bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effects and risk assessment of linear alkylbenzene sulfonates in agricultural soil. 5. Probabilistic risk assessment of linear alkylbenzene sulfonates in sludge-amended soils
Authors: Jensen John , Løkke Hans , Holmstrup Martin , Krogh Paul Henning , Elsgaard Lars 
Published: March 2010

Abstract
Linear alkylbenzene sulfonates (LAS) can be found in high concentrations in sewage sludge and, hence, may enter the soil compartment as a result of sludge application. Here, LAS may pose a risk for soil-dwelling organisms. In the present probabilistic risk assessment, statistical extrapolation has been used to assess the risk of LAS to soil ecosystems. By use of a log-normal distribution model, the predicted no-effect concentration (PNEC) was estimated for soil fauna, plants, and a combination of these. Due to the heterogeneous endpoints for microorganisms, including functional as well as structural parameters, the use of sensitivity distributions is not considered to be applicable to this group of organisms, and a direct, expert evaluation of toxicity data was used instead. The soil concentration after sludge application was predicted for a number of scenarios and used as the predicted environmental concentration (PEC) in the risk characterization and calculation of risk quotients (RQ = PEC/PNEC). A LAS concentration of 4.6 mg/kg was used as the current best estimate of PNEC in all RQ calculations. Three levels of LAS contamination (530, 2,600, and 16,100 mg/kg), three half-lives (10, 25, and 40 d), and five different sludge loads (2, 4, 6, 8, and 10 t/ha) were included in the risk scenarios. In Denmark, the initial risk ratio would reach 1.5 in a realistic worst-case consideration. For countries not having similar sludge regulations, the estimated risk ratio may initially be considerably higher. However, even in the most extreme scenarios, the level of LAS is expected to be well beyond the estimated PNEC one year after application. The present risk assessment, therefore, concludes that LAS does not pose a significant risk to fauna, plants, and essential functions of agricultural soils as a result of normal sewage sludge amendment. However, risks have been identified in worst-case scenarios.
Resource allocation-based life histories: A conceptual basis for studies of ecological toxicology
Authors: Congdon Justin D , Dunham Arthur E , Hopkins William A , Rowe Christopher L , Hinton Thomas G 
Published: March 2010

Abstract
Whereas ecological assessments of contaminants are concerned with populations and higher levels of organization, most mechanistic work in toxicology is directed at effects on individuals and their parts. We propose that studies based on individuals can be useful in ecological analysis of polluted systems when based on the concepts of resource allocation-based life history analysis. At the heart of the resource allocation approach is the concept of operative environments of individuals (i.e., environmental factors influencing birth, death, or migration). Contaminants can have strong influences on operative environments, modifying resource allocation strategies that reflect changes in energy assimilation and demands. By examining contaminant-induced responses of individuals from the perspective of changing operative environments, individual-based changes and population dynamics can be addressed in an ecologically rigorous manner.
The use of carbamates, atropine, and 2-pyridine aldoxime methoiodide in the protection of Artemia salina against poisoning by carbophenothion
Authors: Sánchez-Fortún Sebastián , Barahona Victoria 
Published: March 2010

Abstract
The acute toxicity of carbophenothion to three age classes of Artemia salina was evaluated. An increase in toxicity of carbophenothion was found following longer development of A. salina. The effect of pretreatment with the nonselective muscarinic antagonist atropine, the two reversible acetylcholinesterase-inhibitors physostigmine and pyridostigmine, and the cholinesterase-reactivating oxime 2-pyridine aldoxime methochloride (2-PAM) on carbophenothion-induced lethality in 24-h-old A. salina was also investigated. The lethal action of carbophenothion was completely prevented by pretreatment of A. salina with 2-PAM. Atropine and pyridostigmine afforded a maximal protection of approximately 87% and 72%, respectively, compared to control values. In contrast, physostigmine was ineffective. The inhibitory effects of combinations of 10∼5 M atropine with physostigmine, pyridostigmine, or 2-PAM were greater than those elicited by either drug alone, with the maximum protection afforded being 92.58%, 100%, and 100%, respectively. In the presence of 10−7 M atropine, neither pyridostigmine nor 2-PAM provided additional inhibition of the lethality compared to that with either drug alone, whereas the protection afforded by 10∼7 M atropine plus physostigmine increased as the concentration of carbamate increased (up to 10−3 M). Pretreatment with pyridostigmine or physostigmine plus 2-PAM (10−6 M) slightly enhanced the maximal inhibition of carbophenothion lethality compared to that with either drug alone. It is suggested that the most active combined pretreatment studied here was physostigmine plus atropine.
Pollution-induced community tolerance and functional redundancy in a decomposer food web in metal-stressed soil
Authors: Salminen Janne , van Gestel Cornelis A.M. , Oksanen Jari 
Published: March 2010

AbstractPollution may lead to the development of pollution-induced community tolerance (PICT) in a stressed community. We studied the presence of PICT in soil food webs using soil microcosms. Soil microcosms containing soil invertebrates and microbes were collected from polluted and unpolluted areas and exposed to a range of soil zinc concentrations. A pine seedling was planted in each microcosm to measure the effects of the origin of the community and Zn pollution on above-ground plant production. The effects of the treatments on nutrient content in the soil were also measured. The diversity of soil microarthropods and the soil's mineral nutrient content were low at the Zn-polluted site. We did not observe an increasing Zn tolerance among the soil organisms in the polluted soil. However, low population growth rates of soil invertebrates from the polluted site may indicate the deleterious effects on fitness of long-lasting pollution. In the soil from the nonpolluted site, Zn additions caused changes in the invertebrate food web structure. These changes were explained by the good physiological condition of the animals and their insensitivity to Zn. The fact that the food web structure in soil from the polluted site did not change can be used as a rough indicator of PICT. Structural stability is presumed by the lack of Zn-sensitive species at this site and the inability of populations to acclimate by altering their growth or reproduction patterns in response to changing soil conditions. Although microbial-based soil decomposer systems may have a high functional redundancy, our results indicate that metal stress at the polluted site exceeds the tolerance limits of the system. As a consequence, ecosystem function at this site is endangered. This study also shows that the evolution of metal tolerance by soil decomposer organisms may not be a common reaction to soil pollution, although changes of population and community structure indicated severe metal stress on organisms.
Life-cycle toxicity of 4-nonylphenol to medaka (Oryzias latipes)
Authors: Yokota Hirofumi , Seki Masanori , Maeda Masanobu , Oshima Yuji , Tadokoro Hiroshi , Honjo Tsuneo , Kobayashi Kunio 
Published: March 2010

Abstract
We studied the chronic effects of 4-nonylphenol (4-NP) on reproductive status of medaka (Oryzias latipes) over two generations of continuous exposure. The exposure study of the parental (F0) medaka was begun on embryos within 24 h postfertilization and continued with monitoring through embryological development, hatching, posthatch survival, growth, sexual differentiation, and reproduction under flow-through exposures to mean measured 4-NP concentrations of 4.2, 8.2, 17.7, 51.5, and 183 μg/L for up to 104 d. Eggs spawned from the F0 fish at 102 and 103 d posthatch were also examined for hatchability, survival after hatching, growth, and sexual differentiation until 60 d posthatch. The 183-μg/L treatment significantly reduced the embryo survival and swim-up success of the F0 fish. The cumulative mortality after swim-up of the F0 fish exposed to 17.7 and 51.5 μg/L were significantly higher than the control mortality. No concentration-related effect of 4-NP was observed on the growth of surviving F0 fish at 60 d posthatch. However, the sex ratio estimated from the appearance of their secondary sex characteristics was skewed toward female in the 51.5μg/L treatment. Additionally, gonadal histology showed that 20% of the fish in the 17.7-μg/L treatment and 40% in the 51.5-μg/L treatment had testis–ova, indicating that 4-NP affects the gonadal development and survival of medaka at similar concentrations in juveniles. The sex ratio of the F0 fish in the 51.5-μg/L treatment was completely skewed toward female; subsequently, the effects on fecundity and fertility in this generation were monitored at mean measured concentrations of 4.2, 8.2, and 17.7 μg/L from 71 to 103 d posthatch. Fecundity was unaffected by any of the treatments examined. The mean fertility in the 17.7-μg/L treatment was reduced to 76% of that in the controls, although no statistically significant differences were determined. Overall, these results indicate that the lowest-observed-effect concentration (LOEC) and no-observed-effect concentration (NOEC) of 4-NP through the life cycle of the F0 medaka were 17.7 and 8.2 μg/L, respectively. In the F1 medaka, no significant effects were observed on hatching success, posthatch mortality, or growth, but sexual differentiation at 60 d posthatch was affected. Induction of testis–ova in the gonads of the F1 fish was observed in both the 8.2- and the 17.7-μg/L concentrations. The results indicate that 4-NP can have significant effects on reproductive potential of medaka at concentrations as low as 17.7 μg/L.
Toxicity of linear alkylbenzene sulfonates and nonylphenol in sludge-amended soil
Authors: Gejlsbjerg Bo , Klinge Charlotte , Samsøe-Petersen Lise , Madsen Torben 
Published: March 2010

Abstract
The application of sewage sludge to agricultural land brings several chemicals to the soil ecosystem. Linear alkylbenzene sulfonates (LAS) and nonylphenol (NP) are frequently found in sludge at relatively high concentrations. The toxic effects of LAS and NP to two soil invertebrates (Folsomia candida and Enchytraeus albidus) and five different microbial processes (aerobic respiration, nitrification, denitrification, anaerobic CH4 production, and anaerobic CO2 production) were investigated in sludge–soil mixtures. Median lethal concentrations (LC50 values) and median effective concentrations (EC50 values) were quite similar and calculated to be in the range of 1,143 to 1,437 and 71 to 437 mg/kg (dry wt) for LAS and NP, respectively. The EC50 values for nitrification and CH4 production were 431 and 277 mg/kg, respectively, for LAS and 343 and 754 mg/kg, respectively, for NP. Aerobic respiration and denitrification were not inhibited at the tested concentrations. The results show that NP was more toxic than LAS to both F. candida and E. albidus, whereas LAS was more toxic than NP to the anaerobic CH4 production. The safety margins between the lowest 10% effective concentration (EC10) and the estimated environmental concentration were a factor of 11 for LAS and 510 for NP when the concentrations of the contaminants corresponded to the current Danish cutoff values of 1,300 mg/kg for LAS and 30 mg/kg for NP.
Contaminant sensitivity of threatened and endangered fishes compared to standard surrogate species
Authors: Sappington Linda C , Mayer Foster L , Dwyer F. James , Buckler Denny R , Jones John R , Ellersieck Mark R 
Published: March 2010

AbstractStandard environmental assessment procedures aredesigned to protectterrestrial and aquaticspecies. However, it is not known if endangered species are adequately protected by these procedures. At present, toxicological data obtained from studies with surrogate test fishes are assumed to be applicable to endangered fish species, but this assumption has not been validated. Static acute toxicity tests were used to compare the sensitivity of rainbow trout, fathead minnows, and sheepshead minnows to several federally listed fishes (Apache trout, Lahontan cutthroat trout, greenback cutthroat trout, bonytail chub, Colorado pikeminnow, razorback sucker, Leon Springs pupfish, and desert pupfish). Chemicals tested included carbaryl, copper, 4-nonylphenol, pentachlorophenol, and permethrin. Results indicated that the surrogates and listed species were of similar sensitivity. In two cases, a listed species had a 96-h LC50 (lethal concentration to 50% of the population) that was less than one half of its corresponding surrogate. In all other cases, differences between listed and surrogate species were less than twofold. A safety factor of two would provide a conservative estimate for listed cold-water, warm-water, and euryhaline fish species.
Joint acute toxicity of diazinon and ammonia to Ceriodaphnia dubia
Authors: Bailey Howard C , Elphick James R , Krassoi Rick , Lovell Adam 
Published: March 2010

Abstract
Dazinon is an organophosphorous pesticide widely found in municipal effluents as well as in agricultural and urban storm-water discharges. Ammonia is frequently also present in such effluents as a consequence of bacterial degradation of organic material. Because these two contaminants may occur concurrently, their relationship with respect to joint toxicity is of interest, particularly in regard to interpreting the results of effluent tests and subsequent toxicity identification evaluations (TIEs). In this particular case, we obtained an effluent sample that exhibited toxicity to Ceriodaphnia dubia. Toxicity identification evaluations manipulations suggested that ammonia (40 mg/L as total NH3) and diazinon (0.75 μg/L) both contributed to toxicity. As part of the Phase 3 confirmation studies, an independent investigation was conducted to evaluate the interactions between these two toxicants using static tests that incorporated a 48-h exposure period. Chemical concentrations were verified analytically. Mortalities were measured at 24-h intervals and joint toxicity calculated on the basis of toxic units (TUs) for each toxicant. The 48-h LC50 values (lethal concentrations for 50% of the population) for the individual chemicals averaged 0.36 μg/L and 1.11 mg/L for diazinon and un-ionized ammonia, respectively. Under the assumption of strict additivity, the sum of TUs contributed by each toxicant at the LC50 of the mixture should total unity. The TUs associated with the mixtures in laboratory water averaged 1.37 and 1.47, respectively, for 24- and 48-h exposure intervals. These results were similar to those obtained with the actual effluent sample and suggest that diazinon and ammonia exhibit less than additive toxicity when present together.
The effect of calcium and magnesium ratios on the toxicity of copper to five aquatic species in freshwater
Authors: Naddy Rami B. , Stubblefield William A. , May Jeffrey R. , Tucker Scott A. , Hockett J. Russell 
Published: March 2010

AbstractWhile it is generally accepted that water hardness affects copper toxicity, the major ions that contribute to water hardness (calcium [Ca] and magnesium [Mg]) may affect copper toxicity differently. This is important because the Ca:Mg ratio in standard laboratory-reconstituted waters often differs from the ratio in natural surface waters. Copper toxicity was assessed for five different aquatic species: rainbow trout (RBT), fathead minnow (FHM), Ceriodaphnia dubia, Daphnia magna, and an amphipod (Gammarus sp.) under different Ca:Mg ratios (4:0, 3:1, 1:1, 1:3, and 1:4 mass basis) at a common hardness (180 mg/L as CaCO3) and alkalinity (120 mg/L as CaCO3). Copper toxicity increased at lower Ca:Mg ratios for RBT but increased at higher Ca:Mg ratios for D. magna. Fathead minnows (&lt;24 h old) were more sensitive to copper in 1:1 Ca:Mg waters compared to 3:1 Ca:Mg waters. The toxicity of copper did not vary under different Ca:Mg ratios for Gammarus sp., C. dubia, and 28-d-old FHM. The effect of Ca:Mg ratios on copper toxicity changed for D. magna in softer water (90 mg/L as CaCO3) compared with hard water studies.
Effect of copper binding by suspended particulate matter on toxicity
Authors: Ma Huizhong , Kim Sang Don , Allen Herbert E. , Cha Daniel K. 
Published: March 2010

Abstract
The kinetics of Cu(II) interactions with Susquehanna River (mid-Atlantic, USA) particle suspensions using the copper ion selective electrode (Cu-ISE) method indicated that the concentration of Cu2+ in both the suspension and filtrate was kinetically controlled; the reaction of Cu(II) in the suspension was faster than that in the filtrate. Bioassay tests were performed in continuous flow-through bioassay systems to examine the effect of kinetics of Cu(II) interactions with suspended solids on the toxicity of Cu to Ceriodaphnia dubia. The toxicity curves were displaced to higher total Cu concentration as the reaction time increased, indicating that such interaction of Cu with solids was time dependent. Further, the toxicity curves overlapped for reaction times of 6 and 24 h, indicating that the reaction was relatively rapid and that equilibrium was achieved within 6 h. The survival of organisms was related to the free Cu2+ concentration but deviated from the result for bioassays in which dissolved organic matter (DOM) rather than particles reacted with the added Cu(II) to affect the free Cu2+ concentration. It may be interpreted that, besides the toxic effect of Cu2+, particles exert adverse influences on the organisms.
Sensitivity of an infaunal amphipod,Eohaustorius estuarius, to acute waterborne exposures of 4-nonylphenol: Evidence of a toxic hangover
Authors: Hecht Scott , Boese Bruce L. 
Published: March 2010

AbstractThree independent trials were conducted using mortality and burial as endpoints. Amphipod mean lethal concentration to 50% (LC50) was 227 μg/L. One-hour burial as a sublethal endpoint increased the sensitivity of the toxicity test by 40%; however, most amphipods that survived exposure were able to recover within 24 to 48 h. This toxic hangover was dose-dependent.
A levy flight—random walk model for bioturbation
Authors: Reible Danny , Mohanty Sanat 
Published: March 2010

Abstract
Levy flights are employed in a lattice model of contaminant migration by bioturbation, the reworking of sediment by benthic organisms. The model couples burrowing, foraging, and conveyor-belt feeding with molecular diffusion. The model correctly predicts a square-root dependence on bioturbation rates over a wide range of biomass densities. The model is used to predict the effect of bioturbation on the redistribution of contaminants in laboratory microcosms containing pyrene-inoculated sediments and the tubificid oligochaete Limnodrilus hoffmeisteri. The model predicts the dynamic flux from the sediment and in-bed concentration profiles that are consistent with observations. The sensitivity of flux and concentration profiles to the specific mechanisms of bioturbation are explored with the model. The flux of pyrene to the overlying water was largely controlled by the simulated foraging activities.
Evaluation of western fence lizards (Sceloporus occidentals) and eastern fence lizards (Sceloporus undulatus) as laboratory reptile models for toxicological investigations
Authors: Talent Larry G. , Dumont James N. , Bantle John A. , Janz David M. , Talent Scott G. 
Published: March 2010

Abstract
A need is recognized for one or more laboratory reptile models for use in ecotoxicological studies and risk assessments. Maintenance of breeding populations of most reptile species under laboratory conditions is not practical because of their size and slow maturation rate. However, a number of species of spiny lizards (Sceloporus sp.) are small, mature quickly, and reproduce under laboratory conditions. We evaluated three populations of western fence lizards (S. occidentalis) and four populations of eastern fence lizards (S. undulatus) for their performance under laboratory conditions. We reared an F1 generation of each population and compared their performance relative to survival, growth, maturation rate, and reproductive output. A population from the San Joaquin Valley (CA, USA) performed especially well under laboratory conditions and is a good candidate for a laboratory model. We also examined the sensitivity of developing fence lizard embryos to an estrogenic chemical to determine if male secondary sex characteristics were affected. Microinjecting eggs with an estrogenic chemical (17α-ethinylestradiol) feminized males and prevented development of embryonic secondary sex characteristics. Therefore, embryonic fence lizards may be useful for studying the effects of endocrine-disrupting chemicals.
Determining the causes of impairments in the Little Scioto River, Ohio, USA: Part 2. Characterization of causes
Authors: Cormier Susan M. , Norton Susan B. , Suter Glenn W. , Altfater David , Counts Bernie 
Published: March 2010

Abstract
Two stream reaches in the Little Scioto River (OH, USA) were characterized for the causes of impairments measured at two locations. By inductive inference, six candidate causes were winnowed down to three and five candidate causes for each of the two stream reaches. Using a formal strength-of-evidence process, a single cause was determined. At the most upstream location, habitat alterations, including fine-textured substrates and low DO, were characterized as the probable causes for an increased percentage of anomalies of fish, a decreased percentage of mayflies, and an increased percentage of tolerant macroinvertebrates. An increase in the relative weight of fish was attributed to an artificially narrow, deepened channel. Approximately 2 km downstream, polycyclic aromatic hydrocarbon (PAH)-contaminated sediments were identified as the cause for both fish and macroinvertebrate impairments. Causal characterization using first elimination and then a strength-of-evidence approach narrowed and defined the causes of ecological impairment even in this situation, where many complex and interacting candidate causes existed. Applying a formal method highlighted types of data and associations that can strengthen and present a more convincing determination of the causes of impairment.