bluuebunny/crossref_metadata_2025 huggingface dataset:
Chlorinated and brominated persistent organic compounds in biological samples from the environment
Authors: Jansson Bo , Andersson Renate , Asplund Lillemor , Litzen Kerstin , Nylund Kerstin , Sellströom Ulla , Uvemo Ulla-Britt , Wahlberg Cajsa , Wideqvist Ulla , Odsjö Tjelvar , Olsson Mats
Published: March 2010

Eleven selected biological samples representing different ecosystems, trophic levels, and areas mainly in Sweden have been analyzed for 31 halogenated organic compounds or compound groups. The multiresidue analytical method provides a good opportunity to compare the concentrations of the different compounds in the investigated samples. By the use of ratios of these concentrations, comparisons can be done between species and areas. An attempt to describe an environmental distribution profile is demonstrated for some of the compounds using the concentration ratio between these compounds and 2,2′,4,4′,5,5′-hexachlorobiphenyl (PCB 153). Chlorinated paraffins (CPs) were found in all samples (130-4,400 ng/g lipid weight [lw]) and in some of them at higher concentrations than the polychlorinated biphenyls (PCBs). The ratio of CP to PCB 153 is higher in the investigated terrestrial species than in the aquatic, which is not the case for the other compounds. Polybrominated diphenyl ethers (PBDEs) were also found in all but one sample (< 3-2,140 ng/g lw). The concentrations were highest in industrialized areas but were also present in samples from background areas. Seven major congeners of PCBs were determined; the sum ranged from 50 to 200,000 ng/g lw in the investigated samples. Three coplanar PCB congeners were also analyzed (0.42-160 ng/g lw) as well as polychlorinated naphthalenes (PCNs), which were found at levels between 0.038 and 50 ng/g lw. The latter two groups do not seem to biomagnify in the food chain of herring to grey seal to the same extent as the major PCB compounds. Pentachlorobenzene was found in only three of the samples (0.6-35 ng/g lw), whereas hexachlorobenzene was present in all samples (9-330 ng/g lw). Among the organochlorine pesticides, total DDTs ranged from 4 to 280,000 ng/g lw and the hexachlorocyclohexanes (HCHs) from < 19 to 650. Chlordane (< 6-4,000 ng/g lw), toxaphene (not detected-5,700), and dieldrin (< 11-340) were also found. None of the analyzed polychlorinated phenols and guaiacols were detected in any of the investigated samples.
Distributions of butyltins in the surface sediment of Ise Bay, Japan
Authors: Yonezawa Yoshitaka , Nakata Kisaburo , Miyakozawa Yoshikazu , Ochi Akiko , Kowata Takao , Fukawa Hiroaki , Sato Yuuji , Masunaga Shigeki , Urushigawa Yoshikuni
Published: March 2010

Concentrations of tri-n-, di-n-, and mono-n-butyltin (TBT, DBT, and MBT) were determined for surface sediments collected from 44 sites within Ise Bay, Japan. The concentrations of TBT, DBT, and MBT ranged from not detected (ND) to 0.11, ND to 0.073, and ND to 0.098 μg g−1 dry sediment, respectively, excluding one site near a shipyard (TBT concentration 0.54-1.1 μg g−1 dry sediment). The distribution patterns of the three butyltins were similar to each other. The concentration of TBT correlated to the organic carbon (OC) content of the sediment and did not correlate to the sediment particle size. The area with high concentration of butyltin extended from the eastern side of the middle of the bay toward the southwest to Tsu-Matsuzaka Port. This area had a high organic content area and corresponded to the downwelling zone simulated by a baroclinic three-dimensional hydrodynamic model. Another area with high butyltin concentrations, near Yokkaichi Port, was also located in the simulated downwelling zone. The area near Nagoya Port, which is in the simulated upwelling zone, had low butyltin concentrations, although the amount of TBT loading in Nagoya Port was estimated to be several times greater than that in Yokkaichi Port. The ratio of TBT to MBT decreased along the direction of surface flow from Yokkaichi Port to the middle of the bay. These results suggested that the amount of the TBT loading could not explain all of the distribution of the TBT concentration in the sediment, and that tidal bay circulations, hydrodynamically up- and downwelling, and surface flow affected it strongly.
A Mercury saturation assay for measuring metallothionein in fish
Authors: Dutton Michael D. , Stephenson Malcolm , Klaverkamp Jack F.
Published: March 2010

An accurate, rapid, sensitive, and simple method using mercury saturation for quantifying metallothionein (MT) is described. A complex solution (“pseudocytosol”) of enzymatic and non-enzymatic thiols, including rabbit liver MT-II, and supernatants from homogenized samples of rainbow trout liver were incubated in the presence of 203Hg in 10% trichloroacetic acid Excess Hg was bound to and removed by chicken egg albumin, which denatured on contact with the acidic assay medium. After centrifugation, MT labeled with 203Hg remained in the TCA supernatant and was estimated using known stoichiometry for Hg-MT binding. A dilution series was used to establish that nonspecific metal binding, a common problem with other metal saturation assays, is negligible. Analysis of hepatic MT with high Cu content from rainbow trout demonstrated virtually complete displacement of Cu, Cd, and Zn by Hg. When compared to other metal-saturation assays developed for vertebrates, this method requires the least number of technical steps, and one-third or less of total preparatory and analytical time.
Studies on the effects of the insecticides phorate and malathion on soil microorganisms
Authors: Gonzalez-Lopez J. , Martinez-Toledo M. V. , Rodelas B. , Salmeron V.
Published: March 2010

A study was made of the effects of two selected organophosphorus insecticides, phorate and malathion, at concentrations of 10, 50, 100, 200, and 300 μg/g of an agricultural soil on total bacteria populations, fungi, aerobic dinitrogen-fixing bacteria, denitrifying bacteria, nitrifying bacteria, and nitrogenase activity (acetylene-reduction assay). The presence of phorate at a concentration of 300 μg/g or malathion at concentrations of 100 to 300 μg/g significantly decreased dinitrogen fixation. Dinitrogen-fixing bacteria significantly decreased at concentrations of 100 to 300 μg/g of malathion. The presence of 10 to 300 μg/g of malathion significantly reduced the total number of bacteria. However, denitrifying bacteria were significantly increased at concentrations of 50 to 300 μg/g of malathion. Nitrifying bacteria and fungal populations were not affected as a consequence of the addition of the organophosphorus insecticides, showing that these microorganisms can tolerate high amounts of those substances.
Embryotoxicity of 2,3,7,8-tetrachlorodibenzo-p-dioxin in the ring-necked pheasant
Authors: Nosek John A. , Craven Scott R. , Sullivan John R. , Gendron-Fitzpatrick Annette , Peterson Richard E.
Published: March 2010

Fertilized eggs of ring-necked pheasants (Phasianus colchicus) were injected into the albumin or yolk with vehicle or graded doses of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) (0.01, 0.1, 1, 10, 100, 1,000, 10,000, or 100,000 pg TCDD/g egg) on day 0 of embryonic development and toxicity was assessed in 1-d-old hatchlings and 28-d-old chicks. The most sensitive effect of in ovo TCDD exposure was induction of hepatic ethoxyresorufin-O-deethylase (EROD) activity in 1-d-old hatchlings. The ED50 for this response was 312 pg TCDD/g egg. Embryo mortality was the most sensitive sign of toxicity. The TCDD dose that caused 50% mortality above control (LD50) when injected into the egg albumin or yolk was 1,354 and 2,182 pg TCDD/g egg, respectively. At egg TCDD doses up to and including 1,000 pg TCDD/g egg, no effect was detected in 1-d-old hatchlings and 28-d-old chicks in body growth, organ weights, carcass morphometrics, incidence of edema, or incidence of histological alterations in the liver, spleen, heart, Bursa of Fabricius, or thymus. Egg TCDD doses as high as 1,000 pg TCDD/g egg also had no effect on cardiac morphometrics or incidence of cardiac malformations in 1-d-old hatchlings, or on antibody-mediated immunity in 28-d-old chicks. We conclude that embryo mortality is the most sensitive sign of TCDD toxicity in the ring-necked pheasant following in ovo exposure. The ring-necked pheasant embryo is less sensitive than the chicken (Gallus domesticus) embryo and more sensitive than the eastern bluebird (Sialia sialis) embryo to TCDD toxicity.
Sensitivity of early-life-stage golden trout to low pH and elevated aluminum
Authors: Delonay Aaron J. , Little Edward E. , Woodward Daniel F. , Brumbaugh William G. , Farag Aida M. , Rabeni Charles F.
Published: March 2010

Early-life-stage golden trout (Oncorhynchus aguabonita aguabonita) were exposed to acid and Al to examine the response and determine the sensitivity of a western, alpine salmonid to conditions simulating an episodic pH depression. Freshly fertilized eggs, alevins, and swim-up larvae were exposed for 7 d to one of 12 combinations of pH and Al, and surviving fish were held to 40 d post-hatch to determine the effect of exposure on subsequent survival and recovery. Golden trout are sensitive to conditions simulating episodic acidification events typically observed in the field. Significant mortality occurred when the pH of test waters was below 5.0 in the absence of Al or when pH was 5.5 in the presence of 100 μg/L total Al. Behavioral impairments were sensitive indicators of low pH and Al stress. Impaired locomotory and feeding behavior occurred at pH 5.5 without Al and at Al concentrations > 50 μg/L. In contrast, growth, RNA-to-DNA ratio, and whole-body ion concentration were relatively less sensitive indicators of sublethal acid and Al stress.
Quantitative structure-activity relationships for predicting the toxicity of pesticides in aquatic systems with sediment
Authors: Fisher S.W. , Lydy M.J. , Barger J. , Landrum P.F.
Published: March 2010

The toxicity of a series of organophosphorus (OP) and carbamate insecticides was measured against the midge Chironomus riparius in aquatic systems with and without sediment. Five molecular descriptors (molecular volume, Henry's law constant, n-octanol/water partition coefficient (Kow), molecular connectivity, and linear solvation energy) were used in regression analysis as potential predictors of insecticidal activity. The regressions were conducted for each descriptor against toxicity values for the series of chemicals.

Molecular volume and Henry's law constant showed no relationship with toxicity. However, log Kow was moderately successful in describing the effect of sediment on toxicity (r2 = 0.508). Prediction of toxicity was substantially improved when a linear solvation energy (LSE) or molecular connectivity (MC) model was used in regressions. In multiple regressions conducted on carbamates and OPs separately, use of MC or LSE parameters explained up to 95.8% of the variability in toxicity. Based on the results of regression analyses, sorptive interactions between these insecticides and sediment apparently dominate the processes affecting the toxicity of these compounds when sediment is present. In the absence of sediment, the regressions suggest that the molecular structure of the insecticides is more important than solubility or partitioning for determining toxicity.
Environmental science and resource management in the 21st century: Scientific perspective
Authors: Cairns John
Published: March 2010

Ecotoxicology in the 21st century will be part of the larger field of integrated environmental science and resource management. This already established trend has some main impetuses: (a) A definite shift is occurring from only protecting against toxic damage to ensuring robust ecosystem health or condition; (b) the modus operandi of the information age is integrative science, not fragmented science; (c) the most exciting discoveries are occurring at the interfaces of the classical disciplines; (d) the preoccupation with “end-of-the-pipe” waste discharges is rapidly shifting to a system-level or landscape-level perspective; and (e) the professional societies that miss the beginnings of major trends can partially offset this loss by establishing close relationships with the new societies that are riding the crest of the “waves.” It will be extremely important for both individual professionals and professional societies to respond to these rapid changes. Otherwise, individuals will be left in the professional backwaters, and professional societies will be replaced by more agile young societies in the same way that SETAC had its genesis.
Effects of age, species difference, antibiotics and toxicants on intestinal enzyme activity and genotoxicity
Authors: Chadwick R. W. , George S. E. , Kohan M. J. , Allison J. C. , Chang J. , Long J. E. , Duffy M. C. , Dekker J. P. , Forehand L. R.
Published: March 2010

Altered intestinal enzyme activity significantly affects the biotransformation and toxicity of many xenobiotics. This article summarizes research, supported by the U.S. Air Force Bioenvironmental Hazards Research Program, that employs a novel gas-liquid chromatographic assay to investigate the effects of age, species difference, antibiotics, and environmental chemicals on enzyme activity in various regions of the intestinal tract. Significant research findings include the following: (a) age-dependent alterations in enzyme activity in the gastrointestinal (GI) tract of the developing animal that suggest a changing susceptibility to toxicants during this period; (b) discovery of previously unreported mucosal enzymes in the small intestine that are present in germ-free rats and are not susceptible to antibiotics; (c) markedly greater intestinal nitroreductase activity and significantly higher bioactivation of the procarcinogen 2,6-dinitrotoluene (DNT) in CD-1 mice than in Fischer 344 rats; (d) significantly altered intestinal enzyme activity in rats pretreated with lindane, pentachlorophenol, 2,4,5-trichlorophenoxyacetic acid (2,4,5-T), or Aroclor 1254; (e) potentiated DNT genotoxicity by Aroclor 1254 and pentachlorophenol pretreatment; and (f) a transient antagonism of DNT genotoxicity by 2,4,5-T pretreatment. Enzyme activity in the small intestine may have greater toxicological importance than previously thought in the biotransformation of environmental chemicals and as an indicator of change in the microbial flora.
Biochemical and mutagenic characterization of plant-activated aromatic amines
Authors: Plewa Michael J. , Gichner Tomáš , Xin Hua , Seo Kwang-Young , Smith Shannon R. , Wagner Elizabeth D.
Published: March 2010

Plant activation is the process by which promutagenic agents are activated into rautagens by plant systems. With the widespread use of agricultural chemicals on crop plants and with the global exposure of plants to pollutants, the possibility exists that plant-activated agents may be introduced into the human food chain. The plant cell/microbe coincubation assay uses cultured plant cell suspensions as the activating system and bacteria or yeast cells as the genetic indicator organism. After a treatment time, the microbes are plated on selective medium. In this way the activation system and the genetic system can be independently studied. In addition, the viability of the plant cells and the microbial cells can be independently determined so that the toxicity of a test agent can be evaluated. Using cytochrome P450 monooxygenase and peroxidase inhibitors, we are studying the biochemical mechanisms of plant activation of environmental contaminants, especially aromatic amines. We propose a working model for the activation of aromatic amines by cultured tobacco cells into stable frameshift mutagens.
Effects of auxiliary carbon sources and electron acceptors on methanogenic degradation of chlorinated phenols
Authors: Häggblom Max M. , Rivera Maria D. , Young L. Y.
Published: March 2010

We studied the degradation of chlorinated phenols under methanogenic conditions by establishing enrichment cultures on 4-chlorophenol and 2,4-dichlorophenol with or without a supplementary substrate. p-Cresol was chosen as a nonchlorinated aromatic compound structurally similar to the chlorophenols, and propionate was chosen as a readily utilizable carbon source. 2,4-Dichlorophenol was dechlorinated to 4-chlorophenol, which was degraded without further detection of metabolites. The rates of chlorophenol metabolism were enhanced by subsequent refeeding of the respective chlorophenols and supplementary substrates. The addition of p-cresol or propionate as an auxiliary carbon source enhanced the rate of 4-chlorophenol degradation. Methanogenic cultures capable of ortho dechlorination were repeatedly subcultured by dilution into fresh media and refeeding of 2,6-dichlorophenol and either p-cresol or propionate as auxiliary substrates. 2,6-Dichlorophenol was sequentially dechlorinated to 2-chlorophenol and phenol and ultimately mineralized to methane and carbon dioxide. Cultures adapted to 2,4- or 2,6-dichlorophenol also readily dechlorinated other dichlorophenols containing an ortho chlorine. The alternative electron acceptors nitrate, sulfite, and thiosulfate completely inhibited dechlorination of 2,6-dichlorophenol, whereas sulfate slowed the dechlorination rate.
Sorption of chlorobenzenes to mineralizing phytoplankton
Authors: Koelmans Albert A. , Lijklema Lambertus , Jiménez Carmen Sánchez
Published: March 2010

The influence of mineralization of phytoplankton (laboratory Scenedesmus spp.) on the desorption characteristics of 1,2,3,4-tetrachlorobenzene (TeCB) and hexachlorobenzene (HCB) was studied using a purge and trap method. For comparison several field samples, including a sediment, algae at different growth stages, and freeze-dried algae, were used. The desorption characteristics were evaluated using multiple box models similar to those generally used for desorption from sediments. It was found for all adsorbents that the desorption could adequately be described using a two-compartment nonequilibrium biosorption model. Generally, HCB was bound more strongly and released more slowly than TeCB. Aging and mineralization of unicell and coenobian forms of the algal species resulted in a significant 60 to 100% increase of OC-normalized partition coefficients. Generally, sorption affinity as quantified by the OC-normalized partition coefficient (K, oc) was lower, and desorption kinetics faster for algae than for soils and sediments. Evaluation of the biosorption rate parameters using a log k2 vs. log Kp plot showed that in contrast to sediments and soils, no clear inverse relationship between Kp and k2 exists. A bioconcentration experiment with four chlorobenzenes showed good agreement with the sorption parameters measured with the purge method, and showed a linear correlation of the bioconcentration factor with the octano1/water partition coefficient.
Acute toxicity of the herbicide bromoxynil to Daphnia magna
Authors: Buhl Kevin J. , Hamilton Steven J. , Schmulbach James C.
Published: March 2010

The acute toxicities of technical-grade bromoxynil octanoate (BO) and two commercial formulations, Buctril® and Bronate®, to < 24-h-old neonate Daphnia magna (Straus) were determined in soft, hard, and oligosaline water. In addition, effects of life stage, feeding, aging the herbicide, and exposure duration on BO toxicity to daphnids were investigated. Regardless of formulation, life stage, and water quality, BO was found to be extremely to highly toxic to daphnids in standard tests; 48-h EC50 values ranged from 41 to 161 m̈g/L. Bromoxynil octanoate was the most toxic to neonates in soft water and the least toxic in hard water. The acute toxicities of the three bromoxynil herbicides to a given age group of daphnids were similar within the same water type. Overall, neonates and 7-d-old adults were more sensitive than 14- or 15-d-old adults to each herbicide. Feeding daphnids during the toxicity test significantly decreased BO toxicity compared to not feeding them. Aging BO (as Buctril) in hard water decreased its toxicity, and the rate of deactivation was rapid, with an estimated half-life of biological activity of 13 h. Daphnids immobilized by exposures to toxic BO concentrations for ≤ 6 h recovered their mobility, whereas exposures of 18 and 24 h to BO produced toxic effects in daphnids similar to those exposed for 48 h. These results indicated that standard continuous exposure tests may not adequately predict the acute toxicity of BO to freshwater animals in the field.
Absorption, tissue distribution and metabolism of chlorpyrifos in channel catfish following waterborne exposure
Authors: Barron Mace G. , Plakas S. M. , Wilga P. C. , Ball T.
Published: March 2010

The pharmacokinetics, tissue distribution, and metabolism of waterborne chlorpyrifos were investigated in channel catfish (Ictalurus punctatus) fitted with arterial and urinary catheters. Pharmacokinetic analysis indicated rapid absorption of parent chlorpyrifos from water into blood and slower distribution to peripheral tissues. Total 14C residue concentrations were highest in fat and lowest in muscle. Parent chlorpyrifos comprised > 90% of the total 14C residues in the whole fish. 14C residues were excreted by renal and biliary routes as metabolites of chlorpyrifos; excretion of the parent chemical was negligible. Trichloropyridinol (TCP) was the major metabolite in blood (approximately 40% of total residues), whereas the glucuronide conjugate of TCP was the major metabolite in urine (60–90%) and bile (> 90%). The pharmacokinetics and metabolism of water-borne chlorpyrifos in the channel catfish were similar to the disposition of chlorpyrifos in other vertebrates.
Comparison of two freshwater turtle species as monitors of radionuclide and chemical contamination: DNA Damage and residue analysis
Authors: Meyers-Schöne Linda , Shugart Lee R. , Walton Barbara T. , Beauchamp John J.
Published: March 2010

Two species of turtles that occupy different ecological niches were compared for their usefulness as monitors of freshwater ecosystems where both low-level radioactive and nonradioactive contaminants are present. The pond slider (Trachemys scripta) and common snapping turtle (Chelydra serpentina) were analyzed for the presence of 90Sr, 137Cs, 60Co, and Hg, radionuclides and chemicals known to be present at the contaminated site, and single-strand breaks in liver DNA. The integrity of the DNA was examined by the alkaline unwinding assay, a technique that detects strand breaks as a biological marker of possible exposure to genotoxic agents. This measure of DNA damage was significantly increased in both species of turtles at the contaminated site compared with turtles of the same species at a reference site, and shows that contaminant-exposed populations were under more severe genotoxic stress than those at the reference site. The level of strand breaks observed at the contaminated site was high and in the range reported for other aquatic species exposed to deleterious concentrations of genotoxic agents such as chemicals and ionizing radiation. Statistically significantly higher concentrations of radionuclides and Hg were detected in the turtles from the contaminated area. Mercury concentrations were significantly higher in the more carnivorous snapping turtle compared with the slider; however, both species were effective monitors of the contaminants.
Bioaccumulation of heavy metals by benthic invertebrates at the arkansas river, colorado
Authors: Kiffney Peter M. , Clements William H.
Published: March 2010

A one-year biomonitoring study was conducted to determine the extent of metal contamination (Cd, Cu, and Zn) in a benthic community from the Arkansas River (CO), a subalpine stream impacted by discharges from historic mining operations. Elevated concentrations of metals in water were paralleled by higher concentrations in benthic organisms. Significant differences (p < 0.05) in metal concentrations in aufwuchs and benthic macroinvertebrates among upstream (reference) and downstream (impacted) stations were observed. Metal concentrations in aufwuchs and benthic invertebrates remained elevated at some downstream stations, despite decreases in water concentrations. Time of year and functional group contributed to the variation in metal bioaccumulation in benthic macroinvertebrates. Monitoring metal concentrations in aquatic macroinvertebrates was a better indicator of metal bioavailability in the Arkansas River than ambient (water) metal concentrations.
Comparative analysis of variables to measure recovery rates in streams
Authors: Niemi Gerald J. , Detenbeck Naomi E. , Perry James A.
Published: March 2010

We assessed a series of chemical and biological variables for their abilities and cost effectiveness in determining recovery rates in streams. Using data gathered at the experimental streams of the Monticello Ecological Research Station, several water-quality variables (DO, pH, nutrients), macroinvertebrate densities, macrophyte biomass, and periphyton biomass, and several ecosystem-level variables (e.g., primary production) were compiled and analyzed. Water-quality variables were relatively inexpensive to measure, and many would be relatively easily collected for assessing recovery rates; however, their overall explanatory power for determining recovery of streams, especially biological phenomena, was limited. Several biological variables, including gross primary production, respiration, leaf litter decomposition rates, macroinvertebrate richness, and Collembola density, could be measured reasonably well and required relatively small sample sizes (n < 10) for detecting recovery rates. However, collection of most of these variables was more costly than collection of chemical water-quality variables. The ultimate determination of which variables to measure in assessing recovery in a given ecosystem will need to be based on the disturbances being examined, the importance of the variables to stream health, and the available monetary resources. Generally, comprehensive analyses of recovery rates for a variety of aquatic systems will greatly increase our ability to develop a framework for predicting recovery rates and ultimately improving the quality of the environment.
Geochronology of priority pollutants in a sedimentation area of the rhine river
Authors: Beurskens Jacobus E. M. , Mol Ge A. J. , Barreveld Hein L. , van Munster Bert , Winkels Herman J.
Published: March 2010

Eight sediment cores were taken from Lake Ketelmeer, a sedimentation area of the Rhine River, located in the central part of The Netherlands. Priority pollutants (eight metals, six planar and mono-ortho polychlorinated biphenyls, seven polychlorinated dibenzo-p-dioxins, 10 polychlo-rinated dibenzofurans, and eight polycyclic aromatic hydrocarbons) were determined in all or in a selected number of cores. Present-day and historical levels of pollutants since the late 1930s were established through the use of radionuclide time tracers (137Cs, 134Cs) and area-specific geological time markers. Postdepositional redistribution of pollutants and possible transformations were evaluated by analyzing sediment top-layer samples that were taken in 1972. Disappearance in the anaerobic sediment was observed for several chlorinated biphenyls, dioxins, and furans, Disappearance of the chlorinated compounds may be caused by microbial dechlorination reactions in the anaerobic lake sediment. For the persistent metals and polycyclic aromatic hydrocarbons, as well as for the somewhat changed concentrations of chlorinated aromatics, trends in the concentration profiles during the last five decades are described. Rather low concentrations of almost all studied chlorinated compounds were observed in the early 1940s. These low levels were in contrast to the metal and PAH concentrations, which were already high in the late 1930s and were lowered during the second world war. For all studied compounds, maximum concentrations were found between 1955 and 1975. Cadmium and nickel levels remained high until 1980. The highly toxic 2,3,7,8-tetrachlo-rodibenzo-p-dioxin reached concentrations up to 400 ng/kg in the mid-1960s. Recently deposited sediments showed lower pollutant levels. The levels of lead, arsenic, and all studied PAHs were the lowest observed in the past five decades.
Polychlorinated dibenzo-P-dioxin and dibenzofuran residues in estuarine and coastal north sea sediments: Sources and distribution
Authors: Evers Erik H. G. , Klamer Hans J. C. , Laane Remi W. P. M. , Govers Harrie A. J.
Published: March 2010

Sediments from two depositional zones of the North Sea (the Wadden Sea and Oyster Grounds) and from the estuaries of the rivers Rhine, Meuse, Scheldt, Ems, and Humber were analyzed for polychlorinated dibenzofurans (PCDFs) and dibenzo-p-dioxins (PCDDs) using a congener-specific procedure. A simple grain-size correction procedure was utilized for the comparison of PCDF and PCDD concentrations in sediments from different origin. This procedure, which applies wet sieving of fresh sediment and isolating and analyzing the <63-μm grain-size fraction, was found to be appropriate for comparing levels of PCDFs and PCDDs in different estuarine and coastal sediments. PCDFs were more widely encountered than PCDDs in all sediments, except for the Ems-Dollard and the Humber estuary. The highest concentrations were found in the outflow sediments of the rivers Rhine and Humber. Concentrations up to 2,980 ng/kg PCDFs, principally 1,2,3,4,6,7,8-HpCDF and OCDF, and up to 1,760 ng/kg PCDDs, principally OCDD, were determined in the River Rhine sediments. Principal component analysis was used to visualize the compositional changes of PCDD and PCDF profiles in the sediments. Two-dimensional projections based on sample scores from the principal component models showed a marked influence of the River Rhine on the presence of these compounds in the western Wadden Sea and the Oyster Grounds. Based on a chemo-metric evaluation of chromatographic profiles of these coastal, estuarine and related freshwater sediments, we have deduced that these compounds originate primarily from industrial operation discharges, related to the production of chloroaliphatic compounds and the chloralkali industry along the River Rhine. The atmospheric deposition of combustion-generated PCDDs and PCDFs appeared significant only for remote marine environments.
LAS homolog distribution shift during wastewater treatment and composting: Ecological implications
Authors: Prats D. , Ruiz F. , Vazquez B. , Zarzo D. , Berna J.L. , Moreno A.
Published: March 2010

The behavior of LAS (linear alkylbenzene sulfonate) in different environmental compartments was studied through wastewater treatment process steps in sewage treatment plants of Alicante and Benidorm (activated sludge type) as well as in Guardamar (lagoons). The fate of LAS, using a specific HPLC method, was monitored during treatment sludge compostage and soil amendment operations. Finally, the marine sediments close to a submarine wastewater sewer outfall were analyzed. The results show significant differences between distribution of LAS homologs in water and solids (sludges, sediments, and soils), as compared to the original distribution in detergent formulations, yielding a lower LAS average molecular weight in water samples. The change observed in the homolog distribution of LAS implies a reduction in the toxicity to Daphnia, because a lower average molecular weight of LAS is less toxic.
Biodehalogenation: The kinetics and rates of the microbial cleavage of carbon-halogen bonds
Authors: Castro C.E.
Published: March 2010

Specific rate constants associated with defined molecular paths of carbon-halogen bond cleavage from a variety of alkyl halide substrates by six soil organisms are presented. Five aerobes (three pseudomonads, one methylotroph, and one flavobacterium) and one anaerobe (a methano-gen) are compared. The rate constants were obtained with resting cells in phosphate buffer at pH 7.4 in the absence of nutrients or other substances. The observed general rate law is d(X−)/dt = k (RX)(organisms), wherein X− = halide ion, RX = alkyl halide, and (organisms) = number of organisms per liter. At concentrations of substrates ≥10−3 M, the rate may diminish or cease due to the toxicity of the substrate. At high cell densities ≥0.1 g/ml wet weight, the rates may saturate. This is attributed to a packing phenomenon of the cells. There is no simple correlation of rates with the chemical structure of the substrates when the conversions are grouped by reaction type; however, the order of reductive hydrogenolysis roughly follows the carbon-halogen bond dissociation energies. Several factors may contribute to a modulation of the rates observed with defined enzymatic active site models in homogeneous solution. These factors are briefly discussed. The aerobes exhibited a greater chemical diversity than the anaerobe in transforming these substances, and they react with much greater speed. In these biotransformations reductive processes occur more often than substitutions or oxidations. A surprising result was that the aerobes can reductively dehaloge-nate more rapidly than the methanogen.
Antibodies to a synthetic peptide that react specifically with rainbow trout hepatic cytochrome P450 1A1
Authors: Myers Charles R. , Sutherland Leslie A. , Haasch Mary L. , Lech John J.
Published: March 2010

The purpose of this investigation was to develop a specific immunological probe to rainbow trout cytochrome P450 1A1 (CYP1A1). Three oligopeptides corresponding to different regions of trout CYP1A1 (amino acids 162-181, 250-267, 277-294) were coupled to keyhole limpet hemo-cyanin (KLH) using two different methods. All three peptides were coupled to KLH through side-chain amine and carboxyl groups of the peptide; peptides 162-181 and 277-294 were also coupled to KLH through the sulfhydryl group of a cysteine residue of each peptide. These five peptide-KLH conjugates were used to immunize rabbits. Antibody production and specificity were monitored by Western immunoblot analyses. All of the antipeptide antisera showed strong reactivity with the corresponding peptides used to generate the antisera. Four of these five antisera, however, did not react with the trout CYP1A1 protein. In contrast, the antiserum directed against peptide 277-294 (which was coupled to KLH through a sulfhydryl linkage) reacted strongly and specifically with the trout CYP1A1 protein. These antipeptide antibodies had a high affinity for CYP1A1 in liver microsomes from rainbow trout that had been exposed to β-naphthoflavone G3-NF), a known CYP1A1 inducer in trout. Microsomal proteins from control trout were not recognized by the antipeptide antibodies. Preimmune serum from the rabbits did not recognize any proteins in control or β-NF-treated trout. These findings demonstrate that antipeptide antibodies directed against peptide 277-294 can be easily produced in large quantities and used in research or biomonitoring studies for the detection of CYP1A1 in rainbow trout.
Degradation of atrazine in laboratory microcosms: Isolation and identification of the biodegrading bacteria
Authors: Mirgain I. , Green G.A. , Monteil H.
Published: March 2010

Several natural ecosystems, including soil and water microcosms, have been explored for their potential to biodegrade atrazine (2-chloro-4-[ethylamino]-6-[isopropylamino]-1,3,5-triazine). Subculturing soil or water samples with several applications of the herbicide leads to an enhancement of atrazine catabolism correlating with a decrease in the number of bacterial species. A combination of enrichment culture techniques, the imposition of carbon limitation, and plating on selective atrazine-agar plates have permitted the isolation of several bacteria able to biodegrade atrazine from different polluted or unpolluted ecosystems. One of the selected bacteria, originating from an agricultural soil, has been identified as Acinetobacter calcoaceticus, which alone in pure culture can degrade atrazine. From another agricultural soil Pseudomonas alcaligenes associated with an Agrobactenum sp. was selected. A garden soil treated only once with the herbicide was found to contain an association of five different bacteria that together degrade atrazine. Finally, a Pseudomonas putida/Xanthomonas maltophilia pair has been isolated from an aquatic ecosystem. In consortium, in coculture, or in pure culture with well-defined experimental parameters, the induced bacteria degrade added atrazine in 18 h.
Investigations of the structure and reactions of the intermediate in the chlorination of resorcinol
Authors: Heasley Victor L. , Anderson Michael E. , Combes Dianne S. , Elias Daniel S. , Gardner Jeffrey T. , Hernandez Mark L. , Moreland Rodney J. , Shellhamer Dale F.
Published: March 2010

The investigation reported here describes an attempt to establish the structure of the intermediate that undergoes ring-opening in the chlorination of resorcinol and its chloro-derivatives in a nucleophilic solvent such as H2O or CH3OH. The evidence suggests that the pentachloride and not the tetrachloride is the intermediate that reacts with the nucleophiles. Chlorination reactions were conducted in CH3OH/H2O. The structures of the “early-generation” products from incorporation of CH3OH were sufficiently stable to be characterized. These products implicated the pentachloride. Resorcinol, di- and trichlororesorcinol, and the pentachloride gave the same products. The mechanisms of the ring-opening and the reactions leading to the products are described in detail. The assumption is made that the same or similar reactions are involved in the aqueous chlorination of resorcinol, but that decarboxylation and solvolysis reactions rapidly degrade the products immediately following ring-opening.
Assessment of aquatic animal communities in the vicinity of the palmerton, Pennsylvania, zinc smelters
Authors: Carline Robert F. , Jobsis Gerrit J.
Published: March 2010

Emissions from zinc smelters in Palmerton, Pennsylvania, deposited large quantities of heavy metals, predominantly Zn, Pb, Cu, and Cd, on the surrounding landscape from 1898 to 1980. From 1986 to 1987 we studied four small headwater streams that were about 8 to 25 km downwind of the smelters to determine if long-term deposition of heavy metals had any pronounced effects on aquatic communities. Although metal concentrations in soils tended to decrease with increasing distance from the smelters, this trend was not particularly evident in stream sediments, insects, or fish. Diversities of macroinvertebrates and fish were similar among sites. Densities and growth of trout varied among streams, but not in relation to distance from the smelters. We concluded that long-term deposition of heavy metals has not had pronounced effects on aquatic animal communities six to seven years after cessation of primary smelting.
Bioaccumulation of PCB congeners by blue mussels (Mytilus edulis) deployed in New Bedford Harbor, Massachusetts
Authors: Bergen Barbara J. , Nelson William G. , Pruell Richard J.
Published: March 2010

Blue mussels (Mytilus edulis) were deployed to monitor the levels of bioavailable contaminants during a pilot dredging project in New Bedford Harbor (NBH), Massachusetts. Dissolved and particulate seawater samples also were collected periodically during these deployments. Poly-chlorinated biphenyl (PCB) congener concentrations in both mussel tissue and seawater samples were among the quantified contaminants. Large differences in the dissolved and particulate PCB concentrations in seawater and tissue residue concentrations in mussels were observed along a gradient from the upper harbor to Buzzards Bay. Bioconcentration factors (BCFs) were calculated for six PCB congeners at two stations in NBH and a reference site in Buzzards Bay. Equations were generated relating the log BCF to the log octanol/water partition coefficient (Kow) for these congeners. A consistent relationship was found between dissolved PCB congener concentrations and tissue concentrations in the mussels. This study demonstrates the utility of the blue mussel as a monitoring organism for quantifying bioavailable contaminants in seawater and for relating PCB tissue residues with seawater concentrations.
Comparative toxicity of pyrethroid insecticides to terrestrial and aquatic insects
Authors: Siegfried Blair D.
Published: March 2010

The acute toxicities of three pyrethroid insecticides (permethrin, cypermethrin, and bi-fenthrin) and one organophosphate insecticide (chlorpyrifos) were compared by topical application and static exposure to a variety of terrestrial and aquatic insects. Mayflies and damselflies were the most susceptible taxa tested by both exposure methods. The aquatic insects were generally more susceptible than the terrestrial insects when compared on a dose per body weight basis, although the differences were smaller than expected, given the extremely low concentrations that produce toxic effects by static exposure.
Effects on wildlife of Brace® 10G applications to corn in South-Central Iowa
Authors: Johnson Gregory D. , Krueger Henry O. , Balcomb Richard T.
Published: March 2010

Brace® 10G (a.i. isazofos), an organophosphorus insecticide being tested for potential registration for control of various corn pests, was applied to 14 Iowa cornfields in an 18-cm band at planting at 0.73 kg a.i. per hectare. Effects of isazofos on wildlife were evaluated by searching treated fields and adjacent areas for carcasses and monitoring survival of radiomarked northern bob-white and ground-foraging passerines. Fifty carcasses (26 birds, 21 mammals, three herps) were recovered following application. Four of the bird and 12 of the mammal carcasses found postapplication had tissues suitable for residue analysis but did not contain detectable isazofos residues. Brain cho-linesterase (ChE) activities measured in four bird and seven small mammal carcasses were not depressed in relation to reference values. Two radiomarked bobwhite died before application, and two radiomarked bobwhite and three radiomarked passerines died following applications. Three of these birds had sufficient tissues for residue analysis, but none had detectable isazofos residues or brain ChE depression relative to reference values, and pre- and postapplication mortality rates of radio-marked birds were not significantly different.
Evaluation of a laboratory-generated NOEC for linear alkylbenzene sulfonate in outdoor experimental streams
Authors: Fairchild James F. , Dwyer F. James , La Point Thomas W. , Burch Susan A. , Ingersoll Christopher G.
Published: March 2010

Laboratory and field studies were conducted with linear alkylbenzene sulfonate (LAS) to evaluate the use of laboratory-generated NOECs for protecting aquatic organisms in outdoor experimental streams. Fathead minnows (Pimephales promelas) and freshwater amphipods (Hyalella azteca) were exposed in the laboratory to an environmentally realistic mixture of LAS (average chain length C11 9) for 7 d; fathead minnows were also exposed in a 28-d study. Calculated NOEC values based on survival and growth ranged from 0.3 to 0.9 mg/L for fathead minnows and from 0.6 to 1.4 mg/L for amphipods. Toxicity of LAS in 4-, 7-, and 28-d exposures of fathead minnows was similar because mortality occurred within the initial 24 h of exposure; mortality was more sensitive than growth as a chronic end point. The addition of 5% sewage effluent to well and stream water had little effect on the bioavailability of LAS; however, total organic carbon levels were low (<3 mg/L) in all treatments. A 45-d exposure of three outdoor experimental streams to 0.36 mg/L LAS had no effects on survival of fathead minnows or amphipods, dynamics of benthic invertebrates, growth of periphyton, or processing of detrital leaves. Results indicated that the laboratory-generated NOEC for LAS was protective of experimental stream communities under the studied conditions.
In situ response of natural periphyton to an anionic surfactant and an environmental risk assessment for phytotoxic effects
Authors: Lewis M.A. , Pittinger C.A. , Davidson D.H. , Ritchie C.J.
Published: March 2010

In situ toxicity tests were conducted to determine the toxicity of linear alkyl- (dodecyl-) benzenesulfonate (LAS) on a natural periphyton community. Colonized periphyton were exposed to C11 9-LAS in 21-d continuous-flow toxicity studies conducted in the Little Miami River (Ohio) above and below a wastewater treatment plant outfall. The lowest measured first-effect levels were 3.3 and 16.6 mg/L, respectively, in the two locations, based on reductions in structural and functional community characteristics. The presence of 20 to 30% effluent did not increase the toxicity of LAS. The field-derived effect levels confirmed the low phytotoxicity observed in most previously conducted laboratory toxicity studies with cultured algae. In addition, the field-derived effect levels exceeded measured environmental concentrations, which supports the environmental safety of LAS to periphyton.
Biodegradation of the anionic surfactant dialkyl sulphosuccinate
Authors: Hales Stephen G.
Published: March 2010

A range of Organisation for Economic Cooperation and Development (OECD) guideline test systems was used to determine the extent and possible mechanisms of biodegradation of dialkyl sulphosuccinate (DASS, C6/C8). Primary biodegradation of DASS was virtually complete in OECD guideline tests and in simulations of activated sludge sewage treatment systems under both optimal and adverse conditions, and of an anaerobic digester. Ultimate biodegradation increased from about 50% in ready tests to 94% in more powerful inherent tests. [14C]DASS was used to determine the fate of the surfactant in activated sludge and in surface waters. Mechanistic studies were performed to ascertain the biodegradative pathway of [14C]DASS. A putative degradation pathway for DASS is proposed.
Comparative toxicity of two oil dispersants to the early life stages of two marine species
Authors: Singer Michael M. , George Saji , Benner Diana , Jacobson Susan , Tjeerdema Ronald S. , Sowby Michael L.
Published: March 2010

Acute, flow-through, spiked-exposure toxicity tests were performed on the early life stages of two marine species using two oil dispersants. The species represent two common near-shore marine taxa: molluscs (red abalone, Haliotis rufescens) and crustaceans (kelp forest mysid, Holmes-imysis costata). The dispersants were composed of complex mixtures of anionic and nonionic surfactants and solvents. The toxicity data showed that one dispersant, Slik-A-Way, was more toxic than the other, Nokomis® 3, to both species. Median-effect concentration estimates for the two dispersants were significantly different between species. Slik-A-Way median-effect concentrations ranged from 16.8 to 23.9 initial ppm for Haliotis and 25.9 to 34.6 initial ppm for Holmesimysis, whereas Nokomis 3 median-effect concentrations ranged from 21.0 to 24.0 initial ppm for Haliotis and from 118.0 to 123.2 initial ppm for Holmesimysis. Differences in toxicity seen in the two dispersants may be due to differences in surfactant formulations.