD communities will be significant indicators for higher tier risk assessment. The objectives of this study were to investigate exposure characteristics of rice herbicides at riverine ecosystems of Japan, to compare the relative sensitivity of various algal taxa to herbicides, to develop the growth inhibition test method using fresh water ADs, and to construct more realistic and scientifically sound ecological risk assessment procedure for primary productivity. 1. The eighteen kinds of paddy rice herbicides concentration in water samples at Sakura R. and L. Kasumigaura were monitored from 2001 to 2005. The highest concentrations of the rice herbicides were observed at Sakura R. during middle May to early June and these concentration levels at the midstream of Sakura R. were 0.12-8.8μg l^<-1>. The residual rice herbicides observed in Sakura R. water was rapidly diluted and dispersed in L. Kasumigaura and the dilution magnification from downstream of Sakura R. to Tsuchiura bay of L. Kasumigaura was 3 to 17 times. The annual trends of the detected rice herbicides concentration at midstream of Sakura R. were almost correlated with the annual trend of sales amounts of these rice herbicides in Ibaraki prefecture. 2. By comparing EC_<50>(0-72 h) values(50% growth inhibition concentration at 72 h after treatment), the sensitivities of four unicellular algal species to four teen herbicides were investigated. The test species were green algae (Pseudokirchneriella subcapitata and Chlorella vulgaris), a diatom(Achnanthidium minutissimum), and a blue-green alga (Merismopedia tenuissima). Test herbicides were selected based on frequency of recent usage in paddy fields in Japan and were four carbamates (thiobencarb, esprocarb, molinate, dimepiperate), three amides (pretilachlor, mefenacet, cafenstrole), two triazines (dimethametryn, simetryn), two sulfonylureas (bensulfuronmethyl, imazosulfuron), a urea (daimuron), a thiadiazine (bentazone), and a quinone (quinoclamine). The certain amide, triazine and sulfonylurea herbicides were highly hazardous for any tested species of algae. EbC_<50> values of pretilachlor and cafenstrole were 1.7- 4.3 μg l^<-1> for the green alga P. subcapitata, those of triazines were 0.30-25 μg l^<-1> for all test algae, and those of sulfonylureas were 0.70-10 μg l^<-1> for the blue-green alga M. tenuissima. In contrast, the herbicides mefenacet, bentazone, daimuron, and thiocarbamates posed low hazards to these four algae. 3. The effects of forty herbicides on cell morphologies of the freshwater microalgae such as P. subcapitata, A. minutissimum and M. tenuissima were investigated by microscopic observation, measuring side scatter(SSC) intensity and autonomous fluorescence(AF_<610>) of chlorophyll a using a flow cytometry. Morphological changes and differences in chlorophyll a amount of these microalgae were induced by the exposures to high concentration (10mg l^<-1> or water solubility) of herbicides. Especially, the responses on cell shape of P. subcapitata were greater than those of two other species and these reactions observed in P. subcapitata were classified into four types. The cell volumes were greatly increased at the highest concentrations(6 to 12 times of EbC_<50>) of the five herbicides(bensulfuronmethyl, esprocarb, mefenacet, pretilachlor, and thiobencarb) and the blanching cells were observed in incubations with three herbicides (esprocarb, quinoclamine and thiobencarb).The recoverability from morphological changes of P. subcapitata cells was confirmed in exposure experiments with seven kinds of herbicides (bensulfuronmethyl, esprocarb, mefenacet, pretilachlor, quinoclamine, simetryn and thiobencarb). It is clear that every treated P. subcapitata population did not extinct in a short time (72h) exposures of high concentration of seven herbicides, and that the recoverability of P. subcapitata population is apt to decline with increasing the amount of blanching cells. 4. A risk assessment was conducted based on calculated ErC_<50> values and the detected highest concentration of herbicides in the Sakura R., Saka R., L. Kasumigaura and Paddy drain. This assessment strongly suggested that certain amides, triazines, and sulfonylureas may pose a relatively high ecological risk to aquatic ecosystems in Japan. 5. A growth inhibition test method using fresh water attached diatoms was developed by improving microplate algal assay technique for planktonic green algae. Applying the solid culture technique for the pre-culture, using the flat bottom microplate for the test vessel and vortexing the microplate at least twice a day were necessary procedures to ensuring the reproducibility of the test using attached diatoms. Reproducible result was obtained from seven repetitions of growth inhibition tests using dimethametryn, a triazine herbicide on A. minutissimum of attached diatom. The average ErC_<50> values calculated from these tests was 7.9μg l^<-1> (n=7, SE=1.3). The optimum culture condition and the adaptability as test organism were evaluated in ten kind of attached diatoms (A. minutissimum, Craticula molestiformis, Eolimna minima, Eolimna subminuscula, Fistulifera saprophila, Mayamaea atomus, Nitzschia palea, Planothidium frequentissimum, Planothidium lanceolatum, Sellaphora seminulum). The optimum culture temperature was 15-30℃ . The difference of illumination intensity (c.a.2,000lux or c.a.5,000lux) did not influence the growth rate of every diatom at the optimum culture temperature. It is concluded that C. molestiformis, E. minima, E. subminuscula, F. saprophila, M. atomus and N. palea are suitable test species in these diatoms in terms of high growth potential and that M. atomus and N. palea are valuable test species in terms of habitat diversity and easiness of isolation. 6. The 61 strains of the attached diatom(Nitzschia spp.) were isolated from several areas, Saka R., Sakura R. and Hiso R. basins and L. Kasumigaura. The ErC_<50> values of dimethametryn ranged over two orders of magnitude among the strains. Tolerant strains were collected only from midstream site, suggesting that the strains may have been selected by the herbicide in paddy fields. The difference in organic element contents(carbon, nitrogen and sulfur) was not significant between two strains of N. palea which have different susceptibilities to dimethametryn. The results indicated that the changes in dimethametryn susceptibilities of diatoms don't cause serious disadvantages as primary producers. 7. The growth inhibition test for single species was improved to apply for diatom communities, as higher tier impact assessment. Using the method, the susceptibilities of diatom communities from the sites not affected with paddy drainages were concluded to be higher than that from the sites with inflow of drainages. Furthermore, bigger differences in susceptibilities were shown especially during the rice growing period.","subitem_description_type":"Abstract"},{"subitem_description":"河川水生生物の水稲用除草剤による暴露実態を長期のモニタリングで明らかにすると共に、河川生態系の一次生産性に及ぼす水稲用除草剤の影響評価について、より精度の高い評価手法の開発を試みた。その結果、これまで知見が少なかった藻類に対する除草剤の影響が明らかになった。また、フローサイトメトリーによる細胞計測により、細胞の形態に及ぼす影響及び回復性を考慮した簡易な評価を可能とした。さらに、これまで試験が困難であった付着性珪藻を使用した生長阻害試験手法の開発により、現実的な影響評価を可能とした。これらの知見は、農薬の生態影響評価手法の開発に有用な情報を提供するものであり、高次のリスク評価法としての貢献が大きく期待される。","subitem_description_type":"Abstract"}]},"item_10002_identifier_registration":{"attribute_name":"ID登録","attribute_value_mlt":[{"subitem_identifier_reg_text":"10.24514/00002980","subitem_identifier_reg_type":"JaLC"}]},"item_10002_publisher_8":{"attribute_name":"出版者","attribute_value_mlt":[{"subitem_publisher":"独立行政法人 農業環境技術研究所"}]},"item_10002_relation_14":{"attribute_name":"DOI","attribute_value_mlt":[{"subitem_relation_type":"isIdenticalTo","subitem_relation_type_id":{"subitem_relation_type_id_text":"10.24514/00002980","subitem_relation_type_select":"DOI"}}]},"item_10002_source_id_9":{"attribute_name":"ISSN","attribute_value_mlt":[{"subitem_source_identifier":"0911-9450","subitem_source_identifier_type":"ISSN"}]},"item_10002_version_type_20":{"attribute_name":"著者版フラグ","attribute_value_mlt":[{"subitem_version_resource":"http://purl.org/coar/version/c_970fb48d4fbd8a85","subitem_version_type":"VoR"}]},"item_creator":{"attribute_name":"著者","attribute_type":"creator","attribute_value_mlt":[{"creatorNames":[{"creatorName":"石原, 悟"},{"creatorName":"イシハラ, サトル","creatorNameLang":"ja-Kana"},{"creatorName":"ISHIHARA, Satoru","creatorNameLang":"en"}],"nameIdentifiers":[{"nameIdentifier":"6587","nameIdentifierScheme":"WEKO"},{"nameIdentifier":"9000003085005","nameIdentifierScheme":"CiNii ID","nameIdentifierURI":"http://ci.nii.ac.jp/nrid/9000003085005"}]}]},"item_files":{"attribute_name":"ファイル情報","attribute_type":"file","attribute_value_mlt":[{"accessrole":"open_date","date":[{"dateType":"Available","dateValue":"2019-10-09"}],"displaytype":"detail","filename":"niaes_report_No25p1-92p.pdf","filesize":[{"value":"26.4 MB"}],"format":"application/pdf","licensetype":"license_note","mimetype":"application/pdf","url":{"label":"niaes_report_No25p1-92p.pdf","url":"https://repository.naro.go.jp/record/3105/files/niaes_report_No25p1-92p.pdf"},"version_id":"8be3630e-002a-4de7-8456-47abca8bfc59"}]},"item_language":{"attribute_name":"言語","attribute_value_mlt":[{"subitem_language":"jpn"}]},"item_resource_type":{"attribute_name":"資源タイプ","attribute_value_mlt":[{"resourcetype":"departmental bulletin paper","resourceuri":"http://purl.org/coar/resource_type/c_6501"}]},"item_title":"河川生態系の一次生産性に及ぼす除草剤の影響評価手法開発","item_titles":{"attribute_name":"タイトル","attribute_value_mlt":[{"subitem_title":"河川生態系の一次生産性に及ぼす除草剤の影響評価手法開発"},{"subitem_title":"Development of Risk Assessment Procedure for Evaluating Effect of Herbicides on Primary Productivity of River Ecosystem","subitem_title_language":"en"}]},"item_type_id":"10002","owner":"12","path":["405"],"pubdate":{"attribute_name":"公開日","attribute_value":"2019-12-20"},"publish_date":"2019-12-20","publish_status":"0","recid":"3105","relation_version_is_last":true,"title":["河川生態系の一次生産性に及ぼす除草剤の影響評価手法開発"],"weko_creator_id":"12","weko_shared_id":-1},"updated":"2023-05-15T16:33:37.026384+00:00"}