Effects of diazinon on mummichog (Fundulus heteroclitus) larvae produced from eggs differentially treated with PCB126.

During their formation, fish eggs receive a load of contaminants including polychlorinated biphenyls (PCBs) from their mother and then, after spawning, are exposed to pesticides present in water. This is the first study investigating the interaction between PCBs and organophosphorous pesticides in fish. The effect of diazinon was evaluated in mummichog (Fundulus heteroclitus) larvae produced from eggs differentially treated with 3,3',4,4',5 pentachlorobiphenyl (PCB126). A few hours after fertilization, eggs were treated topically with a solution of PCB126 (100 pg/microl) in dimethyl sulfoxide (DMSO) (Group P), DMSO (Group D), or not treated (Group N). Newly hatched larvae from Groups P and D were exposed to diazinon (125-12,900 ng/L) in saltwater and Group N larvae to saltwater alone. Diazinon caused a dose-responsive inhibition of cholinesterase (ChE) activity at environmentally realistic concentrations (> or =361 ng/L), with up to 85% inhibition at 12,900 ng/L. Body length was also inversely related to diazinon at concentrations > or =361 ng/L and was significantly reduced (by 4%) at 12,900 ng/L compared to controls. Mummichog larvae were highly sensitive to PCB126 with an eightfold induction of the activity of ethoxyresorufin-O-deethylase at a dose of 710 pg PCB126 or 3.6 pg TCDD-TEQ/g wet weight. Treatment with PCB126 also caused a slight reduction in body length but no effect on ChE activity. This study indicates that the effects of PCB126 and diazinon on body length are cumulative because no significant synergistic or antagonistic interactions were observed. Longer term studies with several doses of PCB126 are needed to fully assess the overall impact of joint exposure to diazinon and PCB126 on growth and survival of fish larvae.

Reduction of cytochrome P4501A with age in Atlantic tomcod from the St. Lawrence Estuary, Canada: relationship with emaciation and possible effect of contamination.

This study reports a reduction of ethoxyresorufin-O-deethylase (EROD) activity in large-sized, older Atlantic tomcod (Microgadus tomcod) collected in the St. Lawrence Estuary (Quebec, Canada) and investigates its relationship over a 4-year period to sex, gonadosomatic index (GSI), condition factor (CF) and cytochrome P4501A (CYP1A) mRNA levels. In addition, the concentrations of polychlorinated biphenyls (PCBs) were measured in a subsample of fish. The reduction of EROD activity with age was observed each year in both sexes and was not related to the GSI. A high proportion of large-sized fish, with a body length greater or equal to 225 mm, were emaciated (CF < or = 0.55). A 6-16-fold reduction of EROD activity and a 2-4-fold reduction of CYP1A mRNA levels were observed in large-sized emaciated females compared to small-sized non-emaciated females. Concentrations of PCBs in liver increased from 1000 to 4000 ng/g lipid weight as the hepatic lipid content and the CF decreased. The inter-annual variation of EROD activity was associated with the variation in CF with lowest EROD activity and CF in 1999. When emaciated fish were excluded from the analyses, EROD activity was still lower (2-5-fold) in large compared to small fish and was no longer related to CF. For similar levels of CYP1A mRNA, EROD activity was lower in large compared to small fish. Thus, there was post-transcriptional inhibition of CYP1A activity in large-sized tomcod, indicative of cellular dysfunction. This response may be related to aging, chronic exposure to toxic contaminants or to selective pressures favoring less responsive individuals. This study demonstrates that fish age, size, and CF are important variables to consider in studies using EROD activity as an indicator of environmental contamination. The main finding was that a large part of the reduction of CYP1A with age in St. Lawrence Estuary tomcod was associated with severe emaciation of a large proportion of large-sized fish. Hepatic concentrations of contaminants covaried with the CF and the effects of these two variables on CYP1A could not be discriminated.

Global distribution of halogenated dimethyl bipyrroles in marine mammal blubber.

Four halogenated dimethyl bipyrroles (HDBPs), hypothesized to be naturally produced, were quantitated in marine mammal blubber from a number of species obtained from various locations worldwide. HDBPs were found in samples from all locations studied. Concentrations of total HDBPs (SigmaHDBPs) ranged from 0.4 ng/g lipid weight in ringed seals (Phoca hispida) from the White Sea to 2,540 ng/g lipid weight in Dall's porpoise (Phocoenoides dalli) from the northwestern North Pacific Ocean. At their highest levels, SigmaHDBPs made up 11% of the total quantitated organohalogen body burden of adult male Dall's porpoises. In two beluga (Delphinapterus leucas) data subsets, it was found that males contained significantly higher concentrations of SigmaHDBPs than females. No significant effects of age or sex on SigmaHDBPs were observed in harbor seal (Phoca vitulina) and bowhead whale (Balaena mysticetus) data subsets. The geographical distribution of concentrations did not resemble that of the ubiquitous anthropogenic organohalogen, polychlorinated biphenyl congener CB-153. Higher concentrations of HDBPs and different patterns of congeners were observed in samples from Pacific as opposed to non-Pacific Ocean influenced environments. Concentrations of HDBPs in beluga from the Arctic and St. Lawrence River were similar. Their high abundance in north Pacific Ocean biota and widespread occurrence suggest that HDBPs undergo extensive transport from a source located primarily in the Pacific Ocean. Evidence from HDBP congener patterns indicates that both ocean currents and atmospheric transport likely play a role in the movement of HDBPs. These results imply that HDBPs and anthropogenic organohalogens have different sources and support the natural production hypothesis.

Effects of exposure of Mya arenaria and Mactromeris polynyma to contaminated marine sediments on phagocytic activity of hemocytes.

Two species of bivalves, Mya arenaria and Mactromeris polynima, were exposed to contaminated marine sediments from Baie des Anglais, Quebec, for a period of 10 and 12 weeks, respectively, in order to determine if there was an effect on the phagocytic activity of hemocytes from each species. These sediments contain elevated levels of both PAHs and PCBs. Uncontaminated beach sand was used as control sediments. After a period of 4 weeks, each species of bivalves were sampled and hemocyte phagocytic activity was monitored by flow cytometry. While phagocytosis by hemocytes from M. polytiyma was significantly suppressed, those from M. arenaria were not different from beach sand-exposed controls. At the end of the exposure period, the phagocytic activity of hemocytes from both species was suppressed. Physiological parameters such as mantle proteins or malondialdehyde levels, total protein and total glycogen levels in the digestive gland were not affected by exposure to contaminated sediments. Moreover, the suppression of phagocytosis was well correlated with the transfer of contaminants from the sediments to the bivalves and their subsequent bioaccumulation, as demonstrated by the PCB body burden. These results support the use of bivalves as good sentinel species to survey sediment contamination and the usefulness of hemocyte phagocytic activity as a sensitive biomarker of exposure to organic contaminants.

Phagocytic response of macrophages from the pronephros of American plaice (Hipoglossoides platessoides) exposed to contaminated sediments from Baie des Anglais, Quebec.

Sediments of Baie des Anglais on the St. Lawrence estuary have a history of environmental contamination, but little information exists regarding their toxicity. The purpose of the present study was to determine the effects of contaminated Baie des Anglais sediments on American plaice (Hippoglossoides platessoides) immune function. Three sites in Baie des Anglais were selected which vary in proximity to local industries and in their sediment contaminant load. Sites 1 and 2 (within the bay) are the closest to shore and most heavily contaminated while sediments at Site 3, which is outside the bay, are the least contaminated. In the first experiment, American plaice were placed in cages at each site for three weeks and immune function was assessed by measuring the phagocytic activity of pronephric macrophages. At the time of sampling, plaice displayed pronephros cell immune response disturbances indicating that Site 1 and 2 were most toxic and Site 3 the least toxic. The results obtained for phagocytosis revealed that contaminants present in the sediments are bioavailable to fish, which came in contact with them and significantly affected their immune system. In the second experiment, sediments from the most toxic site, Site 1, were collected for a laboratory controlled experiment in which plaice were exposed for up to 3 months to these contaminated marine sediments, while the control group was exposed to relatively uncontaminated beach sand. At the end of the exposure period, plaice were transferred from contaminated sediment to beach sand and sampled one month later in order to determine if immune function had returned to control levels. The total number of macrophages decreased following three months of exposure, while the active macrophages had already decreased after the first month of exposure. Following the rehabilitation period a significant trend toward normal response was noted. Sediments from Baie des Anglais contain primarily less highly chlorinated PCBs and lower concentrations of the intermediate and highly chlorinated PCBs. The total concentration of PCBs (sum of 20 congeners) in the contaminated sediments was 1500 ng/g while in the beach sand, the levels were 13.6 ng/g dry weight. Only the low chlorinated PCB congeners were efficiently transferred from the sediments to the plaice liver. Together, these results suggest that the effect of chemical exposure on the phagocytosis of plaice macrophages may be reversible if the fish are returned to a non-contaminated habitat.

Tris (4-chlorophenyl) methane and tris (4-chlorophenyl) methanol in marine mammals from the Estuary and Gulf of St. Lawrence.

Levels of tris (4-chlorophenyl) methanol (TCPM) and its presumed precursor tris (4-chlorophenyl) methane (TCPMe) are reported in marine mammals from the Estuary and Gulf of St. Lawrence, Canada. These compounds were measured in blubber samples of seals and whales using ion trap mass spectrometry (MS/MS) detection. Detectable concentrations of both TCPM and TCPMe were observed in all of the samples analysed. Concentrations of these compounds varied with species ranging from 1.7 to 153 and from 1.3 to 50.6 ng/g lipid wt. for TCPM and TCPMe, respectively. TCPM was from 1.3 to 10 times more concentrated than TCPMe. The highest levels of both TCPM and TCPMe were observed in adult male beluga whales (Delphinapterus leucas) from the St. Lawrence Estuary, while adult female beluga whales from the same area showed levels similar to those in the seals examined. Among the four seal species investigated, TCPM and TCPMe levels were the highest in grey (Halichoerus grypus) and hooded (Cystophora cristata) seals, and lowest in harp seals (Phoca groenlandica). Intermediate levels were found in harbour seals (Phoca vitulina); however, their concentrations might be underestimated considering the younger mean age of these animals. Ratios of both 4,4'-DDE/sigma DDT and TCPM/sigma TCP were very similar between animals from the same species. Strong correlations between sigma TCP and sigma DDT were also observed for each species of mammals, most likely indicating that both sigma TCP and sigma DDT are bioaccumulated in marine mammals. The relationships between sigma DDT and sigma TCP also demonstrate that sigma TCP are less bioaccumulated than sigma DDT by the marine mammal species examined.

Toxicological characterization of sediments from Baie des Anglais on the St. Lawrence Estuary.

The sediments of Baie des Anglais on the St. Lawrence Estuary have a history of environmental contamination, but no information exists relating to their toxicity. The purpose of the present study was to characterize three sites in and near Baie des Anglais, in terms of sediment toxicity and contaminants. Sites 1 and 2 within the Baie des Anglais are relatively close to local industry and municipal sewage discharge points, while Site 3 is outside the bay. Three microscale bioassays, Microtox, echinoderm fertilization and Toxi-ChromoPad, showed that sediments from Site 1 were the most toxic, followed by Site 2. Site 3 was non-toxic. While the solid phase Microtox test did indicate that Site 1 was most toxic, the absolute response was weak. Liver cytochrome P450 1A1 mRNA in American plaice (Hippoglossoides platessoides), captured at Site 1 in the bay was significantly induced compared to the P450 system of plaice captured at Sites 2 and 3. Hepatic metallothionein mRNA levels were not significantly different between plaice captured at all three sites. Sediment chemical analyses revealed a gradient in polycyclic aromatic hydrocarbons, polychlorinated biphenyls and dibenzofurans (PCDF) with the highest levels recorded at Site 1, about 10-fold less at Site 2 and 100-fold less at Site 3. Amongst the organochlorines the PCDF group were deemed the most important due to their prevalence and known toxicity. Heavy metal concentrations were low and representative of background levels for the St. Lawrence Estuary.

Levels and patterns of PCBs and OC pesticides in harbour and grey seals from the St Lawrence Estuary, Canada.

Blubber samples from harbour (Phoca vitulina) and grey seals (Halichoerus grypus) captured in the St Lawrence Estuary were analysed for PCBs and OC pesticides. Concentrations of sigma PCB, sigma DDT, sigma CHLOR and mirex were higher in harbour than in grey seals, while sigma HCH and HCB were similar in the two species. Age vs. concentration plots showed that sigma PCB, sigma DDT and sigma CHLOR concentrations increased with age in males, but plateaued at sexual maturity in females. Concentrations of sigma HCH decreased and mirex increased with age for post-weaning animals, regardless of gender. HCB did not show age-related trends. PCB congener and OC pesticide patterns varied within harbour seals (based on gender and maturity) and between harbour and grey seals. PCB and OC concentrations in harbour seals were lower than those seen in a sample of significantly older beluga whales. Both species remain in the Estuary year-round. PCB and OC pesticide concentrations were higher in resident harbour seals than in either grey or harp seals that visit the Estuary seasonally. PCB and OC pesticide concentrations in harbour seals from the Estuary were generally higher than in harbour seals from other regions of North America. They were comparable to, or higher than those from the NE Atlantic Ocean and the North Sea, and lower than those from the Wadden and Baltic Seas.

[Multiple trichoepithelioma, cylindroma, miliaria and carcinomatous transformation]. / Trichoépithéliomes multiples, cylindromes, grains de milium, dégénérescence carcinomateuse.

We report a new case of multiple trichoepitheliomas, milia and cylindromas syndrome. This new case differed from the others in that it was complicated by the occurrence of a basal cell carcinoma presenting as an ulcus rodens affecting the nasal pyramid. In such cases, the main differential diagnosis to be excluded is basal cell naevomatosis.