Check out our New Publishers' Select for Free Articles

Archives of Environmental Contamination and Toxicology (v.54, #4)

Biological and Chemical Characterization of Metal Bioavailability in Sediments from Lake Roosevelt, Columbia River, Washington, USA by John M. Besser; William G. Brumbaugh; Chris D. Ivey; Christopher G. Ingersoll; Patrick W. Moran (pp. 557-570).

We studied the bioavailability and toxicity of copper, zinc, arsenic, cadmium, and lead in sediments from Lake Roosevelt (LR), a reservoir on the Columbia River in Washington, USA that receives inputs of metals from an upstream smelter facility. We characterized chronic sediment toxicity, metal bioaccumulation, and metal concentrations in sediment and pore water from eight study sites: one site upstream in the Columbia River, six sites in the reservoir, and a reference site in an uncontaminated tributary. Total recoverable metal concentrations in LR sediments generally decreased from upstream to downstream in the study area, but sediments from two sites in the reservoir had metal concentrations much lower than adjacent reservoir sites and similar to the reference site, apparently due to erosion of uncontaminated bank soils. Concentrations of acid-volatile sulfide in LR sediments were too low to provide strong controls on metal bioavailability, and selective sediment extractions indicated that metals in most LR sediments were primarily associated with iron and manganese oxides. Oligochaetes (Lumbriculus variegatus) accumulated greatest concentrations of copper from the river sediment, and greatest concentrations of arsenic, cadmium, and lead from reservoir sediments. Chronic toxic effects on amphipods (Hyalella azteca; reduced survival) and midge larvae (Chironomus dilutus; reduced growth) in whole-sediment exposures were generally consistent with predictions of metal toxicity based on empirical and equilibrium partitioning-based sediment quality guidelines. Elevated metal concentrations in pore waters of some LR sediments suggested that metals released from iron and manganese oxides under anoxic conditions contributed to metal bioaccumulation and toxicity. Results of both chemical and biological assays indicate that metals in sediments from both riverine and reservoir habitats of Lake Roosevelt are available to benthic invertebrates. These findings will be used as part of an ongoing ecological risk assessment to determine remedial actions for contaminated sediments in Lake Roosevelt.

Aquatic Risk Assessment of Herbicides in Freshwater Ecosystems of South Florida by Lance J. Schuler; Gary M. Rand (pp. 571-583).

Widespread, high-volume use and subsequent off-site transport of herbicides, specifically photosystem II inhibitors (PSII), on agricultural and noncultivated lands in south Florida has resulted in frequent detections in freshwater systems. In light of the current restoration efforts as part of the Comprehensive Environmental Restoration Plan (CERP), increased water flows containing detectable herbicide levels into the Everglades ecosystem and adjacent areas may have adverse consequences to the unique plant communities present in the region. The potential impact of individual herbicides to aquatic plant and algae species was examined using a probabilistic risk assessment approach. Risk was characterized for nine PSII herbicides (four triazines: ametryn, atrazine, simazine, and prometryn; two triazinones: hexazinone and metribuzin; two substituted ureas: diuron and linuron; and a uracil: bromacil) and a pyridazinone herbicide (norflurazon) by comparing the overlap of the 90th percentile surface water concentration (exposure benchmark) from the exposure distributions to the 10th percentile of effects (effects benchmark) determined from species sensitivity distributions of acute laboratory toxicity data. Overall, the risk of the individual herbicides was generally low. A Multiple Substance Potentially Affected Fraction (msPAF) risk approach also was utilized to examine the joint toxicity of the herbicide mixtures based on a concentration addition model. The risk associated with the herbicide mixture (mainly bromacil, diuron, and norflurazon) was determined to be high for Lee (site S79 on the Caloosahatchee River), Martin (site S80 on St. Lucie Canal), and St. Lucie (site S99 on C25 emptying into Indian River Lagoon) counties in south Florida. This study highlights the need to consider joint action of chemical mixtures as part of an ecological risk assessment.

Trophic Distribution of Cd, Pb, and Zn in a Food Web from Altata-Ensenada del Pabellón Subtropical Lagoon, SE Gulf of California by J. Ruelas-Inzunza; F. Páez-Osuna (pp. 584-596).

The aim of the work was to obtain a comparative view of the trophic distribution of Cd, Pb, and Zn in different organisms of the food web (from primary producers to top predators), considering representative species in Altata-Ensenada del Pabellón subtropical lagoon (SE Gulf of California). The study provides the first quantitative information on the biotransference of Cd, Pb, and Zn in a moderately contaminated lagoon ecosystem. After examination of 31 trophic interactions, 20 cases resulted in transference factors (TF) > 1.0 for Cd, 14 cases for Pb, and 18 cases for Zn. For Cd, most of the TF > 1 were found mainly among the low trophic levels (15 of 20 links); for Pb, most of the TF > 1 were found mainly among the high trophic levels (11 of 14 links), and for Zn, most of the TF > 1 were found mainly among the low trophic levels (14 of 18 links). This can be interpreted as partial evidence of biomagnification of Cd, Pb, and Zn for the species involved.

Sources and Properties of Natural Organic Matter (NOM) in Water Along the Dongjiang River (the Source of Hong Kong’s Drinking Water) and Toxicological Assay of Its Chlorination By-Products by Y. Liang; H. C. Hong; L. H. Dong; C. Y. Lan; B. P. Han; M. H. Wong (pp. 597-605).

The Dongjiang River is the major source of the drinking water supply for Hong Kong and also other parts of the Pearl River Delta in China, and the deterioration in the water quality of this river and the excessive levels of trihalomethanes (THMs) in the tap water of some districts in Hong Kong have become a matter of public concern. The main objective of the present study is to investigate the distribution patterns of natural organic matter (NOM) and their association with THM production in the Dongjiang River. We examined the physicochemical and biological properties of the river water and the corresponding sediment elutriate collected from four sampling sites along the Dongjiang River from upstream to downstream and chlorination experiments were conducted. Algal bioassays were performed in order to test the chlorination effects. The results showed that: (1) upstream NOM was derived from terrestrial input, while that at mid- and downstream was most likely derived from phytoplankton; (2) phytoplankton is a major contributor to NOM in the sediments, whereas sediments seem to be the site for major microbial degradation of NOM, biogeochemical recycling of nutrients and a potential NOM pool for the overlaying water during sediment resuspension; (3) dissolved organic carbon (DOC) in surface water is a good indicator for THM production, whereas ultraviolet (UV) absorbance at 254 nm (UV₂₅₄) is a better predictor for THM formation in the elutriates; (4) the bioassay results showed that toxic compounds other than THMs in the chlorinated water are the major factors causing algal growth inhibition.

Comparison of Bioluminescent Dinoflagellate (QwikLite) and Bacterial (Microtox) Rapid Bioassays for the Detection of Metal and Ammonia Toxicity by Gunther Rosen; Alexandra Osorio-Robayo; Ignacio Rivera-Duarte; David Lapota (pp. 606-611).

This study compared the sensitivity of two rapid toxicity tests, QwikLite and Microtox, to seven metals and ammonia. Both of these tests measure a reduction in light production from bioluminescent microorganisms (dinoflagellates and marine bacteria, respectively) as a means of toxicity detection and are simple and inexpensive to conduct compared to many standardized acute toxicity tests. For QwikLite tests, three marine dinoflagellate species (Lingulodinium polyedrum, Ceratocorys horrida, and Pyrocystis noctiluca) were separately evaluated following a 24-h exposure period. The marine bacterium, Vibrio fischeri, was used in the Microtox tests, in 15-min exposures to the same metal preparations as those used for the QwikLite tests. The QwikLite tests were generally one to two orders of magnitude more sensitive than the Microtox tests, as indicated by lower median effects concentrations (EC₅₀). Both QwikLite and Microtox, however, resulted in similar toxicity rankings for the metals tested. The dinoflagellate species used in the QwikLite tests responded similarly for most compounds tested, with L. polyedrum appearing to be somewhat more sensitive than the other two species for most metals evaluated. QwikLite was also more comparable in sensitivity to several commonly used standardized toxicity tests. As with all toxicity tests, species selection for QwikLite should take into account study-specific factors, including the potential for sensitivity to confounding factors, such as ammonia.

Removal of Cadmium by Myriophyllum heterophyllum Michx. and Potamogeton crispus L. and Its Effect on Pigments and Total Phenolic Compounds by Aysel Sivaci; Emire Elmas; Fatih Gümüş; E. Ridvan Sivaci (pp. 612-618).

In this study, cadmium biosorption by Myriophyllum heterophyllum Michx. and Potamogeton crispus L. was investigated. Although both species were found to be capable of removing cadmium from water, the performance of P. crispus was the most significant. These species were treated with 0, 4, 8, 16, 32, and 64 mg L⁻¹ cadmium solutions for 24, 48, 72, and 96 h, respectively. Cadmium uptake of both species was lowest at 4 mg L⁻¹and highest at 64 mg L⁻¹. Photosynthetic pigments and total phenolic compounds in both species were determined after exposure to various concentrations of cadmium for various times. Depending on the cadmium accumulation in both species, it was shown to decrease the level of chlorophyll a, chlorophyll b, and carotenoids (24 and 96 h). The anthocyanin concentration in P. crispus increased at all cadmium concentrations studied (0, 4, 8, 16, 32, and 64 mg L⁻¹), whereas in Myriophyllum heterophyllum it increased at the lower cadmium concentrations (0, 4, and 8 mg L⁻¹) but decreased at higher cadmium concentrations (16, 32, and 64 mg L⁻¹), for all exposure periods. The total phenolic compound level in both species increased with cadmium concentration during the 24 and 96 h exposure periods.

Uptake, Removal, Accumulation, and Phytotoxicity of 4-Chlorophenol in Willow Trees by A. S. Ucisik; S. Trapp (pp. 619-627).

4-chlorophenol (4-CP) is a well-known hazardous chlorinated compound and a precursor for the synthesis of the herbicide 2,4-dichlorophenoxyacetate. The relation between uptake, accumulation, toxicity, and removal of 4-CP in willow trees (Salix viminalis) was determined. In addition, the feasibility of implementing phytoremediation as a treatment method for 4-CP contamination was investigated. Willows were exposed to 4-CP levels ≤79.9 mg/L in hydroponic solution. The transpiration of the trees was used to determine toxic effects. Almost no inhibition of transpiration was detected at concentrations ≥15 mg/L. For concentrations ≥37.3 mg/L, transpiration decreased to ≤50%, and the trees wilted. Trees exposed to 79.9 mg/L wilted and eventually died. For concentrations of 79.9 mg/L, a significantly higher amount of 4-CP remained at the end of experiments in the test system compared with the amount remaining at all other concentrations. The loss of chemical from the system in experiments with trees was high, ≤99.5%. In treeless experiments, the mass loss of 4-CP was only 6% to 10%. The results indicated that degradation in the root zone is the main reason for the removal of 4-CP from the media. Phytoremediation of 4-CP in willow trees seems to be a remediation option, especially at concentrations <37.3 mg/L, at which point degradation of 4-CP is rapid and efficient, and the toxic effects on trees are not lethal.

Levels of Organochlorine Pesticides in Crops and Related Products From Vojvodina, Serbia: Estimated Dietary Intake by B. Škrbić; Z. Predojević (pp. 628-636).

Levels of 16 organochlorine pesticides (OCPs) were investigated in 39 composite samples of agricultural crops, related by-products, and foodstuffs collected in Vojvodina, Serbia, in 2002 through 2004. After extraction and cleanup, OCPs were determined by capillary gas chromatography using electron-capture detection. The highest mean level of 0.971 ng/g whole weight (ww) was found for α-HCH in wheat flour samples. OCPs levels were well lower than the respective maximum residue limits set by current European and Serbian regulations. Mean OCP levels were low (<1 ng/g ww) for all sample types. The most frequently determined residue was 4,4′-DDT (identified in 76.9% of all samples analyzed), followed by γ-HCH (66.7%), β-HCH (48.7%), and endosulfan II (41.0%). OCP levels were compared with data from other international surveys. Calculated daily intakes of OCPs by way of consumption of the crop products included in this study according to data of the Serbian National Institute for Statistics were compared with the acceptable daily intakes established by the Food and Agriculture Organization/World Health Organization. The average level of contamination of the Vojvodina diet was believed to be harmless regarding the studied food commodities.

Zooplankton Chitobiase Activity as an Endpoint of Pharmaceutical Effect by S. M. Richards; S. E. Kelly; M. L. Hanson (pp. 637-644).

Numerous human and veterinary pharmaceuticals are constantly entering surface waters, despite little understanding of their potential impacts on aquatic ecosystems. To address this concern, an attempt to create a simple, reproducible, inexpensive, and sublethal toxicity bioassay for freshwater zooplankton was initiated. The approach was centered on characterizing the response of a zooplankton enzyme, chitobiase, to the presence of a toxicant. The aim of the present research was to develop a reproducible laboratory-based assay for Daphnia magna chitobiase activity and to screen four commonly prescribed pharmaceuticals using that assay. The four pharmaceuticals tested for potential effects on D. magna chitobiase activity were atorvastatin, lovastatin, fluoxetine, and sertraline. We were able to detect exposure-associated differences in chitobiase activity at concentrations of 0.1 μg/L fluoxetine after 24 and 72 hours of exposure. Differences were also detected for the other compounds. The response of chitobiase was found to be promising as an assay to measure sublethal effects in D. magna and perhaps other zooplankton species.

Effect of Alachlor and Metolachlor on Toxicity of Chlorpyrifos and Major Detoxification Enzymes in the Aquatic Midge, Chironomus tentans (Diptera: Chironomidae) by Ying Jin-Clark; Troy D. Anderson; Kun Yan Zhu (pp. 645-652).

The toxicities of two herbicides (alachlor and metolachlor) and an organophosphate insecticide (chlorpyrifos) were evaluated individually and with either herbicide in binary mixture with chlorpyrifos in fourth-instar larvae of the aquatic midge (Chironomus tentans). Alachlor alone up to 1,000 micrograms per liter of water (μg/L) did not exhibit significant toxicity, whereas metolachlor at 1,000 μg/L affected 58% of midges in 72-h bioassays. However, alachlor at 1,000 μg/L and metolachlor at 10, 100, and 1,000 μg/L enhanced the toxicity of chlorpyrifos to the midges. Furthermore, alachlor and metolachlor at 1,000 μg/L reduced acetylcholinesterase (AChE) activity by 34.3% and 27.6%, respectively, in the treated midges. Although alachlor at 1,000 μg/L did not significantly affect protein production in the treated midges, it reduced glutathione S-transferases (GST) total activities by 1.9- to 2.1-fold. In contrast, metolachlor at 1,000 μg/L reduced protein production by 3.2-fold, which was associated with a 2.8-fold reduction of cytochrome P450 O-deethylation total activity and 1.4- to 1.7-fold reductions of GST total activities in the treated midges. Such reduced total activities of the major detoxification enzymes in herbicide-treated midges might impede the metabolic detoxification of chlorpyrifos and, therefore, increase the susceptibility of the midges to chlorpyrifos. Thus, it is likely that coexistence of chlorpyrifos and these herbicides, particularly metolachlor, in surface waters may pose increased risks to midges in aquatic environments.

Effects of Sublethal Doses of Acetamiprid and Thiamethoxam on the Behavior of the Honeybee (Apis mellifera) by Abdessalam Kacimi El Hassani; Matthieu Dacher; Vincent Gary; Michel Lambin; Monique Gauthier; Catherine Armengaud (pp. 653-661).

Acetamiprid and thiamethoxam are insecticides introduced for pest control, but they can also affect non-target insects such as honeybees. In insects, these neonicotinoid insecticides are known to act on acetylcholine nicotinic receptors but the behavioral effects of low doses are not yet fully understood. The effects of acetamiprid and thiamethoxam were studied after acute sublethal treatment on the behavior of the honeybee (Apis mellifera) under controlled laboratory conditions. The drugs were either administered orally or applied topically on the thorax. After oral consumption acetamiprid increased sensitivity to antennal stimulation by sucrose solutions at doses of 1 μg/bee and impaired long-term retention of olfactory learning at the dose of 0.1 μg/bee. Acetamiprid thoracic application induced no effect in these behavioral assays but increased locomotor activity (0.1 and 0.5 μg/bee) and water-induced proboscis extension reflex (0.1, 0.5, and 1 μg/bee). Unlike acetamiprid, thiamethoxam had no effect on bees’ behavior under the conditions used. Our results suggest a particular vulnerability of honeybee behavior to sublethal doses of acetamiprid.

Acute and Chronic Toxicity of Imidacloprid to the Aquatic Invertebrates Chironomus tentans and Hyalella azteca under Constant- and Pulse-Exposure Conditions by Sarah J. Stoughton; Karsten Liber; Joseph Culp; Allan Cessna (pp. 662-673).

The toxicity of imidacloprid, a nicotinic mimic insecticide, to the aquatic invertebrates Chironomus tentans and Hyalella azteca, was first evaluated in static 96-hour tests using both technical material (99.2% pure) and Admire^®, a commercially available formulated product (240 g a.i. L^-1). The 96-h lethal concentration (LC)50 values for technical imidacloprid and Admire^® were 65.43 and 17.44 μg/L, respectively, for H. azteca, and 5.75 and 5.40 μg/L, respectively, for C. tentans. Admire^®was subsequently used in 28-day chronic tests with both species. Exposure scenarios consisted of a constant- and a pulse-exposure regime. The pulse exposure lasted for four days, after which time the animals were transferred to clean water for the remaining 24 days of the study. Assessments were made on both day 10 and day 28. In the C. tentans under constant exposure, larval growth on day 10 was significantly reduced at 3.57 μg/L imidacloprid, the lowest-observed-effect concentration (LOEC). The no-observed-effect concentration (NOEC) and LOEC for the 28-day exposure duration (adult survival and emergence) were 1.14 and greater than 1.14 μg/L, respectively; the associated LC50 and LC25 were 0.91 and 0.59 μg/L, respectively. The LOEC for the pulse treatment was greater than 3.47 μg/L, but the day 10 LC25 was 3.03 μg/L. In the H. azteca tests, the day 10 and 28 constant exposure, as well as the day 28 pulse exposure, LOEC (survival) values were similar at 11.95, 11.46, and 11.93 μg/L, respectively. The day 10 and 28 constant exposure effective concentration (EC)25s (dry weight) were also similar, at 6.22 and 8.72 μg/L, respectively, but were higher than the pulse-exposure day 10 LOEC and EC25 (dry weight) values of 3.53 and 2.22 μg/L, respectively. Overall, C. tentans was more sensitive to acute and chronic imidacloprid exposure, but less sensitive to a single pulse, than H. azteca. Chronic, low-level exposure to imidacloprid may therefore reduce invertebrate survival and growth, but organisms are able to recover from short-term pulse exposure to similar imidacloprid concentrations if the stressor is removed after four days.

Effluent Toxicity Test Using Developmental Stages of the Marine Polychaete Hydroides elegans by H. Thilagam; S. Gopalakrishnan; K. Vijayavel; P. Vivek Raja (pp. 674-683).

The US Environmental Protection Agency (USEPA) has established a suite of methods that use coastal invertebrate species as bioassay organisms to test industrial and domestic effluent as well as coastal waters for potential toxicity. Although these methods are used globally, the potential of such toxicity tests has not been adequately explored for Asian coastal waters. This study describes bioassay utilizing the gametes of Hydroides elegans to monitor coastal water quality and is based on the sensitivity of H. elegans embryo and larva to different concentrations of effluents and water samples collected from different regions of east coast of India. Among the water samples collected from different regions, seawater from Ennore station showed decrease in percentage of development, and 25% effluent concentration led to development arrest of H. elegans embryos. The different morphological effects produced by effluents clearly reflect the defect in early differentiation of embryonic cells. Since fertilization can be inhibited in the presence of any xenobiotic, both fertilization and early development can be used as a biological indicator for a rapid bioassay to monitor pollution. Toxicity tests utilizing early life stages of H. elegans are suitable for the assessment of effects produced by low levels of pollutants due to their high sensitivity to various contaminants relative to other marine species and also due to the relative simplicity of the bioassay.

Cellular and Stress Protein Responses to the UV Filter 3-Benzylidene Camphor in the Amphipod Crustacean Gammarus fossarum (Koch 1835) by Volker Scheil; Rita Triebskorn; Heinz-R. Köhler (pp. 684-689).

Chemical ultraviolet (UV) filters are used in various products and could be released into the environment, for example, via sunscreens used at swimming lakes. UV filters have been found in surface waters in the past but only a few investigations have concentrated on the effects of these substances in the environment. This study investigates the effects of a UV filter in the amphipod Gammarus fossarum at the cellular and molecular level. Stress protein (Hsp70) responses and reactions of hepatopancreatic cells and cells of gut appendices were investigated in the freshwater amphipod Gammarus fossarum after short-term exposure (4 days) to five different concentrations of the UV filter 3-benzylidene camphor (3-BC; 33 ng/L, 330 ng/L, 3.3 μg/L, 33 μg/L, 330 μg/L) and two control conditions (water and solvent ethanol). Male as well as female gammarids showed increased Hsp70 levels after exposure to low concentrations of 3-BC, with a maximum response at 3.3 μg/L, while the higher concentrations resulted in lower Hsp70 levels. This effect was most likely due to a cessation of Hsp70 synthesis following pathological impact as indicated by strong cellular responses and cellular damage obtained in epithelia of the hepatopancreas and the gut appendices after treatment with 330 μg/L 3-BC. Although environmentally relevant concentrations of 3-BC did not seem to have an adverse effect in this short-term study, higher concentrations of 3-BC are surely detrimental. It is known that chronic exposure generally requires much lower concentrations to cause harm than acute exposure. Additionally, juvenile stages may be even more sensitive than the adults tested. Therefore, on the basis of this study, 3-BC-effects in the field cannot be excluded and should be regarded possible.

The Effects of Water Quality and Age on the Acute Toxicity of Copper to the Florida Apple Snail, Pomacea paludosa by E. C. Rogevich; T. C. Hoang; G. M. Rand (pp. 690-696).

Copper (Cu)-containing compounds have been used in Florida as fungicides, herbicides, and soil amendments, resulting in elevated Cu in the aquatic ecosystem. The Florida apple snail (Pomacea paludosa), a key species in south Florida, may be adversely affected by Cu. Water-quality parameters, such as hardness, dissolved organic carbon (DOC), pH, and alkalinity, affect metal bioavailability and toxicity in aquatic organisms; however, it is uncertain to what extent these factors affect Cu toxicity in the Florida apple snail. The research presented here characterized the acute (96-hour) toxicity of Cu in water to the Florida apple snail at various life stages and under different water-quality parameters. Cu was more toxic to juvenile than adult apple snails. There was no difference between the 96-hour LC₅₀ at pH 5.5 and 6.5; however, the 96-hour LC₅₀values at pH 7.5 and 8.5 were greater than at lower pHs. The decrease in Cu²⁺ above pH 7, as predicted by the MINTEQ model, accounted for the pH effect. Cu toxicity decreased as DOC increased from 0.2 to 30 mg/L. Unlike other aquatic organisms, hardness had no effect on Cu toxicity to the Florida apple snail, suggesting another mechanism of toxicity. Whole-body tissue analysis indicated that the lethal body burden of 120-day-old snails exposed to Cu for 4 days was 30 mg/kg Cu dry weight. Multiple regression analysis indicated that Cu toxicity was a function of organism age, DOC, and pH.

Effects of Acclimation on the Toxicity of Stream Water Contaminated with Zinc and Cadmium to Juvenile Cutthroat Trout by D. D. Harper; A. M. Farag; W. G. Brumbaugh (pp. 697-704).

We investigated the influence of acclimation on results of in situ bioassays with cutthroat trout in metal-contaminated streams. Cutthroat trout (Oncorhynchus clarki) were held for 21 days (1) in live containers at a reference or “clean” site having dissolved metals near detection limits (0.01 μg/L cadmium [Cd] and 2.8 μg/L zinc [Zn]; hardness 32 mg/L as CaCO₃) and (2) at a site in a mining-impacted watershed having moderately increased metals (0.07 μg/L Cd and 38 to 40 μg/L Zn; hardness 50 mg/L as CaCO₃). The 96-hour survival of each treatment group was then tested in situ at five sites from September 5 to 9, 2002, and each group exhibited a range of metal concentrations (0.44 to 39 μg/L arsenic [As], 0.01 to 2.2 μg/L Cd, and 0.49 to 856 μg/L Zn). Survival was 100% at three sites for both treatments. However, a higher percentage of metal-acclimated fish survived at the site with the second highest concentrations of Cd and Zn (0.90 and 238 μg/L, respectively) compared with fish acclimated at the reference site (100% vs. 55%, respectively). Survival was 65% for acclimated fish and 0% for metal-naïve fish at the site with the largest metal concentrations (2.2 μg/L Cd and 856 μg/L Zn). Water collected from the site with the largest concentrations of dissolved metals (on October 30, 2002) was used in a laboratory serial dilution to determine 96-hour LC₅₀ values. The 96-hour LC₅₀ estimates of naïve fish during the in situ and laboratory experiments were similar (0.60 μg Cd/L and 226 μg Zn/L for in situ and 0.64 μg Cd/L and 201 μg Zn/L for laboratory serial dilutions). However, mortality of naïve cutthroat trout tested under laboratory conditions was more rapid in dilutions of 100%, 75%, and 38% site water than in situ experiments.

Metal Concentrations of Common Freshwater and Marine Fish from the Pearl River Delta, South China by K. C. Cheung; H. M. Leung; M. H. Wong (pp. 705-715).

Sediments and fish, including tilapia (Oreochromis mossambicus), bighead carp (Aristichthys nobilis), grass carp (Ctenopharyngodon idellus), and mandarin fish (Siniperca chuatsi) were collected from different fish ponds in the Pearl River Delta (Tanzhou, Sanjiao, Guangzhou, Shipai, Changan, and Mai Po) for the analysis of metalloids and heavy metals [arsenic (As), cadmium (Cd), chromium (Cr), mercury (Hg), and lead (Pb)]. The pollution of As in pond sediments was great; however, As in the edible parts of pond fish were within the international permissible safety levels for human consumption. Axial muscles from 10 species each of freshwater and marine fish purchased from markets in Hong Kong were also analyzed for As, Cd, Cr, Cu, Hg, Ni, Pb and Zn. Freshwater fish contained 0.24 to 2.13 mg/kg As, 0.10 to 0.17 mg/kg Cd, 0.09 to 0.36 mg/kg Cr, 0.06 to 0.35 mg/kg Cu, 0.07 to 0.34 mg/kg Hg, 0.04 to 0.36 mg/kg Ni, 0.11 to 0.52 mg/kg Pb, and 2.67 to 19.1 mg/kg Zn (wet weight). Marine fish had higher Hg and lower Pb concentrations than freshwater fish. A few fish species had average concentrations greater than the international standards for Cd and Pb established by the European Union and the China National Standard Management Department. Total Hg concentrations in 10 of 20 market fish species were generally greater than those of the World Health Organization’s recommended limit of 0.2 mg/kg for at-risk groups, such as children and pregnant women. Daily intake through fish consumption of these metals were compared with the Provisional Tolerable Weekly Intake proposed by the Joint Food and Agriculture Organization/World Health Organization Expert Committee on Food Additives. There appears to be potential threat to local people from Hg contamination because of the high marine fish consumption rate (142 g/d/person).

Temporal Trends and Spatial Variability of Mercury in Four Fish Species in the Ontario Segment of the St. Lawrence River, Canada by Richard R. Goulet; J. D. Lalonde; F. Chapleau; S. C. Findlay; D. R. S. Lean (pp. 716-729).

The Massena (New York) and Cornwall (Ontario) region has a long history of Hg discharge into the St. Lawrence River. The objectives of this study were to evaluate if Hg levels have declined in this portion of the river since 1975 and to compare Hg level in fish species upstream and downstream of this area in order to evaluate the anthropogenic contribution to Hg levels in fish. Mercury levels in four fish species were monitored over a 20-year period (1975–1995). A general linear model and an analysis of covariance were used to extract temporal trends and spatial variability, respectively, while correcting the data for fish length. Over time, Hg levels declined in most fish species. In the four regions studied, Hg levels in fish were similar, which suggests that other sources like atmospheric deposition and Hg loading from the Great Lakes may also contribute to the Hg burden in fish in the St. Lawrence River. This indicates that fish, with large home range, are good biomonitors of temporal Hg releases but their ability to avoid point sources makes them less appealing as biomonitors to address spatial variability in Hg releases.

Effects of Cadmium, Mercury, and Selenium on Reproductive Indices in Male Lesser Scaup (Aythya affinis) in the Western Boreal Forest by B. Pollock; K. L. Machin (pp. 730-739).

Combined lesser scaup (Aythya affinis) and greater scaup (A. marila) populations decreased from the 1980s to the 1990s and have not recovered. Factors limiting reproduction, including effects of contaminants and trace elements, have been highlighted as a concern in female scaup, but no studies have examined possible effects on male scaup. We examined the effects of cadmium, mercury, selenium, and corticosterone on pair status and on male reproductive indices, including testosterone, testes mass, and seminiferous tubule diameter, in male lesser scaup collected in the western boreal forest near Yellowknife, Northwest Territories, May and June, during 2004 and 2005. Male scaup that were larger in size (p = 0.048) and with better body condition (p = 0.038) were more likely to be paired. No relations were observed between independent variables and testosterone and testes mass. However, results suggested that seminiferous tubule diameter is influenced by a complex array of biologic and toxicologic parameters, which differ depending on pair status. Tubule diameters of paired male scaup were negatively influenced by hormones, whereas contaminants influenced diameter in unpaired male scaup. The effects of selenium were attenuated when bound with cadmium but not mercury. When selenium concentrations were high (greater than median value), there was a positive effect of cadmium on tubule diameter (R ² = 0.30, n = 10, p = 0.007) but a negative relation with mercury (R ² = 0.15, n = 10, p = 0.09). Seminiferous tubule diameter may be a sensitive indicator of sublethal effects of contaminants. This study showed contaminant and trace element effects at concentrations lower than threshold levels associated with major toxic effects. This study also demonstrated the complex nature of biologic systems and the importance of considering interactions to accurately characterize effects of metals.

Heavy Metal Distribution in Chicks of Two Heron Species from Korea by Jungsoo Kim; Tae-Hoe Koo (pp. 740-747).

This study presents concentrations of iron, manganese, zinc, copper, lead, and cadmium in tissues of black-crowned night heron (Nycticorax nycticorax) (n = 8) and grey heron (Ardea cinerea) (n = 9) chicks from Pyeongtaek heronry, Gyeonggi-do, Korea, 2001. Iron (respectively, 45.8 ± 24.0 μg/wet g, 155 ± 123 μg/wet g), zinc (38.3 ± 5.34 μg/wet g, 50.9 ± 14.0 μg/wet g), and copper (9.93 ± 2.26 μg/wet g, 30.2 ± 12.9 μg/wet g) concentrations in feathers, manganese concentrations in livers (3.26 ± 0.68 μg/ wet g, 1.50 ± 0.58 μg/wet g), kidneys (1.43 ± 0.27 μg/wet g, 0.84 ± 0.34 μg/wet g), and bones (1.34 ± 0.50 μg/wet g, 3.17 ± 1.31 μg/wet g) were different between black-crowned night heron and grey heron chicks. Lead concentrations in bones (0.11 ± 0.04 μg/wet g, 0.61 ± 0.42 μg/wet g) and cadmium concentrations in liver (13.5 ± 2.30 μg/wet kg, 10.3 ± 1.59 μg/wet kg), kidney (6.61 ± 2.54 μg/wet kg, 2.31 ± 1.29 μg/wet kg), and muscle (5.25 ± 5.91 μg/wet kg, 1.37 ± 0.90 μg/wet kg) differed between chicks of the two heron species. The differences of heavy metal concentrations in tissues in herons and egrets were reported to other similar studies. Heavy metal concentrations for both heron species were at background levels. In both species, lead concentrations were higher in livers than in bones and cadmium concentrations were higher in livers than in kidneys. We suggest that it is not chronic exposure but acute exposure to lead and cadmium contamination around breeding site that leads to these observations. Therefore, lead and cadmium concentrations in tissues can be used as a bioindicator of acute local contamination.

Effects of Sulfur Dioxide on the Expressions of EGF, EGFR, and COX-2 in Airway of Asthmatic Rats by Ruijin Li; Ziqiang Meng; Jingfang Xie (pp. 748-757).

The pathogenesis of asthma involves a combination of genetic and environmental factors. The epidemiology studies have shown that SO₂might play an important role in the initiation or exacerbation of the asthma disease. To investigate the asthmatic molecular mechanisms exposed to SO₂, male Wistar rats were divided randomly into four equal groups of six animals each: (1) SO₂ group, (2) ovalbumin (OVA) group (asthma group), (3) SO₂plus OVA group, and (4) control group. The rats were challenged by ovalbumin (OVA) or SO₂ (5.6 mg/m³) inhalation alone or together. The mRNA and protein levels of asthma-related genes (EGF, EGFR, and COX-2) were analyzed in lungs and tracheas using real-time reverse transcription–polymerase chain reaction assay, radioimmunoassay method, and Western blot analysis, respectively. The results showed that inhaled SO₂ alone increased the mRNA and protein expressions of three tested genes in lung and trachea tissues, but only the mRNA levels of EGFR and COX-2 in tracheas were significantly increased compared with the control. However, OVA exposure significantly induced the mRNA and protein expressions of EGF, EGFR, and COX-2 compared with the control. Meanwhile, OVA plus SO₂ inhalation enhanced the mRNA and protein levels of these genes in rat airways, versus exposure to OVA alone. These results suggested that SO₂ could increase the expressions of EGF, EGFR, and COX-2 on the transcription and translation levels in the lungs and tracheas from asthmatic rats, which might be one of the possible mechanisms by which SO₂ pollution aggravates asthma disease.

Concentrations of Metals in Blood and Feathers of Nestling Ospreys (Pandion haliaetus) in Chesapeake and Delaware Bays by B. A. Rattner; N. H. Golden; P. C. Toschik; P. C. McGowan; T. W. Custer (pp. 758-759).

Sections

Personal tools

Archives of Environmental Contamination and Toxicology (v.54, #4)

Sections

Personal tools

Local resources

Archives of Environmental Contamination and Toxicology (v.54, #4)