bluuebunny/crossref_metadata_2025 huggingface dataset:
The presence of morphologically intermediate papilla syndrome in United Kingdom populations of sand goby (Pomatoschistus spp.): Endocrine disruption?
Authors: Kirby Mark F. , Bignell John , Brown Elaine , Craft John A. , Davies Ian , Dyer Robert A. , Feist Steven W. , Jones Gary , Matthiessen Peter , Megginson Colin , Robertson Fiona E. , Robinson Craig
Published: March 2010

The sand goby (Pomatoschistus spp.) is a small estuarine fish. Its abundance, life history, and sedentary nature lead to its adoption as a key species in the U.K. Endocrine Disruption in the Marine Environment (EDMAR) Program. This study investigated the presence of classic markers of estrogenic exposure by determining vitellogenin (VTG) and zona radiata protein (ZRP) mRNA levels and ovotestis in estuarine-caught male gobies and investigated morphological changes in the urogenital papilla (UGP). Laboratory exposures to estrogens were also conducted to ascertain the responses of these markers. Wild-caught male fish showed no evidence of ovotestis, VTG, or ZRP mRNA induction. Laboratory exposures suggested that sensitivity of the goby to VTG/ZRP mRNA induction was similar to flounder. The UGP inspection of wild-caught specimens revealed evidence of feminization of male papillae, a condition denoted as morphologically intermediate papilla syndrome (MIPS). Morphologically intermediate papilla syndrome was more prevalent at estrogenically contaminated sites. Juvenile goby experimentally exposed to 17β-estradiol for 11 to 32 weeks exhibited signs of the MIPS condition, showing that it was inducible by estrogenic exposure and could therefore be a form of estrogenic endocrine disruption. The estuaries where the MIPS condition was most prevalent (>50% at certain sites) were the Tees, Mersey, and Clyde. The potential of the MIPS condition to significantly interfere with reproductive performance is discussed as well as its use as a monitoring tool for endocrine disruption in the estuarine environment.
Adsorption of metals to membrane filters in view of their speciation in nutrient solution
Authors: Weltje Lennart , den Hollander Wim , Wolterbeek Hubert Th.
Published: March 2010

Filtration of a solution may lower metal concentrations through adsorption of metal species to the filter. Processes such as filter-sterilizing nutrient solution and filtration of field water are sensitive to these sorption artifacts, yet basic data on the affinity of different filters for metals are lacking. This article describes the adsorption of five metals to eight types of 0.2-μm membrane filters used for sterilizing a plant (Lemna minor L.) culture medium. Filters of cellulose acetate, cellulose nitrate, mixed cellulose ester, nylon, polyamide, polycarbonate, polyester, and polyvinylidene fluoride were tested for their affinity toward mono- (K), di-(Mn, Cu, Zn), and trivalent (lanthanum [La]) metals. Metal concentrations were quantified using radioisotopes and speciation was calculated. Results showed that metals had the lowest affinity for polycarbonate and nylon filters and the highest affinity for cellulose- and polyester-type filters. Furthermore, it was shown that the metal load on cellulose filters correlated best with free ion concentrations (indicating electrostatic attraction), while loads on other filters correlated better with total metal concentrations. Filtering a 5-ml solution of pH 5 did not affect its metal concentrations, ranging from 10 nM (La) to 49 μM (K). To minimize filtration artifacts, we propose using polycarbonate or nylon filters, especially when dealing with low volumes of high pH and low metal species concentrations.
Assessing the toxicity of dodecylbenzene sulfonate to the midgeChironomus ripariususing body residues as the dose metric
Authors: Hwang Haejo , Fisher Susan W. , Kim Kyeok , Landrum Peter F. , Larson Robert J. , Versteeg Donald J.
Published: March 2010

Dodecylbenzene sulfonate (DBS) is a component of linear alkylbenzene sulfonate (LAS), an anionic surfactant, mainly used in household detergents. Due to the large quantity of DBS in use, there is concern over adverse environmental effects. This work examined the toxicokinetics and toxicity of the 2-phenyl isomer of dodecylbenzene sulfonate in 4-d, 10-d, and partial life-cycle tests on the midge, Chironomus riparius, exposed to aqueous solutions. Toxicokinetics were determined in 10-d uptake and 5-d elimination tests. The toxicokinetics were based on parent compound concentration in water and yielded an uptake coefficient (ku) of 17.5 (14.87–20.20) ml/g/h, an elimination rate constant (ke) of 0.073 (0.062–0.085) per h, a bioconcentration factor (BCF) of 56 to 240, and a half-life (t1/2) of 9.5 (8.0–11.0) h. Biotransformation measurements did not reveal evidence for DBS metabolism. Thus, body residues, determined in the toxicity study, represent parent compound. In toxicity tests, 4- and 10-d LR50s (the body residue required to cause 50% mortality) in live midges were 0.72 (0.65–0.79) and 0.18 (0.08–0.42) mmol/kg, respectively. Thirty-day LR50s were 0.18 (0.09–1.64) and 0.21 (0.15–0.39) mmol/kg in duplicate studies. Of the sublethal endpoints, only developmental time increase was significant, with the lowest-observed-effect residues of 0.085 (0.067–0.105) and 0.100 (0.087–0.114) mmol/kg for male and female midges, respectively. Deformities in surviving larvae were also observed as chronic responses for body residues exceeding the 30-d LR50. The body residues required for mortality suggest that DBS acts like a polar narcotic in the midge.
Exposure to the polychlorinated biphenyl mixture Aroclor® 1254 alters melanocyte and tail muscle morphology in developingXenopus laevistadpoles
Authors: Fisher Marla A. , Jelaso Anna M. , Predenkiewicz Amy , Schuster Lindsey , Means Jay , Ide Charles F.
Published: March 2010

Polychlorinated biphenyls (PCBs) are ubiquitous environmental contaminants that have damaging effects on both ecosystem and human health. Numerous studies have shown that exposure to PCBs can alter growth and development of aquatic organisms, including frogs. In this report, developing Xenopus laevis tadpoles were exposed to the PCB mixture Aroclor® 1254. Tadpoles were exposed from 5 through 9 d postfertilization to either 0, 1, 10, 50, or 100 ppm Aroclor 1254. Exposure to an acute, high concentration of Aroclor 1254 (10, 50, and 100 ppm) caused statistically significant reductions in survival and body size. In addition, tadpoles exposed to these higher concentrations showed histological abnormalities, including aberrant tail tip, myotomal, and melanocyte morphologies. Described adverse health effects associated with PCB exposure of developing frogs will serve as useful health endpoints in ongoing and future molecular-based studies that correlate health effects with changes in gene expression.
In vitro and in vivo estrogenicity and toxicity of o-, m-, and p-dichlorobenzene
Authors: Versonnen Bram J. , Arijs Katrien , Verslycke Tim , Lema Wouter , Janssen Colin R.
Published: March 2010

The estrogenicity of o-, m-, and p-dichlorobenzene (DCB) was evaluated with a yeast estrogen screen (YES) and zebrafish (Danio rerio) vitellogenin (VTG) assays. With the YES, p-DCB and m-DCB were found to be estrogenic in a concentration-responsive manner. The relative potency measured with the YES (relative to 17β-estradiol) was 2.2 × 10−7 for p-DCB and 1.04 × 10−8 for m-DCB. Following acute toxicity tests with the zebrafish, plasma VTG production was measured to examine the in vivo estrogenic activity of the three compounds after a 14-d exposure. Adult zebrafish were exposed to different concentrations of o-, m- and p-DCB, ranging from 0.1 to 32 mg/L; ethynylestradiol ([EE2]; 5 ng/L, 10 ng/L, 50 ng/L, and 100 ng/L) was used as a positive control. After exposure, blood samples were taken and protein electrophoresis was performed to determine the relative VTG content. Gonadosomatic indices (GSI) and condition factors (CF) were also calculated. Elevated VTG levels and decreased female GSIs were found in fish exposed to ≥5 ng EE2/L and in fish exposed to ≥10 mg p-DCB/L. Low GSIs coincided with high levels of VTG in the blood of female zebrafish. This relation was not only found in fish exposed to EE2 but also in controls and fish exposed to DCB. Therefore, a direct or indirect effect of VTG on the GSI is suggested rather than a direct toxic effect of the tested compounds on the gonads.
Laboratory and field validation of multiple molecular biomarkers of contaminant exposure in rainbow trout (Oncorhynchus mykiss)
Authors: McClain J. Scott , Oris James T. , Burton G. Allen , Lattier David
Published: March 2010

Novel primers for three different genes (CYP1A1, vitellogenin, and metallothionein) for use in reverse transcriptionpolymerase chain reaction (RT-PCR) were developed and tested in laboratory flow-through experiments using model compounds benzo[a]pyrene, estradiol, and cadmium. Field validations of the molecular biomarkers were performed using 8-d or 48-h in situ, caged exposure of juvenile rainbow trout (Oncorhynchus mykiss). Expression levels of gene transcription (messenger RNA [mRNA]) were monitored in gill and liver tissue after exposure at sites downstream of a known source of creosote contamination in the Little Scioto River (Marion, OH, USA) and metals and hydrocarbon contamination in Dick's Creek (Middletown, OH, USA). Significant increases of liver cytochrome P4501A1 gene (CYP1A1) and vitellogenin were measured in both streams at sites downstream of contaminant sources. Significant increases of gill CYP1A1 were also observed. Significant increases of gill and liver metallothionein occurred in Dick's Creek. A sample of gill tissue taken from each fish prior to placement in the Little Scioto River provided a preexposure control measurement for each individual. Expression of CYP1A1 and vitellogenin in trout at both streams indicated that exposure to bioavailable hydrocarbons and endocrine-disrupting compounds had taken place. Previous to this study, estrogenic compounds had not been detected in the Little Scioto River. Metallothionein expression confirmed the presence of metals in Dick's Creek. These results suggest a mixed contaminant environment that poses physiological hazard to existing teleost populations. Multiple molecular biomarkers provided a sensitive, physiologically based method of determining contaminant presence and bioavailability to aquatic organisms.
Associations between regional differences in polychlorinated biphenyls and dichlorodiphenyldichloroethylene in blood of nestling bald eagles and reproductive productivity
Authors: Bowerman William W. , Best David A. , Giesy John P. , Shieldcastle Mark C. , Meyer Michael W. , Postupalsky Sergej , Sikarskie James G.
Published: March 2010

The relationship between regional reproduction rates of bald eagles (Haliaeetus leucocephalus) and concentrations of p,p′-dichlorodiphenyldichloroethylene (p,p′-DDE) and total polychlorinated biphenyls (PCBs) in blood plasma from nestling bald eagles was assessed. Blood was analyzed from 309 nestlings from 10 subpopulations of eagles across the Great Lakes region. Geometric mean concentrations of p,p′-DDE and total PCBs were inversely correlated to the productivity and success rates of nesting bald eagles within nine subpopulations. Nestlings eight weeks of age and older had significantly greater geometric mean concentrations of total PCBs and p,p′-DDE than nestlings less than eight weeks of age. The ability to use measurements of p,p′-DDE and total PCBs in nestling blood to determine the potential impact of these contaminants on adult nesting on a regional scale was demonstrated.
Environmental polychlorinated biphenyl exposure and cytochromes P450 in raccoons (Procyon lotor)
Authors: Smith Philip N. , Bandiera Stelvio M. , Skipper Sherry L. , Johnson Kevin A. , McMurry Scott T.
Published: March 2010

An investigation involving raccoons as a sentinel species at the Paducah Gaseous Diffusion Plant (PGDP) and Ballard Wildlife Management Area in western Kentucky (USA) delineated the extent of exposure to polychlorinated biphenyls (PCBs). Three separate measures of hepatic cytochrome P450 (CYP) induction were used to evaluate raccoon physiological responses to PCB exposure. Hepatic CYP induction was estimated via determination of total CYP, dealkylase activities, and immunoreactive proteins. There were no differences in raccoon biomarker responses between study sites. Significant relationships between and among PCB residues and biomarkers indicated that hepatic CYP induction had occurred in response to PCB exposure. Pentoxy-resorufin O-deethylase (PROD) activity, CYP1A1, and CYP1A2 were biomarkers most closely associated with PCB exposure. The rank order of responses was CYP1A1 > CYP1A2 > PROD > ethoxyresorufin O-deethylase (EROD) as related to raccoon liver PCB concentrations, whereas the order was CYP1A1 > PROD > EROD > CYP1A2 when regressed with total PCB concentrations in abdominal fat.
Toxicokinetics of sediment-sorbed benzo[a]pyrene and hexachlorobiphenyl using the freshwater invertebratesHyalella azteca, Chironomus tentans, andLumbriculus variegatus
Authors: Schuler Lance J. , Wheeler Matthew , Bailer A. John , Lydy Michael J.
Published: March 2010

This study investigated the effect of long-term sediment aging on the toxicokinetics of benzo[a]pyrene (BaP) and hexachlorobiphenyl (HCBP) using three freshwater benthic invertebrates. Hyalella azteca, Chironomus tentans, and Lumbriculus variegatus were exposed to BaP- and HCBP-spiked sediments that were aged for 7 d or 1.5 years. The toxicokinetics of the two compounds were determined for each test organism using a two-compartment model. The modeling of BaP was more complex because biotransformation was included within the model. The results of this study showed that the HCBP uptake clearance rates (ks) for each species were generally an order of magnitude greater than those determined for BaP and this difference was most likely due to preferential and rapid binding of BaP to sediment particles. Overall, the bioavailability of HCBP in spiked sediments tended to decrease with duration of aging, based on ks values and bioaccumulation factors (BAFs). However, the decreases in bioavailability appear to be species specific. Benzo[a]pyrene did not decline in bioavailability for the species tested because it may resist movement into the micropores of the sediment due to its large size. In addition to the bioassays, this article outlines a method for toxicokinetic modeling of biotransformed compounds and methods for statistical comparisons of kinetic parameters (i.e., ks, kd …) and BAF values.
Contamination of fish in streams of the Mid-Atlantic Region: An approach to regional indicator selection and wildlife assessment
Authors: Lazorchak James M. , McCormick Frank H. , Henry Tala R. , Herlihy Alan T.
Published: March 2010

The extent of contamination of fish in the Mid-Atlantic Region was evaluated as part of the U.S. Environmental Protection Agency's Monitoring and Assessment Program's regional assessment in 1993 through 1994. Fish assemblages from wadeable streams were dominated by small, short-lived fishes (e.g., minnows, darters, and sculpins) that were more widely distributed and abundant than large fishes typically chosen for tissue contaminant studies (e.g., trout, black bass, sunfish, common carp). Chemical concentrations in whole-fish homogenates exceeded detection limits for mercury, DDT, and polychlorinated biphenyls (PCBs) in 75 to 100% of the stream length assessed using small fishes and 84 to 100% of the stream length assessed using large fishes. Wildlife values (WVs) representing a threshold for toxic effect were developed to allow examination of the spatial extent of potential risk to piscivorous wildlife. For mercury, DDT, dieldrin, and chlordane, estimates of the regional extent of streams where fish contaminant concentrations exceeded the WVs were greater when based on small fishes than on large fishes. However, within the distribution of stream lengths assessed using small and large fishes, the percentage of stream kilometers exceeding the WVs were quite similar. Our data demonstrate that the greater abundance and distribution of small, short-lived fishes provide greater estimates of regional extent of contamination for first- through third-order streams and can be used for regional assessments of potential exposure and effects in wildlife.
Developmental toxicity of in ovo exposure to polychlorinated biphenyls: I. Immediate and subsequent effects on first-generation nestling American kestrels (Falco sparverius)
Authors: Fernie Kim , Smits Judit , Bortolotti Gary
Published: March 2010

We determined that in ovo exposure to polychlorinated biphenyls (PCBs) alters growth off first-generation nestlings during and one year after parental exposure. Captive American kestrels (Falco sparverius) laid eggs with environmentally relevant total PCB levels (34.1 μg/g whole-egg wet wt) when fed PCB-spiked (Aroclor® 1248, 1254, and 1260) food (7 mg/kg body wt/d) for 100 d in 1998. In 1999, the same adults laid eggs with estimated total PCBs of 29.0 μg/g. Nonsurviving PCB-exposed chicks were small (mass, bones) in 1998. Survivors showed a strong sex-specific growth response (mass, bones) compared to respective sex controls: Only female hatchlings were larger, and only male nestlings had longer feathers (1998); maximal growth and bone growth rates also differed (males were advanced, faster; females delayed, slower) (1999); and male nestlings fledged earlier and were smaller, while females were larger (1998, 1999). However, regardless of sex, PCB-exposed nestlings generally grew at faster rates in both years. In 1998, greater contaminant burdens and toxic equivalent concentrations in sibling eggs were associated with nestlings being lighter, having longer bones and feathers, and growing at faster rates (mass, bone) for females but slower rates (mass) for males. Both physiological-biochemical and behavioral changes are likely mechanisms. This study supports and expands on the Great Lakes embryo mortality, edema, and deformities syndrome: While PCB exposure alters nestling size, maximal growth and growth rates also change immediately, are sustained, and are sex specific.
The role of ultraviolet-adaptation of a marine diatom in photoenhanced toxicity of acridine
Authors: Wiegman Saskia , Barranguet Christiane , Spijkerman Elly , Kraak Michiel Harm Steven , Admiraal Wim
Published: March 2010

Cultures of the marine diatom Phaeodactylum tricornutum were grown under laboratory light with a different fraction of ultraviolet radiation (UV) to study the potential role of photoadaptation in determining the sensitivity to photoenhanced toxicity of acridine. In short-term experiments, a higher acridine concentration was needed to inhibit the photosynthetic electron flux, monitored with chlorophyll a fluorescence, in algae exposed to fluorescent light (low UV) than to mercury light (high UV), consistent with the expected role of UV. The two types of light in long-term exposures led to changes in the pigment composition and photosystem I (PS I) to photosystem II (PS II) stoichiometry to optimize the utilization of fluorescent and mercury light. Despite the adaptation of the photosynthetic apparatus to a small fraction of UV, long-term exposure to mercury light did show a constant sensitivity of the photosynthetic efficiency of P. tricornutum to the phototoxic acridine. It is concluded that the prime receptor of photoenhanced toxicity may be unrelated to the photosynthetic machinery.
Failure of the biotic ligand and free-ion activity models to explain zinc bioaccumulation by Chlorella kesslerii
Authors: Hassler Christel S. , Wilkinson Kevin J.
Published: March 2010

Zinc accumulation by Chlorella kesslerii (Chlorophycee) was studied for [Zn2+] ranging from 4 pM to 1 mM. A first-order uptake flux as predicted by the free ion activity model (FIAM) and the biotic ligand model (BLM) was not observed. Furthermore, when algae were preconditioned in slightly limiting (10 pM) versus optimal (1 nM) free zinc concentrations, the internalization flux increased and was nearly constant over the range of [Zn2+] examined. This observation was attributed to the synthesis of membrane-bound zinc transporters. Neither solution Zn chemistry nor surface-bound Zn was a good predictor of Zn uptake fluxes. Several hypotheses were examined to explain the failure of the steady-state uptake models. Although zinc excretion and a Zn diffusion limitation were observed, neither result could explain the majority of observed deviation from the models. Bioaccumulation experiments performed with inhibitors (vanadate and carbonyl cyanide m-chlorophenylhydrazone [CCCP]) demonstrated clearly that zinc transport is an energy-dependent process in Chlorella kesslerii. The presence of an active transport signifies that Zn uptake may function independently of the electrochemical Zn gradient and that, in some cases, both uptake fluxes and receptor-bound Zn may be independent of solution chemistry.
Effects of sublethal concentrations of atrazine and nitrate on metamorphosis of the African clawed frog
Authors: Sullivan Karen Brown , Spence Karla M.
Published: March 2010

Tadpoles of the African clawed frog (Xenopus laevis) were exposed to sublethal concentrations of atrazine (0, 40, and 320 μg/L) and nitrate (0, 37, and 292 mg/L) from feeding stage to metamorphosis. A 3 × 3 factorial design was used to identify both single and interactive effects. At metamorphosis, tadpole weight, snout–vent length (SVL), and hematocrit were determined. Mean mortality was greater in tanks receiving 320 μg/L atrazine; nitrate had no effect on mortality. Significant differences for all mean traits at metamorphosis occurred among atrazine treatments; higher atrazine exposure increased time to metamorphosis and decreased weight, SVL, and hematocrit. Nitrate treatments were not significantly different. Significant interaction tests between atrazine and nitrate occurred for weight and SVL at metamorphosis; the specific type of interaction varied among treatments. Assuming an additive mixture model, at low atrazine (40 μg/L), the addition of 37 mg/L nitrate produced SVL values less than expected (a synergistic effect) while the addition of 292 mg/L nitrate yielded SVL values greater than expected (an antagonistic effect). A similar response was noted for tadpoles in the 320-μg/L atrazine treatments. These results indicate that environmentally realistic concentrations of atrazine exert a negative impact on amphibian metamorphosis. Also, this study suggests that mixtures of agricultural chemicals, even if sublethal, may exert negative and not necessarily consistent mixture effects.
Photoenhanced toxicity of aqueous phase and chemically dispersed weathered Alaska North Slope crude oil to Pacific herring eggs and larvae
Authors: Barron Mace G. , Carls Mark G. , Short Jeffrey W. , Rice Stanley D.
Published: March 2010

The photoenhanced toxicity of weathered Alaska North Slope crude oil (ANS) was investigated in the eggs and larvae of Pacific herring (Clupea pallasi) with and without the chemical dispersant Corexit® 9527. Oil alone was acutely toxic to larvae at aqueous concentrations below 50 μg/L total polycyclic aromatic hydrocarbons (tPAH), and median lethal (LC50s) and effective concentrations (EC50s) decreased with time after initial oil exposure. Brief exposure to sunlight (∼2.5 h/d for 2 d) significantly increased toxicity 1.5- to 48-fold over control lighting. Photoenhanced toxicity only occurred when oil was present in larval tissue and increased with increasing tPAH concentration in tissue. Ultraviolet radiation A (UVA) treatments were less potent than natural sunlight, and UVA + sunlight caused greater toxicity than sunlight alone. The toxicity of chemically dispersed oil was similar to oil alone in control and UVA treatments, but oil + dispersant was significantly more toxic in the sunlight treatments. The chemical dispersant appeared to accelerate PAH dissolution into the aqueous phase, resulting in more rapid toxicity. In oil + dispersant exposures, the 96-h no-observed-effect concentrations in the UVA + sunlight treatment were 0.2 μg/L tPAH and 0.01 μg/g tPAH. Exposure of herring eggs to oil caused yolk sac edema, but eggs were not exposed to sun and UVA treatment did not cause phototoxicity. These results are consistent with the hypothesis that weathered ANS is phototoxic and that UV can be a significant and causative factor in the mortality of early life stages of herring exposed to oil and chemically dispersed oil.
Dynamics of organochlorine pesticides in soils from a southeastern region of Argentina
Authors: Miglioranza Karina S. B. , Aizpún de Moreno Julia E. , Moreno Víctor J.
Published: March 2010

Monitoring of organochlorine pesticides (OCPs) was carried out to identify andquantify the contribution of point and nonpoint sources to the total OCP flux in a southeastern region of Argentina. Natural, recreational, and agricultural soils located in the surrounding of a lagoon were analyzed by gas chromatography with electron-capture detector. Physical and chemical characteristics (texture, humidity, and organic matter content) were determined at different depths (0–15 cm, 15–30 cm, and 45–55 cm). The pattern of OCP distribution was similar in all soil sampled, with DDT and metabolites > hexachlorocyclohexanes (HCHs) > heptachlor > chlordanes. The highest values of OCPs (656.1 ng/g dry wt) were found in the surface natural soil despite its never having received direct OCP application. This would be mainly due to the high organic matter content of the surface natural soils as well as its topographic position (highland hills), with main winds arriving from agricultural areas. Microorganism abundance and edaphic biota in the upper layer would justify the high levels of metabolites found. The agricultural soil (intensive tillage) also showed the highest OCP values (30.19 ng/g dry wt) in the surface horizon. Because of management practices, volatilization could have been one of the major causes of pesticide loss from this target area. Recreational soil showed the lowest OCP levels in the surface layer because of weathering that occurs when the nearby lagoon floods this zone. Our results show that, although most of these pesticides are banned, they are present in these soils and the atmospheric transport and deposition would be the major processes for distributing OCPs from target to natural areas.
Degradation of nonylphenol in spiked soils and in soils treated with organic waste products
Authors: Mortensen Gerda Krog , Kure Liv Kerstin
Published: March 2010

Widespread application of sewage sludge to agricultural soils in Denmark has led to concern about the accumulation and effects of nonylphenol (NP) in the soil ecosystem. We have thus studied the degradation of NP and possible uptake in agricultural plants in greenhouse pot experiments. Different waste products including anaerobic and aerobic sludge, compost, and pig manure were incorporated into a sandy soil. In addition, NP was used to spike soil to known concentrations. Rape (Brassica napus L. cv Hyola 401) was sown in the pots and harvested after 30 d. In order to investigate the influence of plant growth on the degradation, plant-free pots were established. The concentrations in the soil were between 13 and 534 ppb dry weight. No plant uptake was observed above the detection limit at 100 ppb dry weight. When NP was added as waste to the soil, plant growth significantly stimulated the degradation. In experiments with anaerobic and aerobic sludge, respectively, 13 and 8.3% of NP remained in the soil from pots planted with rape compared with 26 and 18% in soil without plant growth. When NP was added as a spike to soil, the degradation was more complete and plant growth did not influence the degradation. Percentages of 2.2 and 1.8 were still in the soil at harvest for planted and plant-free pots, respectively. The degradation of NP was more extensive in sludge-amended soil compared with compost.
Heterogeneous photochemical reactions of decabromodiphenyl ether
Authors: Hua Inez , Kang Namgoo , Jafvert Chad T. , Fábrega-Duque José R.
Published: March 2010

Brominated diphenyl ethers area major class of brominated flame retardants, with production of decabromodiphenyl ether (DBDPE) contributing significantly to this total. Although little is known about the mechanisms and rates of DBDPE decay in the natural environment, photochemical transformation is often suggested as a potentially important fate process. In this study, photochemical reactions of DBDPE precipitated onto hydrated surfaces (quartz glass, silica particles, and humic acid-coated silica particles) were measured. Decabromodiphenyl ether was irradiated within a Rayonet photochemical reactor equipped with lamps having maximum emissions (Λmax) at 300 or 350 nm or with sunlight (West Lafayette, IN, USA at 40°26′N, 86°55′W). When DBDPE is plated onto quartz tubes and hydrated with reagent-grade water, phototransformation occurred over a period of days with each light source. With two lamps (Λmax = 300 nm), about 31% of the initial mass of DBDPE remained after 60 h in the Rayonet reactor. Decabromodiphenyl ether transformed more slowly when irradiated by sunlight, with 30% of the initial compound recovered from tubes after 72 h. In the presence of humic acid (HA) solution, transformation of DBDPE by solar irradiation is slowed even further: approximately 70% remained after 72 h. Solar irradiation of DBDPE adsorbed to humic acid-coated sand particles resulted in the slowest irradiation rates; approximately 88% of the initial mass was recovered after 96 h of exposure. Although the parent compound exhibited slow transformation, analysis by high-performance liquid chromatography (HPLC) indicated some accumulation of transformation products.
Histopathology as a tool for the evaluation of endocrine disruption in zebrafish (Danio rerio)
Authors: van der Ven Leo T. M. , Wester Piet W. , Vos Jeff G.
Published: March 2010

The importance of histology as a tool in the evaluation of endocrine disruption in fish depends on the choice and interpretation of appropriate endpoints, as is illustrated by the analysis of the effects of exposure to the estrogen 17β-estradiol (E2) and the nonaromatizable androgen 17-methyldihydrotestosterone (MDHT). The E2 led to the disappearance of vitellogenic oocytes in the ovary and an increased area of relatively large, eosinophilic cells in the testis, which were identified as spermatogonia under high-power magnification; this was a relative increase, as was shown by histomorphometry, because of a decreased size of spermatogenic cysts and a relative decrease of spermatocyte cysts. The E2 also induced an accumulation of acidophilic fluid in vessels and interstitial spaces, confirmed by immunohistochemistry as vitellogenin, and basophilia in the liver also associated with the production of vitellogenin. The MDHT induced activation of Sertoli cells in the testis and a decreased presence of vitellogenic oocytes and a reduced growth of previtellogenic oocytes in the ovary. These observations indicate the advantages of examining multiple organ systems on whole-body sections and the application of adequate magnifications. Inclusion of additional techniques such as morphometry and immunohistochemistry is valuable to further uncover insidious effects of endocrine disruptors.
Pesticide risk assessment in a lagoon ecosystem. Part II: Effect assessment and risk characterization
Authors: Villa Sara , Vighi Marco , Casini Silvia , Focardi Silvano
Published: March 2010

Ecotoxicological risk assessment for pesticides was performed on a coastal lagoon ecosystem (Orbetello lagoon, central Italy) according to the procedure described in the European technical guidance document (TGD) on risk assessment for new and existing substances. The procedure was applied to individual chemicals and to a mixture of chemicals with the same toxicological mode of action. Biomarker studies, measuring acetylcholinesterase (AchE) activity inhibition, were conducted on Zosterisessor ophiocephalus to compare the results of theoretical risk assessment with experimental measurements of ecotoxicological stress. Value and limitations of the risk assessment procedure and its application to site-specific environmental conditions are discussed. A tool crop risk index (CRI) for assessing the overall impact of pesticide use on a crop is proposed.
Ecotoxicology and spatial modeling in population dynamics: An illustration with brown trout
Authors: Chaumot Arnaud , Charles Sandrine , Flammarion Patrick , Auger Pierre
Published: March 2010

We developed a multiregion matrix population model to explore how the demography of a hypothetical brown trout population living in a river network varies in response to different spatial scenarios of cadmium contamination. Age structure, spatial distribution, and demographic and migration processes are taken into account in the model. Chronic or acute cadmium concentrations affect the demographic parameters at the scale of the river range. The outputs of the model constitute population-level end points (the asymptotic population growth rate, the stable age structure, and the asymptotic spatial distribution) that allow comparing the different spatial scenarios of contamination regarding the demographic response at the scale of the whole river network. An analysis of the sensitivity of these end points to lower order parameters enables us to link the local effects of cadmium to the global demographic behavior of the brown trout population. Such a link is of broad interest in the point of view of ecotoxicological management.
Bioconcentration and acute toxicity of polycyclic musks in two benthic organisms (Chironomus ripariusandLumbriculus variegatus)
Authors: Artola-Garicano Elsa , Sinnige Theo L. , van Holsteijn Ineke , Vaes Wouter H. J. , Hermens Joop L. M.
Published: March 2010

In the current study, the bioconcentration behavior and acute toxicity of two polycyclic musks, Tonalide® 7-acetyl-1,1,3,4,4,6,-hexamethyl-1,2,3,4,-tetrahydronaphthalene (AHTN) and Galaxolide® 1,3,4,6,7,8-hexahydro-4,6,6,7,8,8-hexa-methyl-cyclopenta[γ]-2-benzopyran (HHCB), were studied in two benthic organisms. Polycyclic musks are frequently used fragrances, and they have been detected in different compartments of the environment. The aim of this study was to fill some empirical data gaps for AHTN and HHCB for benthic organisms. Results show that differences exist between both organisms. Chironomus riparius exhibited bioconcentration factors (BCFs) for AHTN and HHCB substantially lower than predicted for nontransformed organics. The BCFs for both chemicals increased after coexposure of the organism to the cytochrome P450 inhibitor piperonyl butoxide. Thus, the low BCF values were the result of rapid biotransformation of AHTN and HHCB in the midge larvae. Bioconcentration kinetics indicated that both chemicals induced their own cytochrome P450–mediated metabolism. Acute toxicity of AHTN to midge larvae was reduced compared to predicted baseline toxicity and was similar for HHCB. Bioconcentration of AHTN and HHCB in the worm (Lumbriculus variegatus) is in agreement with predictions based on the octanol-water partition coefficients of these chemicals. Acute toxicity was found to be similar to predicted values for baseline toxicity. Summarizing, for AHTN and HHCB, acute toxicity and bioconcentration behavior in L. variegatus was in accordance with predicted data for nontransformed organics. In C. riparius, bioconcentration as well as toxicity were reduced.
Breeding performance of great tits (Parus major) along a gradient of heavy metal pollution
Authors: Sens Ellen Jans , Dauwe Tom , Pinxten Rianne , Eens Marcel
Published: March 2010

The possible effects of heavy metal pollution on various breeding parameters of the great tit (Parus major) were studied at four study sites in a pollution gradient near a large nonferrous smelter in Belgium during three consecutive breeding seasons. Significantly more females interrupted their laying period near the pollution source than did females farther away. At the two most polluted sites, hatching success was significantly reduced compared to two lesser-polluted study sites. Overall breeding success was also significantly lower toward the factory complex. This lowered breeding success was caused not only by the decreased hatching success toward the pollution source but also by the significant difference in fledging success among sites. Although a clear relationship was observed between the exposure to heavy metal pollution and an impaired reproduction, not all reproductive parameters were affected. We found no significant differences in the onset of laying, clutch size, length of the incubation period, and the proportion of nests with low-quality eggs among sites. Although nest box occupancy was every year slightly lower toward the smelter compared to farther away, differences among study sites were never significant.
Influence of aging on copper bioavailability in soils
Authors: Lock Koen , Janssen Colin R.
Published: March 2010

Because of long-term chemical processes, metal bioavailability in field soils decreases with time. Metal toxicity may, therefore, be overestimated if toxicity data with freshly spiked soils are used to derive soil quality criteria, a current practice. In the present study, effects of the long-term processes, called aging, on copper partitioning and ecotoxicity are investigated. Twenty-five field soils contaminated by copper runoff from bronze statues and 25 uncontaminated control soils sampled at 5-m distance from these statues were collected in Flanders (Belgium). The soils were selected so that parameters affecting copper bioavailability (pH, cation-exchange capacity, organic matter content, etc.) varied considerably. To assess the effect of aging on copper toxicity, control soils were spiked at total copper concentrations comparable to those of historically contaminated soils. Pore-water copper concentrations and 0.01 M CaCl2–extracted copper concentrations were significantly higher in freshly spiked soils compared to contaminated field soils. However, this could be a pH effect, because pH decreased after spiking. Acute toxicity to Enchytraeus albidus (14 d) as well as chronic toxicity to Folsomia candida (28-d reproduction) and Trifolium pratense (14-d growth) indicated a dose-response relationship between copper toxicity and pore-water copper concentration or the CaCl2-extracted copper fraction.
A thermodynamics-based estimation model for adsorption of organic compounds by carbonaceous materials in environmental sorbents
Authors: van Noort Paul C. M.
Published: March 2010

A model was developed to estimate Langmuir affinities for adsorption of low-polarity organic compounds from either water or air by carbonaceous sorbents. Sorption enthalpies and entropies provided the basic information for the description of sorption affinities in terms of the entropy of melting and either solubility in water or vapor pressure. For m-xylene, polycyclic aromatic hydrocarbons (PAHs) and chlorobenzenes on 10 different sorbents, 80% of the measured sorption affinities fall within a factor of four of the model estimates. Equations for the limiting distribution coefficients in terms of either octanol—air (KOA) or octanol—water partition (Kow) coefficients were derived from regressions of calculated affinities combined with an estimated relation between experimental Langmuir sorption capacities and Kow. Estimated soot—water distribution coefficients were within a factor of three of measured data for polychlorobiphenyls (PCBs) and lower molecular weight PAHs on automotive soot samples and captured the dependence of PCB distribution coefficients on the extent of ortho substitution. For higher molecular weight PAHs, sorption was underestimated. For soot in sediment—water distribution coefficients of PAHs and PCBs, estimated values captured both the trend of measured data with Kow and the dependence on sorbate planarity. Tentative application to aerosol—air distribution explained the observed independence of distribution coefficient–KOA relations for PCBs on the extent of ortho substitution and suggested nonequilibrium conditions for PAHs in comparison with recent measurements.
Reductive dechlorination of polychlorinated biphenyls in sediment from the Twelve Mile Creek arm of Lake Hartwell, South Carolina, USA
Authors: Pakdeesusuk Usarat , Freedman David L. , Lee Cindy M. , Coates John T.
Published: March 2010

Lake Hartwell is a U.S. Army Corps of Engineers reservoir system located on the state line between South Carolina and Georgia, USA. The lake was contaminated with an estimated 200 metric tons of polychlorinated biphenyls ([PCBs]; mainly Aroclor 1016 and 1254), and the entire Twelve Mile Creek watershed and the Seneca River arm of Lake Hartwell were placed on the National Priorities List. Monitored natural attenuation was chosen as a remedy for the contaminated sediment. The relatively warm temperature of Lake Hartwell and lack of significant cocontaminants along with the PCBs distinguish this site from others that have been studied for microbially mediated reductive dechlorination. Microcosm studies were conducted with sediment from two locations in the Twelve Mile Creek arm and confirmed the presence of indigenous microorganisms capable of reductively dechlorinating Aroclor 1254, which contains predominantly tetra-, penta-, and hexachlorobiphenyl. The average number of total chlorines per biphenyl decreased from 4.8 to 4.9 to 2.9 to 3.0, following 250 to 260 d of incubation. The maximum observed dechlorination rates were 0.29 to 0.87 μg-atoms Cl− per gram sediment dry weight per week. The onset of dechlorination activity correlated strongly with maximum methanogenesis, which occurred without a lag in samples from the site that showed signs of in situ fermentation activity. Dechlorination occurred primarily at the meta and para positions (58–63% removal), with no apparent decrease in ortho chlorines. This most closely resembles pattern M, characterized by preferential removal of unflanked and flanked meta chlorines. The microcosm results are consistent with sediment cores analyzed from the same locations, which indicate accumulation with depth of the same ortho- and para-substituted congeners. It therefore appears that the success of monitored natural attenuation for Lake Hartwell will hinge on covering the recalcitrant PCBs with a sufficient amount of uncontaminated sediment to isolate them from the food chain.
Biodegradation of plasticizers by Rhodotorula rubra
Authors: Gartshore James , Cooper David G. , Nicell Jim A.
Published: March 2010

The degradation of plasticizers by the yeast Rhodotorula rubra J-96-1 (American Type Culture Collection 9449) in the presence of glucose was studied. The plasticizers included the commonly used bis-2-ethylhexyl adipate (B(EH)A), dioctyl phthalate (DOP), and dioctyl terephthalate (DOTP), and the less commonly used dipropylene glycol dibenzoate (D(PG)DB) and diethylene glycol dibenzoate (D(EG)DB). The proposal had been made that the latter two plasticizers be used as alternatives to the first three, which have been associated with negative environmental impacts. The degradation of D(PG)DB or D(EG)DB led to a significant increase in solution toxicity, which was associated with the production of metabolites resulting from the incomplete breakdown of the plasticizers. The toxic metabolites in the D(PG)DB system were identified as isomers of dipropylene glycol monobenzoate. A pathway for the formation of this metabolite was proposed. The metabolite observed when D(EG)DB was being degraded was tentatively identified as diethylene glycol monobenzoate by analogy to the D(PG)DB system. In contrast, no metabolites were observable and toxicity did not increase in the media during the degradation of B(EH)A, DOP, or DOTP by R. rubra. Collectively, these results do not support the use of D(PG)DB and D(EG)DB as environmentally safe alternatives to B(EH)A, DOP, or DOTP.
Assessing the long-range transport potential of polybrominated diphenyl ethers: A comparison of four multimedia models
Authors: Wania Frank , Dugani Chandrasagar B.
Published: March 2010

Data from a comprehensive literature search of environmentally relevant physical-chemical properties for nine poly-brominated diphenyl ethers (PBDE), ranging from a monobrominated congener to the fully brominated decabromodiphenyl ether, were evaluated and adjusted to achieve both internal and interhomologue consistency. These data were then used in four model-based long-range transport potential (LRTP) assessment methods. The models TaPL3-2.10, ELPOS-1.1.1, Chemrange-2, and Globo-POP-1.1 were found to yield comparable predictions. A comparison of the LRTP estimates for the PBDEs with those of benchmark chemicals (polychlorinated biphenyls [PCBs]) suggest that the lower-brominated congeners have a LRTP comparable to that of PCBs known to be subject to significant LRT, whereas the highly brominated congeners have a very low potential to reach remote areas. This is in agreement with field measurements in remote regions that indicate that the lighter components of commercially produced PBDE mixtures predominate. Deviations between Chemrange and the models based on the concept of a characteristic travel distance were due to differences in the assumed height of the air compartment, which influences the relative importance of atmospheric degradation and deposition processes. The three models assuming a uniform temperature of 25°C may underestimate the LRTP of the smaller congeners. Only atmospheric parameters had a notable influence on the LRTP estimates by TaPL3, ELPOS, and Chemrange, whereas the relative enrichment of chemicals in the Arctic calculated by Globo-POP is additionally sensitive to the parameters related to the interaction of temperature with air—surface exchange and degradation in surface compartments.
Effect of dissolved organic matter of various origins and biodegradabilities on the bioaccumulation of polycyclic aromatic hydrocarbons inDaphnia magna
Authors: Gourlay Catherine , Tusseau-Vuillemin Marie-Hélène , Garric Jeanne , Mouchel Jean-Marie
Published: March 2010

As a preliminary study of the influence of urban organic matter on the bioavailability of polycyclic aromatic hydrocarbons (PAHs), the effect of different types of dissolved organic matter (DOM) on the bioaccumulation of fluoranthene, pyrene, or benzo[a]pyrene in Daphnia magna was studied. Commercial humic substances, DOM from the aeration basin of a wastewater treatment plant, and highly biodegradable DOM (algae or animal extracts) were tested. The bioaccumulation of benzo[a]pyrene was reduced by each DOM (up to 80% reduction with humic substances). Pyrene bioaccumulation was also decreased by each DOM to a lesser extent. Fluoranthene bioaccumulation was affected by the presence of humic acids only. In each experiment, the solution containing humic DOM led to the lowest bioaccumulation. Supposing that only dissolved PAHs were bioavailable, the reduction of bioaccumulation allowed a biological estimate of the partition coefficients of DOM and PAH, KDOC. The estimated coefficients were positively related to the aromaticity of DOM and negatively related to its biodegradability.