Environmental risk assessment of groundwater from remediated fuel spill sites on land into the marine environment at subantarctic Macquarie Island

An ecotoxicological risk assessment of groundwater from two Macquarie Island fuel spill sites was conducted to assess the level of risk posed by the sites to the adjacent marine receiving environment. Experiments were conducted on Macquarie Island during the summer season of 2017/18. The two fuel spill sites (known as: Fuel Farm and Power House, see file: Map-macquarie_building_and_structures_14676.pdf) within the vicinity of the Macquarie Island research station had undergone intensive in situ remediation by the Australian Antarctic Division over the previous decade. Despite remediation efforts, groundwater leaching from the sites continued to contain some residual fuel contamination, with sheen observed at several shoreline seeps and chemical analysis of groundwater samples confirmed some hydrocarbon contamination remained. This study aimed to assess the level of residual risk posed by groundwater from these sites as it enters the adjacent marine environment.We ran a series of toxicity tests using composited samples of salinity-adjusted groundwater discharge, as an exposure medium to test the sensitivity of 11 locally collected marine invertebrate species to the groundwater. Groundwater sampling was conducted over two periods: 23-29/11/17 and 18-20/12/17, for use in two rounds of toxicity testing (referred to as test round 1 (A and B) and test round 2). Groundwater samples were collected from 22 groundwater monitoring points; 12 surface seeps and 7 previously installed piezometers. These monitoring points were located along the coastal margin of the of the fuel spill sites, at their boundary with the adjacent marine environment (see: Locations-Fuel Farm-groundwater monitoring.pdf and Locations-Powerhouse-groundwater monitoring.pdf). The 22 groundwater samples were used to prepare seven salinity-adjusted composite test solutions (TS), each composed of equal volumes of up to nine groundwater samples. Salinity adjustment was to approximately that of ambient seawater (34 ppt), using hypersaline brine (prepared from locally collected clean seawater, which was frozen, then partially defrosted to collect concentrated brine). A total of approximately 6 L of was prepared for each of the seven TSs. See file: MI Ecotox-2017-18_TestSolutions_v03.xlsx for TS details (including: collection, preparation and physicochemical analysis results).Eleven locally collected marine invertebrate species were used in the tests. Biota were collected from two sites on Macquarie Island, both within the vicinity of the research station but away from areas of known fuel contamination: 1). Garden Bay on the East Coast (54° 29' 56.9" S, 158° 56' 28.8" E) and 2). Hasselborough Bay on the West Coast (54° 29' 45.6" S, 158° 55' 55.8" E). See: Map-macquarie_building_and_structures_14676.pdf. Dates of collection of test biota were 1/12/2017 (for test round 1A), 6/12/2017 (for test round 1B) and 20 and 22/12/17 (for test round 2). The 11 test taxa were from six broad taxonomic groups: 2 amphipods (Paramoera sp., Parawaldeckia kidderi), 2 flatworms (Obrimoposthia wandeli, Obrimoposthia ohlini), 2 copepods (Tigriopus angulatus, Harpacticus sp.), 2 gastropods (Laevilitorina caliginosa, Macquariella hamiltoni), 2 bivalves (Gaimardia trapesina, Lasaea hinemoa) and 1 isopod (Exosphaeroma gigas).Test biota were observed for 14 or 21 days and survival observed periodically. Full details of toxicity test conditions are provided in the file: MI Ecotox-2017-18_RawTestObs v02.xlsx (worksheets: TestSummary, Species and Endpoints). This file also contains, on subsequent worksheets, the raw toxicity test observations for each text taxa. These raw result data are compiled in the file: MI Ecotox-2017-18_Test-DATA.xlsx, worksheet: Survival-ALL contains survival data for all tests and taxa. Subsequent worksheets provide data for each test taxa separately and also include any sublethal observations that were made. All data associated with test solution collection, composition and chemistry are provided in the file: MI Ecotox-2017-18_TestSolutions.xlsx.The following (A. – I.) provides a description for the files provided with this record: A.    MI Ecotox-2017-18_A-Map-Groundwater monitoring sites.pngImages of study sites. A.) Overall Macquarie Island station environment, with Fuel Farm (red) and Power House (blue) indicated and showing the close proximity of the two land based sites to the adjacent high energy marine receiving environment. B.) Line map indicating relative location sites; Power House (blue) and Fuel Farm (red) sites, within the Macquarie Island station area. C.) and D.) Aerial images of the two sites, showing groundwater monitoring point locations (piezometers and seeps) used to prepare the seven test solutions (TS) as per key; Power House (TS4 and TS5) and Fuel Farm (TS1, TS2, TS3, TS6 and TS7), respectively. Monitoring point labels correspond with those provided in the file: MI Ecotox-2017-18_D-TestSolutions.xlsx / TS-Collection. B.    MI Ecotox-2017-18_B-Map-macquarie_building_and_structures_14676.pdfMap of overall Macquarie Island station area, showing locations referred to in this study relative to other station infrastructure; Fuel Farm and Power House (land based fuel contaminated sites) and Hasselborough Bay and Garden Bay (clean marine areas for collection of test biota). Produced by the Australian Antarctic Data Centre, July 2018. Map available at: https://data.aad.gov.au/aadc/mapcat/. Map Catalogue No. 14676. © Commonwealth of Australia 2018. C.    MI Ecotox-2017-18_C-RawTestObs.xlsxToxicity test condition details (in worksheets named: TestSummary, Species, Endpoints) and raw toxicity test observations for each text taxa (in subsequent worksheets).D.    MI Ecotox-2017-18_D-TestSolutions.xlsxDetails of test solutions, including collection, composition and chemistry.E.    MI Ecotox-2017-18_E-Test-DATA.xlsxCompiled raw toxicity test results in long format. Worksheet: Survival-ALL contains survival data for all tests and taxa. Subsequent worksheets provide data for each test taxa separately and includes sublethal observations if made). F.    MI Ecotox-2017-18_F-ScanLabBook.pdfScanned copy of the laboratory notebook associated with these tests. Notes were recorded by Cath King and Jessica Holan during the 17/18 Macquarie Island field season. G.    MI Ecotox-2017-18_G-ScanObservationSheets.pdfScanned copy of the handwritten raw observation sheets used to record test observations (observations scored by: Cath King and Jessica Holan). H.    MI Ecotox-2017-18_H-ChemicalAnalysis-ALS-COA.pdfCertificate of Analysis for chemistry results for samples analysed by Australian Laboratory Services (ALS) Environmental, Melbourne. Includes Total Recoverable Hydrocarbons (TRH; with and without silica gel clean up), nutrients (nitrogen) and a standard toxicity test (Microtox). Client sample ID with “Ecotox TS” prefix are those relevant to this study (other samples are associated with broader site remediation monitoring for the 17/18 season).I.    MI Ecotox-2017-18_I-ChemicalAnalysis-ALS-QAQC.pdfQuality Assurance (QA) and Quality Control (QC) report provided by ALS, in association with the Certificate of Analysis. As previous, Client sample ID with “Ecotox TS” prefix are relevant to this study. J.    MI Ecotox-2017-18_J-size measurements.zipMeasures of specimen body lengths (mm). The .zip file contains a text file named: SizeMeasurements-README.txt, providing a description of the content associated with these data.

本研究针对麦夸里岛两处燃油泄漏场地的地下水开展生态毒理学风险评估（ecotoxicological risk assessment），以研判该场地对邻近海洋受纳环境造成的风险等级。实验于2017/18夏季在麦夸里岛开展。

两处燃油泄漏场地分别为燃油农场（Fuel Farm）与动力站（Power House），详见文件Map-macquarie_building_and_structures_14676.pdf。该两处场地位于麦夸里岛研究站周边，过去十年间由澳大利亚南极局（Australian Antarctic Division）开展了高强度原位修复（in situ remediation）。尽管采取了修复措施，场地渗出的地下水仍残留部分燃油污染物，多处海岸渗泉可见油膜，且地下水样品的化学分析证实仍存在烃类污染。本研究旨在评估这些场地的地下水进入邻近海洋环境后所带来的残余风险水平。

我们采用经盐度调节的地下水排放混合样品作为暴露介质，开展了一系列毒性测试，以探究11种本地采集的海洋无脊椎动物（marine invertebrate）对该地下水的敏感性。地下水采样分为两个时段：2017年11月23日至29日，以及2017年12月18日至20日，对应两轮毒性测试（分别记为测试轮次1（A、B组）与测试轮次2）。共从22个地下水监测点位采集样品：其中12个地表渗泉与7个预先安装的测压管（piezometers）。这些监测点位沿燃油泄漏场地的海岸边缘布设，位于场地与邻近海洋环境的交界地带（详见文件Locations-Fuel Farm-groundwater monitoring.pdf与Locations-Powerhouse-groundwater monitoring.pdf）。

22份地下水样品被用于制备7份经盐度调节的复合测试液（composite test solutions, TS），每份测试液由最多9份地下水样品按等体积混合而成。盐度调节至接近环境海水的水平（34 ppt），所用高盐卤水由本地采集的清洁海水制备：先将海水冷冻，再部分解冻以收集浓缩卤水。7份测试液每份均制备约6升。测试液的详细信息（包括采集、制备与理化分析结果）详见文件MI Ecotox-2017-18_TestSolutions_v03.xlsx。

本测试采用11种本地采集的海洋无脊椎动物。生物样品采集自麦夸里岛的两个点位，均位于研究站附近但远离已知燃油污染区域：1）东海岸花园湾（Garden Bay，"54° 29' 56.9" S, 158° 56' 28.8" E"）；2）西海岸哈塞尔伯勒湾（Hasselborough Bay，"54° 29' 45.6" S, 158° 55' 55.8" E"）。详见文件Map-macquarie_building_and_structures_14676.pdf。受试生物的采集日期分别为：2017年12月1日（测试轮次1A）、2017年12月6日（测试轮次1B），以及2017年12月20日与22日（测试轮次2）。11个测试类群隶属于6个大类群：2种端足类（Paramoera sp.、Parawaldeckia kidderi）、2种扁形动物（Obrimoposthia wandeli、Obrimoposthia ohlini）、2种桡足类（Tigriopus angulatus、Harpacticus sp.）、2种腹足类（Laevilitorina caliginosa、Macquariella hamiltoni）、2种双壳类（Gaimardia trapesina、Lasaea hinemoa）以及1种等足类（Exosphaeroma gigas）。

对受试生物进行14或21天的观察，并定期记录存活情况。毒性测试条件的详细信息详见文件MI Ecotox-2017-18_RawTestObs v02.xlsx（工作表：TestSummary、Species and Endpoints）。该文件的后续工作表还包含每个测试类群的原始毒性测试观测数据。这些原始结果数据汇总于文件MI Ecotox-2017-18_Test-DATA.xlsx，其中"Survival-ALL"工作表包含所有测试与类群的存活数据，后续工作表分别提供每个测试类群的数据，同时包含所记录的亚致死观测（sublethal observations）结果。与测试液采集、组成与化学性质相关的所有数据均收录于文件MI Ecotox-2017-18_TestSolutions.xlsx。

以下（A. – J.）为本记录附带文件的说明：
A. MI Ecotox-2017-18_A-Map-Groundwater monitoring sites.png：研究场地图像。A）麦夸里岛研究站整体环境，标注了燃油农场（红色）与动力站（蓝色），展示了两处陆地场地与邻近高能海洋受纳环境的紧邻关系。B）线地图展示了麦夸里岛研究站区域内相关场地的相对位置：动力站（蓝色）与燃油农场（红色）。C）与D）两处场地的航拍图像，标注了用于制备7份测试液（TS）的地下水监测点位（测压管与渗泉），对应标识如下：动力站对应TS4与TS5，燃油农场对应TS1、TS2、TS3、TS6与TS7。监测点位标签与文件MI Ecotox-2017-18_D-TestSolutions.xlsx / TS-Collection中提供的标签一致。
B. MI Ecotox-2017-18_B-Map-macquarie_building_and_structures_14676.pdf：麦夸里岛研究站整体区域地图，展示了本研究提及的场地相对于其他研究站基础设施的位置：燃油农场与动力站（陆地燃油污染场地），以及哈塞尔伯勒湾与花园湾（采集受试生物的清洁海洋区域）。该地图由澳大利亚南极数据中心（Australian Antarctic Data Centre）于2018年7月制作，可于https://data.aad.gov.au/aadc/mapcat/ 获取，地图目录编号为14676。© 澳大利亚联邦2018。
C. MI Ecotox-2017-18_C-RawTestObs.xlsx：毒性测试条件详细信息（工作表名称：TestSummary、Species、Endpoints），以及每个测试类群的原始毒性测试观测数据（后续工作表）。
D. MI Ecotox-2017-18_D-TestSolutions.xlsx：测试液的详细信息，包括采集、组成与化学性质。
E. MI Ecotox-2017-18_E-Test-DATA.xlsx：长格式的原始毒性测试结果汇总。工作表"Survival-ALL"包含所有测试与类群的存活数据，后续工作表分别提供每个测试类群的数据，并包含所记录的亚致死观测结果。
F. MI Ecotox-2017-18_F-ScanLabBook.pdf：与本次测试相关的实验室记录本扫描件。笔记由Cath King与Jessica Holan在2017/18麦夸里岛野外季期间记录。
G. MI Ecotox-2017-18_G-ScanObservationSheets.pdf：用于记录测试观测结果的手写原始观测表扫描件（观测评分由Cath King与Jessica Holan完成）。
H. MI Ecotox-2017-18_H-ChemicalAnalysis-ALS-COA.pdf：澳大利亚实验室服务公司（ALS）环境事业部（墨尔本）分析的样品化学结果分析证书。包含总可回收烃类（TRH；含与不含硅胶净化步骤）、营养盐（氮）以及标准Microtox毒性测试。带有"Ecotox TS"前缀的客户样品ID与本研究相关（其余样品与2017/18季更广范围的场地修复监测相关）。
I. MI Ecotox-2017-18_I-ChemicalAnalysis-ALS-QAQC.pdf：ALS提供的与分析证书相关的质量保证（Quality Assurance, QA）与质量控制（Quality Control, QC）报告。如前所述，带有"Ecotox TS"前缀的客户样品ID与本研究相关。
J. MI Ecotox-2017-18_J-size measurements.zip：标本体长（mm）测量数据。该压缩包包含一个名为SizeMeasurements-README.txt的文本文件，对这些数据的内容进行说明。