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Archives of Environmental Contamination and Toxicology (v.53, #4)
Polycyclic Aromatic Hydrocarbons in Indoor Air and Dust in Kuwait: Implications for Sources and Nondietary Human Exposure by Bondi Gevao; Majed Al-Bahloul; Jamal Zafar; Khalid Al-Matrouk; Murad Helaleh (pp. 503-512).
This study reports concentration of polycyclic aromatic hydrocarbons (PAHs) in indoor air and dust samples collected from 24 homes in Kuwait. Mean ΣPAHs in indoor air ranged from 1.3 to 16 ng/m3 with a geometric mean of 5.6 ng/m3, whereas the dust concentrations varied over three orders of magnitude, from 3 to 2920 ng/g, with a geometric mean of 165 ng/g. The low-molecular-weight tricyclic and tetracyclic PAHs dominated the air profile constituting ∼70–90 % of the measured compounds, with phenanthrene (51%), fluorene (13 %), fluoranthere (8 %), and pyrene (7 %) being the major contributors. The PAH profile in dust was dominated by the high-molecular-weight PAHs, with three compounds (benzo[a]pyrene, benzo[k]fluoranthene, and benzo[b]fluoranthene) contributing ∼60% of the average ΣPAHs measured in the samples. Indoor-to-outdoor (I/O) ratios for individual compounds were <1 for the majority of compounds, suggesting that there were no significant indoor sources for these compounds in these homes.Using the measured concentrations in air and dust, together with estimates of inhalation and inadvertent dust ingestion rates for children and adults, estimated human nondietary exposure on a BaPequiv basis were 547 pg/kg body weight/day and 205 pg/kg body weight/day for children and adults, respectively. Exposure from dust ingestion contributes about 42% of nondietary intake of ΣPAHs in children, but only 11% for adults. The threefold difference in exposure estimates between children and adults in this study supports previous reports that children are at greater risk from pollutants that accumulate indoors.
Production of Ozone and Reactive Oxygen Species After Welding by H. H. Liu; Y. C. Wu; H. L. Chen (pp. 513-518).
Many toxic substances including heavy metals, ozone, carbon monoxide, carbon dioxide, and nitrogen oxides are generated during welding. Ozone (O3) is a strong oxidant that generates reactive oxygen species (ROS) in tissue, and ambient ROS exposure associated with particles has been determined to cause DNA damage. Ozone is produced within 30 seconds during welding. However, the length of time that O3 remains in the air after welding is completed (post-welding) is unknown. The current study aimed to assess the distributions of ambient ROS and O3 before the start of welding (pre-welding), during welding, and after welding. The highest O3 levels, equal to 195 parts per billion (ppb), appeared during welding. Ozone levels gradually decreased to 60 ppb 10 minutes after the welding was completed. The highest ROS level was found in samples taken during welding, followed by samples taken after the welding was completed. The lowest ROS level was found in samples taken before the welding had started. Ozone and ROS levels were poorly correlated, but a similar trend was found for O3 and ROS levels in particles (μM/mg). Although particles were not generated after welding, ROS and O3 still persisted for more than 10 minutes. Meanwhile, because O3 continues after welding, how long the occupational protective system should be used depends on the welding materials and the methods used. In addition, the relationship between metal fumes and ROS generation during the welding process should be further investigated.
Keywords: O3 ; Particle; ROS; Ultraviolet light; Welding
Redistribution of Fractions of Zinc, Cadmium, Nickel, Copper, and Lead in Contaminated Calcareous Soils Treated with EDTA by Mohsen Jalali; Zahra V. Khanlari (pp. 519-532).
Effect of ethylene diamine tetraacetic acid (EDTA) on the fractionation of zinc (Zn), cadmium (Cd), nickel (Ni), copper (Cu), and lead (Pb) in contaminated calcareous soils was investigated. Soil samples containing variable levels of contamination, from 105.9 to 5803 mg/kg Zn, from 2.2 to 1361 mg/kg Cd, from 31 to 64.0 mg/kg Ni, from 24 to 84 mg/kg Cu, and from 109 to 24,850 mg/kg Pb, were subjected to EDTA treatment at different dosages of 0, 1.0, and 2.0 g/kg. Metals in the incubated soils were fractionated after 5 months by a sequential extraction procedure, in which the metal fractions were experimentally defined as exchangeable (EXCH), carbonate (CARB), Mn oxide (MNO), Fe oxide (FEO), organic matter (OM), and residual (RES) fractions. In contaminated soils without EDTA addition, Zn, Ni, Cu, and Pb were predominately present in the RES fraction, up to 60.0%, 32.3%, 41.1%, and 36.8%, respectively. In general, with the EDTA addition, the EXCH and CARB fractions of these metals increased dramatically while the OM fraction decreased. The Zn, Ni, Cu, and Pb were distributed mostly in RES, OM, FEO, and CARB fractions in contaminated soils, but Cd was found predominately in the CARB, MNO, and RES fractions. The OM fraction decreased with increasing amounts of EDTA. In the contaminated soils, EDTA removed some Pb, Zn, Cu, and Ni from MNO, FEO, and OM fractions and redistributed them into CARB and EXCH fractions. Based on the relative percent in the EXCH and CARB fractions, the order of solubility was Cd > Pb > Ni > Cu > Zn for contaminated soils, before adding of EDTA, and after adding of EDTA, the order of solubility was Pb > Cd > Zn > Ni > Cu. The risk of groundwater contamination will increase after applying EDTA and it needed to be used very carefully.
Keywords: EDTA; Fractionation; Contaminated soil; Calcareous soils; Heavy metals
Nickel Exposure Enhances the Susceptibility of Lichens Usnea amblyoclada and Ramalina celastri to Urban Atmospheric Pollutants by J. H. Rodriguez; H. A. Carreras; M. L. Pignata; C. M. González (pp. 533-540).
In the present study, the effect of nickel incorporation on the chemical response of Ramalina celastri (Spreng.) Krog & Swinsc. and Usnea amblyoclada (Müll. Arg.) Zahlbr. exposed to urban atmospheric pollutants was assessed. Lichen thalli were treated with Ni solutions and then transplanted to two areas of the city of Córdoba with different levels of pollution. After exposure, the concentration of chlorophyll a, chlorophyll b, phaeophytin a, hydroperoxy conjugated dienes, malondialdehyde, sulphur content, electric conductivity of the immersion water, and nickel content were measured. Also, a Pollution Index was calculated for each lichen species. The exposure to Ni altered the physiological response to atmospheric pollutants in both lichen species, making them more sensitive to any damage caused by them. When the species were compared, it was observed that R. celastri accumulated more sulphur than U. amblyoclada.
Monensin Is Not Toxic to Aquatic Macrophytes at Environmentally Relevant Concentrations by Erin B. McGregor; K. R. Solomon; M. L. Hanson (pp. 541-551).
Monensin, a common livestock feed additive, has been detected in surface waters around areas of intensive agriculture. The effect of this ionophore antibiotic on floating (Lemna gibba) and submersed (Myriophyllum spicatum, Elodea canadensis, Egeria densa) freshwater macrophytes was investigated under seminatural field conditions using 12,000 l of outdoor microcosms. Exposure concentrations of 0, 12, 25, 50, and 100 μg/l (n = 3) were evaluated over a 35-day period. Submersed plants were grown individually in 115-ml plastic “cone-tainers” and assessed for various growth and pigment end points. E. canadensis and M. spicatum also were grown in assemblages to represent model populations and two-species communities. Few statistically significant differences from control organisms were observed for any of the monitored end points. Overall, monensin is deemed unlikely to cause toxicity in freshwater macrophytes at current environmental concentrations. However, the ability to characterize toxicity in macrophytes is based partially on the relative growth rates (RGRs) of the plants. The greater the RGR, the more sensitive the assay may be to contaminants. The RGRs of E. canadensis and M. spicatum grown in model populations and communities were found to be significantly higher than the RGRs of plants grown individually. This implies that the “cone-tainer” method, although simple and easy to perform, may underestimate toxicity in simulated field studies.
Contrasting Effects of Heavy Metals on Sponge Cell Behavior by Emma Cebrian; María Jesús Uriz (pp. 552-558).
Mediterranean coastal areas are highly contaminated by heavy metals, which have been reported to produce harmful effects in marine organisms. Sponges are particularly vulnerable to waterborne metals because they are able to process large amounts of water. Dissociated sponge cells can move in response to external stimuli, and the cell body changes shape through production of pseudopodia and phylopodia. We studied for first time the effects of heavy metals (cadmium copper and mercury) on motility and aggregation of isolated sponge cells. Cell shape was assessed by using several shape indices. The three metals studied induced changes of different sign on cell shape. Mercury arrested movement of sponge cells, which tended to be rounded, without pseudopodia. In contrast, moderate concentrations of copper and cadmium enhanced pseudopodia formation and cell motility. On the other hand, the three metals enhanced cell aggregation at the concentrations assayed. Our results show that sponge cells respond to metal pollution in different ways and that these responses can be assessed by calculating several shape indices.
Keywords: Heavy metals; Sublethal effects; Ecotoxicology; Sponge cells; Bioassays
Ecotoxicity Assessment of River Sediments and a Critical Evaluation of Some of the Procedures Used in the Aquatic Oligochaete Tubifex tubifex Chronic Bioassay by Z. Maestre; M. Martinez-Madrid; P. Rodriguez; T. Reynoldson (pp. 559-570).
Sediment from 27 river sites in Northern Spain were tested with the aquatic oligochaete Tubifex tubifex (Annelida, Clitellata) 28-day chronic bioassay. Sampling sites were chosen from those established by regulatory water agencies for water-quality surveillance networks in rivers of the Basque Country and the Ebro basin. Inclusion of this test in an assessment programme with chemical and benthic community data currently collected by the water agencies will enable a more comprehensive ecotoxicological assessment. Cocoon and adult biomass were used as end points in addition to percent mortality, number of cocoons, young per adult, and percent of hatch end points as proposed in the American Society for Testing and Materials (ASTM) guidelines. Ecotoxicity assessment of the sediments was carried out by comparing mortality, growth, and reproduction in test sediments with their respective experimental control. Cluster analysis resulted in four groups of sediments that were compared using multidimensional scaling ordination (MDS), and the contribution of toxicity end points and the relationship of chemical variables to the MDS ordination space were assessed by principal component correlation (PCC). A gradient of sediments from nontoxic (4 controls and 6 sediments) to severely toxic (8 sediments) was observed, with all of the original biological end points contributing significantly to the ordination. The most toxic sediments could be separated into 2 groups based on the effects of pollutants on mortality (4 sediments) or on reproduction and growth (4 sediments). Remaining sites were grouped together as toxic sediments but showed a variable degree of sublethal effects. The acceptability criteria for validation of the bioassay, as recommended by the ASTM, measured in the control batch of each bioassay were achieved for survival and cocoon production (coefficient of variation [CV] and variability with regard to their average calculated through laboratory control charts). However, the ASTM criteria were found to be strict for the CV for total number of young, and a more realistic criterion is proposed. New criteria are also suggested to improve quality assurance of the bioassay, namely, a minimum number of cocoons per adult in the control group.
Uptake and Elimination of 4-Nonylphenol by the Clam Tapes philippinarum by E. Lietti; M. G. Marin; V. Matozzo; S. Polesello; S. Valsecchi (pp. 571-578).
The present study is the first dealing with the accumulation and elimination of 4-nonylphenol (NP) by the Manila clam, Tapes philippinarum. Specimens of T. philippinarum were exposed to NP-spiked seawater, and the NP contents in whole soft tissue, gills, digestive gland, and haemolymph were measured. Actual NP concentrations in seawater and microalgae (Isochrysis galbana) used for feeding were also determined, and the algal bioconcentration factor (BCF) value (640 ml/g) was calculated. Volatilisation was the main cause of dissipation of NP from experimental tanks, attaining up to 78% of the NP added. NP accumulated by algae used for feeding was negligible with respect to the total added NP, and we concluded that in our experiments, clams accumulated NP mainly from water and not food intake. Accumulation followed a two-compartment, first-order rate coefficient model, with an uptake rate coefficient of 13.8 ± 0.6 mL g−1h−1(fresh weight [fw]) and an elimination coefficient of 0.0070 ± 0.0005 h−1. Ninety percent of the steady state was reached after 14 days of exposure, and the BCF value at the steady state was 1958 ± 158 mL g−1 fw (1.8 ± 0.2.105 based on lipid weight). Slightly less than 50% of NP bioaccumulated through water was allocated into the gills, whereas the rest was found in the digestive gland. In the first 8 hours, clams eliminated 51% of the NP accumulated, and only 2% of the NP accumulated was detected in the clams at the end of the elimination phase (day 14). Two-compartment first-order decay model described the elimination of the accumulated NP by considering the clam as two compartments each with a different elimination rate. The sudden elimination of NP in the initial hours can be attributed to the elimination of NP accumulated into the gills and readily available for excretion (k e = 0.30 ± 0.07 h−1). The slower step of the elimination process should be the mobilisation of NP accumulated in internal organs, which must be carried into the haemolymph for excretion (k e = 0.0091 ± 0.0002 h−1). Because T. philippinarum has been demonstrated to accumulate NP dissolved in water, high NP levels can be hypothesised in clams from highly contaminated environments. This research was performed according to all national and international guidelines for animal welfare.
Toxicity of Two Pulsed Metal Exposures to Daphnia magna: Relative Effects of Pulsed Duration-Concentration and Influence of Interpulse Period by Tham C. Hoang; Jeffrey S. Gallagher; Joseph R. Tomasso; Stephen J. Klaine (pp. 579-589).
Aquatic organisms living in surface waters experience fluctuating contaminant exposures that vary in concentration, duration, and frequency. This study characterized the role of pulsed concentration, pulsed duration, and the interval between pulses on the toxicity of four metals (Cu, Zn, Se, and As) to Daphnia magna. During 21-d toxicity tests, neonatal D. magna were exposed to single or double pulses. Pulsed concentrations and durations ranged from 32 to 6000 µg/L and 8 to 96 h, respectively. Intervals between two pulses ranged from 24 to 288 h. Mortality, growth, and reproduction were characterized for exposures. For single-pulse exposures of Cu and As, metal concentration had a stronger effect on survival of D. magna than did pulsed duration: pulses with 2X concentration and 1Y duration resulted in more mortality than did pulses with 1X concentration and 2Y duration. In contrast, effects of pulsed duration were stronger than metal concentration for Zn. However, the effects of duration and concentration were similar for Se. The relative effects of pulsed concentration and duration found in the present study revealed that the common method using area under the curve (AUC = concentration × duration) may not always accurately estimate environmental risk from metals (e.g., for Cu, Zn, As). In addition, the occurrence of delayed mortality in the present study revealed that using continuous exposure bioassays might underestimate metal toxicity to aquatic biota. For double-pulse exposures, the toxicity of the second pulse was influenced by the first pulse for all four metals. This influence was dependent on the pulsed concentration and duration and the interval between pulses. Further, toxicity caused by the second pulse decreased as the time between the exposures increased. For all four metals, there existed an interval great enough that the toxicity of the two pulses was independent. This would result in less toxicity for multiple exposures than continuous exposures with the same total exposure duration. The interval time at which the effects of the two pulses were independent increased with increasing concentration. Growth and cumulative reproduction of D. magna over 21 d were not significantly affected by pulsed exposures examined in the present study, indicating recovery of the organisms.
Keywords: Pulsed exposure; Metal toxicity; Daphnia magna
Effects of the Fungicide Benomyl on Earthworms in Laboratory Tests Under Tropical and Temperate Conditions by Jörg Römbke; Marcos V. Garcia; Adam Scheffczyk (pp. 590-598).
Soil organisms play a crucial role in the terrestrial ecosystem. Plant protection products (PPPs) are known to affect soil organisms and might have negative impacts on soil functions influenced by these organisms. Little research has been performed to date on the impact of PPPs on tropical soil ecosystems. Therefore, in this study it was investigated whether the effects of the fungicide benomyl (chosen as a model substance) differ between tropical and temperate regions and whether data generated under temperate conditions can be used for the Environmental Risk Assessment (ERA) in tropical regions. The effect of benomyl on earthworms was evaluated in acute and chronic laboratory tests modified for tropical conditions. These tests were performed at two temperatures (20°C and 28°C) and with two strains (temperate and tropical) of the compost worm Eisenia fetida. The fungicide was spiked in two natural and two artificial soils. In addition to the organization for economic cooperation and development (OECD) artificial soil, a tropical artificial soil (TAS), containing a tropical fern product (xaxim) instead of peat, was developed in this study. The results from the laboratory tests and a literature review showed that the effects of benomyl were, on average, lower under tropical conditions (LC50: 450–630 mg active ingredient (a.i.)/kg; EC50: 0.8–12.9 mg a.i./kg) than under temperate conditions (LC50: 61–67 mg a.i./kg; EC50: 1.0–1.6 mg a.i./kg) by a maximum factor of 10.3 (acute tests) and 12.9 (chronic tests). This result might be caused by an increased degradation of benomyl, and/or its first metabolite carbendazim, at higher temperatures, but a different sensitivity of the two worm strains cannot be ruled out. Despite the lower toxicity under tropical conditions and assuming comparable application rates, a preliminary assessment confirms the risk of benomyl to soil invertebrates under both conditions.
Keywords: Fungicide; Risk assessment; Laboratory
Toxicity of Nonylphenol, Nonylphenol Monoethoxylate, and Nonylphenol Diethoxylate and Mixtures of these Compounds to Pimephales promelas (Fathead Minnow) and Ceriodaphnia dubia by Matthew C. TenEyck; Thomas P. Markee (pp. 599-606).
Three phenolic compounds were evaluated for their toxicity to the freshwater species Pimephales promelas (fathead minnow) and Ceriodaphnia dubia. Acute toxicity tests using nonylphenol (NP), nonylphenol monoethoxylate (NP1EO), and nonylphenol diethoxylate (NP2EO) were conducted using the single chemicals and as binary and tertiary mixtures. These compounds frequently coexist in surface waters as the result of discharges from wastewater treatment plants that are inefficient at removing nonylphenolic compounds. The mean lethal concentrations (LC50s) for NP, NP1EO, and NP2EO to the fathead minnow were 136, 218, and 323 µg/L, respectively. The LC50s of NP, NP1EO, and NP2EO to C. dubia were 92.4, 328, and 716 µg/L, respectively. The degree of toxic interactions was evaluated by converting mixture LC50 estimates to toxic units (TUs). When exposed to fathead minnows, the binary mixtures of NP plus NP1EO and NP plus NP2EO produced 0.87 and 0.70 TUs, respectively. The tertiary mixture for the same species produced a TU of 0.86. When exposed to C. dubia, the binary mixtures of NP plus NP1EO and NP plus NP2EO produced 0.48 and 1.12 TUs, respectively, whereas the tertiary mixture gave a TU of 0.90. This research suggests that the compounds are additive or synergistic when present in mixtures.
Keywords: Nonylphenol; Additive; Mixtures; Pimephales promelas ; Ceriodaphnia dubia
A Biomonitoring Study Assessing the Residual Biological Effects of Pollution Caused by the HAVEN Wreck on Marine Organisms in the Ligurian Sea (Italy) by A. Viarengo; F. Dondero; D. M. Pampanin; R. Fabbri; E. Poggi; M. Malizia; C. Bolognesi; E. Perrone; E. Gollo; G. P. Cossa (pp. 607-616).
Residual biological effects of the 1991 HAVEN oil spill off the Ligurian (Arenzano) coast were assessed in this study. Samples of the fish species Boops boops, Mullus barbatus, and Uranoscupus scaber were collected from two polluted sites near the HAVEN wreck and from an uncontaminated area. In addition to this, mussels were caged along the coast affected by the HAVEN disaster. The physiological status of fish and mussels was assessed using a battery of stress and exposure biomarkers. The PAH content of mussel and fish tissues was also analyzed. Significant biological responses were observed in lysosomal membrane stability, neutral lipid and lipofuscin accumulation and micronucleus frequency for mussels caged at two sites close to the HAVEN wreck. Chemical analyses indicated, however, that these effects are not caused by aromatic hydrocarbons. For this reason, we suggest that the aftermath of the HAVEN disaster contributes very little to coastal ecosystem pollution. This was also confirmed by the few biological effects observed in fish specimens (Boops boops) collected from surface waters. Nevertheless, it is important to point out that benthic fish displayed a stress syndrome potentially caused by aromatic hydrocarbons released from the oil tanker, as witnessed by an enhanced EROD activity and increased lipofuscin and neutral lipid lysosomal contents.
Keywords: Biomonitoring; aromatic hydrocarbons; bioindicators; biomarkers; fish; mussel
Studies on the Genotoxicity of Endosulfan in Different Tissues of Fresh Water Fish Mystus vittatus Using the Comet Assay by Shilpi Sharma; N. S. Nagpure; Ravindra Kumar; Sanjay Pandey; Satish K. Srivastava; Poonam J. Singh; P. K. Mathur (pp. 617-623).
Endosulfan, a widely used organochlorine pesticide, is readily bio-accumulative in fishes and can be indirectly harmful to human populations. Limited efforts have been made to study long-term genotoxic effects of endosulfan in different tissues of fish using gentoxicity biomarkers. Therefore, the current investigation was undertaken to detect single-cell DNA strand breaks induced by endosulfan in the fresh water teleost fish Mystus vittatus using the comet assay. The LC50 value of technical grade endosulfan was first determined for the fish species in a semistatic system, and on the basis of the LC50 value, the sublethal and nonlethal concentrations were determined. The DNA damage was measured in gill, kidney, and erythrocytes as the percentage of DNA in comet tails of fish specimens exposed to the sublethal and nonlethal concentrations of endosulfan. In general, significant effects (p < 0.01) from both concentration and time of exposure were observed in exposed fishes. It was found that all the tissues at all concentrations exhibited the highest DNA damage on day 1, after which there was a nonlinear decline in the percentage of tail DNA. The comparison of DNA damage among the tissues at different concentrations could not show the sensitivity of particular tissue to endosulfan. The current study explored the utility of the comet assay for in vivo laboratory studies using fish species to screen the genotoxic potential of chemical agents.
Keywords: Comet assay; DNA damage; Endosulfan; Fish; Genotoxicity.
Acute and Postexposure Effects of Ammonia Toxicity on Juvenile Barramundi (Lates calcarifer [Bloch]) by Asle Økelsrud; Richard G. Pearson (pp. 624-631).
Lethal and sublethal effects of ammonia toxicity to juvenile barramundi (Lates calcarifer) were investigated under laboratory conditions following the OECD guidelines for testing of chemicals. Acute toxicity was tested in a static nonrenewal system at pH 9.0 and temperature around 29°C. The 24-, 48-, and 96-h LC50 values for barramundi were 3.89, 3.67, and 3.31 mg total ammonia N L−1 and 1.59, 1.47, and 1.3 mg nonionized ammonia N L−1, respectively. Estimated lethal concentrations indicated a relatively high sensitivity to acute ammonia toxicity for barramundi and equaled the 25th percentile most sensitive North American fish species with regard to the species mean acute value (USEPA 1999). A 3-week postexposure experiment on surviving individuals from the acute toxicity test, in clean water, indicated that exposure to acute concentrations up to 1.16 mg nonionized ammonia N L−1 did not have any significant effects on growth.
Keywords: Ammonia; Toxicity testing; Short-term exposure; Local water quality guidelines
Physiological and Biochemical Effects of Lithium in Rainbow Trout by Victoria Tkatcheva; Natasha M. Franklin; Grant B. McClelland; Richard W. Smith; Ismo J. Holopainen; Chris M. Wood (pp. 632-638).
The physiological responses of juvenile rainbow trout (Oncorhynchus mykiss) to lithium (as LiCl) in moderately hard freshwater (CaCO3 = 120–140 ppm, Na+ = ∼0.6 mM) were studied. The study employed a 15-day step-up exposure regime; 66 μg/L Li for the first 9 days and 528 μg/L for the next 6 days. The concentrations of plasma ions, apolipoprotein AI, total cholesterol, and fatty acids, as well as metabolic enzyme citrate synthase (CS) and Na+,K+-ATPase activities in the gill were measured. Li affected fish by exacerbated diffusive Na+ losses at the gills in the beginning of exposure and a decrease of branchial CS activity. Detrimental effects were shown in fish exposed to 528 μg Li/L. These included a reduction of gill Na+,K+-ATPase activity, possibly related to observed lower concentrations of free fatty acids and cholesterol in gill tissue.
Keywords: Lithium; Fish gill; Plasma ions; Apolipoprotein AI; Lipids; Enzyme activity
Alteration of Larval Development and Metamorphosis by Nitrate and Perchlorate in Southern Leopard Frogs (Rana sphenocephala) by Manuel E. Ortiz-Santaliestra; Donald W. Sparling (pp. 639-646).
Amphibians are sensitive to a great variety of agrochemicals. Nitrate compounds are commonly applied as fertilizers, whereas perchlorate salts occur as by-products of the military industry and in some nitrate fertilizers. Both compounds are highly soluble and can easily diffuse between ground and surface water, thus potentially affecting amphibians. Nitrate reduces embryonic and larval survival and development, whereas perchlorate has a well-known goitrogenic effect and inhibits metamorphosis. We present the results of an experiment that assessed the combined effects of these two chemicals on the development and metamorphosis of southern leopard frogs (Rana sphenocephala) larvae. Individual frogs were exposed in a block design throughout their larval stages until they metamorphosed. Nitrate at 100 mg/l increased larval mortality and reduced the growth of developing tadpoles. Perchlorate at 15 mg/l was not lethal to larvae, but inhibited metamorphosis, resulting in high mortality during metamorphosis compared with control animals. At 30 mg/l of perchlorate, larvae experienced increased mortality. Together, the chemicals exhibited additive effects on developmental rate and survival. When nitrate and perchlorate occur simultaneously in the environment, they can have greater effects on an amphibian population than either chemical alone.
Keywords: Amphibian decline; Developmental toxicology; Fertilizers; Goitrogenic disruption; Thyroid hormones
Heavy Metal Levels in Ribbon Snakes (Thamnophis sauritus) and Anuran Larvae from the Mobile-Tensaw River Delta, Alabama, USA by J. Albrecht; M. Abalos; T. M. Rice (pp. 647-654).
The Mobile-Tensaw River Delta (MTD) drains more than 75% of the state of Alabama and leads into Mobile Bay and the Northern Gulf of Mexico. Although it is a relatively healthy watershed, the MTD is potentially impacted by inputs of contaminants such as heavy metals. The levels of lead, copper, cadmium, and mercury were measured in whole body samples of Eastern Ribbon Snakes (Thamnophis sauritus) collected from the MTD. Lead, copper, and cadmium levels were also measured in anuran larvae (Rana catesbeiana, R. clamitans, and Hyla cinerea). These organisms were chosen because they are abundant in the MTD and are underrepresented in environmental contaminant biomonitoring studies. Ribbon snakes had significantly lower levels of lead, copper, and cadmium compared to whole body levels in anuran larvae, indicating that these metals were not biomagnifying through upper trophic levels. Copper and mercury levels were significantly correlated with age/growth indices in ribbon snakes. Although detectable levels of all metals were found in anuran larvae and ribbon snakes, these levels appear to be less than body burdens that would be associated with toxic effects. Populations of ribbon snakes in our particular collection sites within the MTD appear to be at minimal risk of exposure to toxic levels of metals. However, the MTD contains low- and high-impact areas, and other populations within this watershed could be at higher risk of exposure to heavy metals. We found the Eastern Ribbon Snake to be an excellent snake model for contaminant biomonitoring because of its abundance, reasonable size, and ease of collection.
Effect of In Ovo Exposure to an Organochlorine Mixture Extracted from Double Crested Cormorant Eggs (Phalacrocorax auritus) and PCB 126 on Immune Function of Juvenile Chickens by E. T. Lavoie; F. Wiley; K. A. Grasman; D. E. Tillitt; J. G. Sikarskie; W. W. Bowerman (pp. 655-661).
Organochlorine (OC) contaminants including polychlorinated biphenyls (PCBs) and p, p’-dichlorodiphenyldichloroethylene (DDE) have been associated with immune modulation in wild fish-eating birds from the Great Lakes. The objective of this study was to evaluate the immune function of juvenile chickens after in ovo exposure to PCB 126 or an environmentally relevant OC mixture extracted from eggs of double crested cormorants (Phalacrocorax auritus) from Green Bay, Lake Michigan, USA. Fertile white leghorn chicken (Gallus domesticus) eggs were injected before incubation with 0.55–1.79 ng TCDD equivalents (TEQ)/egg PCB 126 and 1.2–4.9 ng TEQs/egg of cormorant egg extract into the air cell in two separate experiments. After hatching, the immune function was tested using in vivo phytohemagglutinin (PHA) skin response in 11-day-old chicks, antibody titers to immunization with sheep red blood cells (SRBC) in 28-day-old chicks, and, at necropsy, thymus and bursal mass and cellularity. PCB 126 decreased antibody titers at all doses and decreased the thymus and bursa index but not cellularity at 1.79 ng TEQ/egg. The cormorant egg extract caused no significant alterations in immune function even though it has been demonstrated as immunotoxic in chicken embryos. However, twofold to threefold increases in total anti-SRBC titers in 28-day-old chicks exposed to 1.2 or 2.4 ng TEQ/egg of cormorant extract were similar to elevations in anti-SRBC titer observed in Caspian tern (Sterna caspia) chicks from a highly OC-contaminated site in Saginaw Bay, Lake Huron. Posthatch exposure to OC through fish consumption in addition to in ovo OC exposure might be associated with the immune modulation reported in wild birds. Chicks in this study might have begun to compensate for embryonic immunotoxicity by the ages at which we studied them.
Arsenic, Cadmium, Copper, Lead, and Selenium in Migrating Blue-Winged Teal (Anas discors L.) by A. M. Fedynich; B. M. Ballard; T. J. McBride; J. A. Estrella; J. M. Garvon; M. J. Hooper (pp. 662-666).
The blue-winged teal (Anas discors L.), an abundant waterfowl species in North America, winters primarily in Mexico, Central America, and South America. Its transcontinental migratory behavior provides the opportunity to examine contaminant acquisition across a diverse biogeographic landscape that has varied environmental regulations and wildlife laws. We determined concentrations of arsenic (As), cadmium (Cd), copper (Cu), lead (Pb), and selenium (Se) in liver samples of blue-winged teal migrating through southern Texas during autumn 1998 (n = 47) and spring 1999 (n = 46). Concentrations for As (range 0.006 to 0.22 μg/g wet weight [ww]), Cd (range 0.007 to 8.14 μg/g ww), and Pb (range 0.012 to 1.79 μg/g ww) were at background levels for birds, whereas Cu (8.1 to 227.3 μg/g ww) and Se (0.36 to 5.07 μg/g ww) were increased in several individuals. All 24 hatch-year (HY) blue-winged teal had detectable levels of Cd, Cu, Pb, and Se, and eight had detectable levels of As. A seasonal effect was found for Cd, in which the mean Cd concentration in autumn was lower (p < 0.015) than in spring. Comparisons between autumn-collected HY and autumn-collected after-hatch-year (AHY) blue-winged teal found the mean concentration of Cd was higher (p < 0.001) in AHY birds. A seasonal effect occurred for Cu, in which the mean concentration was higher (p < 0.001) in autumn than in spring. Comparisons between seasons using only AHY blue-winged teal found that the mean concentration of Cu was higher (p < 0.001) in autumn than in spring. No sex effects (p > 0.05) were found for the five elements examined. Results indicated that blue-winged teal were acquiring all five elements; that HY blue-winged teal were exposed to these elements in North America; and that increased Se concentrations in 15% of the 93-bird sample were at levels known to cause impairment in birds.
Effects of Subchronic Exposure via Drinking Water to a Mixture of Eight Water-Contaminating Metals: A Biochemical and Histopathological Study in Male Rats by S. H. Jadhav; S. N. Sarkar; R. D. Patil; H. C. Tripathi (pp. 667-677).
In the current study, we examined whether subchronic exposure via drinking water to low doses of a mixture of metals (arsenic, cadmium, lead, mercury, chromium, manganese, iron, and nickel), found as contaminants in various water sources of India, and to concentrations equivalent to WHO maximum permissible limits (MPL) in drinking water for individual metals, can alter systemic physiology of male rats. Data on water contamination with metals in India were collected from the literature and metals were selected on the basis of their frequency of occurrence and contamination level above MPL. Male Wistar rats were exposed to the mixture at 0, 1, 10, and 100 times the mode concentrations (the most frequently occurring concentration) of the individual metals via drinking water for 90 days. One more group of rats was exposed to the mixture at a concentration equivalent to the MPL (WHO) in drinking water for individual metals. Toxic potential of the mixture was evaluated by assessing general toxicological end points, serum chemistry and histopathology of vital organs. The mixture decreased body weight and water consumption and increased weights of brain, liver, and kidneys with 10× and 100× doses. After 30 days of exposure, no appreciable changes were found in any blood clinical markers. After 60 days, only the 100× dose, while after 90 days both 10× and 100× doses increased activities of aspartate aminotransferase and alkaline phosphatase and levels of urea nitrogen and creatinine and decreased total protein and albumin levels, but alanine aminotransferase activity and glucose level were not affected. At 10× and 100× exposure levels, qualitatively similar, but dose-dependent vascular, degenerative, and necrotic changes were observed in brain, liver, and kidney. The results indicate that subchronic exposure to the metal mixture affected general health of male rats by altering the functional and structural integrity of kidney, liver, and brain at 10 and 100 times the mode concentrations of the individual metals in Indian water sources, but exposure at mode concentrations of contemporary water contamination levels or at concentrations equivalent to the MPL for individual metals in drinking water may not cause any health hazards in male rats.
Delayed and Competitively Inhibited Excretion of Urinary Hippuric Acid in Field Workers Coexposed to Toluene, Ethyl Benzene, and Xylene by I. F. Mao; F. K. Chang; M. L. Chen (pp. 678-683).
The purpose of this study was to investigate whether the metabolic suppression of hippuric acid (HA) occurs in field workers coexposed to toluene, xylene and ethyl benzene. Eleven male spray painters were recruited into this study and monitored for 2 weeks using a repeated-measures study design. The sampling was conducted for 3 consecutive working days each week. Toluene, ethyl benzene, and xylene in the air were collected using 3M 3500 organic vapor monitors. Urine samples were collected before and after work shift, and urinary HA, methyl hippuric acid, mandelic acid, and phenylgloxylic acid concentrations were determined. In the first week, toluene concentrations were 2.66 ± 0.95 (mean ± SE) ppm, whereas ethyl benzene and xylene concentrations were 27.84 ± 3.61 and 72.63 ± 13.37 ppm, respectively, for all subjects. Pre–work shift HA concentrations were 230.23 ± 37.31 mg/g creatinine, whereas pre–work shift HA concentrations were 137.81 ± 14.15 mg/g creatinine. Mean urinary HA concentration was significantly greater in the pre–work shift samples than in the pre–work shift samples (p = 0.043). In the second week, toluene concentrations were much lower (0.28 ppm), whereas ethyl benzene and xylene were 47.12 ± 8.98 and 23.88 ± 4.09 ppm, respectively, for all subjects. Pre–work shift HA concentrations were 351.98 ± 116.23 mg/g creatinine, whereas pre–work shift HA concentrations were 951.82 ± 116.23 mg/g creatinine. Mean urinary HA concentration was significantly greater in the pre–work shift samples than in the pre–work shift samples (p <0.01); a significant correlation (r = 0.565; p = 0.002) was found between pre–work shift urinary HA levels and ethyl benzene exposure. This study showed that urinary HA peak was delayed to next morning for workers coexposed to toluene, ethyl benzene, and xylene; xylene and ethyl benzene probably played competitive inhibitors for metabolism of toluene. The study also presumed that urinary HA became the major metabolite of ethyl benzene at the end of work shift, when the exposure concentrations of ethyl benzene were 2.0 times those of xylene.