应用生物配体模型研究湘江水体中铜的生物有效性

为评估湘江水体中铜的生物有效性,通过铜对青鳉的急性毒性实验确定铜对青鳉的半致死浓度(LC₅₀),然后利用生物配体模型(Biotic Ligand Model, BLM)确定青鳉的累积半致死浓度(LA₅₀)。同时对湘江水样的预测结果表明,铜对青鳉的LA₅₀为12.43 nmol?gw^-1;BLM预测的与实验观测的LC₅₀差异倍数小于2,表明BLM预测结果非常准确。在此基础上预测铜对青鳉LC₅₀预测范围为344.70～761.96 μg?L^-1。湘江各点水质最终急性值(FAV)相差不大(11.04～14.25 μg?L^-1),但水中溶解态铜含量相差较大(0.29～10.48 μg?L^-1),同时毒性单位值(TU)相差较大(0.06～1.48 μg?L^-1),其中最小值在舂陵水入湘江下游采样断面,最大值在株洲断面。在全部调查断面中,只有株洲断面TU大于1(1.48),说明株洲断面水中铜含量超过了该断面水中BLM确定的标准最大浓度1.48倍。     

生物配位体模型预测铜对剑水蚤毒性及其受水质参数的影响

本研究以大型蚤毒性试验标准为参照进行剑水蚤的铜毒性试验,并以生物配体模型(BLM)为主要工具,实现对毒性数据的校正和毒性效应的预测.在不同水质参数下,实测铜的48 h LC_(50)为141—566μg·L~(-1),相应的BLM预测值为143—1208μg·L~(-1),表明BLM对铜的毒性预测良好.pH升高、DOC以及钙、镁、钠离子浓度的增加均对铜毒性有不同程度减弱作用,钾离子对铜毒性影响较小,BLM对这一现象的描述较好.利用Visual MINTEQ软件对不同水参数条件下铜形态分布进行模拟,辅助解释实验现象,发现钙、镁、钠、钾离子对铜形态分布影响较小.DOC的加入则使络合态铜含量增加,而pH升高导致游离态铜浓度下降,水合态铜浓度升高.本研究表明,预测铜对剑水蚤的毒性要充分考虑水质参数的影响,BLM在铜对剑水蚤的毒性预测方面表现了非常好的应用潜力.     

腐殖酸对铜的吸附与解吸特征

采用铜离子选择电极研究了铜在腐殖酸两组分(富里酸FA、胡敏酸HA)中的吸附-解吸特征,以及介质pH对这种吸附-解吸的影响。结果表明,腐殖酸对铜的吸附量为FA>HA,吸附强度为HA>FA,解吸量FA-Cu>HA-Cu。腐殖酸两组分对铜的吸附,当介质pH为4.00～7.00时,很好地符合Langmuir等温吸附方程;当pH<4.0时,符合Freundlich方程。FA、HA与铜作用的条件稳定常数与介质pH有关,pH提高则条件稳定常数增大;但在低pH段和高pH段,其增长规律不一致,当4.00相似文献   

水环境中重金属铜暴露下青鳉鱼的行为响应

采用生物行为传感器监测青鳉鱼在重金属铜暴露下的行为数据,分析不同暴露浓度(20、10、5、1和0.1 TU)下青鳉鱼的行为响应。20、10、5、1和0.1 TU的暴露浓度下青鳉鱼对重金属污染的行为反应模式符合环境胁迫阈值模型,且不同浓度梯度重金属对青鳉鱼产生不同的行为毒性效应。利用重金属作用下青鳉鱼的行为变化来研究重金属环境胁迫导致的生物行为响应机制,从而得到重金属暴露下生物行为的实时变化过程和趋势,可对水环境生态系统质量进行综合评价。     

水环境中重金属铜暴露下青鳉鱼的行为响应

本研究采用生物行为传感器监测青鳉鱼重金属铜暴露下的行为数据，分析不同暴露浓度(20、10、5、1和0.1 TU)下青鳉鱼的行为响应。20、10、5、1和0.1 TU的暴露浓度下青鳉鱼对重金属污染的行为反应模式符合环境胁迫阈值模型，且不同浓度梯度重金属对青鳉鱼产生不同的行为毒性效应。通过本研究，利用重金属作用下青鳉鱼的行为变化来研究重金属环境胁迫导致的生物行为响应机制，从而得到重金属暴露下生物行为的实时变化过程和趋势，可对水环境生态系统质量进行综合评价。     

基于机器视觉的鱼类行为特征提取与分析

近年来,水污染问题备受关注。生物式水质监测成为目前国家环境保护工作的重要任务之一。为准确监测水质污染情况,本文以青鳉鱼(Oryzias latipes)为研究对象,采用非接触式的机器视觉监测技术,提取青鳉鱼的生理特征(呼吸频率)和运动特征(胸鳍和尾鳍的摆动频率),并分析这些特征与水质之间的关系。本文采用支持向量机(Support Vector Machine,SVM)准确提取鱼鳃,并根据鱼鳃呼吸面积大小变化计算出鱼的呼吸频率。基于形态学细化算法提取青鳉鱼骨架,求出胸鳍和尾鳍的摆动频率。结果显示:不同浓度铜离子暴露实验测得的青鳉鱼生理特征和运动特征与实际情况一致;通过对不同铜离子浓度下的毒性实验数据对比,发现了青鳉鱼的生理特征和运动特征会随不同的铜离子浓度发生相应变化,可以作为水质监测的评价标准。     

高锰酸钾及氯化锰对日本青鳉的急、慢性毒性(Toxic Effects of Potassium Permanganate and Manganese Chloride on the Early Life Stage of Japanese Medaka（Oryzias latipes）)

饮用水生产中投加高锰酸钾可能引起高锰酸钾及其副产物二价锰的毒性效应.利用日本青鳉的胚胎-幼鱼发育阶段评价了以高锰酸钾为预氧化剂的饮用水生产工艺安全性.结果表明,高锰酸钾对日本青鳉的LC50-96h为1.48mg·L-1.慢性暴露中,对孵化时间影响的最低可观察效应浓度(LOEC30d)为0.1mg·L-1;暴露于0.4mg·L-1的高锰酸钾对30d后日本青鳉的体长、体重、累计死亡率均有显著影响,但对孵化率率无显著影响.氯化锰(Mn2+)对日本青鳉的LC50-96h为550mg·L-1,对体重影响的LOEC30d为3.2mg·L-1.当高锰酸钾的使用浓度在0.5～1.5mg·L-1之间,其在滤后水中的高锰酸钾残余浓度低于检出限,而降解中间体产物Mn2+浓度小于0.5mg·L-1,均低于本文报道的LOECs数值.     

铜在日本青鳉体内的累积特征及其对肝脏组织结构的影响

为了解水体铜(Cu(Ⅱ))在日本青鳉(Oryzias latipes)脑、鳃、肝脏、性腺和肌肉组织中的累积特征,以及Cu(Ⅱ)对肝脏组织结构的影响,本文采用生态学单因子梯度实验,进行20 d的日本青鳉毒性暴露试验。结果显示,日本青鳉各个组织对Cu(Ⅱ)的累积量随着浓度的升高而增多,但不同组织对Cu(Ⅱ)的累积量有较大的差异,铜累积量由大到小依次为:肝脏脑鳃性腺肌肉。铜暴露后的日本青鳉肝细胞出现肿大、大小不一、排列混乱,静脉扩张淤血,部分肝细胞固缩和坏疽等现象。肝脏是日本青鳉蓄积铜的主要器官之一,实验发现高浓度的Cu(Ⅱ)对肝脏组织结构造成了明显的损伤,进而严重影响日本青鳉的存活率。     

松花江腐殖酸的提取、表征及与重金属的络合作用

本文提得了第二松花江水及底泥中的黄腐酸(FA)和棕腐酸(HA),测定了总酸性基、羧基、醌基等官能团并进行了元素分析,研究了红外、紫外及荧光光谱,与一般水体腐殖酸的特征相同。 选用凝胶过滤法研究了腐殖酸与汞、镉、锌的络合作用,测定了水及底泥的FA和HA对Zn、Cd、Hg的络合容量,其趋势为Hg>Cd>Zn,计算了条件稳定常数,logA值显示出汞与腐殖酸的稳定性高于汞与水体中除S~(2-)及SH-外的其它配位络合物,合成了腐殖酸汞固体络合物,用红外光谱确定其络合作用,测定了腐殖酸汞在水中的溶解度。     

吡啶硫酮锌对水生生物的急性毒性(Acute Toxicity Effects of Zinc Pyrithione on Aquatic Organisms)

在没有下水处理设施的地区,去屑洗发香波中所含有的吡啶硫酮锌(zinc pyrithione,ZPT)随着生活废水被直接排放到河中.为了考察流入河中的ZPT对水生生物的影响,设想ZPT最终被底质吸附,在添加和未添加底质两种试验条件下,采用静水生物测试法对麦穗鱼、青鳉、泥鳅鱼、直突摇蚊亚科二龄幼虫、河蚬进行了室内急性毒性试验.结果表明,添加底质时,ZPT对麦穗鱼、青鳉、泥鳅鱼、直突摇蚊亚科二龄幼虫、河蚬48h的半致死浓度LC50分别为0.06、0.09、0.27、0.07和5.05mg·L-1;未添加底质时,ZPT对麦穗鱼、青鳉、泥鳅鱼、直突摇蚊亚科二龄幼虫、河蚬48hLC50分别为0.10、0.11、0.22、0.12和5.34mg·L-1.统计结果显示,添加与未添加底质,ZPT对上述供试生物的48hLC50值无显著差异(p>0.05).根据我国相关标准判定ZPT对麦穗鱼、青鳉、直突摇蚊亚科2龄幼虫属剧毒物质.     

Predictions of Cu toxicity in three aquatic species using bioavailability tools in four Swedish soft freshwaters

Background

The EU member countries are currently implementing the Water Framework Directive to promote better water quality and overview of their waters. The directive recommends the usage of bioavailability tools, such as biotic ligand models (BLM), for setting environmental quality standards (EQS) for metals. These models are mainly calibrated towards a water chemistry found in the south central parts of Europe. However, freshwater chemistry in Scandinavia often has higher levels of DOC (dissolved organic carbon), Fe and Al combined with low pH compared to the central parts of Europe. In this study, copper (Cu) toxicities derived by two different BLM software were compared to bioassay-derived toxicity for Pseudokirchneriella subcapitata, Daphnia magna and D. pulex in four Swedish soft water lakes.

Results

A significant under- and over prediction between measured and BLM calculated toxicity was found; for P. subcapitata in three of the four lakes and for the daphnids in two of the four lakes. The bioassay toxicity showed the strongest relationship with Fe concentrations and DOC. Furthermore, DOC was the best predictor of BLM results, manifested as positive relationships with calculated LC₅₀ and NOEC for P. subcapitata and D. magna, respectively.

Conclusion

Results from this study indicate that the two investigated BLM softwares have difficulties calculating Cu toxicity, foremost concerning the algae. The analyses made suggest that there are different chemical properties affecting the calculated toxicity as compared to the measured toxicity. We recommend that tests including Al, Fe and DOC properties as BLM input parameters should be conducted. This to observe if a better consensus between calculated and measured toxicity can be established.

     

Toxicity of copper to the marine amphipod Allorchestes compressa in the presence of water-and lipid-soluble ligands

Acute toxicity tests were carried out on the marine amphipod Allorchestes compressa Dana using copper sulphate and some organocopper complexes. For copper sulphate, 96 h LC₅₀ values of 0.11 and 0.5 mg Cu l^-1 were determined for the juveniles and the adults, respectively, juveniles being 4.5 times more sensitive to copper than adults. Organocopper complexes were tested on adults only. The three water-soluble ligands nitrilotriacetic acid, 8-hydroxyquinoline-5-sulphonic acid and tannic acid ameliorated copper toxicity by decreasing the concentration of free ionic copper, while lipid-soluble ligands such as oxine and potassium ethylxanthogenate increased copper toxicity, presumably as a result of the complexes diffusing through the cell membrane and participating in injurious reaction. The copper complex with 2,9-dimethyll, 10-phenanthroline was the most toxic complex tested. It is suggested that the presence of these ligands in the receiving water should be taken into consideration when establishing water-quality criteria.     

Survival and growth of bivalve larvae under heavy-metal stress

In a study of the toxicity of mercury, silver, copper, nickel, and zinc to larvae of the American oyster Crassostrea virginica and hard clam Mercenaria mercenaria, the concentrations at which 5% (LC₅), 50% (LC₅₀), and 95% (LC₉₅) of the larvae died were determined, as well as growth at the LC₅ and LC₅₀ values. The order of toxicity for oyster larvae was Hg>Ag>Cu>Ni, and for clam larvae Hg>Cu>Ag>Zn>Ni. Growth of larvae of both species, with the exception of clam larvae in nickel-treated water, was not reduced at the LC₅ values, but was markedly reduced at the LC₅₀ values.     

Influence of some abiotic environmental factors on acute toxicity of inorganic lead to Cyprinus carpio var communis (Linn.) and Catla catla (Ham.) in simulated toxic aquatic environment

With the increase of water hardness from 60 to 720?mg/L CaCO₃, total alkalinity from 32 to 376?mg/L CaCO_3, pH from 7.6 to 7.9 and chloride from 28 to 350?mg/L, 96?h LC₅₀ on the basis of total lead increased from 8.2 to 1291?mg/L for Cyprinus carpio and 5.3 to 865?mg/L for Catla catla, when soil sediments were included these values were further raised to 1356 and 874?mg/L, respectively. The dissolved lead LC₅₀ values in all the treatments of soil and water was consistent with fixed amount of dissolved lead (1.04–1.78?mg/L) being needed for median lethal toxicity. Total lead toxicity also decreased with increase in pH from 6.3 to 11.3. 96?h LC₅₀ values increased for common carp 15 to 631?mg/L and for catla, 8 to 355?mg/L. But dissolved lead toxicity was found to increase with the increase of pH from 6.3 to 11.3 for both common carp (LC₅₀, 3.53 to 0.24?mg/L) and catla (LC₅₀, 2.21 to 0.09?mg/L). Removal of dissolved Pb with increasing carbonate content, particulate matter and pH due to adsorption, precipitation or coprecipitation reaction, reduced the dissolved lead concentration and thus the total lead toxicity. Increase in toxicity of lead with increase of exposure time was the biological response of longer contact time and decrease in dissolved lead toxicity with decrease in pH was due to increase H⁺ ion competition.     

Cardioprotective effect of Lagenaria siceraria (Mol) ameliorates isoproterenol-induced cardiac toxicity in rats by stabilizing cardiac mitochondrial and lysosomal enzymes

A study was conducted to determine the effect of the chironomid larval tube on heavy metal toxicity. Silica gel was provided as a substrate with which the chironomid larvae could construct larval tubes. A series of 96 h LC₅₀ bioassays were conducted with and without the presence of the silica gel substrate, to allow comparison between the two test conditions. From the study it was observed that a 10–15% variation in LC₅₀ value occurred. The 96 h LC₅₀ for copper at the temperatures 35, 28, 20, 15, and 10°C was observed to be 7.5, 9.5, 7.5, 4.5, 3.6, and 2.8 mg L^?1, respectively. The same test when conducted in the presence of silica gel produced LC₅₀ values of 26.50, 33.50, 15.82, 12.77, and 9.94 mg L^?1 for the same temperatures. This would demonstrate that the larval tube did, to some extent, protect the larvae from the effects of the heavy metal.     

The toxicity of heavy metals to embryos of the American oyster Crassostrea virginica

The acute toxicity of 11 heavy metals to embryos of the American oyster Crassostrea virginica was studied and the concentrations at which 50% of the embryos did not develop were determined. The most toxic metals and their LC₅₀ values were mercury (0.0056 ppm), silver (0.0058 ppm), copper (0.103 ppm) and zinc (0.31 ppm). Those metals that were not as toxic and their LC₅₀ values were nickel (1.18 ppm), lead (2.45 ppm) and cadmium (3.80 ppm). Those metals that were relatively non-toxic and their LC₅₀ values were arsenic (7.5 ppm), chromium (10.3 ppm) and manganese (16.0 ppm). Aluminum was non-toxic at 7.5 ppm, the highest concentration tested.     

Phenanthrene adsorption by soils treated with humic substances under different pH and temperature conditions

The mobility of phenanthrene (PHE) in soils depends on its sorption and is influenced by either the existing soil humus or exogenous humic substances. Exogenous humic acids (HAs) were added to soil to enhance the amount of soil organic carbon (SOC) by 2.5, 5.0, and 10.0 g kg⁻¹. PHE desorption of the treated soils was determined at two pH levels (3.0 and 6.0) and temperatures (15 and 25 °C). Soil PHE adsorption was related to pH and the type and quantity of added HAs. Humic acid (HA) and fulvic acid (FA) derived from peat had different effects on adsorption of PHE. Adsorption increased at first and then decreased with increasing quantity of exogenous FA. When the soil solution pH (in 0.005 M CaCl₂) was 4.5 or 3.0, the turning points were 2.5 g FA kg⁻¹ at pH 3.0 and 5 g FA kg⁻¹ at pH 4.5. When soil solution pH was 6, the amount of adsorbed PHE was enhanced with increasing exogenous HAs (HA or FA) and amount of adsorption by soil treated with FA was higher than with HA. Adsorption of PHE in the FA treatment at 10.0 g kg⁻¹ was lower than the controls (untreated soil or treatment with HAs at 0 g kg⁻¹) when the soil solution pH was 3.0. This suggests that FA adsorbed by soil was desorbed at low pH and would then increase PHE solubility, and PHE then combined with FA. PHE adsorption was usually higher under lower pH and/or lower temperature conditions. PHE sorption fitted the Freundlich isotherm, indicating that exogenous humic substances influenced adsorption of phenanthrene, which in turn was affected by environmental conditions such as pH and temperature. Thus, exogenous humic substances can be used to control the mobility of soil PAHs under appropriate conditions to decrease PAH contamination.     

Toxicity of zinc,cadmium and copper to the shrimp Callianassa australiensis. I. Effects of individual metals

The acute toxicity of zinc, cadmium and copper to Callianassa australiensis (Dana) was evaluated in static tests. Each test lasted up to 14 d and LC₅₀ values were calculated for 4, 7, 10 and 14 d intervals. The toxicity of each metal increased with exposure time; thus the 4 d LC₅₀ values of 10.20, 6.33 and 1.03 mg l^-1 were considerably higher than the 14 d LC₅₀ values of 1.15, 0.49 and 0.19 mg l^-1 for zinc, cadmium and copper respectively. Toxicity curves reveal that none of the values were asymptotic, indicating that median lethal threshold concentrations were not reached for any of the metals. This suggests that 14 d is an insufficient time in which to complete meaningful, acute lethality tests for marine shrimps. Longer tests are necessary if lethal threshold concentrations are to be used with application factors to derive safe concentrations for the protection of C. australiensis.     

Effect of Water Variables On Lead Tolerance in Postlarvae of Penaeus Indicus (H. Milne Edwards)

Lead tolerance in Penaeus indicus post-larvae (PL) was studied in relation to the water variables: salinity, temperature and pH. the LC₅₀ for 96 hrs was 7.22 ppm at ambient conditions of salinity (20%_o), temperature (29°C) and pH (7.2). the post-larvae were found to be sensitive to salinity variations with a significant (P < 0.05) low LC₅₀ values at lower (2%_o) and higher (29%_o) ranges. Though a decrease in LC₅₀ value was observed both at higher (45°C) and lower (10°C) temperatures, it was significantly (P < 0.05) low only at higher temperature indicating more toxicity. the LC₅₀ values also showed a significant (P < 0.05) decrease in acidic (pH 2.8) and alkaline (pH 11.0) conditions. the data indicate that lead toxicity increases in the PL of P. indicus with variations in the water variables.     

Temperature effects on the toxicity of four trace metals to adult spotted Babylonia snails (Babylonia areolata)

A study was conducted to determine the median lethal toxicity of four heavy metals on the marine gastropod Babylonia areolata. Median lethal toxicity tests were conducted to observe the sensitivity of this gastropod to metals and how variations in temperature might affect toxicity of test elements. Four heavy metals were used in the study. It was observed that the 96-hr LC₅₀ (in mg/L) for the different metals was found to be nickel (Ni) 33.53 (35.22–28.43), copper (Cu) 44.59 (46.43–41.53), cadmium (Cd) 21.53 (23.43–18.37), and zinc (Zn) 27.34 (28.81–24.24) at room temperature 24 °C. With temperature as a variable, median lethal concentration (LC₅₀) values were observed to increase from 22.41 mg/L at 10 °C to 27.34 mg/L at 28 °C and reduce to 18.43 mg/L at 30 °C and a further rise in toxicity was observed at 35 °C where LC₅₀ value was 12.7 mg/L as seen in the case of Zn. It was also observed that at 40 °C thermal and chemical toxicity overlapped as 100% mortality was observed in controls. This trend was noted in all metals for Babylonia areolata indicating that temperature played an important role in determining LC₅₀ values of toxicants.