Effect of Nickel and Cadmium on Ammonium Uptake Kinetics of Free and Immobilized Cells of Anacystis nidulans

The stress effect of Ni and Cd on the ammonium uptake varied significantly (ANOVA test) in free and immobilized state of the test organism. The effect due to the interaction between different variables (cell state type, metal type and metal dose) was studied to depict the significant or non‐significant variation in the ammonium uptake by free and immobilized cells in the presence of metal ions. Ammonium uptake exhibited a competitive mode of inhibition in the presence of Ni in both free and immobilized state of the organism. However, Cd exhibited non‐competitive and competitive inhibition in free and immobilized cells, respectively. The study demonstrates that there is a considerable influence of metal ions on the ammonium uptake. Cd was found to be more toxic compared to Ni in both free and immobilized state.     

Sea-surface microlayer toxicity off the Florida Keys

A survey of sea-surface microlayer (SSML) toxicity was initiated off the Florida Keys in early 1993. Ex situ toxicity tests, based on the development of the sea urchin, Lytechinus variegatus, demonstrated that 59.2% of SSML samples taken from visibly slicked areas (n=27) were toxic compared to collected subsurface water. A random subset of samples tested a second time using a fish early life-stage test with embryos from the spotted seatrout, Cynoscion nebulosus, confirmed the presence of the toxicant. Results from a partial toxicity identification evaluation (TIE) procedure indicated that an organic compound(s) containing a non-polar functional group was the primary determinant of toxicity in all of the SSML samples tested. While subsequent GC-MS analyses failed to identify a specific compound, they did tend to rule out common xenobiotics, such as organochlorine pesticides as potential toxicants. Preliminary tests, done by an outside laboratory, indicated that two of the most toxic SSML samples contained a brevetoxin, a biotoxin produced by Gymnodinium breve. This is the first report of natural toxins concentrating in the SSML; however, without a completed TIE, including a Phase III—toxicity confirmation procedure, the identification of any toxic agent remains speculative.     

Toxicity identification in metal plating effluent: implications in establishing effluent discharge limits using bioassays in Korea

Because of complexity and diversity of toxicants in effluent, chemical analysis alone gives very limited information on identifying toxic chemicals to test organisms. Toxicity identification evaluation (TIE) techniques have been widely used to identify toxicants in various samples including industrial wastewater as well as natural waters. In response to new regulation for effluent discharge in Korea, which will be effective from 2011, a necessity of studies emerges that investigates toxicity levels in industrial effluents. This work was a preliminary study examining toxicity levels in effluent from one metal plating factory using Daphnia magna (48 h immobility) and identifying toxicity-causing substances. Toxicity tests showed variability on different sampling occasions and the results of TIE methods indicated that both organic compounds and metals contributed to the observed toxicity in metal plating effluent. Further studies are necessary to help reduce effluent toxicity especially from direct dischargers, who will have to comply with the new regulation.     

Effect of glyphosate-based herbicide on early life stages of Java medaka (Oryzias javanicus): A potential tropical test fish

Glyphosate is globally a widely used herbicide, yet there is little information on their toxicity to marine fishes. Java medaka, a small tropical fish native to coastal areas in several Southeast Asian countries, is viewed as a suitable candidate for toxicity test and thus was used for this study. Java medaka adults were cultured in the laboratory and the fertilized eggs of the F₂ generation were exposed to different concentrations of glyphosate-based herbicide (100, 200, 300, 400 and 500 ppm) until they hatched. The survival and hatching rates of the embryos, changes in the heart rate and morphological impairments were recorded. Generally, survival and hatching percentage decreased as glyphosate concentration increased. Absence of pectoral fin(s) and cornea, permanently bent tail, irregular shaped abdomen, and cell disruption in the fin, head and abdomen are among the common teratogenic effects observed. Furthermore, risk factor also increased with the increased in glyphosate concentrations.     

Partitioning behavior of perfluorinated compounds between sediment and biota in the Pearl River Delta of South China

Surface sediment and biota were collected from 12 sampling sites – seven along the Pearl River Delta and five along the Hong Kong coastline. Perfluorinated compound (PFC) concentrations were detected using a high-performance-liquid-chromatogram–tandem-mass-spectrometry system. Analytical results indicated that the total PFC concentrations were in the range of 0.15–3.11 ng/g dry weight in sediments, while the total PFC concentrations in oyster and mussel samples were between 0.46–1.96 and 0.66–3.43 ng/g wet weight, respectively. The major types of PFCs detected in the sediment samples were perfluorooctanesulfonic acid (PFOS) and perfluorobutanoic acid (PFBA), with concentrations ranging from low limits of quantification to 0.86 ± 0.12 ng/g dry weight and 1.50 ± 0.26 ng/g dry weight, respectively. In bivalve samples, PFOS was the dominant contaminant with concentrations ranging from 0.25 ± 0.09 to 0.83 ± 0.12 ng/g wet weight in oysters and 0.41 ± 0.14 to 1.47 ± 0.25 ng/g wet weight in mussels. An increase in PFC concentration was found to be correlated with increased human population density in the study areas.     

Assessing metal toxicity in sediments using the equilibrium partitioning model and empirical sediment quality guidelines: A case study in the nearshore zone of the Bohai Sea,China

Surface sediments were collected from five nearshore (wastewater discharges, aquaculture facilities and a seaport) sites in Bohai Bay and Laizhou Bay, China. The equilibrium partitioning (EqP) model and empirical sediment quality guidelines (SQGs) were applied to assess the potential metal toxicity in the collected sediments. The results show that, based on the EqP model, 35% of stations exhibited potential metal toxicity. Several metals (Cu, Ni and Cr) exceeded the empirical SQGs (9–93% of the time), however these guidelines may not be suitable for use in the Bohai Sea owing to the background concentrations. The EqP model is a more useful method for assessing potential metal toxicity in Bohai Sea sediment than the empirical SQGs. Additionally, we have provided new understanding about methods for assessing sediment metal toxicity in the Bohai Sea that may be useful in other coastal areas in China.     

Metabolism and organ distribution of nonylphenol in Atlantic salmon (Salmo salar)

Nonylphenol (NP) is a breakdown product of alkylphenol polyethoxylates (APEs), an important class of non-ionic surfactants that are widely used in many detergent formulations and plastic products for industrial and domestic use. A complex microbial degradation pattern, characterized by the formation of several metabolic products that are more toxic than the parent compound, has been established for APEs. We have studied the in vivo metabolism and organ distribution of NP in juvenile salmon. Fish were exposed to a single oral dose of [³H]-4-n-NP (1295 KBq, 25 μg) and sampled at 24, 48 and 72 h after exposure. Metabolites were separated by radio-high-performance liquid chromatography and tentatively identified by co-chromatography with standards characterized by mass spectrometry. Our results show that 4-n-NP was mainly metabolized in vivo to its corresponding glucuronide conjugate and to a lesser extent to various hydroxylated and oxidated compounds. Biliary excretion at 72 h after dosing amounted to 2.83±0.75% of the administered radioactivity. Kinetic analysis shows that NP-glucuronide accounted for 83, 95 and 81% of total radioactivity in the HPLC-injected bile sample at 24, 48 and 72 h, respectively, after exposure. The half-life of residues in carcass and muscle was between 24 and 48 h after exposure.     

双壳类清滤率在海洋污染物毒性研究中的应用

以海湾扇贝(Argopectenirradians)和紫贻贝 (Mytilusedulis)的清滤率为指标 ,研究了金矿废水及其组分、三苯基氯化锡及塔玛亚历山大藻的毒性 ,结果表明金矿废水及其主要组分丁级黄药、CN-和重金属Cd2 +、Cu2 +、Zn2 +对海湾扇贝清滤率的半抑制浓度EC50 分别为40.6 %、7.52、0.226、0.189、0.02、1.10mg/L ;三苯基氯化锡对海湾扇贝的半抑制浓度EC50 为4.86×10-9g/L;塔玛亚历山大藻能抑制紫贻贝的清滤率,半抑制浓度EC50为6000cells/ml。由以上结果可见 ,双壳类清滤率能快速、敏感地反应污染物的影响 ,是海洋污染物毒性研究的一个良好指标。     

三氯异氰尿酸对剑尾鱼(Xiphophorus helleri)毒性及其抗氧化酶影响

采用生物毒性测试与评价方法对常用消毒剂药物三氯异氰尿酸（Trichloroisocyanuric acid,TCCA）对剑尾鱼的急性毒性及其Ⅰ、Ⅱ相代谢酶活性影响进行了研究。结果表明,TCCA对剑尾鱼的96hLG0为2．15mg／L。TCCA对剑尾鱼肝脏还原型谷光苷肽（GSH）、谷胱苷肽硫转酶（GST）和7。乙氧基异吩恶唑酮-脱乙基酶（EROD）都存在诱导作用。雌雄个体在GST和EROD的诱导响应时间有显著差异性,其中雄性个体GST对TCCA暴露响应比雌性个体敏感。