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Archives of Environmental Contamination and Toxicology (v.53, #2)

Effects of Injection Systems and Plastic Mulches on Distribution and Emissions of Cis- and Trans-1,3-Dichloropropene and Chloropicrin by Li-Tse Ou; John E. Thomas; L. Hartwell Allen Jr; Joseph C. Vu; Donald W. Dickson (pp. 141-150).

The concentration and distribution of a soil fumigant in the subsurface of field plots are two key factors in the determination of the fumigant efficacy. Subsurface concentrations of the biologically active compounds cis- and trans-1,3-dichloropropene (1,3-D) and chloropicrin (CP) were determined in soil at two adjacent injection traces and midpoint between the two traces in plastic-covered field beds after injection of the fumigant Telone C35 by conventional chisels or by a coulter rig (Avenger coulters). Two of the four beds were covered with metallic polyethylene film (MPE) and the remaining two were covered with virtually impermeable film (VIF). Three hours after chisel injection, concentrations of the three compounds at the two adjacent injection traces in the two beds were highly variable. Large concentrations of the compounds were detected at the side traces, whereas the compounds were not detected at the middle traces (bed centers) in the two chisel-injected beds covered with MPE or VIF. Initial concentrations of the three compounds at the two adjacent injection traces in the two Avenger-coulter-injected beds were more uniform than in the chisel-injected beds but still variable. Also, the three compounds had diffused horizontally to midpoint between the two injection traces in all four beds, generally in smaller concentrations. Concentrations of the three compounds in the shallow subsurface soil layer (0.5–30 cm) in the beds became progressively more uniform and then declined slowly. Volatilization losses from the two Avenger-coulter-injected beds and the chisel-injected bed covered with VIF were low. Combination of Avenger coulter injection and VIF provided better retention of the compounds in this soil layer and, thus, likely would provide better fumigant efficacy and crop yield.

Distribution of Selected Halogenated Organic Compounds Among Suspended Particulate, Colloid, and Aqueous Phases in the Mississippi River and Major Tributaries by C. E. Rostad; S. R. Daniel (pp. 151-158).

Suspended particulate, colloid, and aqueous phases were separated and analyzed to determine spatial variation of specific organic compound transport associated with each phase in a dynamic river system. Sixteen sites along the Mississippi River and its major tributaries were sampled at low-flow conditions to maximize the possibility of equilibrium. Across the solubility range studied, the proportion transported by each phase depended on the compound solubility, with more water-soluble compounds (dacthal, trifluralin) transported predominantly in the aqueous phase and less-water soluble compounds (polychlorinated biphenyls, chlordane-related compounds) transported predominantly in the particulate and colloid phases.

Recent Sedimentary History of Organic Matter and Nutrient Accumulation in the Ohuira Lagoon, Northwestern Mexico by Ana Carolina Ruiz-Fernández; Mauro Frignani; Tommaso Tesi; Humberto Bojórquez-Leyva; Luca Giorgio Bellucci; Federico Páez-Osuna (pp. 159-167).

²¹⁰Pb-derived sediment accumulation rates, as well as a suite of geochemical proxies (Al, Fe, δ¹³C, δ¹⁵N), were used to assess the time-dependent variations of C, N, and P fluxes recorded in two sediment cores collected at Ohuira Lagoon, in the Gulf of California, Mexico, during the last 100 years. Sedimentary C, N, and P concentrations increased with time and were related to land clearing, water impoundment, and agriculture practices, such as fertilization. C:N:P ratios and δ¹³C suggested an estuarine system that is responsive to increased C loading from a N-limited phytoplankton community, whereas δ¹⁵N values showed the transition between an estuarine-terrestrial to an estuarine-more marine environment, as a consequence of the declining freshwater supply into the estuary due to the channeling and impoundment of El Fuerte River between 1900 and 1956. The recent increases in nutrient fluxes (2- to 9-fold the pre-anthropogenic fluxes of C and N, and 2 to 13 times for P) taking place in the mainland from the 1940s, were related to the expansion of the intensive agriculture fields and to the more recent development of shrimp farming activities.

Aquatic Toxicity of Leachates Generated from Electronic Devices by Roi Dagan; Brajesh Dubey; Gabriel Bitton; Timothy Townsend (pp. 168-173).

Heavy metal leaching of electronic waste has been documented in recent literature. Heavy metal aquatic toxicity in the toxicity characteristic (TC) leachates produced from 56 electronic devices were tested using the aquatic toxicity assays such as Ceriodaphnia dubia 48-hr acute toxicity assay, the Selenatastrum capricornutum chronic algal growth inhibition assay (test used only for circuit-board leachates), and the MetPLATE acute heavy metal toxicity tests. The electronic devices tested, include 9 circuit boards (printed wire boards), 2 videocassette recorders, 4 remote controls, 1 cathode ray tube, 15 cellular phones, 1 calculator, 5 smoke detectors and their PC board components, 3 printers, 4 laptop computers, and 7 personal computer central processing units (CPUs). The toxicity tests showed toxicity in 51 of the 56 Toxicity Characteristic Leaching Procedure leachates of electronic devices assayed.

Keywords: E-waste leachates; Metal toxicity; MetPLATE; Toxicity testing

Assessment of Diazinon Toxicity in Sediment and Water of Constructed Wetlands Using Deployed Corbicula fluminea and Laboratory Testing by J. L. Bouldin; J. L. Farris; M. T. Moore; S. Smith Jr; C. M. Cooper (pp. 174-182).

Constructed wetlands for mitigation of nonpoint agricultural runoff have been assessed for their ability to decrease potential toxicity from associated contaminants. After a simulated runoff event, constructed wetlands positioned in series were used to measure the effects of the organophosphate insecticide diazinon. Water, sediment, and plant samples from five sites were analyzed for diazinon concentrations from 0.5 hours to 26 days; peak concentrations were measured in sediment after 0.5 hours (268.7 μg/kg) and in water and plant tissue after 3 hours (121.71 μg/L and 300.7 μg/kg, respectively). Cholinesterase activity and changes in shell growth were measured from Corbicula fluminea deployed at corresponding sites. Water collected after 9 hours from all wetland sites contained diazinon concentrations sufficient to cause toxicity to Ceriodaphnia dubia, but not to Pimephales promelas. C. dubia survival was decreased in water sampled through 7 days from the site nearest runoff introduction, whereas C. fluminea deployed at this same site experienced 100% mortality after 26 days. Clams from lower sites survived wetland conditions, but growth and ChE activity were significantly decreased lower than that of clams from a control site. C. dubia exposed to water from these sites continued to have decreased survival throughout the 26-day sampling. Sediment sampled from 48 hours through 14 days at the lowest wetland site decreased the laboratory survival of Chironomus dilutus, and sediment from upper sites elicited an effect only on day 26. Although wetland concentrations of aqueous diazinon were decreased lower than toxic thresholds after 26 days, decreased ChE activity in deployed clams provided evidence of residual diazinon effects to deployed organisms.

Metal Content and Toxicity of Produced Formation Water (PFW): Study of the Possible Effects of the Discharge on Marine Environment by L. Manfra; G. Moltedo; C. Virno Lamberti; C. Maggi; M. G. Finoia; S. Giuliani; F. Onorati; M. Gabellini; R. Di Mento; A. M. Cicero (pp. 183-190).

A preliminary chemical and ecotoxicological assessment was performed on the produced formation water (PFW) and superficial sediment around a gas platform (Fratello Cluster), located in the Adriatic Sea (Italy), in order to evaluate the effects of PFW discharged from the installation. The ecotoxicological bioassays, with the marine bacterium Vibrio fischeri and the sea urchin Paracentrotus lividus, were associated with chemical data to estimate the possible effects on living organisms. PFW collected on the platform was toxic, but no significant effect was recorded on marine sediment. Only the sediment station nearest to the discharge point showed higher values of some contaminants (zinc and arsenic) in comparison to other sites and only some stations showed low toxicity.

Thermal and Biocidal (Chlorine) Effects on Select Freshwater Plankton by S. Zargar; T. K. Ghosh (pp. 191-197).

Impact of select levels of temperature, individually and in combination, with different initial chlorine concentrations on the growth and reproduction of phytoplankter Chlorella vulgaris and zooplankton C. reticulata, C. viridis, and Diaptomus forbesi was evaluated. During the experiment, optimum growth temperature for the alga was estimated as 26°C, even though alga showed considerable growth up to 36°C. However, initial chlorine at concentrations ≥0.25 mg l⁻¹ adversely affected growth (P < 0.05 to 0.001) at all select temperature levels (26°C, 31°C, 33°C, 36°C, 39°C, 42°C, and 45°C). Investigations toward effects of different temperatures (26°C, 31°C, 33°C, and 36°C) on zooplankton indicated that survivability of these organisms was affected at temperatures ≥33°C. However, the percent growth rates of zooplankters at 26°C were significantly higher (P < 0.05) than those at 31°C, 33°C, and 36°C. Initial chlorine levels of 0.5 and 0.25 mg l⁻¹ were lethal to zooplankton; however, zooplankton survival was not affected at 0.06 mg l⁻¹ chlorinated water at all selected temperatures.

Heavy Metals in Aquatic Macrophytes from Two Small Rivers Polluted by Urban, Agricultural and Textile Industry Sewages SW Poland by A. Samecka-Cymerman; A. J. Kempers (pp. 198-206).

This article presents the results from a study of the comparison of 2 lowland rivers: the Olobok and the Pilawa in southwest Poland polluted by urban, agricultural, and textile industry sewages. pH and concentrations of Ca, Cd, Co, Cr, Cu, Fe, K, Mg, Mn, Ni, Pb, Zn, nitrate, nitrite, ammonia, phosphate, and sulfate were measured in water samples and concentrations of Ca, Cd, Co, Cr, Cu, Fe, K, Mg, Mn, N, Na, Ni, P, Pb, S, and Zn were measured in stream bottom sediments and in the aquatic macrophytes Elodea canadensis, Callitriche verna, Potamogeton crispus, Potamogeton natans, and Ceratophyllum demersum from the river Olobok and Elodea canadensis, Polygonum amphibium, Potamogeton crispus, and Veronica beccabunga from the river Pilawa. The matrix of concentrations of 16 elements in 27 plant samples of 7 species from 15 sampling sites of 2 rivers and concentrations of 15 elements and pH in water samples and 16 elements and pH in bottom sediment samples of these sites was submitted to numerical classification, which revealed that sampling sites from the rivers were differentiated by the value of factor 1 of principal component analysis (PCA), which was related to the pH of water, Ca, Cu, Mg, Mn, and Ni in water and Cd, Cr, Cu, Fe, K, Mg, Na, Ni, P, and S in bottom sediments. More polluted parts of both rivers were differentiated from less polluted parts by the value of factor 2 of PCA, which was related to Pb, Zn, and sulfates in water and Ca and Zn in bottom sediments. Macrophytes from the Olobok and Pilawa rivers were differentiated by the value of factor 1, which was related to Ca, Co, Cr, Cu, Fe, Mg, Ni, N, Na, Pb, and S. Groups of macrophytes of more and less polluted parts of both rivers differed by the value of factor 2, which was related to P, K, and Mn. Downstream of the sewage outputs in both rivers, a significantly increased level of pollution occurs with elements correlated with factor 1: Among others were Cu and Cr, typical for the textile industry along the river Pilawa, and among others were Mn and Ni, typical for the urban and agricultural activities in the river Olobok.

Keywords: Ca; K; Mg; N; Na; P; S; Heavy metal; Biomonitoring; Elodea Canadensis; Callitriche verna; Ceratophyllum demersum; Polygonum amphibium; Potamogeton sp.; Veronica beccabunga

Acute and Chronic Toxicity of Effluent Water from an Abandoned Uranium Mine by S. C. Antunes; R. Pereira; F. Gonçalves (pp. 207-213).

Inactive or abandoned mines represent a significant source of environmental, chemical, physical, and aesthetic impact. Among concerning situations, the occurrence of abandoned or semi-abandoned mine-associated ponds (for sedimentation of solids, for effluent neutralization, or for washing the ore) is a common feature in this type of system. These ponds are a source of contamination for the groundwater resources and adjacent soils, because they lack appropriate impermeabilization. The use of this water for agriculture may also pose chronic risks to humans. In Portugal, these problems have been diagnosed and some remediation projects have been developed. The purpose of our study was to evaluate the acute and chronic toxicity of water samples collected from the aquatic system surrounding an abandoned uranium mine (Cunha Baixa, Mangualde, Central Portugal). The present study focuses on the water compartment, whose toxicity was evaluated by means of standard toxicity assays using two Daphnia species (D. longispina and D. magna). Three different ponds were used in the characterization of the aquatic system from Cunha Baixa mine: a reference pond (Ref), a mine effluent treatment pond (T), and a mine pit pond (M). Metal analyses performed in the water samples from these ponds showed values that, in some cases, were much higher than maximum recommendable values established (especially Al, Mn) by Portuguese legislation for waters for crop irrigation. Acute toxicity was only observed in the mine pit pond, with EC₅₀ values of 28.4% and 50.4% for D. longispina and D. magna, respectively. The significant impairment of chronic endpoints, translated in reductions in the population growth rate for both species, gives rise to concerns regarding the potential risks for aquatic zooplanktonic communities, from local receiving waters, potentially exposed to point source discharges of the treated and nontreated effluent from Cunha Baixa uranium mine.

The Effects of Nonylphenol and Octylphenol on Embryonic Development of Sea Urchin (Paracentrotus lividus) by O. Cakal Arslan; H. Parlak; R. Oral; S. Katalay (pp. 214-219).

In this study, embryotoxic and genotoxic effects of nonylphenol (NP) and octylphenol (OP), which are the derivates of alkylphenol (APs), were evaluated using the gametes and embryos of the sea urchin Paracentrotus lividus. The sperm and eggs of sea urchins were exposed to increasing concentrations of NP (0.937–18.74 μg/L) and OP (5–160 μg/L) under static conditions. The endpoints were sperm fertilization success, quantitative and morphologic changes in mitotic activity, larval malformations, developmental arrest, and embryonic/larval mortality. A dose–response-related reduction (approximately 20%) was observed in fertilization success and significant increases in the number of larvae with skeleton malformations at the pluteus stage of the contaminated sperms. The spermiotoxic and embryotoxic concentrations were determined as 0.937 μg/L for NP and 4.685 μg/L for OP for this species. The embryotoxicity of NP and OP is concentration dependent, and significant growth reduction at the early life stages and an increase in larval malformations as skeleton deformities at the pluteus stage were observed. Cytogenetic analysis of embryos showed a decreasing curve in mitotic indexes (number of mitosis per embryo) with increasing concentrations of NP and OP. It can be concluded that NP and OP adversely affect the reproduction and embryonic developmental stages of the P. lividus and this is of great ecological importance because of the hazard at the population level.

Developing Toxicity Scores for Embryotoxicity Tests on Elutriates with the Sea Urchin Paracentrotus lividus, the Oyster Crassostrea gigas, and the Mussel Mytilus galloprovincialis by Chiara Losso; Marco Picone; Alessandra Arizzi Novelli; Eugenia Delaney; Pier Francesco Ghetti; Annamaria Volpi Ghirardini (pp. 220-226).

Bioassays are routinely employed for sediment quality assessment. In order to be able to effectively use Bioassays responses in regulatory and management frameworks, toxicity scores, which rank toxicity data in defined classes that are continuous and difficult to interpret, should be reliable and suitable tools to support decisions about the presence or absence of toxicity in tested samples and on how toxic a sample is. A statistical approach is needed to define thresholds for toxicity scores. The Minimum Significance Difference (MSD) criterion allowed the evaluation of toxicity thresholds for each test-matrix and organism pair, based on large sets of experimental data. The MSD values were normalized with respect to the control, ranked in ascending order, and the 90th percentile was identified; the Toxicity Threshold (TT) was calculated by subtracting the 90th percentile from 100 and the Toxicity Limit (TL) was estimated as the percentage of control response multiplied by TT. Taking into account sample responses normalized with respect to control (S), when S > TL, the sample is considered nontoxic; when S ≤ TL, toxicity is statistically present. The MSD criterion was applied on a dataset of results from both published and ongoing projects using the validated embryotoxicity tests with the echinoid Paracentrotus lividus, the oyster Crassostrea gigas, and the mussel Mytilus galloprovincialis, on elutriates from sediments of the Venice Lagoon. Once the threshold defining presence or absence of toxicity had been calculated, four other toxicity classes were developed: low (for toxicity data expressed as percentage of effect), medium, high, and very high toxicity (for toxicity data expressed as TU50).

Keywords: Toxicity threshold; Elutriates; Venice Lagoon

Toxicity of Organophosphates on Morphology and Locomotor Behavior in Brine Shrimp, Artemia salina by J. Venkateswara Rao; P. Kavitha; N. M. Jakka; V. Sridhar; P. K. Usman (pp. 227-232).

The acute toxicity and hatching success of four organophosphorus insecticides—acephate (ACEP), chlorpyrifos (CPP), monocrotophos (MCP), and profenofos (PF)—was studied in a short-term bioassay using brine shrimp, Artemia salina. Fifty percent hatchability inhibition concentration and median lethal concentration (LC₅₀) values were calculated after probit transformation of the resulting data. Among the insecticides tested, CPP is found to be the most toxic and also to inhibit hatching success of A. salina cysts in a concentration-dependent manner. In addition, the effect of these pesticides on locomotor behavior (swimming speed) and morphologic differences were studied in LC₅₀-exposed nauplii after 24 hours. The in vivo effect of these insecticides on acetylcholinesterase (Enzyme commission number (EC 3.1.1.7) activity was also determined in LC₅₀-exposed nauplii after 24 hours. Maximum percent decrease in their swimming speed and significant morphologic alterations were noticed in CPP-exposed brine shrimps. The order of toxicity was CPP > PF > MCP > ACEP in all the parameters studied.

Waterborne Amitrole Affects the Predator–Prey Relationship Between Common Frog Tadpoles (Rana temporaria) and Larval Spotted Salamander (Salamandra salamandra) by Anne-Lise Mandrillon; Philippe Saglio (pp. 233-240).

Within their aquatic habitats, larval amphibians are often subjected to multiple natural and anthropic stressors. Among these, predation and waterborne pollution represent two types of stressing factor that frequently co-occur. In this connection, the present laboratory study was designed to investigate the effects of amitrole, a commonly used triazole herbicide, on the predator–prey relationship between common frog tadpoles (Rana temporaria) and larval spotted salamander (Salamandra salamandra). Tadpoles were exposed for 3 days to 0, 0.01, 0.1, 1, and 10 mg/L amitrole, either in the absence or in the presence of larval salamanders. Tadpole behavior (refuge use, movements) was monitored every day, and the predation efficiency was assessed at the end of the experiment by counting the number of surviving tadpoles. In the absence of the predator, amitrole-exposed tadpoles (at 0.01, 0.1, and 1 mg/L) increased their refuge use and decreased their rate of movements. In the presence of the predator, amitrole contamination did not affect tadpole behavior, except on the first day, where tadpoles exposed to 10 mg/L were found to be significantly more active than unexposed control tadpoles. Throughout the experiment, control tadpoles were the only group to show significant reductions of activity and visibility in response to the predator’s presence. In contrast, tadpoles exposed to 0.01 and 0.1 mg/L amitrole increased their refuge use in response to the predator, whereas their rate of movements remained unaffected. Furthermore, exposures of tadpoles to the two highest amitrole concentrations (1 and 10 mg/L) resulted in the loss of both behavioral responses to the predator’s presence. Interestingly, the lack of antipredator behavior in amitrole-exposed tadpoles did not enhance their vulnerability to predation by the larval salamander. Moreover, tadpoles exposed to the two highest herbicide concentrations showed a better survival than unexposed controls, indicating that amitrole contamination also had detrimental effects on the predatory behavior of the larval salamander. These findings emphasize the need to consider the effects of contaminants on both predator and prey before drawing conclusions about the possible consequences of prey behavioral modifications on the predation risk.

The Effects of the Fungicide Methyl Thiophanate on Adrenal Gland Morphophysiology of the Lizard, Podarcis sicula by Maria De Falco; Rosaria Sciarrillo; Anna Capaldo; Tiziana Russo; Flaminia Gay; Salvatore Valiante; Lorenzo Varano; Vincenza Laforgia (pp. 241-248).

Endocrine-disrupting chemicals (EDCs) are a large group of substances able to modulate endocrine-signaling pathways, altering the normal function of the endocrine system. Although the fungicide methyl thiophanate (MT) is not considering a specific reproductive and developmental toxicant, it can induce histopathological damages in rat thyroid and adrenal glands that have a pivotal role in both processes. We investigated the MT effects on adrenal glands of Podarcis sicula lizard, the endemic species of Southern Italy living in open country and in cultivated fields. Reptiles are good bioindicators because they are easily harvested; they have a wide distribution and large populations. Moreover, they have good sensitivity to contaminants, and bioaccumulate and biomagnify pollutants to levels equal to or greater than those of birds and mammals. We used 1.5% MT/water to pollute terraria, food, and water twice a week for 15 and 30 days, and we evaluated adrenal toxicity through biochemical (adrenal and pituitary hormone plasma levels) and histological parameters (adrenal gland histopathology). We demonstrated a time-dependent increase of corticosterone plasma levels and a decrease of ACTH plasma levels, a hypertrophy of the steroidogenic tissue, and an enlargement of blood capillaries. Moreover, we observed a time-dependent increase of adrenaline plasma levels and adrenaline-producing cells, and an opposite trend of noradrenaline plasma concentrations. We also observed lymphocyte and macrophage infiltrations, signs of cell degeneration. Our findings on the bioindicator P. sicula provide an interesting basis to further elucidate the systemic mechanisms of EDCs.

PCB Levels and Accumulation Patterns in Waterbird Eggs and in Their Prey at Lake Kerkini, a North-Eastern Mediterranean Wetland of International Importance by V. Antoniadou; I. K. Konstantinou; V. Goutner; T. M. Sakellarides; T. A. Albanis; E. Bintoudi (pp. 249-260).

Seven “target” PCB levels were determined and compared in waterbird eggs, in their prey, and in water at Lake Kerkini, northern Greece, to investigate PCB bioaccumulation patterns and to define the best bioindicator of target PCBs for this area. PCBs were analysed from eggs of Phalacrocorax carbo, Podiceps cristatus, Ardea cinerea, Egretta garzetta, and Nycticorax nycticorax and from prey types Alburnus alburnus, Rutilus rutilus, Lepomis gibbosus. Carassius auratus, and Rana sp. PCBs analysed were detected in all bird eggs, prey, and water but contamination patterns differed among these sample types. The lipid-corrected geometric means of the congeners analysed were significantly different among most bird species and among some prey species. PCB congeners 118, 138, 153, and 180 accounted for around 80% of the total PCB contamination in bird egg samples. Percent congener concentrations of high-chlorinated PCBs tended to increase from water through prey to most bird egg samples whereas the low chlorinated PCBs (28 and 52) decreased. Bioaccumulation factors (BAFs) also exhibited an increasing trend for higher chlorinated PCBs from prey types to bird eggs. The greatest BAFs of six of the congeners were shared between Phalacrocorax carbo and Ardea cinerea. Among prey, the BAFs of four PCBs were highest in Lepomis gibbosus. Biomagnification factors varied between 1.01 and 39.57. In contrast to low chlorinated PCBs, high chlorinated congeners biomagnified considerably through fish prey. The highest biomagnification took place in Phalacrocorax carbo. No relationship was found between the lipid content of samples and BAFs of PCBs probably due to biotransformation differences of the congeners in the biota sampled.Due to the greatest PCB concentrations especially of the higher chlorinated PCBs in the eggs of Phalacrocorax carbo and its considerable bioaccumulation tendencies, it is proposed as the best PCB biomonitor of target PCBs at Lake Kerkini. Lepomis gibbosus had the highest concentrations of most congeners and exhibited the greatest bioaccumulative properties among prey and can be used as an alternative biomonitor.

The Presence and Impact of Environmental Lead in Passerine Birds Along an Urban to Rural Land Use Gradient by Karin E. Roux; Peter P. Marra (pp. 261-268).

Contamination of wetlands by lead shot and lead fishing weights has generated a tremendous amount of research into the impact of lead poisoning on wildlife. Less well known are the potential threats to wildlife posed by lead contaminants still prevalent in urban environments. Despite a U.S. federal ban on lead-based paint and gasoline in 1978 and 1986, respectively, lead residue is still prevalent at hazardous levels in urban and suburban environments and may present a health concern for people and wildlife, particularly birds. We quantified soil lead content in residential properties across a rural-to-urban land-use gradient in the metropolitan Washington, D.C. area and then assessed the impact of lead contamination on body condition in adult and nestling passerine birds at the same sites. Soil lead concentration was significantly higher in urban sites compared to rural sites. Accordingly, adult and nestling birds captured in urban sites had significantly higher blood lead concentrations than their rural counterparts. However, only gray catbird nestlings exhibited lower body condition as a result of lead contamination. Birds continue to breed in urban habitats despite numerous negative attributes to these environments including light, noise, pedestrian and toxic contaminants, such as lead. These sites often contain habitat that appears suitable for roosting, nesting, and foraging and thus may act as an ecological trap for breeding birds because breeding success is often negatively associated with increasing urbanization. Lead contamination is one more feature of urbanization that birds and other wildlife must face in an increasingly developed world.

Mercury and Drought Along the Lower Carson River, Nevada: I. Snowy Egret and Black-Crowned Night-Heron Annual Exposure to Mercury, 1997–2006 by C. J. Henny; E. F. Hill; R. A. Grove; J. L. Kaiser (pp. 269-280).

The dynamic nature of the annual volume of water discharged down the Carson River over a 10-year period, which included a century flood and drought, was examined in order to gain a better understanding of mercury movement, biological availability, and exposure to waterbirds nesting at Lahontan Reservoir. Total annual water discharge directly influenced total mercury (THg) in unfiltered water above the reservoir and downstream of a mining area, whereas methyl mercury (MeHg) at the same site was negatively related to annual discharge. Annual water storage at Lahontan Reservoir in the spring and early summer, as expected, was directly related to annual Carson River discharge. In contrast to the findings from above the reservoir, annual MeHg concentrations in water sampled below the reservoir were positively correlated with the total discharge and the amount of water stored in the reservoir on 1 July; that is, the reservoir is an important location for mercury methylation, which agrees with earlier findings. However, unfiltered water MeHg concentrations were about 10-fold higher above than below the reservoir, which indicated that much MeHg that entered as well as that produced in the reservoir settled out in the reservoir. Avian exposure to mercury at Lahontan Reservoir was evaluated in both eggs and blood of young snowy egrets (Egretta thula) and black-crowned night-herons (Nycticorax nycticorax). Annual MeHg concentrations in unfiltered water below the reservoir, during the time period (Julian Days 90–190) when birds were present, correlated significantly with mercury concentrations in night-heron blood (r ²= 0.461, p = 0.027), snowy egret blood (r ²= 0.474, p = 0.024), and night-heron eggs (r ² = 0.447, p = 0.029), but not snowy egret eggs. A possible reason for lack of an MeHg water correlation with snowy egret eggs is discussed and relates to potential exposure differences associated with the food habits of both species. THg concentrations in water collected below the reservoir were not related to egg or blood mercury concentrations for either species.

Keywords: Total mercury; Methyl mercury; Mining, Snowy egret; Black-crowned night-heron; Lahontan Reservoir; Carson River, Nevada; Water discharge

Coaccumulation of Cadmium and Zinc in Tissues of Sentinel Mallards (Anas platyrhynchos) Using a Former Dredge-Disposal Impoundment by J. M. Levengood; L. M. Skowron (pp. 281-286).

Six- to eight-month-old female farm-raised mallards (Anas platyrhynchos) were used to examine the accumulation of and association among cadmium (Cd), zinc (Zn), and copper (Cu) from an impoundment constructed to contain sediments dredged from a lake contaminated by a zinc smelter. Cd was not detectable in the livers t of farm-raised mallards (day 0), although sentinel mallards accumulated hepatic Cd in the first 7 days after release. By day 14, mean concentrations of Cd in kidneys (= 2.82 mg/kg wet weight) had increased 3.4-fold. The mean pancreatic Cd concentration increased 59% between days 7 and 14. Renal Zn increased nominally, whereas pancreatic Zn increased 63% in sentinel ducks after release. Hepatic Zn increased significantly in the first week of release. Renal and pancreatic Cu concentrations did not change significantly, whereas concentrations of Cu in livers of ducks increased 50% in the 7 days after release before decreasing by nearly the same degree. Concentrations of Cd and Zn were correlated in livers of sentinel mallards on days 7 and 14. Cd and Cu were not correlated in the tissues of any cohort. Cu and Zn were correlated in the livers of farm-raised mallards, in the pancreases of sentinel mallards at day 7, and in the kidneys of the ducks in all three treatments. The relationship between Cd and Zn in tissues of ducks in our study was complicated by simultaneous exposure to increased and heterogeneous concentrations of Cd and Zn, both of which can induce metallothionein and compete for this and other ligands.

Increased Thyroid Hormone Levels in Tree Swallows (Tachycineta bicolor) on Reclaimed Wetlands of the Athabasca Oil Sands by Marie-Line Gentes; Anne McNabb; Cheryl Waldner; Judit E. G. Smits (pp. 287-292).

The oil sands of Alberta, Canada are one of the world’s largest reserves of crude oil. Oil sands mining companies are now investigating the ecological impacts of reclamation strategies in which wetlands are used for the bioremediation of waste materials. To examine the endocrine disrupting potential of chemicals in Oil Sands Process Materials (OSPM), thyroid hormone concentrations were measured in plasma and thyroid glands of nestling tree swallows (Tachycineta bicolor) from wetlands partly filled with mine tailings. Plasma triiodothyronine (T₃) concentrations and thyroxine (T₄) content within thyroid glands were elevated in nestlings from OSPM sites compared to those from the reference site. Results suggested enhanced hormone synthesis by the thyroid glands independently of activation of the pituitary–thyroid axis, as well as increased deiodination of T₄ into T₃ in peripheral tissues. This might have resulted from exposure to oil sands associated chemicals such as polycyclic aromatic hydrocarbons and from environmental factors such as food availability. Modulation of thyroid function might have negative effects on metabolism, behavior, feather development, and molt, which could compromise postfledging survival.

A Comparative Analysis of Polybrominated Diphenyl Ethers and Polychlorinated Biphenyls in Southern Sea Otters that Died of Infectious Diseases and Noninfectious Causes by Kurunthachalam Kannan; Emily Perrotta; Nancy J. Thomas; Kenneth M. Aldous (pp. 293-302).

Southern sea otters (Enhydra lutris nereis) from the California coast continue to exhibit a slower population regrowth rate than the population in Alaska. Infectious diseases have been identified as a frequent cause of death. Infectious diseases caused by varied pathogens including bacteria, fungi, and parasites were suggestive of compromised immunological health of mature animals in this population. To test the hypothesis that elevated exposure to immunotoxic contaminants such as polybrominated diphenyl ethers (PBDEs) and polychlorinated biphenyls (PCBs) contribute to disease susceptibility via immunosuppression, we determined concentrations of PBDEs and PCBs in livers of 80 adult female sea otters that died of infectious diseases, noninfectious causes, or emaciation. Concentrations of PBDEs and PCBs in sea otter livers varied widely (10–26,800 ng/g and 81–210,000 ng/g, lipid weight, respectively). Concentrations of PBDEs in sea otters were some of the highest values reported for marine mammals so far. Although PCB concentrations in sea otters have declined during 1992–2002, the mean concentration was at the threshold at which adverse health effects are elicited. Concentrations of PBDEs and PCBs were significantly correlated, suggesting co-exposure of these contaminants in sea otters. No significant association was found between the concentrations of PBDEs and the health status of sea otters. Concentrations of PCBs were significantly higher in otters in the infectious disease category than in the noninfectious category, suggesting an association between elevated PCB concentrations and infectious diseases in Southern sea otters.

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Archives of Environmental Contamination and Toxicology (v.53, #2)

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Archives of Environmental Contamination and Toxicology (v.53, #2)