黄河水源水浮游藻类及藻类毒素污染状况动态研究

目的 :探讨黄河水源水浮游藻类和藻毒素污染状况及影响因素。方法 :于 1998年 5～ 12月在河南省S市、Z市、P市水源水设采样点 ,对水源水浮游藻类、藻类毒素污染情况及总氮、总磷、COD等指标进行了连续检测。结果 :河南省黄河水源水总氮检出范围为 2 5 7～ 6 .79mg/L ,总磷的检出范围为 0 0 1～ 0 .32mg/L ,蓝藻和绿藻为浮游藻类的优势种群。MC的阳性率 ( >2 0ng/L)为 82 6 1% ,最高达到 95 7 9ng/L。结论 :按照Carlson提出的富营养化指数TSI(TP)判定标准 ,结合TN、TP、COD及藻类密度等指标 ,认为河南省境内黄河水源水已呈现富营养化特征。磷是黄河水源水浮游藻类生长的主要限制因子 ,控制黄河水源水富营养化应以控制磷为主。     

氯酚在鲫鱼体内的分布、存在形式与生物富集研究

用气相色谱－电子捕获检测器法测定鱼组织中４种有代表性的氯酚（ＣＰｓ）及其共轭物。选取ＣＰｓ分别对鲫鱼在室温（２２±５）℃进行９６ｈ半静态染毒实验。实验发现：２４ｈ换一次水,能充分保证ＣＰｓ实验水的浓度恒定,鱼的存在并不影响实验水的浓度。实验水系统中,ＣＰｓ在鲫鱼（Ｃｒｕｉｃａｎｃａｒｐｓ）体内的分布和积累的研究结果表明,ＣＰｓ在鱼体内以游离ＣＰｓ及其共轭物２种形式存在。ＣＰｓ总量在各鱼组织间的分布顺序为：胆＞肝、肾＞肌肉,随着氯（Ｃｌ）原子数目的增多,ＣＰｓ共轭物所占比例亦增大,而ＰＣＰ共轭物所占比例则较ＴＣＰ有所下降。胆组织中ＣＰｓ共轭物由葡萄糖苷酸共轭物和硫酸酯共轭物２种形式组成,其中葡萄糖苷酸含量大于９３％。通过计算生物浓缩因子（ＢＣＦ）值来度量ＣＰｓ在鱼组织中的生物富集效果。由胆中游离氯酚和硫酸酯共轭物得到的ＢＣＦ值均与正辛醇／水体系的分配系数ＫＯＷ没有相关性;而通过葡萄糖苷酸共轭物和ＣＰｓ总量分别计算得到的ＢＣＦ值均与ＫＯＷ有较好的相关性,（ｒ＞０．９６）。鲫鱼鱼胆的ＢＣＦ,在２．０×１０３～６．３×１０３之间。     

Accumulation, tissue distribution, and maternal transfer of dietary 2,3,7,8,-tetrachlorodibenzo-p-dioxin: impacts on reproductive success of zebrafish.

TCDD (2,3,7,8-tetrachlorodibenzo-p-dioxin) is a reproductive toxicant and endocrine disruptor in nearly all vertebrates; however, the mechanisms by which TCDD alters the reproductive system is not well understood. The zebrafish provides a powerful vertebrate model system to investigate molecular mechanisms by which TCDD affects the reproductive system, but little is known regarding reproductive toxic response of zebrafish following chronic, sublethal exposure to TCDD. Here we investigate the accumulation of TCDD in selected tissues of adult female zebrafish and maternal transfer to offspring following dietary exposure to TCDD (0.08-2.16 ng TCDD/fish/day). TCDD accumulated in tissues of zebrafish in a dose- and time-dependent manner, except for brain. Chronic dietary exposure resulting in the accumulation of 1.1-36 ng/g fish did not induce an overt toxic response or suppress spawning activity. The ovosomatic index was impacted with an accumulation of as little as 0.6 ng/g fish, and 10% of the females showed signs of ovarian necrosis following accumulation of approximately 3 ng/g TCDD. Offspring health was impacted with an accumulation of as little as 1.1 ng/g female; thus the lowest observed effect level (LOEL) for reproductive toxicity in female zebrafish is approximately 0.6-1.1 ng/g fish. Maternal transfer resulted in the accumulation of 0.094-1.2 ng/g, TCDD, which was sufficient to induce the typical endpoints of larval TCDD toxicity, commonly referred to as blue sac syndrome. This study provides the necessary framework to utilize the zebrafish model system for further investigations into the molecular mechanisms by which TCDD exerts its reproductive toxic responses.     

Accumulation and toxicity of CuO and ZnO nanoparticles through waterborne and dietary exposure of goldfish (Carassius auratus)

Dietary and waterborne exposure to copper oxide (CuO) and zinc oxide (ZnO) nanoparticles (NPs) was conducted using a simplified model of an aquatic food chain consisting of zooplankton (Artemia salina) and goldfish (Carassius auratus) to determine bioaccumulation, toxic effects, and particle transport through trophic levels. Artemia contaminated with NPs were used as food in dietary exposure. Fish were exposed to suspensions of the NPs in waterborne exposure. ICP‐MS analysis showed that accumulation primarily occurred in the intestine, followed by the gills and liver. Dietary uptake was lower, but was found to be a potential pathway for transport of NPs to higher organisms. Waterborne exposure resulted in about a 10‐fold higher accumulation in the intestine. The heart, brain, and muscle tissue had no significant Cu or Zn. However, concentrations in muscle increased with NP concentration, which was ascribed to bioaccumulation of Cu and Zn released from NPs. Free Cu concentration in the medium was always higher than that of Zn, indicating CuO NPs dissolved more readily. ZnO NPs were relatively benign, even in waterborne exposure (p ≥ 0.05). In contrast, CuO NPs were toxic. Malondialdehyde levels in the liver and gills increased substantially (p < 0.05). Despite lower Cu accumulation, the liver exhibited significant oxidative stress, which could be from chronic exposure to Cu ions. © 2014 Wiley Periodicals, Inc. Environ Toxicol 30: 119–128, 2015.     

In vitro evaluation of the metabolic stability of nine fragrance chemicals in trout and human hepatocytes

In vitro metabolic stability of nine fragrance chemicals: p-tolyl acetate, cashmeran, ethylene brassylate, celestolide, galaxolide, traseolide, ambretone, tonalide and pentadecanolide, was evaluated in trout and human hepatocytes. The compounds were incubated with trout hepatocytes at 12°C and human hepatocytes at 37°C. Quantification of compound disappearance with time was performed using gas chromatography/mass spectrometry. in vivo hepatic intrinsic clearance values were calculated from the in vitro data. Significant metabolism was observed with trout hepatocytes for five of the nine fragrance chemicals, while all nine were metabolized significantly with human hepatocytes. Previously published models were used to examine expected bioaccumulation and persistence in whole organisms. Calculated half-lives due to metabolism of the nine chemicals are significantly shorter for humans than trout: <1 hour and <1 day, respectively. For all chemicals with demonstrated hepatic metabolism, the models indicate a lack of accumulation. For those where metabolism was demonstrated in trout, calculated bioconcentration factors would not be classified as bioaccumulative under prevailing regulatory systems.     

Toxicity thresholds for juvenile freshwater mussels Echyridella menziesii and crayfish Paranephrops planifrons,after acute or chronic exposure to Microcystis sp

Survival of juvenile freshwater mussels (Echyridella menziesii (Gray, 1843) formerly known as Hyridella menziesi) and crayfish (Paranephrops planifrons, White, 1842) decreased after four days exposure to microcystin‐containing cell‐free extracts (MCFE) of Microcystis sp. at concentrations typical of severe cyanobacterial blooms. Crayfish survival was 100, 80, and 50% in microcystin concentrations of 1339, 2426, and 11146 μg L^?1 respectively, and shade‐ and shelter‐seeking behavior was negatively affected when concentrations were ≥2426 μg L^?1. Mussel survival decreased to 92% and reburial rates decreased to 16% after exposure for 96 h to MCFE containing microcystins at concentrations of 5300 μg L^?1. Crayfish survival was 100% when fed freeze‐dried Microcystis sp. incorporated into an artificial diet (6–100 μg microcystin kg^?1 ww) at dietary doses from 0.03 to 0.55 μg g^?1 body weight d^?1 for 27 days. Specific growth rate was significantly lower in crayfish fed ≥0.15 μg g^?1 body weight day^?1 compared with controls, but not compared with a diet incorporating nontoxic cyanobacteria. Microcystins accumulated preferentially in crayfish hepatopancreas and mussel digesta as MCFE or dietary concentrations increased. These laboratory data indicate that, assuming dissolved oxygen concentrations remain adequate, and no simultaneous exposure to live Microcystis sp. cells, cell‐free microcystins will only be a significant stressor to juvenile crayfish and mussels in severe Microcystis sp. blooms. In contrast, crayfish were negatively affected by relatively low concentrations of microcystins in artificial diets compared with those measured locally in benthic cyanobacterial mats. © 2012 Wiley Periodicals, Inc. Environ Toxicol 29: 487–502, 2014.     

Overview of the toxic effects of titanium dioxide nanoparticles in blood,liver, muscles,and brain of a Neotropical detritivorous fish

The toxicity of titanium dioxide nanoparticles (TiO₂‐NP) in the blood, liver, muscle, and brain of a Neotropical detritivorous fish, Prochilodus lineatus, was tested. Juvenile fish were exposed to 0, 1, 5, 10, and 50 mg L^?1 of TiO₂‐NP for 48 hours (acute exposure) or 14 days (subchronic exposure) to evaluate changes in hematology, red blood cell (RBC) genotoxicity/mutagenicity, liver function (reactive oxygen species (ROS) production, antioxidant responses, detoxification, and histopathology), acetylcholinesterase (AChE) activity in muscles and brain, and Ti bioaccumulation. TiO₂‐NP did not cause genetic damage to RBC, but acutely decreased white blood cells (WBC) and increased monocytes. Subchronically, RBC decreased, mean cell volume and hemoglobin increased, and WBC and lymphocytes decreased. Therefore, NP has the potential to affect immune system and increase energy expenditure, reducing the fish's ability to avoid predator and to resist pathogens. In the liver, acute exposure decreased ROS and increased glutathione (GSH) content, while subchronic exposure decreased superoxide dismutase activity and increased glutathione‐S‐transferase (GST) activity and GSH content. GSH and GST seem to play an essential role in metabolizing NP and ROS, likely increasing hepatocytes' metabolic rate, which may be the cause of observed cell hypertrophy, disarrangement of hepatic cords and degenerative morphological alterations. Although most studies indicate that the kidney is responsible for metabolizing and/or eliminating TiO₂‐NP, this study shows that the liver also has a main role in these processes. Nevertheless, Ti still accumulated in the liver, muscle, and brain and decreased muscular AChE activity after acute exposure, showing neurotoxic potential. More studies are needed to better understand the biochemical pathways TiO₂‐NP are metabolized and how its bioaccumulation may affect fish homeostasis and survival in the environment.     

Mechanism and prediction for contamination of freshwater bivalves (Unionidae) with the cyanobacterial toxin microcystin in hypereutrophic Lake Suwa,Japan

Seasonal changes of microcystin (MC) bioaccumulation in three freshwater Unionid bivalves, Anodonta woodiana, Cristaria plicata, and Unio douglasiae, were investigated in the hypereutrophic Lake Suwa. Total MC concentrations (MC-RR and -LR) as determined by reverse-phase high-performance liquid chromatography were at high levels in the hepatopancreas of C. plicata and U. douglasiae, with maxima at 297 and 420 microg/g dry weight, respectively. The amounts and seasonal changes in the accumulated MC concentration differed in all species. The total MC concentration of A. woodiana was always less than that of other species (maximum concentration of 12.6 microg/g dry weight). The toxin concentration of C. plicata remained very low in summer, when the Microcystis bloom occurred, but increased rapidly in autumn, when the toxic bloom disappeared. For U. douglasiae, simple regression analyses were performed to clarify the relationship between MC bioaccumulation and environmental parameters such as water temperature, chlorophyll a, suspended solids (SS), intracellular MC per unit volume of lake water and per-unit weight of SS and extracellular MC. The toxin concentration of U. douglasiae correlated more closely with qualitative factors, with intracellular toxin per SS (p < 0.001, R(2) = 0.72) than with quantitative factors such as chlorophyll a and intracellular toxin per unit volume of lake water. No correlation could be found between MC in the tissues and extracellular MC. These results indicate that a long-term survey is needed to assess the safety of bivalves. The study should take into consideration both interspecific differences in toxin content and what is the optimal monitoring parameter.     

ADMAdda5]-microcystins in Planktothrix agardhii strain PH-123 (cyanobacteria)--importance for monitoring of microcystins in the environment

Two major and two minor microcystins (MCYST) were isolated from a hepatotoxic Danish strain of Planktothrix agardhii (Gomont) Anagnostidis et Komárek by reversed-phase high-performance liquid chromatography. The microcystins were characterized by UV spectroscopy, amino acid analysis, fast atom bombardment mass spectrometry (FABMS), and high-resolution FABMS. The major microcystins were further analysed by collisionally induced tandem electrospray ionization MS. The microcystins were found to be demethylated variants of MCYST-HtyR (homotyrosine-arginine) and MCYST-LR (leucine-arginine). The two major microcystins contained an acetyl-demethyl variant (ADMAdda) of 3-amino-9-acetoxy-2,6,8-trimethyl-10-phenyldeca-4,6-dienoic acid (Adda). This is the first report of [ADMAdda5]-microcystins in Planktothrix. The two [ADMAdda5]-microcystins inhibited protein phosphatase activity but showed low cross-reactivity with antibodies of an enzyme-linked immunosorbent assay (ELISA), emphasizing the potential underestimation of the toxicity of natural blooms dominated by Planktothrix when microcystin content is quantified using only an ELISA.     

福建省部分水源微囊藻毒素污染调查

目的 报告福建省部分饮用水水源微囊藻毒素污染状况调查结果,探讨饮用水水源微囊藻毒素的危害及预防措施.方法 1998,2000年在厦门同安肝癌高发区抽样采集浅井水49份、自来水4份、水库水3份,竞争酶联免疫吸附法（ELISA）测定水样中微囊藻毒素;2001年8-9月份采集福州山仔水库微囊藻水华,小鼠生物法测定微囊藻水华急性毒性,高效液相色谱法定性、定量测定微囊藻毒素类型和含量.结果 厦门同安农村饮用水水源普遍存在微囊藻毒素污染,夏季藻类生长高峰期,水库水微囊藻毒素检出率100%,浅井水检出率77.5%;同安水源中优势藻为颤藻,其次为微囊藻.福州山仔水库微囊藻水华LD50为9.9 g藻浆/kg,平均死亡时间2.5 h.每克鲜藻浆含微囊藻毒素20.5μg,主要毒素类型为MC-RR,其次为MC-LR和MC-YR.结论 福建省部分饮用水水源存在微囊藻毒素污染,山仔水库微囊藻毒素主要类型为MC-RR,有明显的肝毒性.