Mercury Biomagnification in the Aquaculture Pond Ecosystem in the Pearl River Delta

This is the first study to investigate the rate of mercury (Hg) biomagnification in the aquaculture pond ecosystem of the Pearl River Delta (PRD), China, by analyzing total mercury (THg) and methyl mercury (MeHg) concentrations in various species of fish at different trophic levels (TLs). Species representing a gradient of trophic positions in the aquaculture pond food chains were chosen for analyzing THg and MeHg concentrations. In this study, there were two kinds of the aquaculture pond food chains: (1) omnivorous (fish feeds, zooplankton, grass carp [Ctenopharyngodon idellus], and bighead carp [Aristichthys nobilis]) and (2) predatory (zooplankton, mud carp [Cirrhina molitorella], and mandarin fish [Siniperca kneri]). Bighead carp and mandarin fish had the highest MeHg and THg concentrations, i.e., an order of magnitude higher than other species, in their respective food chains. More than 90% of the THg concentrations detected in bighead carp, mandarin fish, and mud carp were in the methylated form. In this study, %MeHg increased with TLs and MeHg concentrations, reflecting that MeHg is the dominant chemical species of Hg accumulated in higher concentrations in biota, especially biota associated with higher TLs in the food chains. The trophic magnification factors were 2.32 and 2.60 for MeHg and 1.94 and 2.03 for THg in omnivorous and predatory food chains, respectively, in PRD. Hg concentrations in fish tissue correlated to Hg levels in the ambient environment, and sediment seemed to be the major source for Hg accumulated in fish. In addition, feeding habit also affected Hg accumulation in different fish species. Four significant linear relationships were obtained between log-THg and δ¹⁵N and between log-MeHg and δ¹⁵N. The slope of the regression equations, as biomagnification power, was smaller in magnitude compared with those reported for temperate and arctic marine and freshwater ecosystems, indicating that THg and MeHg biomagnifications were lower in this PRD subtropical aquaculture pond ecosystem. This was probably due to low Hg bioavailability at lower TLs as well as individual feeding behavior of fish.     

Distribution of Mercury in Several Environmental Compartments in an Aquatic Ecosystem Impacted by Gold Mining in Northern Colombia

Mercury (Hg) used in gold amalgamation is a major source of contamination in developing countries. Water, sediments, plankton, fish, and human samples from Grande Marsh, a Hg-polluted marsh located in the south of Bolívar, municipality of Montecristo, Colombia, were collected during both the rainy and the dry seasons (2003–2006), at three different sampling sites, and analyzed for total Hg (T-Hg) content. Water, sediment, seston, phytoplankton, and zooplankton T-Hg concentrations were 0.33 ± 0.03 μg/L, 0.71 ± 0.03, 1.20 ± 0.06, 0.52 ± 0.03, and 0.94 ± 0.05 μg/g dry weight (wt), respectively. T-Hg levels in these compartments were highly pair-correlated (p < 0.05), and for all of them, except sediments, greater values were found during the dry season. Significant differences were observed for T-Hg concentrations in fish according to their trophic position. Average highest T-Hg values were found in carnivorous species such as Caquetaia kraussi (1.09 ± 0.17 μg/g fresh wt), Hoplias malabaricus (0.58 ± 0.05 μg/g fresh wt), and Plagioscion surinamensis (0.53 ± 0.07 μg/g fresh wt), whereas the lowest were detected in noncarnivorous species such as Prochilodus magdalenae (0.157 ± 0.01 μg/g fresh wt). In those fish species where seasonal comparisons were possible, specimens captured during the dry season had greater T-Hg levels in muscle. Although the T-Hg mean level for all fish samples (0.407 ± 0.360 μg/g fresh wt) did not exceed the recommended limit ingestion level, risk assessment based on the hazard index suggested that a fish intake of 0.12 kg per day (a small carnivorous specimen) could increase the potential health effects related to Hg exposure in the local human population, whose hair T-Hg median value was 4.7 μg/g, and presented a low but significant correlation with fish consumption (r = 0.250, p = 0.016). In short, Hg pollution from gold mining around Grande Marsh has permeated the food web, and currently levels in fish represent a serious concern for human health.     

深圳某海鲜市场所售牡蛎体内重金属含量及评价

目的了解深圳某海鲜市场所售牡蛎中重金属含量,以便更好地开展卫生质量监控。方法采集深圳某海鲜市场中牡蛎,测定牡蛎中5种重金属（Pb、Cd、Cr、Hg及无机As）含量,根据无公害食品水产品有毒有害物质标准限量对牡蛎的食用安全性进行评估。结果所检牡蛎中Cd含量均高于无公害水产品质量安全标准,含量范围在1．04～2．24mg／kg之间,而Pb、Cr、无机As、Hg4种重金属的含量均低于安全标准。结论深圳某海鲜市场所售牡蛎重金属Cd含量均超标,卫生质量欠佳。     

不同粒径大气颗粒物中金属元素含量及其免疫毒性研究

运用ＤＦＪ－１型五段分级采样器采集太原市空气中颗粒物。用原子吸收分光光度法测定不同粒径颗粒物上六种金属元素Ｐｂ、Ｍｎ、Ｎｉ、Ｃｏ、Ａｓ、Ｚｎ的含量。用淋巴细胞转化功能、白介素２（ＩＬ－２）活性和Ｔ细胞亚群分析观察不同粒径的颗粒物提取液对小鼠的免疫毒性。结果表明Ｐｂ、Ｍｎ、Ａｓ、Ｚｎ含量较高，Ｎｉ、Ｃｏ含量较低。７０％￣８０％的Ｐｂ、Ｎｉ、Ａｓ、Ｚｎ富集在≤２．０μｍ颗粒的免疫毒性较强。     

铅作业女工发铅等重金属含量分析

本文报告了31名接铅正常产女工和32名不接铅正常产女工头发和血中铅、镉、铜、锌、铁五种金属含量水平。结果:接铅组女工发铅水平为54.16μg/g,血铅水平为0.55μmol/L;不接铅女工发铅为10.18μg/g,血铅为0.39μmol/L,前者均显著高于后者,差别显著。发中及血中其它重金属含量,两组没有显著区别。本文讨论了发铅可作为慢性铅接触指标问题及铅等五种重金属在发中含量的正常水平。     

Baseline Trace Metals in Seagrass, Algae, and Mollusks in a Southern Tyrrhenian Ecosystem (Linosa Island, Sicily)

Trace elements were analyzed in organisms collected at five sampling stations along coastal areas of Linosa Island, Sicily (southern Tyrrhenian Sea, Italy). Concentrations of Cd, Cr, Cu, Pb, and Zn were measured in Posidonia oceanica L. Delile tissues, the two brown algae Padina pavonica (L.) Thivy and Cystoseira sp., and the two gastropod mollusks Monodonta turbinata Born and Patella caerulea L. Seawater samples were also collected at each site to assess soluble metal concentrations and to gain relevant information on their bioaccumulation ability. Data were processed by multivariate techniques, such as principal component analysis (PCA) and linear discriminant analysis on PCA factors. The scoreplots obtained showed that the pollutant distribution is more significantly correlated with species than with sites. For seaweeds, P. oceanica was associated with higher Cd, Cu, and Zn levels; Padina species had higher Cr concentrations, and Cystoseira had higher Pb levels. For mollusks, Monodonta species had high concentrations of Cu and Cr and Patella species were associated with Cd. Some general metal bioaccumulation patterns are described but no one sampling site was more contaminated than the others. The hypothesis of Linosa island serving as a reference ecosystem for baseline trace metal levels in southern Tyrrhenian areas is indeed supported by the statistical comparison among other southern Tyrrhenian ecosystems performed with Kruskall Wallis and Mann-Whitney tests. For P. oceanica leaves, P. pavonica, M. turbinata, and P. caerulea, this study confirms their usefulness as possible cosmopolitan biomonitors of trace metals in marine Mediterranean areas.     

广东沿海海域海产品中重金属的含量及评价

目的 了解广东沿海海域海产品中重金属污染状况和食用安全性.方法 2007年4-8月采集广东沿海海域17个海区及2个海鲜批发市场海产品,采用电感耦合等离子体质谱法同时测定海产品中5种元素[铅(Pb)、镉(Cd)、铬(Cr)、铜(Cu)及锌(Zn)]含量,采用单因子污染评价模式对金属含量进行污染评价,根据无公害食品水产品有毒有害物质标准限量对海产品的食用安全性进行评估.结果 广东沿海海域鱼类中5种重金属含量均低于国家无公害标准.而贝类等软体动物中重金属含量相对较高.牡蛎中Zn及Cu含量最高,出现污染超标现象;栉孔扇贝及牡蛎中Cd含量超过无公害标准;除方斑东风螺的Cr含量超过无公害标准,贝类中Cr及Pb含量均低于无公害标准.结论 广东沿海海域鱼类5种重金属安全卫生质量较好,贝类中重金属含量大于鱼类,出现一定的超标现象.     

4种车型列车车厢内冬季空气质量评价

[目的]了解冬季旅客列车车厢内的空气质量. [方法]监测4种25型旅客列车的车厢空气中温度、湿度、风速等微小气候指标及CO、CO2、可吸入颗粒物(PM)、空气细菌总数,甲醛等污染指标,并将测得数据进行分析.[结果]25B型车厢与25T型车厢相比CO、CO2、PM浓度差异均有统计学意义(P＜0.05);25B、25G、25K型车厢与25T型车厢相比空气细菌总数差异有统计学意义(P＜0.05);25T型车厢与25K型车厢相比甲醛浓度有显著性差异(P＜0.05);硬座与硬卧、软卧车厢相比CO2、空气细菌总数差异均有统计学意义(P＜0.05);软卧车厢与硬座、硬卧车厢相比甲醛差异有统计学意义(P＜0.05). [结论]CO、CO2和PM是25B型车的主要污染物;空气细菌是25B、25G、25K型列车的主要污染物;甲醛是25T型列车和软卧车厢的主要污染物;CO2、空气细菌是硬座车厢的主要污染物.     

普通客车超员车厢内空气质量调查

[目的]了解普通非空调列车在超员状态下车厢内的空气质量。[方法]选择同一车型的非空调列车为研究对象,对暑季运输（暑运）、十一黄金周、冬季运输（冬运）3个时间段（分别对应夏、秋和冬春之交）的车厢空气质量进行动态监测。[结果]十一黄金周、冬运超员车厢CO2浓度均超标,分别为0.202％、0.195％,且CO2超标率均高于暑运阶段（P〈0.01）;冬运的可吸入颗粒物（PM10）超标率分别高于暑运、十一黄金周（P〈0.01）。3个时间段超员车厢的温度均高于对照车厢（P〈0.01）;暑运期间CO、CO2、细菌总数3项指标均高于对照车厢（P〈0.05）;而冬运期间CO、CO2、PM10 3项指标高于对照车厢（P〈0.01）。[结论]普通非空调列车超员车厢内的空气质量存在明显的下降。     

HIV education in a Siberian prison colony for drug dependent males

Aim  

To evaluate the effectiveness of an HIV peer training program conducted in a colony for drug dependent male prisoners in Siberia, Russia.     

Mercury Concentrations in Pond Fish in Relation to a Coal-Fired Power Plant

Many studies have reported that atmospheric mercury is the primary cause for bioaccumulation in fish from remote lakes. Few data, however, are available on the possible effects of near-field mercury deposition on mercury concentrations in fish from local waters. Mercury concentrations were surveyed in fish from 23 ponds in the vicinity of a 543-megawatt coal-fired power plant located at Dickerson, Maryland. A stratified random sampling design was used to select ponds within zones delineated by concentric arcs mapped at 3, 7, 10, and 15 km from the plant. For each pond, mercury concentrations were measured by atomic absorption spectrometry in sunfish (bluegill or green sunfish) in all ponds, and largemouth bass, which were present in 14 of the ponds. Mean mercury concentrations in the ponds ranged from 0.01 to 0.38 ppm for sunfish and 0.04 to 0.43 ppm for bass. Stepwise multiple regression identified variables related to tissue concentrations. Differences between strata were tested with analysis of covariance, after adjusting the concentrations to account for differences in water quality. The observed pattern of mercury bioaccumulation did not match the pattern predicted by a wet deposition model. Received: 21 June 1996/Revised: 24 February 1997     

唐山市122辆小汽车车厢内甲醛污染状况调查

目的了解唐山市部分小汽车车厢内甲醛污染状况,为制定相应的防治对策提供依据。方法在唐山市市区选择使用不同年限的122辆小汽车,使用甲醛分析仪测定车内空气中的甲醛质量浓度,同时通过问卷调查获得车型、车龄等基本情况。结果车内空气甲醛的几何均数为0.098mg/m3,95%的可信区间为0.088～0.108mg/m3,参照国家《室内空气质量标准》GB/T18883-2002规定的甲醛浓度0.10mg/m3,58.2%的被调查车辆存在着不同程度的车厢内甲醛污染。车内甲醛污染主要存在于车龄在1年之内,半年之内的甲醛质量浓度最高。车辆档次、开窗习惯、有无使用吸附剂以及座椅材质在本次研究中未显示对车内甲醛浓度产生影响。结论唐山市小汽车车内甲醛污染严重,普遍超标。甲醛污染与车龄有关。     

Ecosystem Recovery Following Selenium Contamination in a Freshwater Reservoir

Belews Lake, North Carolina, was contaminated by selenium in wastewater released from a coal-fired electric generating facility during 1974–1985. Selenium bioaccumulated in aquatic food chains and caused severe reproductive failure and teratogenic deformities in fish. Beginning in 1986, the electric utility company changed its ash disposal practices and selenium-laden wastewater no longer entered the lake. A survey of selenium present in the water, sediments, benthic invertebrates, fish, and aquatic birds was conducted in 1996. Concentrations were compared to pre-1986 levels to determine how much change occurred during the decade since selenium inputs stopped. The data were also examined using a hazard assessment protocol to determine if ecosystem-level hazards to fish and aquatic birds had changed as well. Results reveal that waterborne selenium fell from a peak of 20 μg/liter before 1986, to <1 μg/liter in 1996; concentrations in biota were 85–95% lower in 1996. Hazard ratings indicate that high hazard existed prior to 1986 and that moderate hazard is still present, primarily due to selenium in the sediment-detrital food pathway. Concentrations of selenium in sediments have fallen by about 65–75%, but remain sufficiently elevated (1–4 μg/g) to contaminate benthic food organisms of fish and aquatic birds. Field evidence confirmed the validity of the hazard ratings. Developmental abnormalities in young fish indicate that selenium-induced teratogenesis and reproductive impairment are occurring. Moreover, the concentrations of selenium in benthic food organisms are sufficient to cause mortality in young bluegill and other centrarchids because of Winter Stress Syndrome. At the ecosystem level, recovery has been slow. Toxic effects are still evident 10 years after selenium inputs were stopped. The sediment-associated selenium will likely continue to be a significant hazard to fish and aquatic birds for years.     

江苏某垃圾填埋场污泥库特殊性土的分析与评价

通过对某垃圾填埋场污泥库的勘察,查明了污泥库边界,污泥泥水混合层、流塑层及软塑层的层序分布和埋深。根据污泥含水率、有机质含量等室内试验结果以及动力触探、静力触探等现场试验结果,横向比较了其他填埋场污泥试验数据,分析评价了该污泥的工程特性,其静力触探锥尖阻力主要分布在300～2 100 kPa之间,较其他填埋场的静力触探锥尖阻力检测值较大。工作成果为后续污泥库的治理提供了重要依据,对于完善污泥这类特殊性土的工程勘察评价体系,具有重要的意义。