Tolerance of Five West Coast Marine Toxicity Test Organisms to Ammonia

No abstract available.     

改性石英砂及沸石滤料除氟性能比较研究

研究了以石英砂和沸石为骨架的吸附材料经铝盐改性处理后在处理饮用水中过量氟的处理行为，比较两种改性滤料处理能力的不同并对差异进行分析。实验表明物理空间结构性强的沸石作为改性滤料的应用有着独到的优越性，除氟效率达到98％以上。     

Toxicity and Bioaccumulation of Cadmium in Marine Protozoa Communities

The behavior of cadmium in a protozoan community was analyzed in order to obtain new data concerning the toxicity and bioaccumulation of this heavy metal. For this purpose, microcosms with different concentrations of the pollutant (without cadmium, 500 microg Cd.l-1 and 1000 microg Cd.l-1) were used. Protozoans bioaccumulated 8. 74-283 microg Cd.g-1 dry weight, representing an accumulation capacity of 15.53-69.59 times more than that of bacteria. The addition of cadmium caused a significant reduction in protozoan density, whereas bacterial abundance was not affected.     

Toxicity and Bioaccumulation of Lead in Marine Protozoa Communities

The toxicity and bioaccumulation of lead has been studied using marine protozoa communities developed in laboratory microecosystems. The concentrations tested were 500 and 1000 μg · L⁻¹of lead as lead acetate. The protozoan was able to bioaccumulate 27.02–504 μg Pb · g⁻¹dry weight. Bacteria also bioaccumulated lead, but always to a lesser degree than protozoa. Lead caused a significant reduction in the density of protozoa, which could be an indirect response to the cellular increase of lead. On the other hand, the toxicant did not determine a decrease in the number of bacterial cells; this could be due to their capacity to bioaccumulate a lesser amount of lead, the increase in the number of dead cells, and the elimination of their predators by the toxicant. After 120 h, a recovery of the community was observed.     

居室空气中挥发性有机物与氨的联合毒性

目的探讨居室装修后几种主要的挥发性有机物与氨的联合毒性。方法根据现场45间新装修居室检测所得甲醛、苯、甲苯、二甲苯、乙苯、氨浓度的中位数换算成平均质量百分比,再用分析纯品配制成混合物。分别以3.93、8.47、18.24、39.35g/m3混合物剂量进行昆明种小鼠急性毒性实验,分别以高剂量:3.935g/m3、中剂量:1.970g/m3、低剂量:0.393g/m3进行昆明种小鼠亚急性毒性实验。结果混合物小鼠LC50为26.84g/m3。亚急性毒性实验中,雌性小鼠染毒各剂量组网织红细胞计数,中剂量组红细胞比积(HCT),雌、雄性小鼠高剂量组血清血小板计数(PLT)显著低于对照组(P<0.05)。雌性小鼠高剂量组血清丙氨酸转氨酶(ALT)显著高于对照组。病理学检查发现混合物染毒各剂量组小鼠均可见心内膜下浅层不同程度脂肪变性,肺组织有不同程度淤血,随剂量增加,病变加重;高剂量组小鼠可见肝细胞轻度脂肪变性。结论该混合物对小鼠血液系统、肝脏、心脏以及肺脏有损害作用,雌性小鼠较为敏感,网织红细胞计数可以作为其机体毒性的敏感性损伤变化指标。     

The Development of Marine Toxicity Identification Evaluation (TIE) Procedures Using the Unicellular Alga Nitzschia closterium

Unicellular algae are highly sensitive to a wide range of toxicants and have been used extensively in ecotoxicological testing. This, along with their ability to grow in very small test volumes over short test durations, make them ideal test organisms for use in Toxicity Identification Evaluations (TIEs). Despite this, microalgae have not previously been used in marine TIE studies. In this study, the marine diatom Nitzschia closterium was shown to be a highly suitable test organism after modification of the standard test protocol to reduce test volumes to 6 mL and test duration to 48 h. The alga was tolerant to the chemicals used in phase I of the standard USEPA TIE protocol, and physical TIE manipulations had no effect on algal growth. The cation exchange procedure, however, inhibited algal growth, while the anion exchange procedure stimulated growth, making these two procedures unsuitable for use with this species. Of the buffers trialed for the graduated pH procedure, 0.01 M PIPES buffer was found to be suitable for buffering at pH 7 because it maintained the required pH over the duration of the test and did not affect the growth or sensitivity of the algae to one reference toxicant (copper). A trial TIE on a secondary-treated sewage effluent for discharge into coastal waters showed that the developed protocols could successfully be used to identify ammonia as the major toxicant in the effluent.     

Acute Toxicity of Gallium and Effects of Salinity on Gallium Toxicity to Brackish and Marine Organisms

No abstract available.     

Chronic Toxicity of Ammonia to the Freshwater Bivalve Sphaerium novaezelandiae

The chronic toxicity of total ammonium and unionized ammonia (NH₃) to the native New Zealand freshwater fingernail clam Sphaerium novaezelandiae was assessed in soft water under laboratory conditions. Control survival after 60 days was high (93%) and concentration-response relationships showed the sensitivity of S. novaezelandiae survival was markedly greater to both total and unionized ammonia (6.4× and 4.6×) after 60 days compared with the 30-day exposure at 20°C. Chronic mortality and number moribund (inability to rebury) showed similar sensitivities, but reproduction was a more sensitive endpoint based on a concentration-response analysis. The survival LC50 values for total and unionized ammonia were 3.8 mg (N)/L (pH 7.5) and 0.037 mg (NH₃-N)/L, and reproductive values 0.80 mg (N)/L (pH 7.5) and 0.013 mg (NH₃-N)/L at 60 days. No observed effect concentration (NOEC) values for both survival and reproduction were 0.97 mg (N)/L and 0.011 mg (NH₃-N)/L, and the lowest observed effect concentration (LOEC) values were 5.4 mg (N)/L and 0.046 mg (NH₃-N)/L for survival after 60 days, giving a calculated threshold effect concentration (TEC) of 2.3 mg (N)/L and 0.022 mg (NH₃-N)/L. Comparison of the S. novaezelandiae chronic ammonia sensitivity data with the US EPA criteria showed the survival and reproduction TEC values for total ammonia were 1.9× higher than the chronic criterion, and the lethality value 1.4× above the unionized ammonia criterion. The findings suggest that use of the US EPA criteria would provide minimal protection for S. novaezelandiae for chronic ammonia exposure, and that development of site-specific criteria, covering a wide range of environmental conditions, may be required to adequately protect all life stages of this species. Received: 23 September 1996/Accepted: 27 July 1998     

Predicted Near-Future Oceanic Warming Enhances Mercury Toxicity in Marine Copepods

Bulletin of Environmental Contamination and Toxicology - The effects of acute mercury exposure (118&nbsp;µg/L) on the marine copepod Tigriopus japonicus were examined at 22 and...     

Photoinduced Toxicity of Fluoranthene to Seven Marine Benthic Crustaceans

Seven marine benthic crustaceans were exposed in 4 d water-only toxicity tests to five concentrations of fluoranthene. After exposures, mortality (LC₅₀) and the ability to bury in clean sediment (EC₅₀) were determined. Survivors were then exposed to UV radiation for 1 h. The differences between LC₅₀s and EC₅₀s before and after UV exposure were used to assess photoinduced toxicity. UV exposure enhanced fluoranthene toxicity by as much as tenfold in five of the seven species tested (Rhepoxynius abronius, Eohaustorius estuarius, Leptocheirus plumulosus, Grandidierella japonica, and Corophium insidiosum). Species having the greatest potential for natural exposure to sunlight (Excirolana vancouverensis and Emerita analoga) were the least sensitive to photoinduced fluoranthene toxicity. Although photoinduced toxicity needs to be considered in environmental risk assessments, testing should be done, using ecologically relevant species and exposures. Received: 23 April 1996/Revised: 10 August 1996