2001年～2008年及奥运会期间天津市大气污染特征分析

根据天津市大气质量监测数据,对2001年～2008年及奥运会期间天津市大气污染特征和主要大气污染物的变化规律进行了分析。结果表明,2001年～2008年天津市的PM10、SO2和NO2污染总体呈下降趋势,但质量浓度仍相对较高。2008年8月奥运会期间天津市PM10和SO2质量浓度达到国家空气质量二级标准,NO2质量浓度达到国家空气质量一级标准,空气质量良好。天津市PM10污染相对稳定,SO2和NO2的污染分布呈现明显的季节性,时间上表现为冬强夏弱。气象条件对污染物浓度影响明显,沙尘、大雾等天气可使污染物浓度急剧升高。     

太原市2013年环境空气质量变化特征分析

为全面了解太原市的环境空气质量状况及污染物的时间变化规律,本文选取太原市8个站点2013年1月至12月六种主要污染物(SO2、NO2、PM10、CO、O3、PM2.5)为期一年的监测数据,评价该市2013年环境空气质量的总体情况,研究各污染物在不同时间尺度的变化特征及相互之间的关系。结果表明,2013年太原市环境空气质量以良和轻度污染为主,首要污染物主要为PM2.5和PM10;SO2、NO2、PM10、CO和PM2.5的小时变化规律较为一致,都呈现"双峰型"的变化特征,O3则呈显著的"单峰型"变化规律;上述六种污染物具有明显的季节变化特征,SO2的浓度峰值主要集中在供暖期,NO2和O3—8h浓度在夏季要高于其他季节,PM10的浓度峰值出现在春季(3月)和秋季(10月),CO的浓度峰值集中在11月和12月,PM2.5的浓度峰值主要集中在冬季;相关性分析结果表明,SO2、NO2、PM10、CO、PM2.5浓度日均值在全年各时段均具有很好的正相关性,化石燃料的燃烧可能是上述污染物质的共同来源。     

重庆铜梁县空气质量历时演变与评价

以重庆市铜梁县为例,分析了西部小城镇空气质量的历时演变规律,并对小城镇空气质量进行了评价。结果表明,小城镇空气质量夏季优于冬季,NO2和O3年均浓度(分别为29~33、18~34μg/m3)有所增加,但均在《环境空气质量标准》(GB 3095—2012)标准值内,PM10和SO2的年均浓度则逐年下降,2012年年均浓度比2010年分别下降了34%和19%;PM10、SO2、NO2浓度与温度、风速呈显著负相关关系,与大气压、相对湿度呈显著正相关关系,O3浓度与温度、风速、气压、相对湿度的相关性则刚好与此相反。对铜梁县近3年空气质量状况的评价结果表明,铜梁县空气质量稳步提升,相对于2010年的空气质量状况来说,2012年空气质量等级为优和良的天数分别提高了5%和9%,空气质量等级为轻微污染的天数则降低了9%。研究结果可为小城镇空气质量的宏观调控提供参考。     

“十一五”时期乌鲁木齐市大气污染特征及影响因素分析

为全面了解"十一五"时期(2006—2010年)乌鲁木齐市大气污染状况,评估污染源治理及气象条件对空气质量变化的影响,利用2001年1月—2010年12月主要大气污染物浓度数据和同期地面气象资料,总结"十一五"时期乌鲁木齐市大气污染变化特征,重点分析其变化原因。结果表明:"十一五"时期PM10和SO2年均浓度分别比"十五"下降1.7%和10.3%,采暖季降幅最明显,分别达到2.2%和21.9%;而NO2年均浓度比"十五"升高8.9%,非采暖季增幅最大,为11.7%。2006—2010年PM10、SO2年均浓度整体呈下降趋势,NO2浓度有升高趋势。5年中非采暖季各污染物浓度均达标,采暖季PM10和SO2超标倍数逐年减小,煤烟型污染特征仍然典型。污染源管控(特别是减排工程实施)是"十一五"时期SO2和PM10浓度下降的重要原因,气象条件作用相对有限。NO2浓度升高主要与机动车保有量逐年增加和氮氧化物治理启动滞后有关。     

2015—2017年江苏省秋、冬季空气质量状况

采用2015—2017年秋、冬季江苏省环境空气质量监测数据,从空气质量优良(达标)率、首要污染物、主要污染物浓度分析空气质量现状及特点。结果表明,江苏省秋、冬季空气质量优良(达标)率在60%左右,其中沿海地区空气质量达标率最高(71.1%),西北地区达标率最差(52.2%)。污染日的首要污染物主要为PM 2.5,占比高达91.5%。ρ(PM2.5)/ρ(PM 10)存在地区差异,江苏西北地区扬尘源贡献较大,江苏南部地区的二次颗粒物贡献更明显。ρ(NO2)/ρ(SO2)逐年持续升高,表明大气污染类型从燃煤性污染转变为复合型污染。     

遂宁市2013年大气污染特征及成因

根据遂宁市近年的环境空气监测数据,系统研究了2013年大气污染特征和2007—2013年的变化趋势,分析了颗粒物的组成和主要来源,并与周边地区大气环境监测结果进行了横向比较。研究结果表明,2013年遂宁市环境空气质量达标率为88.1%,大气中SO2、NO2和PM10的年均质量浓度分别为31、30、94μg/m3,空气质量达到二级标准,但劣于往年水平,大气中首要污染物是PM10,夏季和秋季的空气质量明显优于冬季和春季;遂宁市空气质量的变化趋势与周边地区一致,呈现出一定的区域性污染特征,但明显优于周边地区;进一步从5个方面阐述了遂宁市2013年空气质量下降的原因;根据遂宁市大气污染现状,提出了大气防控措施和建议。     

北京地区PM_(2.5)与空气污染物的关系模型

为了研究北京地区PM2.5与空气污染物的质量浓度关系。从PM2.5监测网收集2013-04-01~2014-05-15期间PM2.5、PM10、SO2、NO2、CO、O3等主要空气污染物数据,用多元线性回归模型建立PM2.5与空气污染物的质量浓度关系。结果表明:北京地区PM2.5与空气污染物PM10、SO2、NO2、CO、O3的质量浓度相关系数分别为0.9172、0.6332、0.7683、0.8166和-0.1797,优化的拟合方程为:[PM2.5]=-22.5925+0.569109×[PM10]+23.94913×[CO]+0.113025×[BPM2.5],模型的估算值与观测值相关系数为0.9426,此方程能较好地模拟北京地区的PM2.5质量浓度。     

齐齐哈尔市春季大气中PM2.5的污染特征分析

2013年4—6月分析了齐齐哈尔市大气PM2.5的浓度特征、元素组成、水溶性离子及其来源,并利用单颗粒分析技术获得了单颗粒的形貌、化学组成及粒度分布。结果表明,监测周期PM2.5日均质量浓度为34μg/m3,受气象条件影响显著。PM2.5单颗粒类型主要为烟尘集合体、飞灰和矿物颗粒,分别来源于煤炭燃料的燃烧、机动车尾气排放和扬尘。其中约90%的PM2.5颗粒粒径小于1.0μm,属大气细粒子。全样分析表明,PM2.5主要组成元素是Al、Fe、Ca、K、Mg和Na,而Zn、Cu和Pb因受到人为污染富集度较高。SO42-、NO3-和Cl-为PM2.5主要监测到的水溶性阴离子,NO3-与SO42-的质量浓度比说明了固定排放源对齐齐哈尔市春季大气PM2.5的贡献大于移动排放源。     

燃煤工业城市大气细颗粒物中水溶性无机离子的季节变化特征及来源解析——以邯郸市为例

为探究典型燃煤工业城市邯郸市的大气细颗粒物(PM2.5)污染水平及水溶性无机离子特征,于2016年1—12月采集了当地大气PM2.5样品,然后利用离子色谱法测得水溶性无机离子的组分,分析了不同季节水溶性无机离子随PM2.5的浓度变化特征。通过对PM2.5中的阴离子、阳离子进行分析发现,SO4^2-、NO3^-和NH4^+在春夏秋冬四季均为PM2.5中的主要离子成分,SO4^2-、NO3^-和NH4^+的浓度之和在春夏秋冬四季占各季节总的水溶性无机离子浓度的百分比分别为84.6%、77.4%、89.9%、62.5%。其中,在春季和冬季含量最高的3种离子分别是NO3^-、SO4^2-和NH4^+,夏季含量最高的3种离子分别是SO4^2-、NH4^+和NO3^-,而秋季含量最高的3种离子分别是NH4^+、SO4^2-和NO3^-。相关性分析发现,2016年春季、夏季和秋季PM2.5为酸性,冬季为碱性。SO4^2-、NO3^-、NH4^+浓度分析表明,冬季PM2.5中的一次建筑扬尘排放较多。通过主成分分析法得出,PM2.5中水溶性无机离子主要来源于二次转化和生物质燃烧。     

兰州市大气污染改善成效分析

为客观评价兰州市大气污染的状况,本文以兰州市2009—2013年空气污染检测相关数据为依据,研究了兰州市的大气污染现状和演变情况。研究结果表明:1兰州市大气污染为扬尘、煤烟和机动车尾气的混合型污染,主要污染物为可吸入颗粒物、SO2和NO2。2013年可吸入颗粒物、SO2和NO2的年平均浓度分别为0.153、0.033、0.035mg/m3,可吸入颗粒物是引起兰州空气污染的主要因素;2兰州市空气污染的易发季节为冬、春两季,空气污染的诱发因素为地理环境与大气条件;3近5年来,兰州市空气质量总体呈好转趋势,优良天数逐年增长,增幅达34%;大气中3项主要污染物浓度总体呈下降趋势,SO2累积降幅达到44%;NO2较最高值降幅为27%。     

An investigation on biological stability of product water generated by lab-scale and pilot-scale distillation systems

Material Disposal Area G is the primary low-levelradioactive waste disposal site at Los Alamos NationalLaboratory, New Mexico, and is adjacent to Pueblo of SanIldefonso lands. Pueblo residents and Los Alamos scientists areconcerned about radiological doses resulting from uptake of AreaG radionuclides by mule deer (Odocoileus hemionus) andRocky Mountain elk (Cervus elaphus), then consumption ofdeer and elk meat by humans. Tissue samples were collected fromdeer and elk accidentally killed near Area G and were analyzedfor ³H, ⁹⁰Sr, total U, ²³⁸Pu, ^{239, 240}Pu,²⁴¹Am, and ¹³⁷Cs. These data were used to estimatehuman doses based on meat consumption of 23 kg y^-1. Humandoses were also modeled using RESRAD, and dose rates to deer andelk were estimated with a screening model. Dose estimates tohumans from tissue consumption were 2.9 × 10^-3 mSv y^-1and 1.6 × 10^-3 mSv y^-1 from deer and elk, respectively,and RESRAD dose estimates were of the same order of magnitude. Estimated dose rates to deer and elk were 2.1 × 10^-4 mGyd^-1 and 4.7 × 10^-4 mGy d^-1, respectively. Allestimated doses were significantly less than established exposurelimits or guidelines.     

Metal concentrations in deciduous tree leaves from urban areas in Poland

Accumulation of metals in deciduous tree foliage fromurban areas in western-south Poland was monitored duringthe vegetation season of 2000 year. Concentrations of Al,Ba, Ca, Cd, Cr, Cu, Fe, Mg, Mn, Ni, Pb, Sr, Ti and Znwere measured in birch, willow, linden and maple leavesusing the ICP-AES method. Seasonal variations of metalconcentrations and their relations with sampling sitewere investigated. The most dynamic accumulation of Al,Cd, Cr, Ni and Pb was observed for examined species. Thehighest differences in element concentrations forinvestigated sites were found for Ba, Cd, Mn and Ni.Interelement correlations were investigated. In allfoliar samples synergistic relationships between Al–Crand Ca-Sr were found. Statistically significant negativecorrelations were observed only for Cd and Ti in birch leaves.     

Varying Stable Nitrogen Isotope Ratios of Different Coastal Marsh Plants and Their Relationships with Wastewater Nitrogen and Land Use in New England, USA

The stable nitrogen isotope ratios of some biota have been used as indicators of sources of anthropogenic nitrogen. In this study the relationships of the stable nitrogen isotope ratios of marsh plants, Iva frutescens (L.), Phragmites australis (Cav.) Trin ex Steud, Spartina patens (Ait.) Muhl, Spartina alterniflora Loisel, Ulva lactuca (L.), and Enteromorpha intestinalis (L.) with wastewater nitrogen and land development in New England are described. Five of the six plant species (all but U. lactuca) showed significant relationships of increasing δ ¹⁵N values with increasing wastewater nitrogen. There was a significant (P < 0.0001) downward shift in the δ ¹⁵N of S. patens (6.0 ± 0.48‰) which is mycorrhizal compared with S. alterniflora (8.5 ± 0.41‰). The downward shift in δ ¹⁵N may be caused by the assimilation of fixed nitrogen in the roots of S. patens. P. australis within sites had wide ranges of δ ¹⁵N values, evidently influenced by the type of shoreline development or buffer at the upland border. In residential areas, the presence of a vegetated buffer (n = 24 locations) significantly (P < 0.001) reduced the δ ¹⁵N (mean = 7.4 ± 0.43‰) of the P. australis compared to stands where there was no buffer (mean = 10.9 ± 1.0‰; n = 15). Among the plant species, I. frutescens located near the upland border showed the most significant (R ² = 0.64; P = 0.006) inverse relationship with the percent agricultural land in the watershed. The δ ¹⁵N of P. australis and I. frustescens is apparently an indicator of local inputs near the upland border, while the δ ¹⁵N of Spartina relates with the integrated, watershed-sea nitrogen inputs.     

Effect of heavy metal contaminated shooting range soils on mycorrhizal colonization of roots and metal uptake by leek

We grew leek (Allium porrum) in soils of two shooting ranges heavily contaminated with heavy metals in the towns of Zuchwil and Oberuzwil in Switzerland as a bioassay to test theactivity of arbuscular mycorrhizal (AM) fungi in these soils.Soil samples were taken from (1) front of the shooting house(HOUSE), (2) the area between house and target (FIELD) and (3) the berm (BACKSTOP). Samples of Ribwort plantain (Plantagolanceolata) growing naturally within the shooting ranges werealso collected and the colonization of its roots by mycorrhizalfungi was measured. The number of AM spores in the soils wassignificantly reduced concomitant with the increase in thedegree of soil contamination with metals. In Zuchwil,mycorrhizal fungi equally colonized roots of Ribwort plantainsampled from BACKSTOP and HOUSE. In Oberuzwil, however, plantsfrom BACKSTOP had lower colonization when compared with thosesampled from HOUSE. Colonization of leek was strongly reducedin the BACKSTOP soil of Zuchwil and slightly reduced in theBACKSTOP soil of Oberuzwil when compared with plants grown inrespective HOUSE soil. Concentrations of Cd, Cr, Cu, Ni, Pb andZn in the leaves of leek grown in the BACKSTOP soil was withinthe range considered toxic for human consumption. This pointsto the high degree of bio-availability of these metal in thesesoils. Significant decrease in the number of mycorrhizal sporesin the BACKSTOP soils in Zuchwil and the low colonization ofleek roots grown in these soils point to possible changes inthe species diversity of mycorrhizal fungi in these soils.     

Radionuclide Concentrations in Benthic Invertebrates from Amchitka and Kiska Islands in the Aleutian Chain, Alaska

Concentrations of 13 radionuclides (¹³⁷Cs, ¹²⁹I, ⁶⁰Co, ¹⁵²Eu, ⁹⁰Sr, ⁹⁹Tc, ²⁴¹Am, ²³⁸Pu, ^239,249Pu, ²³⁴U, ²³⁵U, ²³⁶U, ²³⁸U were examined in seven species of invertebrates from Amchitka and Kiska Islands, in the Aleutian Chain of Alaska, using gamma spectroscopy, inductively coupled plasma mass spectroscopy, and alpha spectroscopy. Amchitka Island was the site of three underground nuclear test (1965–1971), and we tested the null hypotheses that there were no differences in radionuclide concentrations between Amchitka and the reference site (Kiska) and there were no differences among species. The only radionuclides where composite samples were above the Minimum Detectable Activity (MDA) were ¹³⁷Cs, ²⁴¹Am, ^239,249Pu, ²³⁴U, ²³⁵U, ²³⁶U, and ²³⁸U. Green sea urchin (Strongylocentrotus polyacanthus), giant chiton (Cryptochiton stelleri), plate limpets (Tectura scutum) and giant Pacific octopus (Enteroctopus dofleini) were only tested for ¹³⁷Cs; octopus was the only species with detectable levels of ¹³⁷Cs (0.262 ± 0.029 Bq/kg, wet weight). Only rock jingle (Pododesmus macroschisma), blue mussel (Mytilus trossulus) and horse mussel (Modiolus modiolus) were analyzed for the actinides. There were no interspecific differences in ²⁴¹Am and ^239,240Pu, and almost no samples above the MDA for ²³⁸Pu and ²³⁶U. Horse mussels had significantly higher concentrations of ²³⁴U (0.844 ± 0.804 Bq/kg) and ²³⁸U (0.730 ± 0.646) than the other species (both isotopes are naturally occurring). There were no differences in actinide concentrations between Amchitka and Kiska. In general, radionuclides in invertebrates from Amchitka were similar to those from uncontaminated sites in the Northern Hemisphere, and below those from the contaminated Irish Sea. There is a clear research need for authors to report the concentrations of radionuclides by species, rather than simply as ‘shellfish’, for comparative purposes in determining geographical patterns, understanding possible effects, and for estimating risk to humans from consuming different biota.     

Kelp as a Bioindicator: Does it Matter Which Part of 5 M Long Plant is Used for Metal Analysis?

Kelp may be useful as a bioindicator because they are primary producers that are eaten by higher trophic level organisms, including people and livestock. Often when kelp or other algae species are used as bioindicators, the whole organism is homogenized. However, some kelp can be over 25 m long from their holdfast to the tip of the blade, making it important to understand how contaminant levels vary throughout the plant. We compared the levels of arsenic, cadmium, chromium, lead, manganese, mercury and selenium in five different parts of the kelp Alaria nana to examine the variability of metal distribution. To be useful as a bioindicator, it is critical to know whether levels are constant throughout the kelp, or which part is the highest accumulator. Kelp were collected on Adak Island in the Aleutian Chain of Alaska from the Adak Harbor and Clam Cove, which opens onto the Bering Sea. In addition to determining if the levels differ in different parts of the kelp, we wanted to determine whether there were locational or size-related differences. Regression models indicated that between 14% and 43% of the variation in the levels of arsenic, cadmium, chromium, manganese, mercury, and selenium was explained by total length, part of the plant, and location (but not for lead). The main contributors to variability were length (for arsenic and selenium), location (mercury), and part of the plant (for arsenic, cadmium, chromium and manganese). The higher levels of selenium occurred at Clam Cove, while mercury was higher at the harbor. Where there was a significant difference among parts, the holdfast had the highest levels, although the differences were not great. These data indicate that consistency should be applied in selecting the part of kelp (and the length) to be used as a bioindicator. While any part of Alaria could be collected for some metals, for arsenic, cadmium, chromium, and manganese a conversion should be made among parts. In the Aleutians the holdfast can be perennial while the blade, whipped to pieces by winter wave action, is regrown each year. Thus the holdfast may be used for longer-term exposure for arsenic, cadmium, chromium and manganese, while the blade can be used for short-term exposure for all metals. Cadmium, lead and selenium were at levels that suggest that predators, including people, may be at risk from consuming Alaria. More attention should be devoted to heavy metal levels in kelp and other algae from Adak, particularly where they may play a role in a subsistence diets.     

Assessing Potential for Recovery of Biotic Richness and Indicator Species due to Changes in Acidic Deposition and Lake ph in Five Areas of Southeastern Canada

Biological damage to sensitive aquatic ecosystems is among the most recognisable, deleterious effects of acidic deposition. We compiled a large spatial database of over 2000 waterbodies across southeastern Canada from various federal, provincial and academic sources. Data for zooplankton, fish, macroinvertebrate (benthos) and loon species richness and occurrence were used to construct statistical models for lakes with varying pH, dissolved organic carbon content and lake size. pH changes, as described and predicted using the Integrated Assessment Model (Lam et al., 1998; Jeffries et al., 2000), were based on the range of emission reductions set forth in the Canada/US Air Quality Agreement (AQA). The scenarios tested include 1983, 1990, 1994 and 2010 sulphate deposition levels. Biotic models were developed for five regions in southeastern Canada (Algoma, Muskoka, and Sudbury, Ontario, southcentral Québec, and Kejimkujik, Nova Scotia) using regression tree, multiple linear regression and logistic regression analyses to make predictions about recovery after emission reductions. The analyses produced different indicator species in different regions, although some species showed consistent trends across regions. Generally, the greatest predicted recovery occurred during the final phase of emission reductions between 1994 and 2010 across all taxonomic groups and regions. The Ontario regions, on average, were predicted to recover to a greater extent than either southcentral Québec or the Kejimkujik area of Nova Scotia. Our results reconfirm that pH 5.5–6.0 is an important threshold below which damage to aquatic biota will remain a major local and regional environmental problem. This damage to biodiversity across trophic levels will persist well into the future if no further reductions in sulphate deposition are implemented.     

Nitrogen Content of Letharia vulpina Tissue from Forests of the Sierra Nevada, California: Geographic Patterns and Relationships to Ammonia Estimates and Climate

Nitrogen (N) pollution is a growing concern in forests of the greater Sierra Nevada, which lie downwind of the highly populated and agricultural Central Valley. Nitrogen content of Letharia vulpina tissue was analyzed from 38 sites using total Kjeldahl analysis to provide a preliminary assessment of N deposition patterns. Collections were co-located with plots where epiphytic macrolichen communities are used for estimating ammonia (NH₃) deposition. Tissue N ranged from 0.6% to 2.11% with the highest values occurring in the southwestern Sierra Nevada (range: 1.38 to 2.11). Tissue N at 17 plots was elevated, as defined by a threshold concentration of 1.03%. Stepwise regression was used to determine the best predictors of tissue N from among a variety of environmental variables. The best model consisted only of longitude (r ² = 0.64), which was reflected in the geographic distribution of tissue values: the southwestern Sierra Nevada, the high Sierras near the Tahoe Basin, and the Modoc Plateau, are three apparent N hotspots arranged along the tilted north–south axis of the study area. Withholding longitude and latitude, the best regression model suggested that NH₃ estimates and annual number of wetdays interactively affect N accumulation (r ² = 0.61; % N ∼ NH₃ + wetdays + (NH₃ × wetdays)). We did not expect perfect correspondence between tissue values and NH₃ estimates since other N pollutants also accumulate in the lichen thallus. Additionally, other factors potentially affecting N content, such as growth rate and leaching, were not given full account.     

Spatial Relationships Between Water Quality and Pesticide Application Rates in Agricultural Watersheds

Pesticide applications to agricultural lands in California, USA, are reported to a central data base, while data on water and sediment quality are collected by a number of monitoring programs. Data from both sources are geo-referenced, allowing spatial analysis of relationships between pesticide application rates and the chemical and biological condition of water bodies. This study collected data from 12 watersheds, selected to represent a range of pesticide usage. Water quality parameters were measured during six surveys of stream sites receiving runoff from the selected watershed areas. This study had three objectives: to evaluate the usefulness of pesticide application data in selecting regional monitoring sites, to provide information for generating and testing hypotheses about pesticide fate and effects, and to determine whether in-stream nitrate concentration was a useful surrogate indicator for regional monitoring of toxic substances. Significant correlations were observed between pesticide application rates and in-stream pesticide concentrations (p < 0.05) and toxicity (p < 0.10). In-stream nitrate concentrations were not significantly correlated with either the amount of pesticides applied, in-stream pesticide concentrations, or in-stream toxicity (all p > 0.30). Neither total watershed area nor the area in which pesticide usage was reported correlated significantly with the amount of pesticides applied, in-stream pesticide concentrations, or in-stream toxicity (all p > 0.14). In-stream pesticide concentrations and effects were more closely related to the intensity of pesticide use than to the area under cultivation.     

Heavy Metals and Selenium in Herring Gulls (LARUS ARGENTATUS) NESTING IN COLONIES FROM EASTERN LONG ISLAND TO VIRGINIA

With increasing interest in assessing the health or well-being ofcommunities and ecosystems, birds are being used asbioindicators. Coloniallynesting species breed mainly in coastal areas that are alsopreferred for humandevelopment, exposing the birds to various pollutants. Inthis paper concentrations of heavy metal and selenium in the feathers ofHerring Gulls(Larus argentatus) nesting in several colonies fromMassachusetts toDelaware are reported. There were significant differencesamong colonies forall metals, with metal concentrations being two to nearly fivetimes higher atsome colonies than others. Selenium showed the leastdifference, and cadmium showed the greatest difference among sites. Concentrations of lead werehighest at Pralls Island; mercury was highest at Shinnecock,Huckleberry andHarvey, and manganese was highest at Captree.