Gordon balch - Academia.edu (original) (raw)

Papers by Gordon balch

Chemosphere, Mar 1, 2006

The endocrine modulating potency of five alkylphenol compounds to fish, including nonylphenol (NP... more The endocrine modulating potency of five alkylphenol compounds to fish, including nonylphenol (NP), three nonylphenol ethoxylate mixtures (NP1EO, NP4EO, NP9EO) and one nonylphenol ethoxycarboxylate (NP1EC) was assessed using in vivo tests conducted with Japanese medaka (Oryzias latipes). Medaka exposed to test materials from 1 day to 100 days post-hatch were monitored for alterations to sex ratios and secondary sex characteristics and development of gonadal intersex (i.e., testis-ova). The treatment with 100 microg l-1 NP (measured 29 microg l-1) induced gonadal intersex in over 80% of exposed males, mixed secondary sex characteristics in over 40% of exposed fish and suppression of the development of papillae on the anal fin of 100% of males. The 30 microg l-1 NP (measured 8.7 microg l-1) treatment induced gonadal intersex in only one of the 22 exposed males and mixed secondary sex characteristics in approximately 20% of the exposed fish. An elevated incidence of fish with mixed secondary sex characteristics and suppression of papillae development was also observed in the treatment with NP1EO at the highest test concentration of 300 microg l-1 (measured 105 microg l-1). There was no evidence of mixed secondary sex characteristics or gonadal intersex in treatments with the remaining test mixtures. This study confirms that NP is an estrogenic compound that could affect gonadal development in fish chronically exposed to concentrations in the range of 10 microg l-1. NP1EO is very weakly estrogenic at concentrations that are an order of magnitude higher than the lowest observed effect concentration for nonylphenol.

Science of The Total Environment, May 1, 1990

In order to investigate the putative association between chemical contamination in western Lake O... more In order to investigate the putative association between chemical contamination in western Lake Ontario and high prevalences of fish tumors, sediments from Hamilton Harbour and Oakville Creek in Lake Ontario and reference sites in non-polluted areas of Ontario, Canada were collected and extracted for organic contaminants. Sediment extracts from Hamilton Harbour had the highest concentrations of polychlorinated biphenyls and organochlorine insecticides (ppb) and contained very high concentrations of polynuclear aromatic hydrocarbons (ppm); although the levels of these compounds varied widely with sampling location in the harbor. A sediment extract from Hamilton Harbour was mutagenic in the Ames bacterial assay, both with and without microsomal activation. High levels of aromatic DNA adducts were induced in cultured mouse C3H1OT1/2 cells after in vitro exposure to Hamilton Harbour sediment extract. In two separate carcinogenicity experiments involving a sac fry microinjection assay with rainbow trout (Oncorhynchus mykiss), Hamilton Harbour sediment extract induced hepatocellular carcinomas in fish. No hepatic neoplasms were observed in fish that had been treated with sediment extract from Oakville Creek, or with extract from a reference sediment. The significance of these results is discussed in relation to the distribution of neoplasms in feral fish within western Lake Ontario.

Aquatic Toxicology, May 1, 2003

This study was focused on determining the effects of exposure to antiandrogens on the gonadal dev... more This study was focused on determining the effects of exposure to antiandrogens on the gonadal development of Japanese medaka (Oryzias latipes). Test compounds included the fungicide, vinclozolin and the clinical antiandrogen, cyproterone acetate. Newly hatched medaka were exposed to aqueous solutions of vinclozolin (2500 microg/l) and the vinclozolin fungicide formulation, Ronilan (1000 and 5000 microg/l) and cyproterone acetate (1 and 10 microg/l), for 3 months. Histological evaluation of the gonadal tissues of exposed fish indicated that the 5000 microg/l concentration of the vinclozolin formulation (Ronilan) induced a low incidence of intersex (i.e. testis-ova) and the 2500 microg/l concentration of vinclozolin-affected spermatogenesis in males. Also, the vinclozolin treatments induced moderate ovarian atresia. Cyproterone acetate also induced a low incidence of testis-ova, but in contrast to the vinclozolin treatment the amount of ovarian tissue in the testis-ova was equal to or greater than the amount of testicular tissue. In the cyproterone acetate treatments, both oogenesis and spermatogenesis were moderately inhibited at all test concentrations. The results of this study indicate that antiandrogens have the potential to alter testicular development and gametogenesis in fish. However, research is needed to determine the mechanisms by which antiandrogens affect fish.

The validity of in vitro cell culture models for the measurement of halogenated aromatic hydrocar... more The validity of in vitro cell culture models for the measurement of halogenated aromatic hydrocarbons (HAH) toxicity or the prediction of potential toxicity depends upon the ability of the mode reflect in vivo toxicity. HAH toxicity is directly related to the affinity for the aromatic hydrocarbon receptor (AhR) which controls cytochrome P45 activity. In the bioassay characterized, normal rainbow trout hepatocyte monolayer cultures (RTL-WI) are employed to measure the modulation of cytochrome P450 monooxygenase activity, using the ethoxyresorufin-O-deethylase (EROD) assay, following the exposure to betanaphthaflavone (BNF) and environmental samples for varying times. Data from this single plate hepatocyte study are compared with liver microsomal EROD activity from rainbow trout exposed to the same samples in vivo.

The objective of this study was to determine if oil sands wastewater had an effect on the general... more The objective of this study was to determine if oil sands wastewater had an effect on the general health and condition of hatchery raised rainbow trout (200 to 400 g). Effects were assessed based on a battery of physiological and biochemical indices and the physical condition of the fish. The trout were exposed to tailings water in the field and in a flow through system under laboratory conditions. The field tests were conducted in 1992 and 1993 in experimental ponds at Syncrude which contained fine tails covered with surface water, fine tails covered with tailings water, and a surface water control pond. The laboratory treatments included Mildred Lake tailings water, dyke drainage water, fractionated tailings pond water (acid fraction containing naphthenic acids), sodium naphthenate, recycle water from Suncor`s tailings pond, and a laboratory control. All body condition factors and blood parameters were normal in the field and laboratory exposed fish and there were no apparent differences between the fish exposed to the tailings water and controls.

Bulletin of Environmental Contamination and Toxicology, Apr 1, 2001

... I Contamination DOI: 10.1007/S00128-001-0032-Z ë and Toxicology Influence of Food-Capture Net... more ... I Contamination DOI: 10.1007/S00128-001-0032-Z ë and Toxicology Influence of Food-Capture Nets on Cadmium Uptake by Net-Spinning Caddisfly (Trichoptera: Hydropsychidae) Larvae J. Hies, RD Evans, G. С Balch Environmental Science Centre, Trent ... 1988a; Greve et al. ...

Chemosphere, Jun 1, 2006

Tadpoles of the African clawed frog, Xenopus laevis were exposed, beginning at stage 50, to a com... more Tadpoles of the African clawed frog, Xenopus laevis were exposed, beginning at stage 50, to a commercial pentabromodiphenyl ether mixture (DE-71) through the diet. Subsequent experiments were conducted using a single intraperitoneal injection at stage 58 with limited quantities of two purified brominated diphenyl ether (BDE) congeners, BDE47 and BDE99 and DE-71 to determine the relative potency of these BDE congeners within the commercial mixture. Significant inhibition of tail resorption, delayed metamorphosis and impacts on skin pigmentation were observed in Xenopus exposed to DE-71 in the diet at nominal doses of 1000 and 5000 microgg(-1) of food. The estimated time required for 50% of the tadpoles to complete metamorphosis was significantly lengthened in Xenopus exposed to a dietary concentration of 1 microg DE-71 per gram of food. Analysis of PBDEs (sum of 32 congeners) in Xenopus from the treatment with 5000 microgg(-1) of DE-71 indicated that the frogs accumulated an average of 1030 microgg(-1) (wet weight) of PBDEs. In the intraperitoneal injection trials, similar inhibitory responses were observed in Xenopus injected with DE-71 at a nominal dose of 60 microg per tadpole, or injected with BDE47 at a nominal dose of 100 microg per tadpole. No responses were observed in Xenopus injected with BDE99 at doses up to 100 microg per tadpole. Complete inhibition of metamorphosis was observed only in the highest DE-71 dietary treatment. The results of this study are consistent with a mechanism of action of PBDEs involving competitive inhibition of binding of thyroid hormones to transporter proteins, although the mechanism cannot be definitively determined from this study. The observed effects may have occurred through other mechanisms, including sublethal toxicity. The doses used in this study are greater than the levels of PBDEs to which anurans are exposed in the environment, so further studies are required to determine whether exposure to PBDEs at environmentally relevant concentrations can affect frog metamorphosis.

Environmental Health Perspectives, Jul 1, 2003

Environmental Health Perspectives, Jun 1, 2004

Environmental Toxicology and Chemistry, 2002

Developments in Environmental Modelling, 2014

ABSTRACT

Environmental Toxicology and Chemistry, 2004

Environmental Toxicology and Chemistry, Nov 1, 1993

Environmental Toxicology and Chemistry, 2004

Sublethal effects observed in fish exposed to environmental estrogens may be mediated via stimula... more Sublethal effects observed in fish exposed to environmental estrogens may be mediated via stimulation of cell death. To investigate whether cell death is induced in fish after chronic exposure to estrogenic chemicals, Japanese medaka (Oryzias latipes) were exposed from hatch until sexual maturity to 10 ng/L 17α‐ethinylestradiol (EE2) or acetone solvent (control). Cell death was evaluated in blinded histological sections of whole medaka using terminal dideoxynucleotidyl‐mediated dUTP nick end‐labeling (TUNEL), which labels nuclei of cells containing apoptotic or necrotic (fragmented) DNA. The major impact of EE2 exposure in both male and female medaka was to significantly increase the number of TUNEL‐positive hepatocytes and kidney tubule cells compared to control. Cell morphology was consistent with apoptosis in the liver and cloudy swelling or necrosis in the tubule cells. The number of TUNEL‐positive interstitial (hematopoietic) and glomerular cells was significantly greater in the kidneys of EE2‐exposed male, but not female, medaka. The EE2 exposure also significantly increased the number of TUNEL‐positive testicular cells in medaka compared to corresponding controls, namely Leydig cells, Sertoli cells, spermatocytes, and spermatids. In medaka with gonadal intersex, areas of fibrosis and areas containing female gonadal cells were relatively unstained with TUNEL. No effect of EE2 exposure on the number of TUNEL‐positive ovarian somatic cells or on the rate of female ovarian follicle atresia was found. These results suggest that chronic exposure to EE2 in medaka is hepatotoxic and nephrotoxic in both sexes, whereas gonadal toxicity is specific to males.

Comparative Biochemistry and Physiology C-toxicology & Pharmacology, Jun 1, 2004

Environmental Toxicology and Chemistry, Sep 1, 1998

... Table Table 2.. Internal and external lesion frequencies in brown bullheads collected from tw... more ... Table Table 2.. Internal and external lesion frequencies in brown bullheads collected from two contaminated sites in the Detroit River (Amherstburg Channel, Trenton Channel, and a less contaminated upstream reference site, Peche Island). Frequency a. ...

Environmental Toxicology and Chemistry, 1995

Environmental Toxicology and Chemistry, 2000

A method was developed to assess the toxicity of VOCs to plants and earthworms (survival of Eisen... more A method was developed to assess the toxicity of VOCs to plants and earthworms (survival of Eisenia foetida). The procedures followed were based on Greene et al. Gas samples for head space analyses were removed, at test initiation a termination, through a bulkhead fitting in the lid equipped with septa. Treatment levels were prepared, at low temperature to minimize volatilization, by spiking a soil sample with the compound of interest and then serially diluting it with clean soil. Root elongation tests were conducted on filter paper supported by 70 mesh silica sand spiked with the volatile of interest. Soils were then inundated with water, shaken with heating, and the headspace reanalyzed for the total contaminant concentration in the test system (total equals headspace plus adsorbed). Enclosing the seeds and worms in containers did not appear to have detrimental effects. VOCs tested included benzene, xylene, toluene, ethylbenzene, tetrachloroethylene, and 1,1,2-trichloroethylene. Each test was repeated three times with different batches of soil, seed lots and worms from different colonies. Endpoints derived based on nominal and measured concentrations included: NOEC, LOEC, LC{sub 50} and LC{sub 25} for earthworm mortality and EC{sub 50} and EC{sub 25} for emergence and root elongation.

Chemosphere, Mar 1, 2006

The endocrine modulating potency of five alkylphenol compounds to fish, including nonylphenol (NP... more The endocrine modulating potency of five alkylphenol compounds to fish, including nonylphenol (NP), three nonylphenol ethoxylate mixtures (NP1EO, NP4EO, NP9EO) and one nonylphenol ethoxycarboxylate (NP1EC) was assessed using in vivo tests conducted with Japanese medaka (Oryzias latipes). Medaka exposed to test materials from 1 day to 100 days post-hatch were monitored for alterations to sex ratios and secondary sex characteristics and development of gonadal intersex (i.e., testis-ova). The treatment with 100 microg l-1 NP (measured 29 microg l-1) induced gonadal intersex in over 80% of exposed males, mixed secondary sex characteristics in over 40% of exposed fish and suppression of the development of papillae on the anal fin of 100% of males. The 30 microg l-1 NP (measured 8.7 microg l-1) treatment induced gonadal intersex in only one of the 22 exposed males and mixed secondary sex characteristics in approximately 20% of the exposed fish. An elevated incidence of fish with mixed secondary sex characteristics and suppression of papillae development was also observed in the treatment with NP1EO at the highest test concentration of 300 microg l-1 (measured 105 microg l-1). There was no evidence of mixed secondary sex characteristics or gonadal intersex in treatments with the remaining test mixtures. This study confirms that NP is an estrogenic compound that could affect gonadal development in fish chronically exposed to concentrations in the range of 10 microg l-1. NP1EO is very weakly estrogenic at concentrations that are an order of magnitude higher than the lowest observed effect concentration for nonylphenol.

Science of The Total Environment, May 1, 1990

In order to investigate the putative association between chemical contamination in western Lake O... more In order to investigate the putative association between chemical contamination in western Lake Ontario and high prevalences of fish tumors, sediments from Hamilton Harbour and Oakville Creek in Lake Ontario and reference sites in non-polluted areas of Ontario, Canada were collected and extracted for organic contaminants. Sediment extracts from Hamilton Harbour had the highest concentrations of polychlorinated biphenyls and organochlorine insecticides (ppb) and contained very high concentrations of polynuclear aromatic hydrocarbons (ppm); although the levels of these compounds varied widely with sampling location in the harbor. A sediment extract from Hamilton Harbour was mutagenic in the Ames bacterial assay, both with and without microsomal activation. High levels of aromatic DNA adducts were induced in cultured mouse C3H1OT1/2 cells after in vitro exposure to Hamilton Harbour sediment extract. In two separate carcinogenicity experiments involving a sac fry microinjection assay with rainbow trout (Oncorhynchus mykiss), Hamilton Harbour sediment extract induced hepatocellular carcinomas in fish. No hepatic neoplasms were observed in fish that had been treated with sediment extract from Oakville Creek, or with extract from a reference sediment. The significance of these results is discussed in relation to the distribution of neoplasms in feral fish within western Lake Ontario.

Aquatic Toxicology, May 1, 2003

This study was focused on determining the effects of exposure to antiandrogens on the gonadal dev... more This study was focused on determining the effects of exposure to antiandrogens on the gonadal development of Japanese medaka (Oryzias latipes). Test compounds included the fungicide, vinclozolin and the clinical antiandrogen, cyproterone acetate. Newly hatched medaka were exposed to aqueous solutions of vinclozolin (2500 microg/l) and the vinclozolin fungicide formulation, Ronilan (1000 and 5000 microg/l) and cyproterone acetate (1 and 10 microg/l), for 3 months. Histological evaluation of the gonadal tissues of exposed fish indicated that the 5000 microg/l concentration of the vinclozolin formulation (Ronilan) induced a low incidence of intersex (i.e. testis-ova) and the 2500 microg/l concentration of vinclozolin-affected spermatogenesis in males. Also, the vinclozolin treatments induced moderate ovarian atresia. Cyproterone acetate also induced a low incidence of testis-ova, but in contrast to the vinclozolin treatment the amount of ovarian tissue in the testis-ova was equal to or greater than the amount of testicular tissue. In the cyproterone acetate treatments, both oogenesis and spermatogenesis were moderately inhibited at all test concentrations. The results of this study indicate that antiandrogens have the potential to alter testicular development and gametogenesis in fish. However, research is needed to determine the mechanisms by which antiandrogens affect fish.

The validity of in vitro cell culture models for the measurement of halogenated aromatic hydrocar... more The validity of in vitro cell culture models for the measurement of halogenated aromatic hydrocarbons (HAH) toxicity or the prediction of potential toxicity depends upon the ability of the mode reflect in vivo toxicity. HAH toxicity is directly related to the affinity for the aromatic hydrocarbon receptor (AhR) which controls cytochrome P45 activity. In the bioassay characterized, normal rainbow trout hepatocyte monolayer cultures (RTL-WI) are employed to measure the modulation of cytochrome P450 monooxygenase activity, using the ethoxyresorufin-O-deethylase (EROD) assay, following the exposure to betanaphthaflavone (BNF) and environmental samples for varying times. Data from this single plate hepatocyte study are compared with liver microsomal EROD activity from rainbow trout exposed to the same samples in vivo.

The objective of this study was to determine if oil sands wastewater had an effect on the general... more The objective of this study was to determine if oil sands wastewater had an effect on the general health and condition of hatchery raised rainbow trout (200 to 400 g). Effects were assessed based on a battery of physiological and biochemical indices and the physical condition of the fish. The trout were exposed to tailings water in the field and in a flow through system under laboratory conditions. The field tests were conducted in 1992 and 1993 in experimental ponds at Syncrude which contained fine tails covered with surface water, fine tails covered with tailings water, and a surface water control pond. The laboratory treatments included Mildred Lake tailings water, dyke drainage water, fractionated tailings pond water (acid fraction containing naphthenic acids), sodium naphthenate, recycle water from Suncor`s tailings pond, and a laboratory control. All body condition factors and blood parameters were normal in the field and laboratory exposed fish and there were no apparent differences between the fish exposed to the tailings water and controls.

Bulletin of Environmental Contamination and Toxicology, Apr 1, 2001

... I Contamination DOI: 10.1007/S00128-001-0032-Z ë and Toxicology Influence of Food-Capture Net... more ... I Contamination DOI: 10.1007/S00128-001-0032-Z ë and Toxicology Influence of Food-Capture Nets on Cadmium Uptake by Net-Spinning Caddisfly (Trichoptera: Hydropsychidae) Larvae J. Hies, RD Evans, G. С Balch Environmental Science Centre, Trent ... 1988a; Greve et al. ...

Chemosphere, Jun 1, 2006

Tadpoles of the African clawed frog, Xenopus laevis were exposed, beginning at stage 50, to a com... more Tadpoles of the African clawed frog, Xenopus laevis were exposed, beginning at stage 50, to a commercial pentabromodiphenyl ether mixture (DE-71) through the diet. Subsequent experiments were conducted using a single intraperitoneal injection at stage 58 with limited quantities of two purified brominated diphenyl ether (BDE) congeners, BDE47 and BDE99 and DE-71 to determine the relative potency of these BDE congeners within the commercial mixture. Significant inhibition of tail resorption, delayed metamorphosis and impacts on skin pigmentation were observed in Xenopus exposed to DE-71 in the diet at nominal doses of 1000 and 5000 microgg(-1) of food. The estimated time required for 50% of the tadpoles to complete metamorphosis was significantly lengthened in Xenopus exposed to a dietary concentration of 1 microg DE-71 per gram of food. Analysis of PBDEs (sum of 32 congeners) in Xenopus from the treatment with 5000 microgg(-1) of DE-71 indicated that the frogs accumulated an average of 1030 microgg(-1) (wet weight) of PBDEs. In the intraperitoneal injection trials, similar inhibitory responses were observed in Xenopus injected with DE-71 at a nominal dose of 60 microg per tadpole, or injected with BDE47 at a nominal dose of 100 microg per tadpole. No responses were observed in Xenopus injected with BDE99 at doses up to 100 microg per tadpole. Complete inhibition of metamorphosis was observed only in the highest DE-71 dietary treatment. The results of this study are consistent with a mechanism of action of PBDEs involving competitive inhibition of binding of thyroid hormones to transporter proteins, although the mechanism cannot be definitively determined from this study. The observed effects may have occurred through other mechanisms, including sublethal toxicity. The doses used in this study are greater than the levels of PBDEs to which anurans are exposed in the environment, so further studies are required to determine whether exposure to PBDEs at environmentally relevant concentrations can affect frog metamorphosis.

Environmental Health Perspectives, Jul 1, 2003

Environmental Health Perspectives, Jun 1, 2004

Environmental Toxicology and Chemistry, 2002

Developments in Environmental Modelling, 2014

ABSTRACT

Environmental Toxicology and Chemistry, 2004

Environmental Toxicology and Chemistry, Nov 1, 1993

Environmental Toxicology and Chemistry, 2004

Sublethal effects observed in fish exposed to environmental estrogens may be mediated via stimula... more Sublethal effects observed in fish exposed to environmental estrogens may be mediated via stimulation of cell death. To investigate whether cell death is induced in fish after chronic exposure to estrogenic chemicals, Japanese medaka (Oryzias latipes) were exposed from hatch until sexual maturity to 10 ng/L 17α‐ethinylestradiol (EE2) or acetone solvent (control). Cell death was evaluated in blinded histological sections of whole medaka using terminal dideoxynucleotidyl‐mediated dUTP nick end‐labeling (TUNEL), which labels nuclei of cells containing apoptotic or necrotic (fragmented) DNA. The major impact of EE2 exposure in both male and female medaka was to significantly increase the number of TUNEL‐positive hepatocytes and kidney tubule cells compared to control. Cell morphology was consistent with apoptosis in the liver and cloudy swelling or necrosis in the tubule cells. The number of TUNEL‐positive interstitial (hematopoietic) and glomerular cells was significantly greater in the kidneys of EE2‐exposed male, but not female, medaka. The EE2 exposure also significantly increased the number of TUNEL‐positive testicular cells in medaka compared to corresponding controls, namely Leydig cells, Sertoli cells, spermatocytes, and spermatids. In medaka with gonadal intersex, areas of fibrosis and areas containing female gonadal cells were relatively unstained with TUNEL. No effect of EE2 exposure on the number of TUNEL‐positive ovarian somatic cells or on the rate of female ovarian follicle atresia was found. These results suggest that chronic exposure to EE2 in medaka is hepatotoxic and nephrotoxic in both sexes, whereas gonadal toxicity is specific to males.

Comparative Biochemistry and Physiology C-toxicology & Pharmacology, Jun 1, 2004

Environmental Toxicology and Chemistry, Sep 1, 1998

... Table Table 2.. Internal and external lesion frequencies in brown bullheads collected from tw... more ... Table Table 2.. Internal and external lesion frequencies in brown bullheads collected from two contaminated sites in the Detroit River (Amherstburg Channel, Trenton Channel, and a less contaminated upstream reference site, Peche Island). Frequency a. ...

Environmental Toxicology and Chemistry, 1995

Environmental Toxicology and Chemistry, 2000

A method was developed to assess the toxicity of VOCs to plants and earthworms (survival of Eisen... more A method was developed to assess the toxicity of VOCs to plants and earthworms (survival of Eisenia foetida). The procedures followed were based on Greene et al. Gas samples for head space analyses were removed, at test initiation a termination, through a bulkhead fitting in the lid equipped with septa. Treatment levels were prepared, at low temperature to minimize volatilization, by spiking a soil sample with the compound of interest and then serially diluting it with clean soil. Root elongation tests were conducted on filter paper supported by 70 mesh silica sand spiked with the volatile of interest. Soils were then inundated with water, shaken with heating, and the headspace reanalyzed for the total contaminant concentration in the test system (total equals headspace plus adsorbed). Enclosing the seeds and worms in containers did not appear to have detrimental effects. VOCs tested included benzene, xylene, toluene, ethylbenzene, tetrachloroethylene, and 1,1,2-trichloroethylene. Each test was repeated three times with different batches of soil, seed lots and worms from different colonies. Endpoints derived based on nominal and measured concentrations included: NOEC, LOEC, LC{sub 50} and LC{sub 25} for earthworm mortality and EC{sub 50} and EC{sub 25} for emergence and root elongation.