Acute Toxicity Assay Using Mysid as an Alternative Test Organism in the Assessment of the Aqueous Fraction of Sediment

The evaluation of sediment quality through biological testing of the aqueous fraction can be applied in dredging situations and is associated with a small number of confounding factors. The use of test organisms that are relatively resistant to contaminants is recommended when working with complex mixtures such as sediments. In this study, the sensitivity of the mysid Mysidopsis juniae to total ammonia and metals was investigated in acute toxicity laboratory tests and the results were compared to those obtained in the traditional test with sea urchin embryos and larvae. The ability of the toxicity identification and evaluation (TIE) technique, with the use of EDTA and sodium thiosulfate, to indicate the factors responsible for adverse effects was determined. The results indicate that mysids are almost 5 times more resistant than the sea urchin to unionized ammonia, more sensitive to Cd2+ and Ni2+ and more resistant to Zn2+ and Pb2+. With the TIE technique and with the use of EDTA as a complexing agent, a greater resolution was observed in the diagnosis of the presence of the metals Cd2+ and Ni2+, which could be applied to the aqueous fraction of the sediment.

Potential Use of the Benthic Foraminifers Bulimina denudata and Eggerelloides advenus in Marine Sediment Toxicity Testing

The benthic foraminifers Bulimina denudata and Eggerelloides advenus are commonly abundant in offshore regions in the Pacific Ocean, especially in waste-discharge sites. The relationship between their abundance and standard macrofaunal sediment toxicity tests (amphipod survival and sea urchin fertilization) as well as sediment chemistry analyte measurements were determined for sediments collected in 1997 in Santa Monica Bay, California, USA, an area impacted by historical sewage input from the Hyperion Outfall primarily since the late 1950s. Very few surface samples proved to be contaminated based on either toxicity or chemistry tests and the abundance of B. denudata did not correlate with any of these. The abundance of E. advenus also did not correlate with toxicity, but positively correlated with total solids and negatively correlated with arsenic, beryllium, chromium, lead, mercury, nickel, zinc, iron, and TOC. In contrast, several downcore samples proved to be contaminated as indicated by both toxicity and chemistry data. The abundance of B.denudata positively correlated with amphipod survival and negatively correlated with arsenic, cadmium, unionized ammonia, and TOC; E. advenus negatively correlated with sea urchin fertilization success as well as beryllium, cadmium, and total PCBs. As B. denudata and E. advenus are tolerant of polluted sediments and their relative abundances appear to track those of macrofaunal toxicity tests, their use as cost- and time-effective marine sediment toxicity tests may have validity and should be further investigated.

Effect of density of fingerling and juvenile pirarucu during transportation on water quality and physiological parameters

ABSTRACT We assessed the effect of stocking density on physiological parameters (blood lactate, glucose, cortisol, hematocrit), water quality (temperature, dissolved oxygen, pH, unionized ammonia, carbon dioxide), and survival during the transportation of fingerling (24.5 ± 4.7 g) and juvenile (615.8 ± 122.2 g) pirarucu (Arapaima gigas) for six hours in plastic bags. The tested densities were 65, 80, 95, 110 and 125 g L-1 for fingerlings, and 50, 80, 110, 140 and 170 g L-1 for juveniles (three replicates each). Parameters were measured prior to and immediately after transportation, and at 24 and 96 hours recovery after transportation. No mortality was observed, except for fingerlings (< 3%) at densities of 110 and 125 g L-1 during recovery. All the water quality parameters were significantly altered after the transportation of fingerlings and juveniles. Water temperature, dissolved oxygen, carbon dioxide and unionized ammonia increased, but pH decreased. Only carbon dioxide and unionized ammonia differed among densities. Cortisol levels did not increase over time, except for the juveniles at 170 g L-1, which still had high cortisol after 96 hours. Glucose significantly increased after transportation for all the treatments and returned to the initial values during the recovery period. Conversely, the lactate values were still high after 96 hours. Hematocrit was assessed only for juveniles and was significantly lower after transportation. We conclude that fingerling and juvenile pirarucu can be safely transported at densities up to 95 g L-1 and 140 g L-1, respectively.

EFEK SUB LETHAL AMONIA AMBIEN TERHADAP HISTOPATOLOGIS IKAN NILA (Oreochromis niloticus) YANG DIPELIHARA DALAM SISTEM BIOFLOK

The purpose of this research were to measure the increasing of unionized ammonia during start-up period of biofloc system for growing Nile Tilapia and to figure out its effect on histopathological changes. There was only one treatment that designed with three replication, which was 40 liters of water that contained eight fishes of each weighed 22.. The biofloc system was treated with C/N ration 12:1. Total Ammonia Nitrogen, pH and temperature were measured daily as long as 14 days. the tissue of gill, liver and kidney were cut off at the end of the experiment for histopathological examination. The result of the experiment showed that the peak of unionized ammonia concentration achieved 0.34±0.05 mg/l at 10th day. Then, decreased rapidly to 0.003±0.0009 mg/l at 14th day. The gill, liver, and kidney had regressive changes as physiologic sub lethal response of unionized ammonia expose. Keywords : Biofloc, unionized ammonia, Nile Tilapia, histopatholocal

Prey preference, environmental tolerances and ichthyotoxicity by the red-tide dinoflagellate Noctiluca scintillans cultured from Tasmanian waters

The large phagotrophic dinoflagellate Noctiluca has become a prominent red tide organism in southeast Australian waters since the 2000s, raising concerns for beach tourism, grazing impacts as well as ichthyotoxicity for finfish aquaculture. Satisfactory culture growth rates (0.23–0.56 per day) were obtained by feeding with small Thalassiosira diatom and Tetraselmis flagellate diets, while optimal growth rates sustained for up to 8 months (0.69 per day) were achieved by feeding in a plankton wheel with the large chain-forming dinoflagellate Gymnodinium catenatum. Noctiluca was highly tolerant towards salinities from 20 to 35 and growth was stimulated by temperatures increasing from 10 to 23°C, which in combination with the key factor of prey abundance explains the incidence in southeast Australia of predominantly summer and spring but occasionally also winter blooms. Fatty acid biomarkers suggest that Tasmanian field populations indiscriminately feed on available diatom and dinoflagellate mixtures. Noctiluca exhibited very limited ichthyotoxicity, and only at the highest cell concentrations of 2 000 000/L (50% reduction in RTgill W1 cell viability). Only the densest red tide surface slicks contained acutely toxic levels of unionized ammonia of 242 to 510 μg/L while inshore slicks generated oxygen concentrations as low as 0–1.5 ppm. Lipid phycotoxins (eicosapentaenoic acid, docosahexaenoic acid) did not appear to contribute to Noctiluca ichthyotoxicity. The fatty acid 20:0 eicosanoic acid may serve as a potential Noctiluca biomarker in marine food webs and sediments.

Analysis of Ammonia Toxicity in Landfill Leachates

Toxicity identification evaluation (TIE) phase I manipulations and toxicity test with D. magna were conducted on leachates from an industrial waste landfill site in Japan. Physicochemical analysis detected heavy metals at concentrations insufficient to account for the observed acute toxicity. The graduated pH and aeration manipulations identified the prominent toxicity of ammonia. Based on joint toxicity with additive effects of unionized ammonia and ammonium ions, the unionized ammonia toxicity () was calculated as 3.3 ppm, and the toxicity of ammonium ions () was calculated as 222 ppm. Then, the contribution of ammonia toxicity in the landfill leachate toxicity was calculated as 58.7 vol% of the total toxicity in the landfill leachate. Other specific toxicants masked by ammonia's toxicity were detected. Contribution rate of the toxicants other than by ammonia was 41.3 vol% of the total toxicity of the landfill leachate.