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Archives of Environmental Contamination and Toxicology (v.61, #4)

In Vitro Assessment of Retinoic Acid and Aryl Hydrocarbon Receptor Activity of Treated Effluent From 39 Wastewater-Treatment Plants in Victoria, Australia by M. Allinson; F. Shiraishi; S. A. Salzman; G. Allinson (pp. 539-546).

This project involved the collection of final effluent samples from 39 wastewater-treatment plants (WWTPs) in Victoria, Australia, in late summer (late February to early March 2007). The 39 WWTPs included 15 lagoon-based plants and 24 with activated sludge-based processes. Samples were collected and subjected to measurement of retinoic acid receptor (RAR) and aryl hydrocarbon receptor (AhR) activity of the dissolved phase using yeast-based recombinant receptor-reporter gene bioassays. More than 90% of the effluents examined in this study elicited RAR activity (<0.5–198 ng/l a-t-RA equivalents [EQ]). All of the effluents had AhR activity (16–279 ng/l βNF EQ). Notwithstanding the paucity of comparative data, on the whole, the levels of RAR and AhR activity observed in this pilot survey of Victorian WWTP effluents were greater than those recently reported internationally. One assumption commonly made is that WWTP discharges will be diluted significantly in the receiving environment, further decreasing the potential risk of the discharges. Making this assumption may not be appropriate for some of Victoria’s more ephemeral waterways or where effluent is discharged to an enclosed water body, such as a lake or terminal wetland. However, even where WWTP discharges represent all of the environmental flow in the warmer months, the observed RAR and AhR activity (as all-trans-retinoic acid (RA) and 2,3,7,8-tetrachloro-dibenzo-p-dioxin [TCDD] EQ, respectively) was still significantly lower than the concentrations of RA, and 2,3,7,8-TCCD known to cause developmental malformations in fish larvae after short-term exposure to these chemicals. Of perhaps greater concern, WWTP effluent can contain significant suspended solids (essentially biosolids), which may be a considerable sink for some hormonally active, hydrophobic compounds, and which may in turn increase the long-term exposure risk for aquatic fauna. Further studies of the nuclear and AhR activity of WWTP effluent suspended soilds are required to address this hypothesis.

Mixture Toxicity of S_N2-Reactive Soft Electrophiles: 2—Evaluation of Mixtures Containing Ethyl α-Halogenated Acetates by D. A. Dawson; T. Mooneyham; J. Jeyaratnam; T. W. Schultz; G. Pöch (pp. 547-557).

Four ethyl α-halogenated acetates were tested in (1) sham and (2) nonsham combinations and (3) with a nonreactive nonpolar narcotic. Ethyl iodoacetate (EIAC), ethyl bromoacetate (EBAC), ethyl chloroacetate (ECAC), and ethyl fluoroacetate (EFAC), each considered to be an SN2-H-polar soft electrophile, were selected for testing based on their differences in electro(nucleo)philic reactivity and time-dependent toxicity (TDT). Agent reactivity was assessed using the model nucleophile glutathione, with EIAC and EBAC showing rapid reactivity, ECAC being less reactive, and EFAC lacking reactivity at ≤250 mM. The model nonpolar narcotic, 3-methyl-2-butanone (3M2B), was not reactive. Toxicity of the agents alone and in mixture was assessed using the Microtox acute toxicity test at three exposure durations: 15, 30 and 45 min. Two of the agents alone (EIAC and EBAC) had TDT values >100%. In contrast, ECAC (74 to 99%) and EFAC (9 to 12%) had partial TDT, whereas 3M2B completely lacked TDT (<0%). In mixture testing, sham combinations of each agent showed a combined effect consistent with predicted effects for dose-addition at each time point, as judged by EC₅₀ dose-addition quotient values. Mixture toxicity results for nonsham ethyl acetate combinations were variable, with some mixtures being inconsistent with the predicted effects for dose-addition and/or independence. The ethyl acetate–3M2B combinations were somewhat more toxic than predicted for dose-addition, a finding differing from that observed previously for α-halogenated acetonitriles with 3M2B.

Combined Effect of N-Acetyl Cysteine, Zinc, and Selenium Against Chronic Dimethylmercury-Induced Oxidative Stress: A Biochemical and Histopathological Approach by Deepmala Joshi; Deepak Mittal; Sadhana Shrivastav; Sangeeta Shukla; Ajai Kumar Srivastav (pp. 558-567).

Mercury (Hg), widely used in industry, is a great environmental health problem for humans and animals. Despite several reports regarding Hg toxicity, there is scarcity of data on its toxic manifestations on Sprague Dawley rats under realistic exposure conditions. Experimental studies have shown that sulphur-containing antioxidants have beneficial effects against the detrimental properties of Hg. The present work was aimed to study the therapeutic potential of combined administration of N-acetyl cysteine (NAC; 2 mmol/kg ip), zinc (Zn; 2 mmol/kg po), and selenium (Se; 0.5 mg/kg po) against dimethylmercury (DMM; 1 mg/kg po)-intoxicated male rats for 12 weeks. Exposure to DMM caused significant alterations in cytochrome P450 (CYP) activity, microsomal lipid peroxidation, and proteins. Activities of transaminases (aspartate aminotransferase/alanine aminotransferase), alkaline phosphatase, and lactate dehydrogenase in serum, as well as activities of CYP enzymes aniline hydroxylase (AH), amidopyrine-N-demethylase (AND) in liver microsomes and activities of acid phosphatase, alkaline phosphatase, glucose-6-phophatase, and succinic dehydrogenase in the liver and kidney, were significantly altered after DMM administration. DMM exposure also induced severe hepato-renal alterations at the histopathological level. NAC, along with Zn and Se, dramatically reversed the alterations in all of the variables more toward control. The study results conclude that protective intervention of combined treatment of NAC, along with Zn and Se, is beneficial in attenuating DMM-induced systemic toxicity.

Fusicoccin Counteracts the Toxic Effect of Cadmium on the Growth of Maize Coleoptile Segments by Renata Kurtyka; Andrzej Kita; Waldemar Karcz (pp. 568-577).

The effects of cadmium (Cd; 0.1–1000 μM) and fusicoccin (FC) on growth, Cd²⁺ content, and membrane potential (E _m) in maize coleoptile segments were studied. In addition, the E _m changes and accumulation of Cd and calcium (Ca) in coleoptile segments treated with Cd²⁺ combined with 1 μM FC or 30 mM tetraethylammonium (TEA) chloride (K⁺-channel blocker) were also determined. In this study, the effects of Ca²⁺-channel blockers [lanthanum (La) and verapamil (Ver)] on growth and content of Cd²⁺ and Ca²⁺ in coleoptile segments were also investigated. It was found that Cd at high concentrations (100 and 1000 μM) significantly inhibited endogenous growth of coleoptile segments and simultaneously measured proton extrusion. FC combined with Cd²⁺ counteracted the toxic effect of Cd²⁺ on endogenous growth and significantly decreased Cd²⁺ content (not the case for Cd²⁺ at the highest concentration) in coleoptile segments. Addition of Cd to the control medium caused depolarization of E _m, the extent of which was dependent on Cd concentration and time of treatment with Cd²⁺. Hyperpolarization of E _m induced by FC was suppressed in the presence of Cd²⁺ at 1000 μM but not Cd²⁺ at 100 μM. It was also found that treatment of maize coleoptile segments with 30 mM TEA chloride caused hyperpolarization of E _m and decreased Cd²⁺ content in coleoptile segments, suggesting that, in the same way as for FC, accumulation of Cd²⁺ was dependent on plasma membrane (PM) hyperpolarization. Similar to FC, TEA chloride also decreased Ca²⁺ content in coleoptile segments. La and Ver combined with Cd²⁺ (100 μM) significantly decreased Cd content in maize coleoptile segments, but only La completely abolished the toxic effect of Cd²⁺ on endogenous growth and growth in the presence of FC. Taken together, these results suggest that the mechanism by which FC counteracts the toxic effect of Cd²⁺ (except at 1000 μM Cd²⁺) on the growth of maize coleoptile segments involves both stimulation of PM H⁺-ATPase activity by FC as well as Cd²⁺-permeable, voltage-dependent Ca channels, which are blocked by FC and TEA chloride-induced PM hyperpolarization.

Sediment-Quality Assessment Using the Polychaete Arenicola marina: Contamination, Bioavailability, and Toxicity by Julia Ramos-Gómez; Javier R. Viguri; Ángel Luque; Carlos Vale; M. Laura Martín-Díaz; T. Ángel DelValls (pp. 578-589).

The sediment quality of Cádiz Bay, Las Palmas de Gran Canaria (LPGC) Port, Santander Bay, Algeciras Bay, and Huelva Estuary (Spain) was evaluated by analysing a battery of biochemical biomarkers―activities of biotranformation enzymes ethoxyresorufin O-deethylase [EROD], dibenzylflourescein dealkylase [DBF], and glutathione S-transferase [GST]; activity of antioxidant enzyme glutathione reductase [GR]; and lipid peroxidation [LPO]―in the polychaete Arenicola marina after laboratory sediment exposure. Huelva Estuary polychaetes showed significantly (p < 0.05) enhanced LPO, GST, and EROD activities compared with control lugworms related to metals and presumably polychlorinated biphenyls. EROD activity significant (p < 0.05) induction was associated polycyclic aromatic hydrocarbons after Santander Bay sediment exposure. Nickel appeared to significantly (p < 0.05) induce GR activity and LPO in LPGC Port sediment–exposed organisms. DBF activity significantly (p < 0.05) increased in polychaetes exposed to sediments from sewage-contaminated areas. A. marina was sensitive at the biochemical level. Integration of sediment characterization and biomarker results allowed the identification of polluted sites as well as the cause of possible sediment toxicity.

Effects of Glyphosate and Polyoxyethylenamine on Growth and Energetic Reserves in the Freshwater Crayfish Cherax quadricarinatus (Decapoda, Parastacidae) by Jimena L. Frontera; Itzick Vatnick; Anouk Chaulet; Enrique M. Rodríguez (pp. 590-598).

Freshwater crayfish Cherax quadricarinatus have a high commercial value and are cultured in farms where they are potentially exposed to pesticides. Therefore, we examined the sublethal effects of a 50-day exposure to glyphosate acid and polyoxyethylenamine (POEA), both alone and in a 3:1 mixture, on the growth and energetic reserves in muscle, hepatopancreas and hemolymph of growing juvenile crayfish. Exposure to two different glyphosate and POEA mixtures caused lower somatic growth and decreased muscle protein levels. These effects, caused by both compounds interacting in the mixture, could also be synergistic because they were expressed even at the lowest concentration. The decrease in protein levels could be related to the greater use of other energy reserves. This hypothesis is supported by the decrease in muscle glycogen stores due to glyphosate exposure and the decrease in lipid reserves associated with exposure to POEA.

Comparison of the Effects of Two Herbicides and an Insecticide on Tropical Freshwater Plankton in Microcosms by C. Leboulanger; M. Bouvy; C. Carré; P. Cecchi; L. Amalric; A. Bouchez; M. Pagano; G. Sarazin (pp. 599-613).

Natural plankton communities from a tropical freshwater reservoir (Combani Reservoir, Mayotte Island, Mozambique Channel) were exposed, in 20-l nutrient-enriched microcosms, to two nominal concentrations of three pesticides: the herbicides diuron (2.2 and 11 μg/l) and paraquat (10 and 40.5 μg/l) and the insecticide fenitrothion (10 and 100 μg/l), commonly used in the tropics for agriculture and disease vector control. Bacterioplankton, phytoplankton, and zooplankton communities were monitored for 5 days after exposure, and the concentrations of toxicant and major nutrients were measured. Bacterioplankton growth was noticeable in all systems and was slightly affected by pesticide at any concentration. A transitory increase in thymidine-based bacterial production was observed in diuron- and fenitrothion-treated microcosms, followed by a marked decrease in all microcosms after 5 days. The functional diversity of bacterioplankton, evaluated using BIOLOG ECO^® microplates, was reduced by exposure to the highest pesticide concentrations. Phytoplankton was affected by pesticides in different ways. Chlorophyll biomass and biovolumes were increased by diuron addition and decreased by paraquat, whereas fenitrothion-treated microcosms remained unaffected relative to controls. Phytoplankton taxonomic diversity was decreased by paraquat and high doses of fenitrothion but was unaffected by addition of diuron. The decrease in diversity was due to a reduction in the number of species, whereas the density of small cells increased, especially after addition of paraquat. Heterotrophic flagellates were sensitive to paraquat and to the highest diuron concentration; a reduction in biomass of up to 90% was observed for 40.5 μg/l paraquat. Zooplankton, dominated by Thermocyclops decipiens and Diaphanosoma excisum, was slightly sensitive to diuron, and very sensitive to paraquat. High concentrations of the insecticide fenitrothion were effective only on young stages. The potential direct and indirect effects of pesticide contamination on such a simplified plankton food web, typical of newly constructed reservoirs, appear to differ significantly depending on the biological compartment considered. The overall sensitivity of tropical plankton is comparable to the sensitivity for temperate systems, and direct and indirect effects appeared rapidly, within 5 days of exposure.

Development of an Empirical Nonlinear Model for Mercury Bioaccumulation in the South and South Fork Shenandoah Rivers of Virginia by Robert N. Brent; Donald G. Kain (pp. 614-623).

Mercury is a globally distributed pollutant that biomagnifies in aquatic food webs. In the United States, 3781 water bodies fail to meet criteria for safe fish consumption due to mercury bioaccumulation. In the risk assessment and management of these impairments (through the total maximum daily load program), an important step is evaluating the relationship between aqueous mercury and mercury in fish tissue. Often, this relationship is simplified to a bioaccumulation factor (BAF): the ratio of fish tissue mercury to aqueous mercury. This article evaluates the relationship between aqueous mercury and fish tissue mercury across a contamination gradient in the South and South Fork Shenandoah rivers of Virginia. The relationship was found to be nonlinear, with BAFs decreasing as the level of contamination increased. This means that protective water column mercury concentration targets established from site-specific BAFs will be overestimated in contaminated areas and will not be sufficiently protective. To avoid this over-prediction in the South and South Fork Shenandoah rivers, an empirical nonlinear Michaelis–Menten model was used to establish a protective water-quality target. Among other models and variables, the Michaelis–Menten model, relating total mercury in the water column to methylmercury in fish tissue, achieved the best empirical fit (r ² = 0.9562). The resulting water-quality targets using this model were 3.8 and 3.2 ng/l for the South and South Fork Shenandoah rivers, respectively. These values are 2.1–2.5 times lower than the water-quality target developed using a site-specific BAF. These findings demonstrate the need to consider nonlinear BAF relationships in mercury-contaminated areas.

Acute Exposure to Glyphosate Herbicide Affects Oxidative Parameters in Piava (Leporinus obtusidens) by Lissandra Glusczak; Vania Lucia Loro; Alexandra Pretto; Bibiana Silveira Moraes; Alice Raabe; Marta Frescura Duarte; Milene Braga da Fonseca; Charlene Cavalheiro de Menezes; Dênia Mendes de Sousa Valladão (pp. 624-630).

In recent years, commercial glyphosate herbicide formulations have been widely used in agriculture to control aquatic weeds. These pesticides may result in disruption of ecological balance, causing damage to nontarget organisms including fish. Teleostean fish (Leporinus obtusidens) were exposed to commercial glyphosate herbicide formulation at 0 (control), 3, 6, 10 or 20 mg L⁻¹ for 96 h. The effects of herbicide on plasmatic metabolic parameters, thiobarbituric acid reactive substances (TBARS), catalase activity, protein carbonyl, and mucus layer parameters were studied. Plasmatic glucose and lactate levels increased but protein levels showed reduction after herbicide exposure. TBARS levels in brain showed a reduction at all tested concentrations. However, liver demonstrated increased TBARS levels at all tested concentrations, whereas in white muscle TBARS production did not change after exposure to herbicide. Fish exposed to all concentrations of glyphosate showed increase in liver catalase activity and protein carbonyl. Herbicide exposure increased protein and carbohydrate levels of the mucus layer at all tested concentrations. The present results showed that, in 96 h, glyphosate changed toxicological parameters analyzed in piava. Parameters measured in this study may be useful in environmental biomonitoring.

Levels, Temporal Trends, and Tissue Distribution of Perfluorinated Surfactants in Freshwater Fish from Asian Countries by Michio Murakami; Nozomi Adachi; Mahua Saha; Chiaki Morita; Hideshige Takada (pp. 631-641).

Perfluorinated surfactants (PFSs) in Asian freshwater fish species were analyzed to investigate tissue distribution, temporal trends, extent of pollution, and level of PFS exposure through food intake. Freshwater fish species, namely carp, snakehead, and catfish, were collected in Japan, Vietnam, India, Malaysia, and Thailand, and 10 PFSs, including perfluorooctanesulfonate (PFOS) and perfluorooctanoate, were analyzed by liquid chromatography–tandem mass spectrometry. PFSs in carp in Tokyo were more concentrated in kidneys (Σ10 PFSs = 257 ± 95 ng/g wet weight [ww]) and livers (119 ± 36 ng/g ww) than in ovaries (43 ± 2 ng/g ww) and muscles (24 ± 17 ng/g ww). Concentrations of PFOS and its precursor, perfluorooctane sulfonamide, in livers of carp and in waters in Tokyo showed a dramatic decrease during the last decade, probably because of 3 M’s phasing-out of the manufacture of perfluorooctanesulfonyl-fluoride-based products in 2000. In contrast, continuing contamination by long-chain perfluorocarboxylates (PFCAs) with ≥ 9 fluorinated carbons was seen in multiple media, suggesting that these compounds continue to be emitted. PFS concentrations in freshwater fish species in tropical Asian countries were generally lower than those in developed countries, such as Japan, e.g., for PFOS in muscle, Vietnam < 0.05–0.3 ng/g ww; India < 0.05–0.2 ng/g ww; Malaysia < 0.05–0.2 ng/g ww; Thailand < 0.05 ng/g ww; and Japan (Tokyo) = 5.1–22 ng/g ww. Daily intake of short-chain PFCAs with ≤ 8 fluorinated carbons from freshwater fish species in Japan was approximately one order of magnitude lower than that from drinking water, whereas daily intake of PFOS and long-chain PFCAs with ≥ 9 fluorinated carbons from freshwater fish species was comparable with or greater than that from drinking water. Because the risk posed by exposure to these compounds through intake of fish species is a matter of concern, we recommend the continued monitoring of PFS levels in Asian developing countries.

Mercury Speciation in Fish Tissues from a Mediterranean River Basin: The Tagus River (Central Spain) as a Case Study by J. J. Berzas Nevado; R. C. Rodríguez Martín-Doimeadios; F. J. Guzmán Bernardo; M. Jiménez Moreno; M. J. Patiño Ropero; A. de Marcos Serrano (pp. 642-652).

An assessment of mercury (Hg) accumulation in fish from the Tagus River aquatic system (central Spain), which has been influenced by pollution from industrial and urban development, was performed. Total Hg (THg), inorganic Hg (IHg), and monomethylmercury (MMHg) were determined in muscle and liver of different fish species, including Cyprinus carpio, Ameiurus melas, and Chondrostoma miegii, sampled from three locations. Although concentrations of THg and Hg species showed wide variability among the fish species, they were also found to be considerably dependent on location and fish tissue. Relative contents of MMHg to THg in muscle varied from 60 to 88%, whereas those found in liver ranged from 7 to 59%. Mean THg concentrations ranged from 126 to 810 ng/g (dry weight [dw]) in liver and from 159 to 1057 ng/g dw in muscle. Therefore, the mean THg concentration in all fish muscle samples was far lower than the maximum residue level recommended by the European Union for fishery products. Nevertheless, the concentrations of Hg in fish muscle reported in this study were somewhat increased compared with other areas geographically distant from most major anthropogenic Hg sources and, in some cases, even greater than those previously reported elsewhere in more polluted areas. In contrast, Hg contents in liver were lower than those found in Hg-contaminated areas, but they were within the range found in other areas exposed to diffuse sources of pollution by Hg. Thus, this article provides an overview of the concentration and distribution of Hg species in fish muscle and liver tissues samples taken from a freshwater system in the Mediterranean River basin.

Behavioral, Clinical, and Pathological Characterization of Acid Metalliferous Water Toxicity in Mallards by John P. Isanhart; Hongmei Wu; Karamjeet Pandher; Russell K. MacRae; Stephen B. Cox; Michael J. Hooper (pp. 653-667).

From September to November 2000, United States Fish and Wildlife Service biologists investigated incidents involving 221 bird deaths at 3 mine sites located in New Mexico and Arizona. These bird deaths primarily involved passerine and waterfowl species and were assumed to be linked to consumption of acid metalliferous water (AMW). Because all of the carcasses were found in or near pregnant leach solution ponds, tailings ponds, and associated lakes or storm water retention basins, an acute-toxicity study was undertaken using a synthetic AMW (SAMW) formulation based on the contaminant profile of a representative pond believed to be responsible for avian mortalities. An acute oral-toxicity trial was performed with a mixed-sex group of mallards (Anas platyrhynchos). After a 24-h pretreatment food and water fast, gorge drinking was evident in both SAMW treatment and control groups, with water consumption rates greatest during the initial drinking periods. Seven of nine treated mallards were killed in extremis within 12 h after the initiation of dose. Total lethal doses of SAMW ranged from 69.8 to 270.1 mL/kg (mean ± SE 127.9 ± 27.1). Lethal doses of SAMW were consumed in as few as 20 to 40 min after first exposure. Clinical signs of SAMW toxicity included increased serum uric acid, aspartate aminotransferase, creatine kinase, potassium, and P levels. PCV values of SAMW-treated birds were also increased compared with control mallards. Histopathological lesions were observed in the esophagus, proventriculus, ventriculus, and duodenum of SAMW-treated mallards, with the most distinctive being erosion and ulceration of the kaolin of the ventriculus, ventricular hemorrhage and/or congestion, and duodenal hemorrhage. Clinical, pathological, and tissue-residue results from this study are consistent with literature documenting acute metal toxicosis, especially copper (Cu), in avian species and provide useful diagnostic profiles for AMW toxicity or mortality events. Blood and kidney Cu concentrations were 23- and 6-fold greater, respectively, in SAMW mortalities compared with controls, whereas Cu concentrations in liver were not nearly as increased, suggesting that blood and kidney concentrations may be more useful than liver concentrations for diagnosing Cu toxicosis in wild birds. Based on these findings and other reports of AMW toxicity events in wild birds, we conclude that AMW bodies pose a significant hazard to wildlife that come in contact with them.

Oral Lead Bullet Fragment Exposure in Northern Bobwhite (Colinus virginianus) by Richard Kerr; Jeremy Holladay; Steven Holladay; Lawrence Tannenbaum; Barbara Selcer; Blair Meldrum; Susan Williams; Timothy Jarrett; Robert Gogal (pp. 668-676).

Lead (Pb) is a worldwide environmental contaminant known to adversely affect multiple organ systems in both mammalian and avian species. In birds, a common route of exposure is via oral ingestion of lead particles. Data are currently lacking for the retention and clearance of Pb bullet fragments in gastrointestinal (GI) tract of birds while linking toxicity with blood Pb levels. In the present study, northern bobwhite quail fed a seed-based diet were orally gavaged with Pb bullet fragments (zero, one or five fragments/bird) and evaluated for rate of fragment clearance, and changes in peripheral blood, renal, immune, and gastrointestinal parameters. Based on radiographs, the majority of the birds cleared or absorbed the fragments by seven days, with the exception of one five-fragment bird which took between 7 and 14 days. Blood Pb levels were higher in males than females, which may be related to egg production in females. In males but not females, feed consumption, body weight gain, packed cell volume (PCV), plasma protein concentration, and δ-aminolevulinic acid dehydratase (δ-ALAD) activity were all adversely affected by five Pb fragments. Birds of both sexes that received a single Pb fragment displayed depressed δ-ALAD, suggesting altered hematologic function, while all birds dosed with five bullet fragments exhibited greater morbidity.

Elemental Contaminants in Livers of Mute Swans on Lakes Erie and St. Clair by Michael L. Schummer; Scott A. Petrie; Shannon S. Badzinski; Misty Deming; Yu-Wei Chen; Nelson Belzile (pp. 677-687).

Contaminant inputs to the lower Great Lakes (LGL) have decreased since the 1960s and 1970s, but elemental contaminants continue to enter the LGL watershed at levels that are potentially deleterious to migratory waterfowl. Mute swans (Cygnus olor) using the LGL primarily eat plants, are essentially nonmigratory, forage exclusively in aquatic systems, and have increased substantially in number in the last few decades. Therefore, mute swans are an ideal sentinel species for monitoring elemental contaminants available to herbivorous and omnivorous waterfowl that use the LGL. We investigated hepatic concentrations, seasonal dynamics, and correlations of elements in mute swans (n = 50) collected at Long Point, Lake Erie, and Lake St. Clair from 2001 to 2004. Elements detected in liver at levels potentially harmful to waterfowl were copper (Cu) [range 60.3 to 6063.0 μg g⁻¹ dry weight (dw)] and selenium (SE; range 1.6 to 37.3 μg g⁻¹ dw). Decreases in aluminum, Se, and mercury (Hg) concentrations were detected from spring (nesting) through winter (nonbreeding). Elemental contaminants may be more available to waterfowl during spring than fall and winter, but study of seasonal availability of elements within LGL aquatic systems is necessary. From April to June, 68% of mute swans had Se levels >10 μg g⁻¹, whereas only 18% of swans contained these elevated levels of Se from July to March. An increase in the number of mute swans at the LGL despite elevated levels of Cu and Se suggests that these burdens do not substantially limit their reproduction or survival. Se was correlated with Cu (r = 0.85, p < 0.01) and Hg (r = 0.65, p < 0.01), which might indicate interaction between these elements. Some element interactions decrease the toxicity of both elements involved in the interaction. We recommend continued research of elemental contaminant concentrations, including detailed analyses of biological pathways and element forms (e.g., methylmercury) in LGL waterfowl to help determine the role of element interactions on their toxicity in waterfowl.

Associations Between Mercury and Hepatic, Renal, Endocrine, and Hematological Parameters in Atlantic Bottlenose Dolphins (Tursiops truncatus) Along the Eastern Coast of Florida and South Carolina by Adam M. Schaefer; Hui-Chen W. Stavros; Gregory D. Bossart; Patricia A. Fair; Juli D. Goldstein; John S. Reif (pp. 688-695).

We evaluated associations between total mercury (Hg) concentrations in blood and skin and endocrine, hepatic, renal, and hematological parameters in free-ranging bottlenose dolphins (Tursiops truncatus). Dolphins in Indian River Lagoon, FL had higher concentrations of Hg in blood (0.67 μg/l wet wt) and skin (7.24 μg/g dry wt) compared with those from Charleston Harbor, SC (0.15 μg/l wet wt, 1.68 μg/g dry wt). An inverse relationship was observed between blood and skin Hg concentrations and total thyroxine, triiodothyronine, absolute numbers of lymphocytes, eosinophils, and platelets. Adrenocorticotropic hormone (ACTH), blood urea nitrogen, and gamma-glutamyl transferase increased with increasing concentrations of Hg in blood and skin; lactate dehydrogenase and neutrophils increased with concentrations in skin only. Hemoglobin and mean corpuscular hemoglobin increased with increasing concentrations of Hg in blood. Selenium was negatively associated with free T4, progesterone, and absolute numbers of monocytes, and positively correlated with absolute numbers of eosinophils and lymphocytes, and mean corpuscular volume. The results suggest the potential for a deleterious effect of Hg in highly exposed dolphins.

Heavy Metals in Hair of Residents in an E-Waste Recycling Area, South China: Contents and Assessment of Bodily State by Jing Zheng; Xiao-Jun Luo; Jian-Gang Yuan; Luo-Yiyi He; Yi-Hui Zhou; Yong Luo; She-Jun Chen; Bi-Xian Mai; Zhong-Yi Yang (pp. 696-703).

Heavy metals were measured in hair from occupationally and nonoccupationally exposed populations in an e-waste recycling area and from residents from a control rural town. The levels of five heavy metals were in the following order of Zn > Pb, Cu > Cd > Ni, with the highest levels found in the occupationally exposed workers. The levels of Cd, Pb, and Cu were significantly higher in residents from the e-waste recycling area than in the control area. Elevated Cd, Pb, and Cu contents along with significant positive correlations between them in hair from the e-waste recycling area indicated that these metals were likely to have originated from the e-waste recycling activities. The similarity in heavy metal pattern between children and occupationally exposed workers indicated that children are particularly vulnerable to heavy metal pollution caused by e-waste recycling activities. The increased Cu exposure might be a benefit for the insufficient intake of Cu in the studied area. However, the elevated hair Cd and Pb levels implied that the residents in the e-waste area might be at high risk of toxic metal, especially for children and occupationally exposed workers.

Toxicity of Chlorpyrifos to Larval Rana dalmatina: Acute and Chronic Effects on Survival, Development, Growth and Gill Apparatus by Ilaria Bernabò; Emilio Sperone; Sandro Tripepi; Elvira Brunelli (pp. 704-718).

Chlorpyrifos [O,O-diethyl-O-(3,5,6-trichloro-2-pyridyl)phosphorothioate] is a widely used non-systemic organophosphorus insecticide frequently detected in surface waters around the world. The goal of this study is to evaluate the acute and chronic effects of this insecticide on Rana dalmatina tadpoles. To assess the sensitivity of this species, the LC50 value (i.e. the concentration at which 50% of tadpoles die) was determined after 96 h. Our results showed that 5.174 mg L⁻¹ chlorpyrifos caused 50% mortality in tadpoles at Gosner stage 25. Chronic toxicity tests were also conducted to evaluate the sublethal effects of chlorpyrifos; tadpoles were exposed to three ecologically relevant concentrations (0.025, 0.05 and 0.1 mg L⁻¹) in static renewal tests from Gosner stage 25 (tadpoles shortly after hatching) until completed metamorphosis (Gosner stage 46). No significant reduction was observed in survival, larval growth (mass), snout–vent length, stage development or number metamorphosed. In contrast, chlorpyrifos exhibited significant chronic toxic effects on larval development, manifested as the appearance of abnormalities, including tail flexure, skeletal and muscle defects in later stages of development in tadpoles exposed to all tested concentrations. We also evaluated the chronic effects of chlorpyrifos on gill morphology and ultrastructure. Tadpoles were sacrificed after 8 days and 30 days of exposure. Observations by both scanning (SEM) and transmission electron microscopy (TEM) showed considerable morphological and ultrastructural changes. The main gill effects recorded were mucous secretion, epithelium detachment and a degeneration phenomenon. Comparing these results with our previous findings, we demonstrate that the first effect of chlorpyrifos on R. dalmatina is gill alteration, thus supporting the role of a morphological approach in toxicological studies.

Keywords: Chlorpyrifos; Gills; Tail; Amphibia; Tadpoles; Ultrastructure

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