Chronic Effects of <Emphasis Type="Italic">Pinus radiata</Emphasis> and <Emphasis Type="Italic">Eucalyptus globulus</Emphasis> Kraft Mill Effluents and Phytosterols on <Emphasis Type="Italic">Daphnia magna</Emphasis>

Two kraft pulp mill effluents were compared in terms of their chronic toxicity to Daphnia magna. One resulted from pulping Pinus radiata and the other came from a parallel processing of Pinus radiata and Eucalyptus globulus (mixed kraft pulp mill effluent). The concentration of phytosterols found in the mixed kraft pulp mill effluent was higher than in the effluent from Pinus radiata, with values of 0.1082 and 0.02 μg/L, respectively. The phytosterols per se are responsible for 12.9% and 8.1% of the deviation from the natural shape, while the kraft pulp mill effluents account for 25.6%–27.8% of shape deviation. The role of β-sitosterol and stigmasterol is discussed in relation to endocrine disruption.     

Acute and Chronic Toxicity of Buprofezin on <Emphasis Type="Italic">Daphnia Magna</Emphasis> and the Recovery Evaluation

The toxic effects of buprofezin on Daphnia magna after both chronic and acute exposures were evaluated according to OECD guidelines. A 48-h acute exposure of buprofezin resulted in daphnid immobility at an EC₅₀ of 0.44 mg/L. In a 14 days chronic exposure of buprofezin (0, 0.025, 0.05, 0.10 and 0.15 mg/L), the development and reproduction of daphnids were all significantly affected and the body length was more sensitive than other observed parameters. However, the adverse effects of buprofezin on parental daphnids can be passed on to their offspring and cannot be recovered in a short time.     

Life History Response of <Emphasis Type="Italic">Daphnia magna</Emphasis> to a Mixotrophic Golden Alga, <Emphasis Type="Italic">Poterioochromonas</Emphasis> sp., at Different Food Levels

The toxicity of Poterioochromonas to Daphnia magna was investigated at different food (Scenedesmus acutus) levels. Poterioochromonas alone of 0.4–20 mg C L⁻¹ was not acutely toxic to D. magna, but did not support D. magna growth, either. When fed mixed diets (2 mg C L⁻¹ in total), D. magna’s survival and reproduction were significantly depressed when Poterioochromonas comprised above 50%, likely due to the inhibition of food ingestion. Large juveniles were less sensitive to poor quality food than neonates. Therefore, Poterioochromonas may affect D. magna living to various extents depending on its concentration, age structure of D. magna populations and availability of other food.     

Behavioral Responses of <Emphasis Type="Italic">Daphnia Magna</Emphasis> to Stresses of Chemicals with Different Toxic Characteristics

Behavior of an organism is affected by exposure to toxic chemicals. However, less has been known about behavioral responses of an organism to stresses of toxic chemicals with different toxic characteristics. In present work, Daphnia magna Straus was exposed to gradient concentrations of deltamethrin, chlorothalonil and nitrofen and the behavioral changes of Daphnia magna under different stress were examined. The results showed that the behavioral responses of Daphnia magna to the tested chemicals were affected in general by exposure concentration, rather than toxic characteristics of the chemicals. The duration of avoidance response (DAR) was in a power regression relationship with the toxic unit (TU), defined as the ratio of exposure concentration of the tested chemical to its LC_50–48. DAR was independent of the toxic characteristics of chemicals. However, significant behavior adjustment could be observed after exposure to deltamethrin while only step-by-step decrease in behavior strength could be observed when exposed to chlorothalonil and nitrofen. It was suggested from the observation that avoidance behaviors of Daphnia magna to exposures of chemicals with different toxic characteristics could be similar, while their specific response could be different.     

Selective Bactericidal Potential of Rice (<Emphasis Type="Italic">Oryza sativa</Emphasis> L. var. <Emphasis Type="Italic">japonica</Emphasis>) Hull Extract on <Emphasis Type="Italic">Microcystis</Emphasis> Strains in Comparison with Green Algae and Zooplankton

We examined the selective inhibitory potential of rice hull extract on the toxic cyanobacterium Microcystis aeruginosa, in comparison with inhibitory effects on two green algae (Ankistrodesmus convolutus and Scenedesmus quadricauda) and a zooplankton (Daphnia magna) species. The inhibitory effect of rice hull extract, measured by algal growth or zooplankton survival using four different concentrations of extract (1, 10, 100 and 1000 μg L⁻¹), was highest on Microcystis strains (average: 98%, range: 95%–99%), followed by D. magna (average: 22%, range: 10%–47%), A. convolutus (average: 20%, range: 16%–24%), and S. quadricauda (average: 8%, range: 0%–15%). Rice hull extract had only a small effect on the growth of the green algae and Daphnia, particularly in the range 1–100 μg L⁻¹, and the inhibitory effect was somewhat diminished even at the 1,000 μg L⁻¹ level, at the end of the experimental period, especially for Daphnia. Our study indicates that rice hull extract has a strong specific algicide potential when used to combat M. aeruginosa.     

Acute and Sub-Lethal Toxicity of Three POEA Surfactant Formulations to <Emphasis Type="Italic">Daphnia magna</Emphasis>

Polyethoxylated tallowamine (POEA) is a non-ionic surfactant used in many herbicide formulations to increase the ability of active ingredients to penetrate leaf cuticles. However, it has also been shown to disrupt respiratory membranes in aquatic organisms. In this study, Daphnia magna was used to examine the lethal and sub-lethal toxicity of three POEA formulations consisting of 5:1, 10:1, and 15:1 average oxide:tallowamine. The formulation consisting of 10:1 was the most acutely toxic with a 48-h LC50 value of 97.0 μg/L and 15:1 was least toxic at 849.4 μg/L. All formulations inhibited growth at concentrations between 100 and 500 μg/L.     

The Effect of some Selected Pesticides on the Growth and Reproduction of Fresh Water <Emphasis Type="Italic">Oreochromis niloticus</Emphasis>, <Emphasis Type="Italic">Chrysicthys nigrodigitatus</Emphasis> and <Emphasis Type="Italic">Clarias gariepinus</Emphasis>

Studies were carried out to determine the toxicity of some selected pesticides on fresh water fish in a tropical environment. The uptake of the pesticides lindane, pentachlorophenol (PCP), and propoxur, which are frequently used on farms, and in industries as well as by loggers and timber men on wood were studied in concrete ponds at the University of Cape Coast, in Ghana. The fish used for the study were Oreochromis niloticus, Clarias gariepinus, and Chrysicthys nigrodigitatus. They were obtained from cultured ponds in the Cape Coast and Mankessim districts in the Central Region and Weija Dam, in the Greater Accra region of Ghana. Single high lethal concentration (SD) or acute treatment and cumulative/chronic (or multiple minor) lethal concentration (CD) treatment were employed in administering the pesticides to the fish via water. Gas chromatograph electron capture detector analysis was done on the dead fish to see the extent of ingestion. The LC₅₀ values obtained for lindane on the three fish samples were as follows: Chrysicthys – 0.38 mg L⁻¹; Oreochromis – 0.42 mg L⁻¹, and Clarias – 1.2 mg L⁻¹. Mortalities occurred in fish within 3–5 days of application. For the PCP on Chrysicthys, Oreochromis, and Clarias species the LC₅₀ values were 0.42, 0.32 and 0.64 mg L⁻¹, respectively, for over a 2- to 3-day period. For a three-time influx period of propoxur the LC₅₀ for Chrysicthys, Oreochromis, and Clarias, were 22.0, 30.40, and 45.04 (all in mg L⁻¹), respectively. The results obtained indicated that the pesticides had adverse effects on the general growth and reproduction of fish as shown by gonadosomatic indices.     

A Linear Model to Predict Chronic Effects of Chemicals on <Emphasis Type="Italic">Daphnia magna</Emphasis>

Chronic toxicity data for Daphnia magna are information requirements in the context of regulations on chemical safety. This paper proposes a linear model for the prediction of chemically-induced effects on the reproductive output of D. magna. This model is based on data retrieved from the Japanese Ministry of Environment database and it predicts chronic effects as a function of acute toxicity data. The proposed model proved to be able to predict chronic toxicities for chemicals not used in the training set. Our results suggest that experiments involving chronic exposure to chemicals could be reduced thanks to the proposed model.     

Effects of Pentachlorophenol on <Emphasis Type="Italic">Galba pervia</Emphasis>, <Emphasis Type="Italic">Tubifex sinicus</Emphasis> and <Emphasis Type="Italic">Chironomus plumousus</Emphasis> Larvae

The 24-h median lethal concentrations of pentachlorophenol to Chironomus plumousus, Tubifex sinicus and Galba pervia were 0.302, 0.977 and 0.293 mg/L, respectively. Bioconcentration factors of C. plumousus, T. sinicus and G. pervia to pentachlorophenol were 108, 367 and 85 at 0.02 mg/L pentachlorophenol, respectively. As pentachlorophenol concentration increased, the G. pervia egg hatching rates became lower, and the total hatched time became longer. Pentachlorophenol teratogenesis was demonstrated by observing the deformation of C. plumousus larvae mentum.     

Effect of <Emphasis Type="Italic">Microcystis aeruginosa</Emphasis> on the rotifer <Emphasis Type="Italic">Brachionus calyciflorus</Emphasis> at different temperatures

Rotifers are one of the smallest metazoans. They serve as a model organism for ecotoxicological studies. More than 60% of the lakes in China are increasingly eutrophic and they are susceptible to blooms of Microcystis aeruginosa. We investigated the effects of M. aeruginosa on the survival and reproduction of Brachionus calyciflorus using the life table method at different temperatures. The findings showed that concentration of M. aeruginosa significantly affected the intrinsic rate of increase (r_m), net reproductive rate (R₀), average lifespan (L) and offspring number (p < 0.05). Temperature also significantly affected the generation time (T), average lifespan (L) and offspring number (p < 0.05). Moreover, the interaction between temperature and concentration had statistically significant effects on offspring number (p < 0.05). M. aeruginosa suppressed the survival and reproduction of B. calyciflorus, particularly at a concentration of 10⁶ cells/mL. The r_m values of the rotifers exposed at 10⁶ cells/mL decreased more than 200% compared with those of the control group. However, at a lower concentration, 10⁴ cells/mL, M. aeruginosa may supply appropriate nourishment to rotifers. In addition, at concentrations of 10⁵ and 10⁶ cells/mL, the inhibition of rotifers by M. aeruginosa heightened with increasing temperature.     

Effects of an Environmentally Realistic Pesticide Mixture on <Emphasis Type="Italic">Daphnia magna</Emphasis> Exposed for Two Generations

Daphnia magna were exposed under semistatic conditions (i.e., conditions taking natural degradation into account) to a pesticide mixture consisting of a pyrethroid insecticide (cyfluthrin) and a pre-emergent herbicide (diuron) as well as pesticides individually using a full life cycle exposure (21 days). Subsequently, offspring from the second reproductive brood were used to continue exposure for a second generation. Survival, time to first brood, total number of offspring produced, number of broods produced, growth rate, and population growth rate were recorded for each generation and concentration. Significant differences existed between F0 and F1 D. magna for survival, in which F1 were less sensitive to pesticide mixtures than F0. In addition, F1 D. magna were significantly smaller than F0, which resulted in longer time to first brood. There were no differences in any end point examined between D. magna exposed to the pesticide mixture and diuron alone, although differences existed in survival, total number of offspring, total number of broods, and population growth rate when F0 D. magna were exposed to cyfluthrin alone. This study illustrates the utility of a two-generation study design that may more fully reflect, and more accurately predict, population level effects of pesticide exposures to short-lived aquatic organisms.     

Characterization of Acute and Chronic Toxicity of DBP to <Emphasis Type="Italic">Daphnia magna</Emphasis>

As a commonly used phthalate compound, di(n-butyl) phthalate (DBP) is an emerging group of polyvinyl chloride plasticizers. The acute toxicity of DBP has been extensively studied using the aquatic indicator organism, Daphnia magna. However, little is known about chronic and transgenerational toxicity of DBP. In this study, acute LC₅₀ values were 3.04 mg/L (24 h) and 2.55 mg/L (48 h). Chronic toxicity tests in the case of maternal exposure to DBP revealed that DBP had negligible effects on growth and reproduction of F3 generation of D. magna, although the growth rate of body length and the intrinsic rate of increase were prominently reduced, to a pretty small extent. At specific concentrations, DBP generated beneficial effects on the parental generation of D. magna and no obvious impacts on the F1 generation. This study showed that maternal exposure to DBP did not cause any transgenerational effects on D. magna.     

An Ecological Risk Assessment of the Acute and Chronic Toxicity of the Herbicide Picloram to the Threatened Bull Trout (<Emphasis Type="Italic">Salvelinus confluentus</Emphasis>) and the Rainbow Trout (<Emphasis Type="Italic">Onchorhyncus mykiss</Emphasis>)

We conducted acute and chronic toxicity studies of the effects of picloram acid on the threatened bull trout (Salvelinus confluentus) and the standard coldwater surrogate rainbow trout (Oncorhynchus mykiss). Juvenile fish were chronically exposed for 30 days in a proportional flow-through diluter to measured concentrations of 0, 0.30, 0.60, 1.18, 2.37, and 4.75 mg/L picloram. No mortality of either species was observed at the highest concentration. Bull trout were twofold more sensitive to picloram (30-day maximum acceptable toxic concentration of 0.80 mg/L) compared to rainbow trout (30-day maximum acceptable toxic concentration of 1.67 mg/L) based on the endpoint of growth. Picloram was acutely toxic to rainbow trout at 36 mg/L (96-h ALC50). The acute:chronic ratio for rainbow trout exposed to picloram was 22. The chronic toxicity of picloram was compared to modeled and measured environmental exposure concentrations (EECs) using a four-tiered system. The Tier 1, worst-case exposure estimate, based on a direct application of the current maximum use rate (1.1 kg/ha picloram) to a standardized aquatic ecosystem (water body of 1-ha area and 1-m depth), resulted in an EEC of 0.73 mg/L picloram and chronic risk quotients of 0.91 and 0.44 for bull trout and rainbow trout, respectively. Higher-tiered exposure estimates reduced chronic risk quotients 10-fold. Results of this study indicate that picloram, if properly applied according to the manufacturer’s label, poses little risk to the threatened bull trout or rainbow trout in northwestern rangeland environments on either an acute or a chronic basis.     

Comparison of Diazinon Toxicity to Embryos of <Emphasis Type="Italic">Xenopus laevis</Emphasis> and <Emphasis Type="Italic">Danio rerio</Emphasis>; Degradation of Diazinon in Water

The aim of this study was to determine the toxic effect of diazinon (organophosphate insecticide) to embryos of Xenopus laevis and Danio rerio. The 96-h LC₅₀ values showed higher toxicity of diazinon for X. leavis in standard solution (9.84 mg/L) compared to the pond water (12.64 mg/L). Teratogenic index for diazinon was 1.3 and 1.6, respectively. The 96-h LC₅₀ diazinon values demonstrated similar sensitivity of embryos D. rerio (8.21–9.34 mg/L) and X. laevis in standard test solutions. Our results reflect that direct application of diazinon into the water can be associated with significant risks to aquatic organisms.     

<Emphasis Type="Italic">Spirulina</Emphasis> enhanced the skeletal muscle protein in growing rats

Background/Aim of the study  This study evaluates the effects of the blue green alga spirulina as the sole dietary source of protein on muscle protein in weaning rats. Methods  Young (30 days) Wistar rats were fed, during 60 days, with 17% protein spirulina (S) and compared to rats fed 17% protein casein (C). We evaluated the muscle total protein and DNA contents and the in vitro protein synthesis and degradation rates as well the myosin protein expression. Results  The groups presented similar body weight (C = 427.3 ± 8.6; S = 434.6 ± 7.7 g) and length (C = 25.4 ± 0.2; S = 25.6 ± 0.2 cm). Soleus muscle total protein (C = 2.9 ± 0.1; S = 2.7 ± 0.1 mg/100 mg) and DNA (C = 0.084 ± 0.005; S = 0.074 ± 0.005 mg/100 mg) contents were also similar in both groups. Protein degradation (C = 427.5 ± 40.6; S = 476.7 ± 50.5 pmol/mg⁻¹ h⁻¹) did not differ between the groups but protein synthesis (C = 17.5 ± 1.0; S = 25.2 ± 1.9 pmol/mg⁻¹ h⁻¹) and myosin content (western blot analyses) were higher (P < 0.05, t test) in spirulina group. Conclusions  Although the spirulina proved adequate protein quality to maintain body growth, the muscle protein synthesis rates were increased by the ingestion of the experimental diet in young rats.     

Ultraviolet Radiation Increases Sensitivity to Pesticides: Synergistic Effects on Population Growth Rate of <Emphasis Type="Italic">Daphnia magna</Emphasis> at Low Concentrations

In the present study we aimed to investigate whether UV-B radiation can exacerbate effects of pesticides fenoxycarb, pirimicarb, and tebufenpyrad on the survival, reproduction, and population growth rate of the standard test species Daphnia magna. We applied sublethal pesticides’ concentrations and UV doses and observed no effects on survival. However, we observed synergistic effects of UV and pesticides on both cumulative reproduction and population growth rate (21 days) for fenoxycarb (100 μg/L) and pirimicarb (10 μg/L), but a less-than-additive effect for tebufenpyrad (5–10 μg/L). In the series exposed to UV and fenoxycarb or pirimicarb, the population growth rate dropped down to 0.1, while in the control series it was around 0.3. The results indicate that concentrations of some toxicants that are nontoxic in standard tests can cause harmful population-level effects when combined with UV.     

Copper Accumulation and Tolerance in <Emphasis Type="Italic">Chrysanthemum coronarium</Emphasis> L. and <Emphasis Type="Italic">Sorghum</Emphasis><Emphasis Type="Italic">sudanense</Emphasis> L.

In the present study, the growth of Chrysanthemum coronarium L. and Sorghum sudanense L. and their copper accumulation were studied using hydroponic experiments. Results showed that the root elongation, dry biomass yield, and chlorophyll content in both plant species decreased significantly with the increasing level of Cu in solution. The concentrations of Cu in the two plants increased greatly with the increasing Cu level in the treatments. However, most of the Cu was accumulated in roots, and only a small portion was translocated into shoots. Compared with S. sudanense, the shoots of C. coronarium had a significantly higher concentration of Cu. The total amount and percentage of water-soluble Cu, and the nonprotein thiol were also higher in the shoots of C. coronarium. In the roots, however, S. sudanense accumulated more Cu than C. coronarium. The treatments with 5 to 50 μmol L⁻¹ Cu significantly increased the uronic acid content in the roots of S. sudanens, but did not have any significant effect for C. coronarium. Higher concentrations of Cu bound to the cell wall and uronic acid in the roots of S. sudanense were speculated to be the main reason to restrain Cu translocation from roots to shoots.     

Effects of Nitrite and Toxic <Emphasis Type="Italic">Microcystis Aeruginosa</Emphasis> PCC7806 on the Growth of Freshwater Rotifer <Emphasis Type="Italic">Brachionus Calyciflorus</Emphasis>

Over the last two centuries, anthropogenic activities have increased the nitrogen amount in aquatic ecosystems, which has resulted in increased occurrences of blooms of cyanobacteria. This study investigated the effects of nitrite and the cyanobacterium Microcystis aeruginosa on population growth in the rotifer Brachionus calyciflorus. The rotifer was treated for 12 days with nitrite alone (medium containing 0, 3, 6, 10 mg NO₂ ⁻ –N L⁻¹), M. aeruginosa alone (medium containing 0 mg NO₂ ⁻–N L⁻¹ + 5.0 × 10⁵ cell ml⁻¹ M. aeruginosa precultured at 0, 3, 6, 10 mg NO₂ ⁻–N L⁻¹), and nitrite in combination with M. aeruginosa (medium containing 3, 10 mg NO₂ ⁻–N L⁻¹ + 5.0 × 10⁵ cell ml⁻¹ M. aeruginosa precultured at corresponding nitrite concentrations). We observed that a nitrite concentration of 10 mg NO₂ ⁻–N L⁻¹ markedly inhibited the growth of B. calyciflorus; however, rotifer growth declined slightly in the presence of M. aeruginosa precultured at 6 mg NO₂ ⁻–N L⁻¹. Furthermore, reduced population growth of B. calyciflorus was observed when it was treated with both nitrite and M. aeruginosa compared to nitrite alone or M. aeruginosa alone. These results suggested that a high tolerance of B. calyciflorus to nitrite levels may be attributed to the absence of specific respiratory structures and pigments; and that the increased toxicity of nitrite in combination with M. aeruginosa may have been due to increased production of microcystin. It is also possible that nitrite and microcystin could act in a synergistic way in causing toxicity.     

Mercury and Selenium Content in <Emphasis Type="Italic">Otolithes ruber</Emphasis> and <Emphasis Type="Italic">Psettodes erumei</Emphasis> from Khuzestan Shore,Iran

In this paper the level of selenium and mercury is analyzed in edible part and liver of Psettodes erumei and Otolithes ruber two commercial fish in Persian Gulf. The average concentration of Hg and Se in edible parts of P. erumei was 0.077 ± 0.062 and 0.044 ± 0.018 (μg g⁻¹ww), and in liver was 0.127 ± 0.122 and 0.132 ± 0.610 (μg g⁻¹ww) respectively. In O. ruber, the average concentration of Hg and Se in edible parts was 0.348–0.27 and 0.06 ± 0.021 (μg g⁻¹ww) and in liver was 0.176 ± 0.174 and 0.093 ± 0.022 (μg g⁻¹ww), respectively. P. erumei has higher mean molar ratio Se/Hg (1.98) compared to O. ruber (0.88).     

Toxicity of Cadmium,Lead, Mercury and Methyl Parathion on <Emphasis Type="Italic">Euchlanis dilatata</Emphasis> Ehrenberg 1832 (Rotifera: Monogononta)

Acute toxicity tests with Cd, Pb, Hg, and methyl parathion were developed to compare the sensitivity of the rotifer Euchlanis dilatata with other model organisms used in aquatic ecotoxicology. Cd was the most toxic chemical (LC50 = 14.8 μg L⁻¹), while methyl parathion was the least toxic (LC50 = 864.2 μg L⁻¹). E. dilatata was more sensitive that other rotifer species, particularly of the genera Brachionus and Lecane. However, E. dilatata was less sensitive to mercury and methyl parathion than the crustacean, Daphnia magna. The high sensitivity of E. dilatata suggests that it may be an adequate benthic model to use in toxicity assessments of metal-contaminated sediments.