长白山北坡森林土壤汞的含量和形态分布

分别于2009年4月和9月对长白山北坡的土壤样品进行了采集,研究北方森林地区不同海拔土壤样品中的总汞和甲基汞的分布情况.长白山土壤THg和MeHg含量分别为0.08～0.73 mg·kg-1和0.05～0.56 μg·kg-1,库存量分别为97 kg·km-2和128 g·km-2,高于吉林省背景值,MeHg的最高含量...     

皮质醇及其衍生物(倍他米松)对青鳉性腺分化影响的探究

皮质醇(Cortisol)是鱼类主要的糖皮质激素, 其含量的高低变化会对鱼类性别分化与性激素合成产生关键影响。倍他米松(Betamethasone)是由人工合成的皮质醇衍生物, 在多个国家和地区的自然水域中被频繁检测到, 对鱼类的生殖造成了很大的危害。本研究以日本青鳉(Oryzias latipes)为实验对象, 将获得的青鳉胚胎分别暴露于含20、200和2000 ng·L-1倍他米松或皮质醇的孵化液中, 研究皮质醇及其衍生物－倍他米松对青鳉仔鱼阶段性激素合成酶与性腺分化的关键节点基因表达的影响, 评估其对性腺分化与生殖内分泌的影响。结果表明, 2000 ng·L-1皮质醇暴露加速青鳉胚胎孵化, 孵化时间提前1天, 200与2000 ng·L-1暴露组倍他米松胚胎孵化时长延缓2天。在仔鱼性腺分化阶段, 皮质醇与倍他米松处理都引起类固醇激素合成酶与性腺分化的关键节点基因表达的显著变化。皮质醇处理下仔鱼的cyp19a1a、hsd17b3、hsd11b2基因表达水平均出现显著下降(p<0.05), 对雌雄激素合成具有抑制效果, 且抑制效果与暴露浓度呈正相关。倍他米松处理下, cyp19a1a、foxl2基因表达水平显著下降, 且dmrt1基因表达水平显著上升(p<0.05), 该结果提示倍他米松处理对青鳉仔鱼有潜在的雄性化。倍他米松与皮质醇暴露下, gsdf基因表达水平均下降, 该结果表明两种糖皮质激素暴露会延缓仔鱼性腺的分化过程。综上所述, 皮质醇与倍他米松的暴露均会干扰生殖内分泌系统, 并延缓仔鱼的性腺分化, 其中倍他米松暴露可能会诱导仔鱼的雄性化。     

五里河沉积物汞的时空变化规律

研究了历史上受纳氯碱污染的辽宁省葫芦岛市五里河沉积物中总汞、甲基汞25年中的时空变化规律.结果表明,经过25年的变化,在人工治理和自然净化作用下,五里河不同地点沉积物总汞和甲基汞含量总体上呈现明显下降的趋势,甲基汞下降尤为显著;但沉积物中汞含量依然处于较高水平,总汞含量为0.491～26.395 mg·kg-1,平均13.766 mg·kg-1,超过辽宁省土壤汞背景值(0.037 mg·kg-1)371倍,甲基汞含量为0.253～12.079 μg·kg-1,污染严重的断面是污染源附近的化工桥以及下游河口附近的茨山北桥.     

中国典型水产品产地居民发汞含量及其影响因素

为评价中国典型水产品产地居民汞暴露的风险,分别在武汉、青岛和厦门三地系统采集139、136和159份当地居民头发样品,测定总汞含量并分析主要影响因素。结果表明:武汉、青岛和厦门居民(n=434)发汞(THg)的中位数(四分位数)为0.435 (0.262,0.820)μg·g~(-1),武汉、青岛和厦门居民头发THg的中位数(四分位数)分别为0.392(0.253,0.611)μg·g~(-1)、0.305(0.204,0.478)μg·g~(-1)和0.814(0.445,1.350)μg·g~(-1);三地分别有10位(7.2%)、8位(5.9%)和64位(40.3%)居民发汞超过美国环保署(USEPA)限值1μg·g~(-1);厦门居民的发汞含量显著高于武汉和青岛(P0.001),居民的发汞含量与食鱼频率呈显著的正相关关系(P0.001);不同年龄段居民的发汞含量存在显著差异(P0.001),且在65岁后居民发汞逐渐降低;与以小麦为主食者相比,以大米为主食者其发汞含量增加的比数比(OR)(95%CI)值为6.47(4.07～10.29);厦门地区居民存在一定的汞暴露风险,而武汉和青岛地区居民的汞暴露风险较低。     

东湖茶港排污口底泥对稀有

以东湖茶港排污口底泥复溶水为试验相,采用96h急性毒性试验和胚胎-卵黄囊吸收阶段毒性试验方法,研究了东湖茶港排污口底泥对稀有(鱼句)鲫的毒性.结果显示,高浓度的复溶水对稀有(鱼句)鲫胚胎、仔鱼和幼鱼具有明显的毒性效应,而胚胎-卵黄囊吸收阶段更为敏感.随着复溶水浓度的增加,稀有(鱼句)鲫受精卵孵化率降低,仔鱼畸形率增高、成活率降低、生长减慢;对胚胎-卵黄囊吸收阶段的NOEC、LOEC和MATC分别为12.5%、25%和17.68%;对幼鱼96h LC50为69.1%.本文的研究还表明,底泥经晾晒后毒性大幅降低,暗示恢复东湖通江状态并让水位自然涨落,可能有助于缓解污染、恢复生态环境.     

铜或镉胁迫对海洋青鳉生理生化指标及产卵量的影响

通过研究海水中不同浓度重金属胁迫对海洋青鳉(Oryzias melastigma)生理生化的影响, 探讨与分析各指标间的相互关系, 为海洋重金属污染的生物监测提供参考。按海水水质标准分别设定铜(Cu)和镉(Cd)离子各3个浓度梯度, 测定海洋青鳉中乳酸(LA)、乳酸脱氢酶(LDH)、睾酮(T)、促卵泡素(FSH)、促黄体生成素(LH))及产卵量的动态变化。海洋青鳉中的LA含量随铜胁迫时间的延长而显著降低, 随镉胁迫浓度的增加而升高; LDH活性在铜胁迫下变化不大, 而随镉胁迫时间的延长略有上升; T含量在短期铜胁迫下有所升高, 但随胁迫时间的延长呈显著下降趋势, 却随镉胁迫浓度升高及胁迫时间延长而上升; FSH与LH含量随铜胁迫浓度增加呈显著下降, 随镉胁迫浓度增加呈先降后升趋势, 两者的含量变化与T的动态密切相关。与此同时, 随铜胁迫时间的延长和胁迫浓度的增加, 青鳉的产卵量也呈显著下降趋势。综合表明, 铜或镉胁迫均能显著影响雌性青鳉的LA含量, 增加能量消耗, 进而影响性激素水平, 最终影响到产卵量, 但两类离子的影响存在较大的差异性。因此, 一定浓度的铜或镉胁迫会导致海洋青鳉鱼体内生理生化的变化, 且存在两性差异性, 雌鱼对铜或镉胁迫的响应敏感强, 可选择雌鱼开展相关污染监测。     

贵州万山汞矿区自然土壤汞污染特征

为阐明万山汞矿区自然土壤汞的污染情况,以汞矿开采冶炼区为起点,沿敖寨河和下溪河等间距(4 kin)分层采集0～30 cm厚度的河滩土、灌木土和林地土,测定了其汞含量,分析了自然土壤汞的空间分布特征.结果表明,矿区同种植被覆盖类型的土壤总汞的含量变化范围较大,河滩土为0.16～389 mg·kg-1、灌木土为0.09～312 mg·kg-1、林地土为0.05～299 mg·kg-1,空间分布特征表现为随距污染源距离的增加而降低;同一采样区内河滩土、灌木土、林地土中土壤总汞的含量依次降低,同一采样点的垂向剖面上总汞含量一般从表层向下依次降低.     

卡培他滨对非靶标生物斑马鱼胚胎的发育毒性研究

为评价抗肿瘤药物卡培他滨(CAP)对非靶标生物的毒性, 以斑马鱼胚胎为受试生物, 研究了CAP对斑马鱼胚胎的发育毒性及对其抗氧化酶系的影响。结果表明, 直接暴露于卡培他滨中, 造成斑马鱼胚胎死亡率和畸形率增加, 且其机能有所下降。当暴露浓度高于20 μg·L-1时, 处理后的斑马鱼胚胎死亡率和畸形率显著升高, 与对照组相比有极显著差异。CAP浓度为0.2 μg·L-1时, 超氧化物歧化酶 (SOD) 活性和过氧化氢酶 (CAT) 活性均显著升高, 表明机体遭受一定程度的氧化损伤; 当浓度高于20 μg·L-1时, SOD和CAT活性显著降低, 表明斑马鱼仔鱼所受氧化损伤超出其自我修复能力, 引发致死性伤害。本文从发育毒性及氧化应激着手, 探究了CAP对非靶标生物的潜在危害, 为其生态效应提供一定的科学依据。     

贵州百花湖鱼体汞污染现状

以西南汞污染严重的贵州百花湖为对象,选取湖中优势鱼、贝类,通过测定其总汞和甲基汞含量,并结合水体、沉积物汞含量和相关水质参数,探讨了百花湖鱼类汞污染的现状及其影响因素.百花湖鱼体总汞平均含量为28.0ng·g-1,变化范围为4.2～143ng·g-1;甲基汞的平均含量为10.9ng·g-1,变化范围为3.0～39.3ng·g-1.虽然百花湖遭受上游贵州有机化工厂含汞废水的严重污染,但鱼体汞含量并没有超过国家食品卫生标准.其主要原因可能是:百花湖的鱼主要是人工养殖的草食性或杂食性鱼类,鱼龄较小,且其摄取的食物汞含量低、食物链简单,不利于汞的富集;其次,其较快的生长速度对鱼体汞具有生物稀释的作用.     

Effects of sediment eluates and extracts from differently polluted small rivers on zebrafish embryos and larvae

The effects on newly fertilized eggs, embryos and larvae of zebrafish Danio rerio following exposure to sediment samples from the more heavily contaminated River Körsch, southern Germany, occurred earlier and were more prominent than in samples from the less contaminated Krähenbach. Dose- and time-related effects following exposure to Körsch sediment eluates and extracts included: (1) hatching failure and subsequent death of larvae exposed to undiluted aqueous sediment eluates and reduced hatching rates at sediment extract concentrations 0·0125%; (2) increased mortality after exposure to 25 and 50% dilutions of aqueous sediment eluates, and dilutions of 0·00625% sediment extracts; (3) reduction of heart beat frequency for 50% dilutions of sediment eluates and concentrations of 0·025% extracts; (4) increased frequency of heart and yolk sac oedema after exposure to 0·0125% sediment extracts. Since adverse effects of sediment extracts observed in zebrafish laboratory tests correlated with reproductive failure in natural populations of brown trout Salmo trutta f. fario in the severely polluted River Körsch, early life stages tests with zebrafish appear to be a suitable tool to assess the contamination rate of natural sediments.     

Toxicity of common biocides used in aquaculture to embryos and larvae of Brachymystax tsinlingensis Li

Brachymystax tsinlingensis Li is a threatened fish species endemic to China. With the problems of environmental factors and seeding breeding diseases, it is important to further improve the efficiency of seeding breeding and the basis of resource protection. This study investigated the acute toxicity of copper, zinc and methylene blue (MB) on hatching, survival, morphology, heart rate (HR) and stress behaviour of B. tsinlingensis. Eggs (diameter: 3.86 ± 0.07 mm, weight: 0.032 ± 0.004 g) of B. tsinlingensis were selected randomly from artificial propagation and developed from eye-pigmentation-stage embryos to yolk-sac stage larvae (length: 12.40 ± 0.02 mm, weight: 0.03 ± 0.001 g) and exposed to different concentrations of Cu, Zn and MB for 144 h in a series of semi-static toxicity tests. The acute toxicity tests indicated that the 96-h median lethal concentration (LC₅₀) values of the embryos and larvae were 1.71 and 0.22 mg l⁻¹ for copper and 2.57 and 2.72 mg l⁻¹ for zinc, respectively, whereas the MB LC₅₀ after 144-h exposure for embryos and larvae were 67.88 and 17.81 mg l⁻¹, respectively. The safe concentrations of copper, zinc and MB were 0.17, 0.77 and 6.79 mg l⁻¹ for embryos and 0.03, 0.03 and 1.78 mg l⁻¹ for larvae, respectively. Copper, zinc and MB treatments with concentrations greater than 1.60, 2.00 and 60.00 mg l⁻¹, respectively, led to a significantly low hatching rate and significantly high embryo mortality (P < 0.05), and copper and MB treatments with concentrations greater than 0.2 and 20 mg l⁻¹ led to significantly high larvae mortality (P < 0.05). Exposure to copper, zinc and MB resulted in developmental defects, including spinal curvature, tail deformity, vascular system anomalies and discolouration. Moreover, copper exposure significantly reduced the HR of larvae (P < 0.05). The embryos exhibited an obvious change in behaviour, converting from the normal behaviour of emerging from the membrane head first to emerging tail first, with probabilities of 34.82%, 14.81% and 49.07% under copper, zinc and MB treatments, respectively. The results demonstrated that the sensitivity of yolk-sac larvae to copper and MB was significantly higher than that of embryos (P < 0.05) and that B. tsinlingensis embryos or larvae might be more resistant to copper, zinc and MB than other members of the Salmonidae family, which benefits their resource protection and restoration.     

重金属离子对黑斑蛙胚胎及蝌蚪的毒性影响

本文研究了5种重金属对黑斑蛙胚胎期及蝌蚪期的毒性作用,结果表明,各重金属离子对胚胎期中的孵化期和开口期毒性较大,其余各期毒性较小。各重金属离子对胚胎的毒性顺序为Hg     

形目鱼类连体胚胎两例

报道了鳉形目鱼类食蚊鱼(Gambusia affinis)和青鳉(Oryzias latipes)的连体胚胎现象各一例.上述连体胚胎均为腹部粘连,内脏各器官分别独立,产出或孵化后短时存活.     

Toxic effects of mercury on the hard clam,Meretrix lusoria,in various salinities

1. The 96-hr lc₅₀ values for juvenile hard clams, Meretrix lusoria, were 328, 392 and 194 μg/l Hg in 10, 20 and 30 ppt salinities at 25 ± 1°C, respectively; for adult hard clams 341 and 140 μg/l Hg in 20 and 30 ppt salinities, respectively.2. Acclimatizing the adult clams to low salinity of 10 ppt lessened the toxicity of mercury. However, juvenile animals appeared to be more sensitive to mercury poisoning after 96 hr exposure in 10 ppt salinity.3. All embryos exposed to 40 μg/l Hg and above died within 30 hr. In the control, 44% of hatched embryos had developed into D-stage larvae, while those exposed to 20 μg/l Hg were still in the trochophore stage. Most of the retarded larvae developed into abnormal forms within 30 hr at 28°C in 15 ppt salinity.4. In order to maintain water quality and protect natural resources, the recommended safe level of mercury is 0.046 (0.039–0.053) μg/l Hg, based on the estimated 30-hr EC₅₀ for the clam embryos, with an application factor of 0.01.     

南四湖典型入湖河流沉积物重金属污染特征与风险评价研究

以南四湖两条典型入湖河流为研究对象,分别对湖东的泗河及湖西的东鱼河沉积物中9种重金属(Cr、Ni、Zn、Cu、Pb、Hg、Cd、As、Mn)含量进行分析,最后采用多种方法解析重金属的来源并对其污染特征和生态风险进行评价。结果表明,两条河流沉积物中重金属均存在一定程度的富集,尤其是Hg、Zn、Cd富集最严重。泗河沉积物中大部分重金属在中游兖州段含量升高,尤其是Hg、Cd含量分别是山东省水系背景值的3.1、3.7倍,分析表明重金属主要来源为周边区域煤矿及其伴生产业产生的“工业三废”,同时说明了重金属高值区与煤矿分布密切相关。东鱼河沉积物中Hg、Cd含量在中游较高,其余重金属含量在上、下游较高,分析结果表明中游Hg、Cd含量较高主要与当地农业活动中农药及化肥的施用有关,上、下游重金属含量较高原因为引黄河水或南四湖水灌溉。     

Geospatial Estimation of Mercury Contamination in Buffalo River Sediments

The Buffalo River Area of Concern (AOC) is associated with heavy metal pollution. This research utilized sediment core data to model the geographic distribution of mercury within surface and subsurface sediments of a section of the AOC. Using ordinary kriging, a geostatistical interpolation technique, mercury concentration prediction maps were created. Standard maps were created by interpolating a prediction surface for the entire study area. In addition, spliced maps were created by interpolating prediction surfaces for three sections of the study area and merging these together to generate a quasi-continuous surface. The latter type of map was needed in order to account for the pronounced meandering nature of the river and to explore the potential existence of regional and local mercury sedimentation patterns. The surface level results show an increased level of mercury contamination from east to west (the direction of river flow), with peak values found in the mid-region of the study area. Additionally, surface sediments were less polluted with mercury than subsurface sediments. Finally, this study highlighted several mercury contamination hotspots, which could be targeted for future sediment restoration endeavors in the AOC.     

Distribution and partitioning of mercury in a river catchment impacted by former mercury mining activity

Mercury distribution and partitioning was studied in the River Idrijca system, draining the area of the former Idrija mercury mine, Slovenia. Mercury dynamics were assessed by speciation analysis of mercury in water and river bed sediment samples during a 2-year study at locations on the River Idrijca and its major tributaries. Simultaneously, the influence of some major physico-chemical parameters that influence the fate of mercury in the aquatic environment was investigated. The distribution of mercury species in the River Idrijca catchment indicated contamination from mine tailings distributed in the town of Idrija and erosion of contaminated soils. The partitioning between dissolved and particulate mercury phases in river water was found to be mostly controlled by the variable content of suspended solids resulting from changing hydrological conditions and complexation with various ligands present in river water, among which dissolved organic carbon (DOC) seems to be the most important. Overall results indicate that mercury is transported downstream from the mining area mainly as finely suspended material including colloids rather than in the dissolved phase. This riverine transport occurs mostly during short, but extreme hydro-meteorological conditions when remobilization of mercury from the river bed sediments occurs. A significant part of the mercury particulate phase in water corresponds to cinnabar particles. During its transport, important Hg transformation mechanisms that increase the risk of mercury uptake by biota take place, evidenced by the increase in the relative contribution of reactive mercury (Hg_R), dissolved gaseous mercury (DGM) and monomethylmercury (MeHg) downstream from the Idrija mine. However, our data revealed relatively low methylation efficiency in this contaminated river system. We attribute this to the site specific physico-chemical conditions responsible for making inorganic mercury unavailable and limiting the capacity of methylating bacteria.     

Increased abundance of IncP-1beta plasmids and mercury resistance genes in mercury-polluted river sediments: first discovery of IncP-1beta plasmids with a complex mer transposon as the sole accessory element

Although it is generally assumed that mobile genetic elements facilitate the adaptation of microbial communities to environmental stresses, environmental data supporting this assumption are rare. In this study, river sediment samples taken from two mercury-polluted (A and B) and two nonpolluted or less-polluted (C and D) areas of the river Nura (Kazakhstan) were analyzed by PCR for the presence and abundance of mercury resistance genes and of broad-host-range plasmids. PCR-based detection revealed that mercury pollution corresponded to an increased abundance of mercury resistance genes and of IncP-1beta replicon-specific sequences detected in total community DNA. The isolation of IncP-1beta plasmids from contaminated sediments was attempted in order to determine whether they carry mercury resistance genes and thus contribute to an adaptation of bacterial populations to Hg pollution. We failed to detect IncP-1beta plasmids in the genomic DNA of the cultured Hg-resistant bacterial isolates. However, without selection for mercury resistance, three different IncP-1beta plasmids (pTP6, pTP7, and pTP8) were captured directly from contaminated sediment slurry in Cupriavidus necator JMP228 based on their ability to mobilize the IncQ plasmid pIE723. These plasmids hybridized with the merRTDeltaP probe and conferred Hg resistance to their host. A broad host range and high stability under conditions of nonselective growth were observed for pTP6 and pTP7. The full sequence of plasmid pTP6 was determined and revealed a backbone almost identical to that of the IncP-1beta plasmids R751 and pB8. However, this is the first example of an IncP-1beta plasmid which had acquired only a mercury resistance transposon but no antibiotic resistance or biodegradation genes. This transposon carries a rather complex set of mer genes and is inserted between Tra1 and Tra2.     

Small-scale Gold Mining in the Puyango River Basin,Southern Ecuador: A Study of Environmental Impacts andHuman Exposures

This study addresses the impact of small-scale gold mining on the environment and communities of the Puyango River basin in the southwest of Ecuador between 1999 and 2001. Our primary objectives were to measure mercury, manganese, and lead in the river, to identify pathways of population exposure, and biological indicators of human exposure. A multi-method design at the catchment scale was applied to the analysis of water, sediments, and particulate matter for mercury, lead, and manganese over two different seasons. A household survey was undertaken, and individuals were assessed for lead (blood samples), and for mercury (urine and hair samples). River water samples had high concentrations of particulate matter (700 mg/L). Mercury and lead levels in water at the gold processing plants were very high in both seasons (250 ng Hg/L and 160 μg Pb/L). Mercury and lead, there was a downstream gradient with the areas adjacent to the gold processing plants having the highest levels. In Portovelo, the Upper Basin city, 14% of the population reported occupational exposure to inorganic mercury. Although no one in Portovelo consumes water from the river, 10% of the population consume local fish. This contrasts the Lower Basin where 98% of the population consume fish, and 100% use river water for drinking and cooking. Lead blood levels over 20 μg/dl were found in 39.4% of the study population and blood mercury over 10 μg/L only in 10.0%. Urinary mercury over 4 μg/L was found in 66.5% of the examined persons. Hair methylmercury did not exceed the safe limit of 2 μg/g, the mean concentration was 1.2 μg/g. Mining activity and erosion contributes to heavy-metal contamination (mercury, lead, and manganese) throughout the Puyango Basin. The relation between environmental contamination is complex and further research is being conducted to understand these relations.