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Archives of Environmental Contamination and Toxicology (v.32, #4)
Pesticides in Canals of South Florida by C. J. Miles; R. J. Pfeuffer (pp. 337-345).
Atrazine, ametryn, bromacil, simazine and norflurazon were the most frequently detected pesticides in surface water samples and DDE, DDD and ametryn were the most frequently detected pesticides in sediment samples collected over the period November 1991 to June 1995 in a monitoring network that includes 27 stations in south Florida canals. The 744 pesticide detections during this time period represent about 2% of the total number of analytical determinations. Many of the most frequently detected compounds were used in large amounts in the monitoring area based on pesticide usage estimates included in this study. Spatial trends in pesticide detections followed use patterns. The maximum atrazine detections occurred in winter to late spring and were associated with usage on turfgrass and agricultural products. Endosulfan residues above the Florida water quality criterion were occasionally observed in surface water in the Homestead area and most of the exceedences occurred in confined waters. Methods with lower MDLs have recently been developed and should increase the number of detections in future sampling. Pesticides which bind strongly to soil, pesticides that are highly persistent and those used in large amounts were some of the more frequently found pesticides in sediments.
Dissipation and Distribution of Atrazine, Simazine, Chlorpyrifos, and Tetradifon Residues in Citrus Orchard Soil by M. J. Redondo; M. J. Ruiz; G. Font; R. Boluda (pp. 346-352).
An environmental fate study was conducted in a citrus orchard plot in València (Spain) in the fall of 1993. Dissipation and distribution of atrazine, simazine, chlorpyrifos and tetradifon residues following their controlled addition for agricultural purposes in a mediterranean red soil (Luvic Calcisol, Rhodoxeralf) were evaluated. During a two-month period, the amounts of applied pesticides in different soil layers (0–0.05, 0.05–0.22, 0.22–0.42, and 0.42–0.52 m) were monitored. In addition, information on soils, weather and agricultural practice were collected. Degradation half-lives were calculated, assuming zero-order kinetics: 11 days for atrazine, 12 days for simazine, 10 days for chlorpyrifos, and 18 for tetradifon. The distribution through the soil profile shows that the pesticide concentrations were always highest in the upper layer (0–0.05 m) of soil, and that atrazine was the most mobile of all the four pesticides investigated.
Comparative Sensitivity of Selenastrum capricornutum and Lemna minor to Sixteen Herbicides by J. F. Fairchild; D. S. Ruessler; P. S. Haverland; A. R. Carlson (pp. 353-357).
Aquatic plant toxicity tests are frequently conducted in environmental risk assessments to determine the potential impacts of contaminants on primary producers. An examination of published plant toxicity data demonstrates that wide differences in sensitivity can occur across phylogenetic groups of plants. Yet relatively few studies have been conducted with the specific intent to compare the relative sensitivity of various aquatic plant species to contaminants. We compared the relative sensitivity of the algae Selenastrum capricornutum and the floating vascular plant Lemna minor to 16 herbicides (atrazine, metribuzin, simazine, cyanazine, alachlor, metolachlor, chlorsulfuron, metsulfuron, triallate, EPTC, trifluralin, diquat, paraquat, dicamba, bromoxynil, and 2,4-D). The herbicides studied represented nine chemical classes and several modes of action and were chosen to represent major current uses in the United States. Both plant species were generally sensitive to the triazines (atrazine, metribuzin, simazine, and cyanazine), sulfonureas (metsulfuron and chlorsulfuron), pyridines (diquat and paraquat), dinitroaniline (trifluralin), and acetanilide (alachlor and metolachlor) herbicides. Neither plant species was uniformly more sensitive than the other across the broad range of herbicides tested. Lemna was more sensitive to the sulfonureas (metsulfuron and chlorsulfuron) and the pyridines (diquat and paraquat) than Selenastrum. However Selenastrum was more sensitive than Lemna to one of two thiocarbamates (triallate) and one of the triazines (cyanazine). Neither species was sensitive to selective broadleaf herbicides including bromoxynil, EPTC, dicamba, or 2,4-D. Results were not always predictable in spite of obvious differences in herbicide modes of action and plant phylogeny. Major departures in sensitivity of Selenastrum occurred between chemicals within individual classes of the triazine, acetanilide, and thiocarbamate herbicides. Results indicate that neither species is predictively most sensitive, and that a number of species including a dicot species such as Myriophyllum are needed to perform accurate risk assessments of herbicides.
Detection of Toxic Organometallic Complexes in Wastewaters Using Algal Assays by S. L. Wong; L. Nakamoto; J. F. Wainwright (pp. 358-366).
Chlorella (a unicellular green alga) and Cladophora (a filamentous alga) were used in algal assays to identify the presence and toxicity of organometallic complexes in four industrial wastewaters. Toxicities of inorganic Pb and organometallic compounds (trimethyl, tetramethyl and tetraethyl leads, cacodylic acid and Cu-picolinate) were examined, using algal cells grown in 10% BBM solution. Inorganic Pb and organometallic compounds altered the fine structure of Chlorella cells in a distinguishable manner. X-ray microanalysis revealed that organometallic compounds accumulated in the neutral lipids of Cladophora cells. By applying the above techniques to the wastewater assays, two of the four wastewaters tested were found to contain organometallic complexes. Wastewater from a chemical company contained only traces of organo-Cu, but one mining effluent contained significant quantities of organo-Cu and organo-Pb, and traces of organo-Cr and organo-Tl (thallium). These studies suggest that X-ray microanalysis of algae may be a useful tool in identifying aquatic systems contaminated with metals and organometallic compounds.
Evaluation of Bleached Kraft Mill Process Water Using Microtox®, Ceriodaphnia dubia, and Menidia beryllina Toxicity Tests by D. P. Middaugh; N. Beckham; J. W. Fournie; T. L. Deardorff (pp. 367-375).
To determine whether a 7- to 10-d embryo toxicity/teratogenicity test with the inland silverside fish, Menidia beryllina, is a sensitive indicator for evaluation of bleached kraft mill effluents, we compared this test with the Microtox® 15-min acute toxicity test and the Ceriodaphnia dubia 7-d chronic toxicity test. Water samples used in each test were collected from three areas in a bleached kraft pulp and paper mill using a 100% chlorine dioxide bleaching process: 1) river water prior to use in the mill; 2) the combined acid/base waste stream from the pulping process prior to biological treatment in the aerated stabilization basin (ASB); and 3) the effluent from the ASB with a retention time of approximately 11 d. Relative toxicity determined by the three tests for each water sampling location was compared. All three toxicity tests were predictive indicators of toxicity; however, the C. dubia and M. beryllina tests were the more similar and sensitive indicators of toxicity. Process water (ASB influent) prior to biological treatment in the ASB was toxic at all concentrations using the Microtox® and C. dubia tests. The fish embryo test showed no toxicity at 1% concentrations, slight toxicity at 10%, and acute toxicity at the 100% ASB influent concentration. Tests with biologically-treated ASB effluent indicated a substantial reduction in observed toxicity to Microtox® bacteria, C. dubia, and M. beryllina. No toxic responses were observed in any test at a 1% ASB effluent concentration which was the approximate effluent concentration in the receiving river following mixing. No relationship was found among any toxicological response and effluent levels of adsorbable organic halides, polychlorinated phenolic compounds, 2,3,7,8-tetrachlorodibenzo-p-dioxin, 2,3,7,8-tetrachlorodibenzofuran, total suspended solids, color, chemical oxygen demand, or total organic carbon.
Psyllids as a Potential Source of Heavy Metals for Predators by E. Głowacka; P. Migula; S.-L. Nuorteva; P. Nuorteva; E. Tulisalo (pp. 376-382).
Contents of Al, Fe, Zn, Cu, Cd, Mn, Ni, and Hg were determined in 14 species of psyllids and in leaves of their host plants from unpolluted sites (Finland) and industrially polluted sites in Poland. Generally, psyllids accumulated low amounts of metals, but their metal burdens increased with age. Exuvia were important for the elimination of Al, Ni, and Mn, and larval wax for Al, Cu, and Ni. Biomagnification of metals, expressed as the concentration factor (cf) was low (cf: 0.56–1.08) for Mn, Al, and Ni, but high for Cd (cf: 5.86). Trioza chenopodii, Cacopsylla ulmi, and Psylla betulae represented the microconcentrators (cf: 0.9–1.25); the remaining species were the macroconcentrators (cf: 2.0–4.9). In polluted areas Psyllopsis fraxini eliminated large amounts of Al, Fe, Cu, Mn, and Cd with honeydew. This way of metal elimination was of less importance in species from unpolluted sites. Adults of Cacopsylla mali, P. fraxini, P. betulae, and Cacopsylla sorbi fall a prey to ants and may be important in transfer of Zn, Fe, Cu, Cd, and Ni. In comparison with aphids their role in metal transfer is marginal, due to better self-defence mechanisms and higher mobility, which protect them from potential predators and parasites.
The Effects of Used Motor Oil, Silt, and the Water Mold Saprolegnia parasitica on the Growth and Survival of Mole Salamanders (Genus Ambystoma) by H. Lefcort; K. A. Hancock; K. M. Maur; D. C. Rostal (pp. 383-388).
Amphibians appear to be declining worldwide. One cause of their decline may be used crankcase oil which leaks from motor vehicles and washes into ponds. Once in ponds, the oil may either be directly toxic to amphibians, or may indirectly affect them by disrupting food chains. The effects of oil may also be compounded by naturally occurring materials in the water column such as silt. Silt may interfere with respiration across gill surfaces. This study examined the effects of oil and silt on the growth and metamorphosis of larval mole salamanders, Ambystoma opacum and A. tigrinum tigrinum. In Experiment One it examined ponds with and without silty water and oil pollution to determine their suitability as habitats for salamander larvae. In Experiment Two it studied the effects of low levels of oil combined with silt on animals raised in the laboratory and fed prey items not raised in oil. In Experiment Three, it explored the effects of oil at an ecosystem level by raising the salamanders in the field in plastic micromesocosms that mimicked small ponds. Finally, in Experiment Four, in the laboratory, it examined the short-term survival of salamanders in high concentrations of oil. This study found that ponds containing oil and silt produce salamanders of reduced size and weight. Furthermore, while salamanders are relatively robust to the short term effects of large concentrations of used motor oil, oil has deleterious effects on the community and therefore exerts an indirect negative effect on salamanders. In the mi- cro-mesocosms containing oil, salamanders were smaller and weighed less than animals not raised in oil. Furthermore, silt results in reduced growth, earlier metamorphosis, and increased susceptibility to the water mold Saprolegnia parasitica.
Photoinduced Toxicity of Fluoranthene to Seven Marine Benthic Crustaceans by B. L. Boese; J. O. Lamberson; R. C. Swartz; R. J. Ozretich (pp. 389-393).
Seven marine benthic crustaceans were exposed in 4 d water-only toxicity tests to five concentrations of fluoranthene. After exposures, mortality (LC50) and the ability to bury in clean sediment (EC50) were determined. Survivors were then exposed to UV radiation for 1 h. The differences between LC50s and EC50s before and after UV exposure were used to assess photoinduced toxicity. UV exposure enhanced fluoranthene toxicity by as much as tenfold in five of the seven species tested (Rhepoxynius abronius, Eohaustorius estuarius, Leptocheirus plumulosus, Grandidierella japonica, and Corophium insidiosum). Species having the greatest potential for natural exposure to sunlight (Excirolana vancouverensis and Emerita analoga) were the least sensitive to photoinduced fluoranthene toxicity. Although photoinduced toxicity needs to be considered in environmental risk assessments, testing should be done, using ecologically relevant species and exposures.
The Effects of Tetrachloroguaiacol on the Growth, Survival, and Development of the Fathead Minnow, Pimephales Promelas by C. L. A. Woodland; E. J. Maly (pp. 394-398).
Fathead minnow (Pimephales promelas) larvae were exposed for 7 days to tetrachloroguaiacol (TeCG), within 24 h of hatching, at concentrations of 0, 25, 50, 100, 200, 400 μg/L. No significant difference in growth or larval survival was found among treatments. Embryos, within 24 h of fertilization, were also exposed to TeCG at concentrations of 0 and 100 μg/L for 10 days. No significant difference was found between the control and treatment groups for larval survival, body length, body width, or for yolk size of the eleutheroembryos. However, a significant difference was found in the hatching success of the eggs (p = 0.05). Since fathead minnows have been known to spawn in areas close to sites that discharge bleached kraft mill effluent (BKME) which contains TeCG, into receiving waters, naturally occurring populations will likely be affected by the toxicant.
Assessment of Cerebral Hemispheric Symmetry in Hatchling Chickens Exposed In Ovo to Polychlorinated Biphenyl Congeners by L. Lipsitz; D. Powell; S. Bursian; D. Tanaka, Jr. (pp. 399-406).
Previous investigators have reported that exposure to a mixture of environmental contaminants, including polychlorinated biphenyls, results in morphologic asymmetry of the cerebral hemispheres in hatchling great blue herons (Ardea herodias) and have suggested that this asymmetry may be a useful biomarker for contamination. This study was made to determine whether exposure to PCB congeners 3,3′,4,4′-tetrachlorobiphenyl (IUPAC #77) and 3,3′,4,4′,5-pentachlorobiphenyl (IUPAC #126) causes similar asymmetry in hatchling domestic chickens (Gallus domesticus). Eggs were injected at day 0 of incubation with either a high dose, low dose, or combination of each congener. At hatching, the chicks were perfused with 10% formalin-saline. The brains were removed, sectioned and stained with cresyl violet. Width and height measurements of each hemisphere were taken at eight locations, caudal to rostral, 400 μm apart starting at the level of the anterior commissure (CA) and ending at the lobus paraolfactorius (LPO). The absolute differences between measurements of the left and right sides were used to run a univariate split plot analysis of variance to determine if the amount of asymmetry present was associated with specific congeners or doses. Significant differences in asymmetry were found between noninjected control groups and vehicle-injected control groups (p ≤ 0.05), but not between noninjected controls and treatment groups. A first degree orthogonal polynomial contrast analysis illustrated a linear trend with asymmetry increasing from the most caudal section at the CA to the most rostral section at the LPO for both non-injected control and treatment groups (p ≤ 0.05). These data indicate that asymmetry may be normal in avian brains resulting from both intrinsic structural asymmetry and extrinsic molding forces acting on the head during development. Both of these factors should be taken into consideration when assessing the usefulness of cerebral asymmetry as a biomarker.
Arsenic Residues in Eggs from Laying Hens Fed with a Diet Containing Arsenic (III) Oxide by A. Holcman; V. Stibilj (pp. 407-410).
Three groups of six hens each were fed for twelve days with diets containing 7.5, 15.0, and 30.0 mg arsenic per kg in the form of As2O3. A control group was included in the trial. The hens from each group were formed into three subgroups. The eggs of two hens, laid in three days, formed a composite sample. The As concentration in the egg whites and yolks was determined in duplicate by radiochemical neutron activation analysis. With increasing As concentration in the poultry feedstuff, its concentration in egg yolk and white also increased, but a plateau appears to be reached quite rapidly. The ratio between the As concentration in yolk and in white is nearly constant (1:3) for all three groups of hens, irrespective of the level of As in the feed. The concentration of arsenic in dry matter of whites was significantly higher than in the dry matter of yolks, while the concentrations of arsenic in fresh samples of yolks were higher in the comparison with fresh samples of whites, but the differences were not significant.
Behavior of Captive American Kestrels Hatched from o,p′-Dicofol Exposed Females by K. N. M. MacLellan; D. M. Bird; L. J. Shutt; D. M. Fry (pp. 411-415).
A two-generation laboratory study was conducted on captive American kestrels (Falco sparverius) to investigate the possible behavioral alterations from the compound o,p′-dicofol. Paired females were exposed to three levels of dicofol by oral gavage. Adults of the second generation, exposed only via the maternal dose of o,p′-dicofol at 5- and 20-mg/kg, displayed negatively correlated changes in reproductive behaviors. Second generation females showed a significant difference (p < 0.05) from control birds in the miscellaneous behavior category, where more time was spent picking at the rope perch, watching flies, laying down on the perch and other such displacement activities. Second generation 5-mg/kg males completed significantly fewer copulations (p < 0.05) than the corresponding control birds. The number of attempted or failed food transfers (a pair bonding activity) was also significantly higher (p < 0.05) in the second generation 5-mg/kg male group. Trials were conducted on second generation males to determine aggressiveness of these individuals when placed in a competitive arena. Primary perch sites and food items were obtained by control birds significantly (p < 0.05) more often than dicofol-exposed males. A bird's maternal dose had a significant negative effect (p < 0.05) on its ability to achieve a high rank order position.
The Urinary Excretion of Arsenic Metabolites After a Single Oral Administration of Dimethylarsinic Acid to Rats by K. Yoshida; H. Chen; Y. Inoue; H. Wanibuchi; S. Fukushima; K. Kuroda; G. Endo (pp. 416-421).
The biotransformation following oral administration of dimethylarsinic acid (DMA), an organoarsenical herbicide and the main metabolite of inorganic arsenic in mammals, was studied in rats. Male F344/DuCrj rats were administered a single dose of DMA (50 mg/kg) orally. Urine was collected at 0, 2, 4, 8, 10, 24, and 48 h after administration by forced urination. Arsenic metabolites in urine were analyzed by ion chromatography with inductively coupled plasma mass spectrometry (IC-ICP-MS). The proportions of urinary elimination of DMA, trimethylarsine oxide (TMAO), methylarsonic acid (MMA), an unidentified arsenic metabolite, and arsenite were determined at various timepoints after administration. Unmetabolized DMA was the most common form excreted during the first 4 h. Thereafter, a gradual decrease in the proportion of DMA was observed, while progressive increases in those of TMAO, the unidentified metabolite, and arsenite occurred. The proportion of TMAO excreted amounted to over 50% of all arsenic in urine between 6 and 24 h. The proportion of the unidentified metabolite and arsenite were each approximately 10% at 10 and 24 h after administration. The findings indicate that DMA administered to rats was initially excreted as unchanged DMA, and later as the methylated metabolite, TMAO. Arsenite, a demethylated metabolite of DMA, also was excreted later than elimination of DMA and TMAO. The hypothesis of demethylation by intestinal microorganisms can be supported by comparing the metabolites following oral and intraperitoneal administration. The unidentified metabolite was readily decomposed by HCl but was left unchanged by NaOH; these findings suggest that it was present in a complexed form in urine.
Comparative Evaluation on the Biological Monitoring of Exposure to Parathion and Its Methyl Analog by M. J. W. Chang; Y. C. Chen; H. J. Yang (pp. 422-425).
The effects of both parathion and methyl parathion on the inhibition of plasma cholinesterase were elaborated in a rat model employing a modified isocratic reverse-phase HPLC method coupled with UV detection for the determination of the urinary metabolite p-nitrophenol (U-4NP). A linearity of r2 > 0.995 was found for a standard curve ranging from 0.06 to 0.96 μg/mL with a % relative error of ≤±10% and a recovery of 89 ± 2%. The % CV at all levels was ≤11%. A linear correlation was observed between the oral administration of parathion and methyl parathion for both the percent inhibiton of cholinesterase as well as the urinary elimination of 4NP. It is tentatively recommended that an U-4NP of 2.0 mg/g creatinine be established as a biological exposure index (BEI) for methyl parathion.
Impact of Carbofuran in the Oocyte Maturation of Catfish, Heteropenustes fossilis (Bloch) by S. Chatterjee; A. B. Dutta; R. Ghosh (pp. 426-430).
Investigations were undertaken to observe the influence of technical grade carbofuran (CF) on the egg maturational processes of catfish, Heteropneustes fossilis (Bloch). Fish were exposed to sublethal doses (0.5, 1, and 2 mg/L) of CF for 30 days at 25 ± 1°C. Control fish were maintained in water. The gonado-somatic index (G.S.I. = ovarian weight × 100/body weight) of the fish, treated with 1 or 2 mg/L CF, was decreased significantly compared to that of the controls. The inhibition was almost at the same level in these doses. CF at the dose of 0.5 mg/L was found to be ineffective. From the histomorphological observations of the ovary, it was observed that CF altered both the area and the percentage occurrence of the various types of primary oocytes in the ovary compared to that of the control fish. The stage I primary oocytes were predominantly higher in CF-treated fish than stage II and stage III which was reversed in control animals. The degeneration of follicular walls, connective tissues and vacuolization in the ooplasm of the stage II and III oocytes were observed in CF-treated fish (0.5–2 mg/L). It appears that CF at sublethal concentrations inhibits oocyte maturational processes in catfish.
Antimony in Drinking Water, Red Blood Cells, and Serum: Development of Analytical Methodology Using Transversely Heated Graphite Furnace Atomization-Atomic Absorption Spectrometry by K. S. Subramanian; R. Poon; I. Chu; J. W. Connor (pp. 431-435).
An atomic absorption spectrometric (AAS) method has been developed for determining μg/L levels of Sb in samples of water and blood. The AAS method is based on the concept of stabilized temperature platform furnace atomization (STPF) realized through the use of a transversely heated graphite atomizer (THGA) furnace, longitudinal Zeeman-effect background correction, and matrix modification with palladium nitrate-magnesium nitrate-nitric acid. The method of standard additions is not mandatory. The detection limit (3 standard deviations of the blank) is 2.6 μg Sb/L for the water, red blood cells (RBCs), and serum samples. Data are presented on the degree of accuracy and precision. The THGA-AAS method is simple, fast, and contamination-free because the entire operation from sampling to AAS measurement is carried out in the same tube. The method has been applied to the determination of Sb in some leachate tap water samples derived from a static copper plumbing system containing Sn/Sb solders, and in small samples (0.5 ml) of RBCs and serum derived from rats given Sb-supplemented drinking water.
Acute and Chronic Toxicity of Azinphos-Methyl to Two Estuarine Species, Mysidopsis bahia and Cyprinodon variegatus by M. G. Morton; F. L. Mayer, Jr.; K. L. Dickson; W. T. Waller; J. C. Moore (pp. 436-441).
The acute and chronic toxicity of azinphos-methyl (Guthion) was evaluated for two estuarine species in the laboratory. Mysids (Mysidopsis bahia) and sheepshead minnows (Cyprinodon variegatus) were selected as the representative invertebrate and vertebrate estuarine test species, respectively. The toxicological endpoints determined for each species included the 96-h LC50, the no-observed-effect concentration (NOEC), the maximum acceptable toxicant concentration (MATC), and the acute-to-chronic ratio. The 96-h LC50 value derived for sheepshead minnows (2.0 μg/L) was seven times higher than the 96-h LC50 value (0.29 μg/L) derived for mysids. The MATCs were 0.024 μg/L and 0.24 μg/L for the mysid and the sheepshead minnow, respectively. The estimated acute-to-chronic ratios were 12 for mysids and 8.3 for sheepshead minnows.
Characterization of the H4IIE Rat Hepatoma Cell Bioassay for Evaluation of Environmental Samples Containing Polynuclear Aromatic Hydrocarbons (PAHs) by K. L. Willett; P. R. Gardinali; J. L. Sericano; T. L. Wade; S. H. Safe (pp. 442-448).
The H4IIE rat hepatoma cell bioassay has been extensively used to assess the toxic equivalents (TEQs) of complex mixtures of halogenated aromatic hydrocarbons in environmental samples. However, there is often a discrepancy between bioassay induction results and toxic equivalents calculated from chemical analysis of samples; the former generally yield higher bioassay-TEQs. Polynuclear aromatic hydrocarbons (PAHs) are a class of chemicals which can significantly contribute to induction-TEQs. Benzo(a)pyrene (BAP), dibenz(a, h)anthracene (DBA), benz(a)anthracene (BA), benzo(k)fluoranthene (BkF), benzo(b)fluoranthene (BbF), chrysene (Chr), and indeno(1,2,3-c,d) pyrene (IdP) are carcinogenic PAHs found in environmental samples, including oysters collected from Galveston Bay. The induction potency of these PAHs relative to 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) was determined individually in rat hepatoma H4IIE cells seeded in 6-well plates, and the induction-derived equivalency factors (EFs) relative to TCDD were 0.000354, 0.00203, 0.000025, 0.00478, 0.00253, 0.00020, 0.0011 for BAP, DBA, BA, BkF, BbF, Chr, and IdP, respectively. Dilutions of a reconstituted PAH mixture containing 23 PAHs (744 to 4466 ng/g total PAHs) with constant percentages of BAP (4.5%), DBA (3.5%), BA (2.4%), BkF (3.7%), BbF (3.5%), Chr (4.7%), and IdP (4.2%) yielded bioassay-derived induction-EQs that ranged from 0.52 to 1.44 ng/g. Oysters exposed in the laboratory to the same PAH mixture for 30 days differentially accumulated the PAHs with time. Bioassay-EQs for these oyster extracts ranged from 0.94 to 5.79 ng/g. These results were similar to the chemically calculated EQs which varied from 0.81 to 3.13 ng/g.
PCB Congener Accumulation by Periphyton, Herbivores, and Omnivores by W. R. Hill; G. E. Napolitano (pp. 449-455).
The concentrations of 20 polychlorinated biphenyl (PCB) congeners were measured in periphyton, herbivorous fish (stoneroller minnows, Campostoma anomalum), and omnivorous fish (striped shiners, Luxilus chrysocephalus) in an industrially contaminated stream and a reference stream in eastern Tennessee. The sum of the concentrations of the 20 congeners, normalized by dry mass, was one to two orders of magnitude higher in stonerollers and shiners than in periphyton. Normalizing PCB concentrations by lipid mass reduced concentration differences between periphyton and stonerollers, but PCBs per unit lipid in stonerollers were still 50–350% higher than those in periphyton. Shiners had significantly higher lipid-specific PCB concentrations than did stonerollers, so a trophic hierarchy of primary producer < herbivore < omnivore was evident in lipid-specific PCB concentrations. Differences in lipid type, exposure duration, and exposure sources may account for the trophic-level differences in total PCBs. Congener profiles were roughly similar in periphyton, stonerollers, and shiners: five congeners (IUPAC numbers 101, 110, 138, 153, and 180) constituted >60% of the total mass of PCBs analyzed in all three trophic levels. However, stoneroller and shiner tissue was enriched in congeners 153, 118, and 187 relative to periphyton; congeners 153 and 187 are resistant to metabolic breakdown by monooxygenases found in fish liver. Principal component analysis of congener percentages separated periphyton from fish and distinguished between sampling locations.
Rock-Shells (Thais clavigera) as an Indicator of As, Cu, and Zn Contamination on the Putai Coast of the Black-Foot Disease Area in Taiwan by B. C. Han; W. L. Jeng; M. S. Jeng; L. T. Kao; P. J. Meng; Y. L. Huang (pp. 456-461).
This study presents the distribution of arsenic (As), copper (Cu), and zinc (Zn) in various seafoods—oysters (Crassostrea gigas), false fusus (Hemifuscus tuba), venus clams (Cyclina sineasis), green mussels (Perna viridis), blood clams (Arca granosa), flounders (Psettodes erumei), and rock-shells (Thais clavigera) collected from the Putai coast of the black-foot disease (BFD) area in Taiwan. Special attention is paid to evaluate the relationships among As, Cu, and Zn and effect of body size on metal concentration in Thais clavigera. Maximum Zn and Cu geometric mean (GM) concentrations (GM = 615 and 376 μg/g, dry wt, respectively) are found in oysters (Crassostrea gigas), and the values are much higher than those of the other organisms by about 1.7–208 and 1.8–375 times, respectively. Similarly, Thais clavigera has a high capacity for accumulating Cu and Zn collected from the same location. One interesting point is that relatively high As concentrations (GM = 65.7 μg/g, dry wt) in Thais clavigera are found as compared with those in other organisms (range from GM = 2.37 to 40.2 μg/g, dry wt). The As concentrations are significantly higher in Thais clavigera (1.62–27.7 times) than those in other organisms (p < 0.05), except for the false fusus (Hamifuscus tuba). A linear regression analysis shows a significant increase in Zn concentration with increasing Cu concentration in Thais clavigera. On the other hand, the As concentration is correlated with Cu and Zn concentrations (r = 0.77 and 0.77, respectively; p < 0.05) in Thais clavigera. Double logarithmic plots of metal content and concentration against dry-body weight and shell length show linear relationships. The result indicates that large individuals have higher contents of Cu, Zn and As, and have slopes of 1.58, 1.38, and 1.34, respectively. In addition, metal concentrations against shell length for all animal sizes also indicate that Cu, Zn and As have slopes of 1.92, 1.18, and 1.11, respectively. In conclusion, Thais clavigera has a high capactiy for accumulating As, Cu, and Zn and is a potential bioindicator for monitoring As, Cu and Zn.
Nitrite Mediated T Lymphocyte Responses in the Intestinal Immune System of Mice Infected with Trichinella spiralis Nematode by I. P. Grudzinski; F. C. P. Law (pp. 462-466).
The effects of orally administered sodium nitrite (20 mg NaNO2/kg b.w) on the responses of T and B lymphocytes collected from the mesenteric lymph nodes were studied in resistant AKR/J, H-2k haplotype mice infected with Trichinella spiralis nematode. On days 6, 9, and 12 postinfection, the mesenteric lymph node cells (MLNC) were collected from the mice and assayed for lymphocyte subsets (CD4+, CD8+, B220+), cytokines (IL-2, IL-5), and INF-γ. At the same time, the number of adult worms in the small intestine were counted. Infection of the nitrite-treated mice with T. spiralis L1 larvae caused a marked increase in the number of adult worms in the small intestine. However, preincubation of T. spiralis L1 larvae with nitrite before infecting the mice resulted in a significant reduction in the number of adult worms (p < 0.05). Preincubation of T. spiralis L1 larvae with nitrite also caused an increase in the number of CD4+ and CD8+ cells as well as IL-2, IL-5, and INF-γ levels. An increased level of CD8+ subsets and a depression of IL-2 and IL-5 production by MLNC were observed in mice infected with larvae without nitrite pretreatment. Since supplementary rIL-1α was found to alter INF-γ secretion by MLNC in vitro, the pattern of MLNC proliferation was examined further with the nitrite-treated mice. Sodium nitrite increased thymidine incorporation into the MLNC. However, INF-γ production was not enhanced when rIL-1α was added to the MLNC culture obtained from nitrite-treated mice.