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Archives of Environmental Contamination and Toxicology (v.54, #1)

Swelling of Four Glove Materials Challenged by Six Metalworking Fluids by Wenhai Xu; Shane S. Que Hee (pp. 1-8).

The performance of protective gloves against metalworking fluids (MWFs) has rarely been studied because of the difficult chemical analysis associated with complex MWFs. In the present study, glove swelling was used as a screening parameter of glove compatibility after challenge of the outer surfaces of chloroprene, latex, nitrile, and vinyl disposable gloves by six MWF concentrates for 2 hours in an ASTM F-739-type permeation cell without collection medium. Swelling relative to original thickness was up to 39% for latex, 7.6% for chloroprene, and 3.5% for nitrile. Shrinking up to 9.3% occurred for vinyl. Chloroprene and latex did not swell significantly for the semisynthetic and synthetic MWFs. Vinyl, previously not tested, was a good candidate for MWFs other than the soluble oil type. Although nitrile was recommended by the National Institute for the Occupational Safety and Health (NIOSH) for all types of MWFs, its swelling after 2-hour challenge was significant with Student t-tests for the soluble oil, synthetic, and semisynthetic MWFs. Glove swelling can be used as a screening chemical degradation method for mixtures such as MWFs with difficult chemical analysis. Further studies need to be conducted on the relationship between permeation and glove swelling.

Dioxin-Like Toxicity in the Saginaw River Watershed: Polychlorinated Dibenzo-p-Dioxins, Dibenzofurans, and Biphenyls in Sediments and Floodplain Soils from the Saginaw and Shiawassee Rivers and Saginaw Bay, Michigan, USA by Kurunthachalam Kannan; Se Hun Yun; Arthur Ostaszewski; John M. McCabe; Deborah Mackenzie-Taylor; Allan B. Taylor (pp. 9-19).

Sediment and floodplain soils in the Saginaw River Watershed, Michigan, USA, have been demonstrated to be contaminated with a variety of organic compounds, including polychlorinated biphenyls (PCBs), polychlorinated dibenzo-p-dioxins (PCDDs), and polychlorinated dibenzofurans (PCDFs). Existing data indicate that, at some locations, the contamination exceeds human health risk-based regulatory levels and ecological risk-based screening levels. In this study, concentrations of PCBs including non-ortho coplanar congeners, PCDDs, and PCDFs were measured in more than 120 sediment and floodplain soil samples collected from the Shiawassee River (a tributary of the Saginaw River), the Saginaw River, and Saginaw Bay, to determine the sources and magnitude of contamination, and to elucidate the contributions from individual contaminant groups to the overall 2,3,7,8-tetrachlorodibezo-p-dioxin equivalents (TEQs). Sediment and soil extracts were also analyzed for total dioxin-like activity by means of the H4IIE-luc cell bioassay. Elevated concentrations of PCBs (>1000 ng/g, dry weight) were found in surface sediment and floodplain soil samples collected from the Shiawassee River near Chase Lake, from Middleground Island in the Saginaw River, and from subsurface sediments in Saginaw Bay. Concentrations of PCDDs and PCDFs in sediment and floodplain soils from the Saginaw River and Saginaw Bay were 2 to 3 orders of magnitude higher than concentrations in the samples from the Shiawassee River. The highest PCDD/F concentration (55,200 pg/g, dry weight in a subsurface layer) was found in sediment collected at the mouth of the Saginaw River. Concentrations of PCDFs were greater than the concentrations of PCDDs in sediment from the Saginaw River. 2,3,7,8-TCDF, 1,2,3,7,8-PeCDF, and 2,3,4,7,8-PeCDF were the major PCDF congeners found in sediments from the Saginaw River. The elevated concentrations of PCDFs, and the predominance of the less highly chlorinated PCDF congeners, in sediments from the Saginaw River were similar to previously determined characteristics of the PCDF contamination of the Tittabawassee River, another tributary of the Saginaw River. These results suggest the existence of a major source of PCDFs within the watershed. A few localized areas of high PCDD/F and PCB concentrations, with unique congener compositions, in the Saginaw River indicated the presence of other minor sources, such as wastewater treatment plants. PCDFs were the major contributors to TEQs in sediment and soils from the Saginaw River and Saginaw Bay. Approximately 30% of the samples analyzed in this study had values exceeding the screening level of 50 pg TEQ/g, dry wt, suggested for soils by the Agency for Toxic Substances and Disease Registry.

Polychlorinated Dibenzo-p-Dioxins, Dibenzofurans, and Dioxin-Like Polychlorinated Biphenyls in Sediment and Mussel Samples from Kentucky Lake, USA by Bommanna G. Loganathan; Kurunthachalam Senthil Kumar; Shigeki Masunaga; Kenneth S. Sajwan (pp. 20-30).

Sediment and mussel tissues from the Kentucky Dam Tailwater (KDTW) and Ledbetter Embayment (LE) of Kentucky Lake, Kentucky, USA, were analyzed to examine the presence of 2,3,7,8-substituted polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs), and non-, mono-, and di-ortho-chlorine-substituted polychlorinated biphenyls. Concentrations of target compounds varied with locations and sample matrices. In general, KDTW sediment samples contained slightly higher amounts of PCDD/DFs (average: 1100, range: 120-2400) than the LE sediments (average: 920, range: 580-1300) on a pg/g dry wt (dw) basis. Dioxin-like PCBs in KDTW were (average: 550, range: 70–2,000) higher than in LE (average: 320, range: 44-1000) on a ng/g dw basis. In contrast, mussel tissues had greater concentrations of PCDD/DFs in LE (average: 6500, range: 2200–13,000) than in KDTW (average: 3500, range: 2500-4800). Dioxin-like PCBs were slightly higher in KDTW (average: 76, range: 18–100) than in LE (average: 49, range: 24–96) on a ng/g fat wt basis. Biota sediment accumulation factors (BSAFs) were calculated using tissue concentrations and sediment concentrations based on dry weight. PCDD/DFs BSAF was in the range of 0.21-25 in LE and 0.093-13 in KDTW. 1,2,3,7,8,9-HxCDF in LE and 2,3,7,8-TCDF in KDTW had a greater BSAF, while BSAF for dioxin-like PCBs ranged from 0.84 to 13 in LE and from 2.3 to 12 in KDTW in which PCB-169 had the greatest BSAF in LE and PCB-167 in KDTW. Toxic equivalency (TEQ) was greatest in mussel from LE (mean: 193 pgTEQ/g fat wt) followed by mussel from KDTW (32 pgTEQ/g fat wt), sediment in KDTW (13 pgTEQ/g dry wt), and sediment in LE (7.6 pgTEQ/g dry wt). In general, PCDD/DF had a greater contribution to toxicity in mussels, while dioxin-like PCBs had a greater contribution to toxicity in sediment at both locations.

Assessing Caffeine as an Emerging Environmental Concern Using Conventional Approaches by M. T. Moore; S. L. Greenway; J. L. Farris; B. Guerra (pp. 31-35).

Organic wastewater contaminants, including pharmaceuticals, caffeine, and nicotine, have received increased scrutiny because of their detection in water bodies receiving wastewater discharge. Despite recent measurement in United States streams, caffeine’s effect on freshwater organisms is not well documented. The present study measured caffeine’s lethal and sublethal effects on the freshwater species, Ceriodaphnia dubia, Pimephales promelas, and Chironomus dilutus. These organisms, which are used in standard testing or effluent monitoring, were exposed to aqueous caffeine solutions under static exposure for 48 hours and daily renewed static exposure for 7 days. Averaged responses of 48-hour acute end points indicated that C. dubia was more sensitive to caffeine exposures (LC₅₀ = 60 mg/L) than either P. promelas (LC₅₀ = 100 mg/L) or C. dilutus (LC₅₀ = 1,230 mg/L). Exposure-response slopes confirmed these findings (3% mortality/mg/L for C. dubia; 0.5% mortality/mg/L for P. promelas; and 0.07% mortality/mg/L for C. dilutus). Comparative 7-day responses between C. dubia and P. promelas (LC₅₀ = 46 and 55 mg/L, respectively) were more similar than the broad range of acute values. Sublethal effects measured for caffeine exposure included impaired C. dubia reproduction (IC₅₀ = 44 mg/L) and inhibited P. promelas growth (IC₅₀ = 71 mg/L). According to the results of this study, combined with earlier studies reporting environmental concentrations and product half-lives, caffeine should pose negligible risk for most aquatic vertebrate and invertebrate organisms.

Enantioselective Chronic Toxicity of Fipronil to Ceriodaphnia dubia by W. Aaron Wilson; Brad J. Konwick; Arthur W. Garrison; Jimmy K. Avants; Marsha C. Black (pp. 36-43).

Fipronil is a phenylpyrazole pesticide that has greatly increased in popularity in recent years. As a chiral molecule, fipronil is released into the environment as a 1:1 mixture (called a racemate) of its two enantiomers. Previous toxicity work has indicated that the enantiomers of fipronil exhibit significantly different levels of acute toxicity to the nontarget organism Ceriodaphnia dubia. In this work we examine the chronic effects of the pure enantiomers and racemate on the survival, development, mobility, and reproduction of C. dubia adults and the survival and mobility of their offspring. Based on 8-day trials, the (+) enantiomer of fipronil showed a significantly greater reduction in the number of offspring (LOEC = 2 μg/L) than either the racemate (LOEC = 15 μg/L) or the (−) enantiomer (LOEC = 30 μg/L). The (+) enantiomer was also shown to be significantly more toxic to neonates born during the course of the experiment (LC50₂₄ = 18.1 μg/L, LC50₄₈ = 10.3 μg/L) than the racemate (LC50₂₄ = 33.3 μg/L, LC50₄₈ = 30.3 μg/L), but only after 48 h. Both the (+) enantiomer and the racemate were significantly more toxic to C. dubia than the (−) enantiomer (LC50₂₄ = 65.2 μg/L, LC50₄₈ = 50.1 μg/L) at both time points. Qualitative mobility data followed a similar trend, with the (+) enantiomer causing greater impairment in mobility at low concentrations. These data imply that the (−) enantiomer has less impact on the reproductive success of C. dubia than either the (+) enantiomer or the racemate. Enantiomerically pure or enriched formulations of (−) fipronil may reduce impacts to the nontarget organism C. dubia.

The Influence of Salinity and Dissolved Organic Carbon on the Toxicity of Copper to the Estuarine Copepod, Eurytemora affinis by L. W. Hall Jr.; R. D. Anderson; B. L. Lewis; W. R. Arnold (pp. 44-56).

The objectives of this study were to determine the influence of salinity (2.5, 5, 15, and 25 ppt) at dissolved organic carbon (DOC) concentrations of 1.3–3.3 mg/L and DOC concentrations of 2, 4, 6, and 8 mg/L at a fixed salinity of 10 ppt on the acute toxicity (96-h LC50s) of copper to the sensitive estuarine copepod, Eurytemora affinis. For both salinity and DOC experiments, various other chemical constituents such as DOC, Ca²⁺, Cl^-, Mg²⁺, Na⁺, K⁺, SO ₄ ^2- , hardness, alkalinity, salinity, pH, temperature, and dissolved oxygen were measured at selected copper concentrations at test initiation and test termination. Dissolved copper, copper speciation, and organic copper complexation were measured at various test conditions during the salinity and DOC experiments. Ninety-six-hour dissolved copper LC50 values for the four salinities ranged from 58 μg/L (25 ppt) to 104 μg/L (5 ppt) with intermediate values of 71 μg/L (2.5 ppt) and 68 μg/L (15 ppt). The 58, 68, and 71 μg/L LC50 values were not significantly different. Copper LC50 values at 5 ppt were higher than at both 15 and 25 ppt. The isosmotic salinity of E. affinis is approximately 5–10 ppt, which was a likely factor for why the LC50 value increased for copper at 5 ppt. The dissolved copper 96-h LC50s for E. affinis increased from 76 to 166 μg/L as DOC increased from 2 to 8 mg/L. This result is not surprising and is consistent with reported values for other saltwater species.

Predictability of Copper, Irgarol, and Diuron Combined Effects on Sea Urchin Paracentrotus lividus by S. Manzo; S. Buono; C. Cremisini (pp. 57-68).

The aim of this work was to investigate the mixture toxicity of Irgarol (2-methylthio-4-t-butylamino-6-cyclopropylamino-s-triazine), Diuron (3-(3,4-dichlorophenyl)-1,1-dimethylurea), and copper upon the sea urchin Paracentrotus lividus and to compare the observed data with the predictions derived from approaches of Concentration Addition (CA) and Independent Action (IA). Copper spermiotoxicity was more sensitive (EC50 = 0.018 mg/L) than embryotoxicity (EC50 = 0.046 mg/L). The offspring malformations were mainly P1 type (skeletal alterations) in both cases, probably because copper competes to fix Ca²⁺. Irgarol and Diuron toxicity has been previously investigated. EC50 mixture embryotoxicity showed an EC50 of 1.79 mg/L, whereas spermiotoxicity mixture effects were lower than 11%. Both CA and IA modeling approaches failed to predict accurately mixture toxicity. For embryotoxicity, the IA model overestimated the mixture toxicity at effect levels of <80%. CA does not represent the worst-case approach showing values lower than IA (embryotoxicity) or similar (spermiotoxicity).

Keywords: Mixture toxicity; Copper; Irgarol; Diuron; Paracentrotus lividus

Effects of Water-borne Copper on the Y-organ and Content of 20-hydroxyecdysone in Eriocheir sinensis by Zhi-biao Yang; Yun-long Zhao; Na Li; Jian Yang; Xiu-guo Hua (pp. 69-74).

The effects of water-borne copper (Cu²⁺) (0.01, 0.10, 1.00, and 5.00 mg/L) on Y-organ (YO) microstructure and ultrastructure and on the content of 20-hydroxyecdysone (20-HE) in Eriocheir sinensis were studied using single gradient factor experiments. Results demonstrated that there was no significant difference in YO microstructure and ultrastructure when E. sinensis was exposed to 0.01, 0.10, and 1.00 mg/L water-borne Cu²⁺. However, exposure to 5.00 mg/L Cu²⁺ caused serious damage to the YO microstructure, with an obvious decrease in hemocoel and the disappearance of the basement membrane between cell fibers. In addition, there was an intumescence of cells around the hemocoel, the cell nucleus became enlarged or even rounded, and some cells around the hemocoel crumpled with only the cell nucleus isolated or even huddled in the hemocoel. Similarly, effects of water-borne Cu²⁺ on the YO ultrastructure were observed: obvious enlargement and rounding of the cell nucleus, high heterochromatinization of the nucleus chromatin, disappearance of the YO cell membrane in some severely damaged cells, and varied damage in cellular organelles, such as the disappearance of cristae in mitochondria and disruption of the nucleus membrane. The hemocyte nucleus showed considerable heterochromatinization. In addition, when the Cu²⁺ concentration increased, the content of 20-hydroxyecdysone (20-HE) decreased in all Cu²⁺ treatment groups (P < 0.05). Results of this study indicate that high water-borne Cu²⁺ concentration impaired the basic structure of YO, which is regarded as the secretion site of 20-HE, and hence decreased the content of 20-HE in hemolymph. Therefore, molting frequency as well as the growth of E. sinensis is inhibited when exposed to high concentrations of water-borne Cu²⁺.

Heavy Metal Distribution in Tissues of Six Fish Species Included in Human Diet, Inhabiting Freshwaters of the Nature Park “Hutovo Blato” (Bosnia and Herzegovina) by Elizabeta Has-Schön; Ivan Bogut; Valentina Rajković; Stjepan Bogut; Milan Čačić; Janja Horvatić (pp. 75-83).

The aim of the study was to quantify heavy metal (mercury, lead, cadmium, and arsenic) concentration in tissues (muscles, liver, kidney, gills, and gonads) of six fish species (carp: Cyprinus carpio, tench: Tinca tinca, pumpkinseed: Lepomis gibosus, prussian carp: Carassius auratus gibelio, hasselquist: Salmo dentex, eel: Anguilla anguilla) from the freshwaters of the Nature Park Hutovo Blato, Bosnia and Herzegovina, and determine whether they are potentially harmful for human health if included in the diet. Fish were angled from the Svitava Lake in the second part of August of the year 2003, and fish tissues were stored at −18°C until analysis. Heavy metal concentration was determined by atomic absorption spectrophotometry in the Veterinary Institute Brno, Czech Republic, and expressed as mg·kg⁻¹ of wet tissue. Concentration of mercury, lead, and arsenic in most tissues of all analyzed fish types is lower than the maximal allowed concentration (MAC) in most countries. Cadmium concentration is also low in muscles and gonads, but kidney, liver, and gill concentrations exceed MAC value in most countries. Hasselquist, an endemic type for that region, differs from other fish types in the fact that it has very low cadmium concentration in liver and kidney, but the highest concentration of arsenic in most tissues, especially muscles. In muscles and gonads of all fish types analyzed, Pb is present in higher concentration than Cd, whereas in liver, gills, and particularly kidney, the situation is opposite, suggesting diverse metabolic pathways and unequal bioaccumulation of these two metals in different fish tissues. Although the region of the Nature Park Hutovo Blato in Bosnia and Herzegovina is not an agricultural territory, the intensive agricultural activities in the neighboring regions already result in high cadmium concentration in inner organs of fish species analyzed. Therefore, fish types in the freshwaters of the Park may be included in the human diet, but without inner organs and gills (or the whole head).

Keywords: Mercury; Lead; Cadmium; Arsenic; Carp (Cyprinus carpio) ; Pumpkinseed (Lepomis gibosus) ; Eel (Anguilla anguilla) ; Tench (Tinca tinca) ; Prussian carp (Carassius auratus gibelio) ; Hasselquist (Salmo dentex) ; Hutovo blato

A Real-Time PCR Method for the Quantification of the Two Isoforms of Metallothionein in Lake Trout (Salvelinus namaycush) by Julieta Werner; Vince Palace; Christopher Baron; Robert Shiu; Alison Yarmill (pp. 84-91).

Metallothioneins (MTs) are low-molecular-weight proteins whose physiologic roles are the regulation of essential metals Cu and Zn, sequestration of heavy metals, and free radical scavenging. Induced production of MTs in a wide variety of organisms exposed to heavy metals has made them popular exposure indicators. While it has been postulated that the three different isoforms of MT play different physiologic roles, methods to discern induction separately have not been available. The development of real-time polymerase chain reaction (real-time PCR) primers and TaqMan probes to measure the two MT isoforms found in salmonid fish are described. Assuming a high degree of homology between the isoforms and within different groups of salmonids, the sequences for MT-I and MT-II from rainbow trout were used to develop primers and probes for lake trout using the Primer3 program. Two sections of each isoform that varied by only a few nucleotides were targeted. SYBR Green validated the primer specificity, and melt curve analysis further ensured that only one product was amplified. Analysis of archived samples from fish captured in unmanipulated reference lakes or from lakes experimentally treated with cadmium or ethynylestradiol (EE2) afforded an examination of seasonal and contaminant influences on MT-I and MT-II mRNA expression.

Change of Abundance of Arthropods in Pine Forests Caused by Aerial Insecticide Spray by Tae-Sung Kwon (pp. 92-106).

As pine wilt disease (PWD) spread rapidly throughout the Republic of Korea, pine stands were subjected to insecticide spraying that was gradually increased, which raised concerns regarding the negative impact of insecticides sprayed on nontarget organisms of pine forests. This study aims to estimate the changes in the abundance of arthropods caused by long-term insecticide spraying common in PWD-infected forests. Four pine stands were selected as sprayed and unsprayed sites in two locations in the southern regions of Busan and Gyongnam-do, showing the peaks of PWD epidemics. Beatings, sweepings, and pitfall trappings were used for collecting arthropods at the crown, undergrowth, and ground for 4 years, starting in May 2001. Long-term effects caused by yearly repeated insecticide treatments were not found to be related to changes in the abundance of arthropods, but short-term impacts within a year showed different influences according to habitats and functional groups.

Comparison of Metal Bioavailability in Frogs from Urban and Rural Sites of Western Ukraine by O. B. Stolyar; N. S. Loumbourdis; H. I. Falfushinska; L. D. Romanchuk (pp. 107-113).

The seasonal and spatial fluctuations of heavy metals in the liver of the frog Rana ridibunda from a river in Western Ukraine were investigated. Liver weight was seen to increase from spring to summer/autumn, most probably as a result of accumulation of metabolites, especially fat and glycogen. The concentrations of the metals found in the liver of the frog was in the order: Fe>Cu∼Zn>Mn>Cd. For most metals, the highest concentration was recorded in the frogs inhabiting the urban site. The highest level of Cu in the liver was observed in the spring, in the agricultural site, while the highest level of other metals was observed in the summer. The most probable explanation for the high concentration of Cu in the rural site was that in this wetland there were discharge effluents from fungicides with Cu in their formula. Compared to other metals, the bioavailability of Cu was approximately 1000 times higher. The high concentration of Fe rather reflects its fluctuation in the water. Despite its very low concentration in the water (below the limit of detection), Cd was detected in the liver of frogs inhabiting both sites. This is an indication that tissues accumulate Cd, despite the very low concentration detected in the water. This may be an indication of intermittent exposure of frogs to Cd and possibly of other heavy metals.

Concentrations of Metals in Blood and Feathers of Nestling Ospreys (Pandion haliaetus) in Chesapeake and Delaware Bays by B. A. Rattner; N. H. Golden; P. C. Toschik; P. C. McGowan; T. W. Custer (pp. 114-122).

In 2000, 2001, and 2002, blood and feather samples were collected from 40–45-day-old nestling ospreys (Pandion haliaetus) from Chesapeake Bay and Delaware Bay and River. Concentrations of 18 metals, metalloids, and other elements were determined in these samples by inductively coupled plasma-mass spectroscopy, and Hg concentrations were measured by cold vapor atomic absorption spectroscopy. When compared to concurrent reference areas (South, West, and Rhode Rivers), mean As and Hg concentrations in blood were greater (p < 0.05) in two of three Chesapeake Bay regions of concern (Baltimore Harbor [As: 1.18 vs. 0.548 μg/g dw], Anacostia River [Hg: 0.305 vs. 0.178 μg/g dw], and Elizabeth River [As: 0.876 vs. 0.663 μg/g dw; Hg: 0.260 vs. 0.180 μg/g dw]). Lead was detected more frequently in blood of nestlings from the highly industrialized Elizabeth River compared to the rural reference area. When compared to the concurrent reference area, mean Al, Ba, Hg, Mn, and Pb concentrations in feathers were substantially greater (p < 0.05) in one or more Chesapeake regions of concern (Anacostia River [Al: 206 vs. 62.1 μg/g dw; Ba: 3.31 vs. 0.823 μg/g dw; Mn: 65.4 vs. 22.9 μg/g dw] and Elizabeth River [Al: 165 vs. 63.5 μg/g dw; Hg: 1.24 vs. 0.599 μg/g dw; Pb 1.47 vs. 0.543 μg/g dw]). When compared to the coastal Inland Bays reference area, feathers of nestlings from northern Delaware Bay and River had greater concentrations (p < 0.05) of Ba (1.90 vs. 0.660 μg/g dw), Fe (258 vs. 109 μg/g dw), Mn (18.5 vs. 4.66 μg/g dw), Mo (0.130 vs. 0.040 μg/g dw), Pb (1.96 vs. 0.624 μg/g dw), and V (0.671 vs. 0.325 μg/g dw), presumably due to extensive metal-working and petroleum refinery activities. Concentrations of Hg in nestling feathers from Delaware were frequently greater than in the Chesapeake. The present findings and those of related reproductive studies suggest that concentrations of several heavy metals (e.g., Cd, Hg, Pb) in nestling blood and feathers from Chesapeake and Delaware Bays were below toxicity thresholds and do not seem to be affecting chick survival during the nestling period.

The Effects of 3,3′,4,4′,5-Pentachlorobiphenyl (PCB 126) on Mink (Mustela vison) Reproduction and Kit Survivability and Growth by K. J. Beckett; B. Yamini; S. J. Bursian (pp. 123-129).

This study was conducted to determine if dietary exposure to 3,3′4,4′,5-pentachlorobiphenyl (PCB 126) would have an adverse effect on the reproductive performance of female mink (Mustela vison) and survivability and growth of their kits. Standard dark, female mink were fed diets containing PCB 126 at concentrations of 0, 0.24, 2.4, and 24 μg PCB 126/kg feed (0, 24, 240 and 2,400 ng 2,3,7,8-tetrachlorodibenzo-p-dioxin [TCDD] toxic equivalents [TEQs]/kg, respectively) from 21 days prior to breeding until weaning of their kits at six weeks of age. There were no significant differences in the number of females that whelped or the average litter size between the control group and the 0.24 μg PCB 126/kg feed group. In addition, kit body weights at birth and at three, six and 28 weeks of age as well as kit survivability through weaning were similar between the two groups. In contrast, female mink fed diets containing 2.4 and 24 μg PCB 126/kg feed that had confirmed matings, failed to whelp. Histological examination of their uterine horns verified fetal implantation sites or placental scars, which indicated partial fetal development. Based on the impaired reproductive performance reported in this study, a no observable adverse effect level (NOAEL) of 0.24 μg PCB 126/kg feed (24 ng TEQs/kg) and a lowest observable adverse effect level (LOAEL) of 2.4 μg PCB 126/kg feed (240 ng TEQs /kg) were determined.

Effectiveness of Various Exposure Metrics in Defining Dose-Response Relationships for Mink (Mustela vison) Exposed to Polychlorinated Biphenyls by P. C. Fuchsman; T. R. Barber; M. J. Bock (pp. 130-144).

We conducted a quantitative analysis of published results from more than 50 tests of polychlorinated biphenyl (PCB) effects on mink reproduction, which provided a basis for evaluating how well different methods of measuring and assessing PCB concentrations can approximate a toxicologically relevant dose for this endpoint. Several dose metrics were identified for comparison. Dietary dose metrics included the daily intake of total PCBs and the daily intake of 2,3,7,8-tetrachlorodibenzo-p-dioxin toxicity equivalence concentrations (TECs), calculated using World Health Organization toxicity equivalence factors (TEFs). Internal dose metrics included whole-body total PCBs, whole-body TECs calculated using World Health Organization TEFs, and whole-body TECs calculated using alternative TEFs specifically identified for internal dose assessment. Accounting for the bioaccumulative potential (i.e., internal dose) of ingested PCBs proved to be more important than accounting for the concentrations of dioxin-like PCB congeners in explaining the observed variation in reproductive success. This was true regardless of whether internal doses were estimated from dietary data based on homolog concentrations (whole-body total PCBs) or congener concentrations (whole-body TECs). For each of the PCB dose metrics, a range of toxicity reference values is identified based on the species-specific PCB toxicity database compiled for this evaluation.

Accumulation of Organotin Compounds in Tissues and Organs of Dolphins from the Coasts of Thailand by Hiroya Harino; Madoka Ohji; Gullaya Wattayakorn; Karnjana Adulyanukosol; Takaomi Arai; Nobuyuki Miyazaki (pp. 145-153).

The concentration of organotin (OT) in seven species of dolphin (bottlenose dolphin, finless porpoise, Indo-Pacific humpbacked dolphin, long-beaked common dolphin, Pantropical spotted dolphin, spinner dolphin, and striped dolphin), which were stranded on the coasts of Thailand, were measured. Butyltin (BT) and phenyltin (PT) compounds in tissues and organs of the dolphins were in the range of 16-1,152 μg kg⁻¹ and <1-62 μg kg⁻¹, respectively. The highest concentration of tributyltin (TBT) was generally observed in the liver. Because of the lower concentration of TPT, a trend in body distribution was not observed. Monobutyltin (MBT) among all the BTs was the dominant species in tissues and most organs except the liver. However, dibutyltin (DBT) was predominant in the liver. Monophenyltin (MPT) was not detected in all dolphins in the study. The higher concentration of BTs was observed with the increase in body length of dolphins. On the other hand, no significant difference in the concentration of OTs between genders was observed. The concentrations of OTs in tissues and organs were compared among dolphin, whales, and dugongs stranded on the coasts of Thailand. The concentrations of BTs were high and in the order of whales > dugongs > dolphins and the concentrations of PTs in whales were higher than those in dolphins and dugongs.

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Archives of Environmental Contamination and Toxicology (v.54, #1)