Polyethylene passive sampling was performed to quantify gaseous and freely dissolved polychlorina... more Polyethylene passive sampling was performed to quantify gaseous and freely dissolved polychlorinated biphenyls (PCBs) in the air and water of Lakes Erie and Ontario during 2011-2012. In view of differing physical characteristics and the impacts of historical contamination by PCBs within these lakes, spatial variation of PCB concentrations and air-water exchange across these lakes may be expected. Both lakes displayed statistically similar aqueous and atmospheric PCB concentrations. Total aqueous concentrations of 29 PCBs ranged from 1.5 pg L(-1) in the open lake of Lake Erie (site E02) in 2011 spring to 105 pg L(-1) in Niagara (site On05) in 2012 summer, while total atmospheric concentrations were 7.7-634 pg m(-3) across both lakes. A west-to-east gradient was observed for aqueous PCBs in Lake Erie. River discharge and localized influences (e.g., sediment resuspension and regional alongshore transport) likely dominated spatial trends of aqueous PCBs in both lakes. Air-water exchange...
... 268 PA Helm et al. 6.2 Biotic Environment . . . . . ... 1). PCNs are structurally similar to ... more ... 268 PA Helm et al. 6.2 Biotic Environment . . . . . ... 1). PCNs are structurally similar to polychlori-nated dibenzo-p-dioxins (PCDDs), dibenzofurans (PCDFs), and biphenyls (PCBs), particularly those PCBs having planar character with no chlorines in the ortho (2,6) positions (Fig. ...
Introduction In the last few years flame retardants have received considerable attention from env... more Introduction In the last few years flame retardants have received considerable attention from environmental scientists, and more recently regulators, as the physical-chemical properties that make such compounds very useful as flame retardants also give rise to environmental concern. Polybrominated diphenylethers, especially the penta and octa formulations, now face regulation worldwide. Although focus has been on the brominated flame retardant chemicals, a chlorinated flame retardant, called Dechlorane Plus (DP), was recently measured in air and sediment samples for the first time in the Great Lakes region where it has been produced since the 1970s (Hoh et al. 2006). This compound has not been commonly identified in the environment before. An earlier chlorinated flame retardant developed by Hooker Chemical (now Oxychem, Niagara Falls, NY, USA), called Dechlorane or Mirex, was banned because of its toxicity to marine invertebrates. In 1972, DP was developed to replace Mirex with prod...
The arctic has been contaminated by legacy organochlorine pesticides (OCPs) and currently used pe... more The arctic has been contaminated by legacy organochlorine pesticides (OCPs) and currently used pesticides (CUPs) through atmospheric transport and oceanic currents. Here we report time trends and air-water exchange of OCPs and CUPs from research expeditions conducted between 1993-2013. Compounds determined in both air and water were trans- and cis-chlordanes (TC, CC), trans- and cis-nonachlors (TN, CN), heptachlor exo-epoxide (HEPX), dieldrin (DIEL), chlorobornanes (ΣCHBs, toxaphene), dacthal (DAC), endosulfans and metabolite endosulfan sulfate (ENDO-I, ENDO-II, ENDO SUL), chlorothalonil (CHT), chlorpyrifos (CPF) and trifluralin (TFN). Pentachloronitrobenzene (PCNB, quintozene) and its soil metabolite pentachlorothianisole (PCTA) were also found in air. Concentrations of most OCPs declined in surface water, whereas some CUPs increased (ENDO-I, CHT and TFN) or showed no significant change (CPF, DAC), while most compounds declined in air. Chlordane compound fractions TC/(TC+CC) and TC...
Environmental pollution (Barking, Essex : 1987), Jan 18, 2015
Microplastics are a source of environmental pollution resulting from degradation of plastic produ... more Microplastics are a source of environmental pollution resulting from degradation of plastic products and spillage of resin pellets. We report the amounts of microplastics from various sites of Lake Ontario and evaluate their potential for preservation in the sediment record. A total of 4635 pellets were sampled from the Humber Bay shoreline on three sampling dates. Pellet colours were similar to those from the Humber River bank, suggesting that the river is a pathway for plastics transport into Lake Ontario. Once in the lake, high density microplastics, including mineral-polyethylene and mineral-polypropylene mixtures, sink to the bottom. The minerals may be fillers that were combined with plastics during production, or may have adsorbed to the surfaces of the polymers in the water column or on the lake bottom. Based on sediment depths and accumulation rates, microplastics have accumulated in the offshore region for less than 38 years. Their burial increases the chance of microplast...
The Science of the total environment, Jan 15, 2005
Two annually laminated cores collected from Lake DV09 on Devon Island in May 1999 were dated usin... more Two annually laminated cores collected from Lake DV09 on Devon Island in May 1999 were dated using 210Pb and 137Cs, and analyzed for a variety of halogenated organic contaminants (HOCs), including polychlorinated biphenyls (PCBs), organochlorine pesticides, short-chain polychlorinated n-alkanes (sPCAs), polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs), and polybrominated diphenyl ethers (PBDEs). Dry weight HOC concentrations in Lake DV09 sediments were generally similar to other remote Arctic lakes. Maximum HOC fluxes often agreed well with production maxima, although many compound groups exhibited maxima at or near the sediment surface, much later than peak production. The lower than expected HOC concentrations in older sediment slices may be due to anaerobic degradation and possibly to dilution resulting from a temporary increase in sedimentation rate observed between the mid-1960s and 1970s. Indeed, temporal trends were more readily apparent for those compound classe...
The Science of the total environment, Jan 15, 2005
Gas-particle partitioning relationships were developed for partitioning of polychlorinated naphth... more Gas-particle partitioning relationships were developed for partitioning of polychlorinated naphthalenes (PCNs) and non- and mono-ortho PCBs in arctic air by regressing observed gas-particle partition coefficients, K(P), at Alert and Dunai in the high Arctic with temperature-adjusted experimental vapor pressures (p(L) degrees ) and octanol-air partition coefficients (K(OA)). Slopes were near -0.5 and 0.5 for log p(L) degrees and log K(OA), respectively, at both sites, indicating that aerosol characteristics and partitioning processes were similar at the two sites. The K(OA) absorption model provided an adequate estimate of the percentage of PCNs and non-/mono-ortho PCBs associated with particulate matter, based on fraction of organic matter (f(OM)) ranging from 0.074 to 0.12, compared to the Junge-Pankow adsorption model, which slightly over-estimated the distribution on particles. There were no indications that partitioning to soot carbon influences the observed gas-particle distrib...
In this paper, a microscopic system for cell physiological research is presented. The setup which... more In this paper, a microscopic system for cell physiological research is presented. The setup which is to a large extent based on commercially available products was designed to establish a platform for time-coordinated electrophysiological and fluorescence optical compound experiments on living neurons in brain slices. Instruments for infrared differential interference contrast video microscopy ~IRDICM!, confocal scanning laser microscopy ~CSLM!, and for patch clamp studies have been assembled into one unit. Using the IRDICM equipment, a neuron can be patched somatically and dendritically. Loading the neuron with a Ca21 indicating dye substance can be examined epifluorescence optically using the Hg lamp or Xe lamp of the microscope. A stimulus initiating the propagation of an action potential through a dendrite can be synchronized to the electronic control unit of the CSLM, and changes in the concentration of Ca21 in the dendrite can be recorded in a time-coordinated way. The setup h...
Elevated concentrations of some persistent organic pollutants (POPs) in fish from arctic and suba... more Elevated concentrations of some persistent organic pollutants (POPs) in fish from arctic and subarctic lakes have been hypothesized to be due to processes within food webs and fish physiology. We investigated limnological processes and contaminant chemistry as explanations of these elevated concentrations by developing and applying fugacity-based mass balance models to a relatively small lake in the high arctic and a series of larger lakes in the southern Yukon River basin. The results indicate that high arctic lakes are transient and inefficient sinks for POPs. The mobility of POPs in high arctic lakes is conferred by their hydrologic regime (i.e. partial through flow of melt water loadings) and minimal scavenging and retention in sediments due to extremely low organic carbon in settling and sediment particles. Contaminant dynamics in lakes of the south Yukon River basin are governed by hydrology (i.e., water residence time), because, similarly to high arctic lakes, most of the contaminant inventory resides in the water column due to inefficient scavenging by settling particles. For the less persistent compounds, long water residence time shifts the major loss process from export to degradation. Model results also suggest relatively short degradative half-lives of the hexachlorocyclohexanes (sum of HCHs) and endosulfan, particularly in high arctic Amituk Lake.
Polyethylene passive sampling was performed to quantify gaseous and freely dissolved polychlorina... more Polyethylene passive sampling was performed to quantify gaseous and freely dissolved polychlorinated biphenyls (PCBs) in the air and water of Lakes Erie and Ontario during 2011-2012. In view of differing physical characteristics and the impacts of historical contamination by PCBs within these lakes, spatial variation of PCB concentrations and air-water exchange across these lakes may be expected. Both lakes displayed statistically similar aqueous and atmospheric PCB concentrations. Total aqueous concentrations of 29 PCBs ranged from 1.5 pg L(-1) in the open lake of Lake Erie (site E02) in 2011 spring to 105 pg L(-1) in Niagara (site On05) in 2012 summer, while total atmospheric concentrations were 7.7-634 pg m(-3) across both lakes. A west-to-east gradient was observed for aqueous PCBs in Lake Erie. River discharge and localized influences (e.g., sediment resuspension and regional alongshore transport) likely dominated spatial trends of aqueous PCBs in both lakes. Air-water exchange...
... 268 PA Helm et al. 6.2 Biotic Environment . . . . . ... 1). PCNs are structurally similar to ... more ... 268 PA Helm et al. 6.2 Biotic Environment . . . . . ... 1). PCNs are structurally similar to polychlori-nated dibenzo-p-dioxins (PCDDs), dibenzofurans (PCDFs), and biphenyls (PCBs), particularly those PCBs having planar character with no chlorines in the ortho (2,6) positions (Fig. ...
Introduction In the last few years flame retardants have received considerable attention from env... more Introduction In the last few years flame retardants have received considerable attention from environmental scientists, and more recently regulators, as the physical-chemical properties that make such compounds very useful as flame retardants also give rise to environmental concern. Polybrominated diphenylethers, especially the penta and octa formulations, now face regulation worldwide. Although focus has been on the brominated flame retardant chemicals, a chlorinated flame retardant, called Dechlorane Plus (DP), was recently measured in air and sediment samples for the first time in the Great Lakes region where it has been produced since the 1970s (Hoh et al. 2006). This compound has not been commonly identified in the environment before. An earlier chlorinated flame retardant developed by Hooker Chemical (now Oxychem, Niagara Falls, NY, USA), called Dechlorane or Mirex, was banned because of its toxicity to marine invertebrates. In 1972, DP was developed to replace Mirex with prod...
The arctic has been contaminated by legacy organochlorine pesticides (OCPs) and currently used pe... more The arctic has been contaminated by legacy organochlorine pesticides (OCPs) and currently used pesticides (CUPs) through atmospheric transport and oceanic currents. Here we report time trends and air-water exchange of OCPs and CUPs from research expeditions conducted between 1993-2013. Compounds determined in both air and water were trans- and cis-chlordanes (TC, CC), trans- and cis-nonachlors (TN, CN), heptachlor exo-epoxide (HEPX), dieldrin (DIEL), chlorobornanes (ΣCHBs, toxaphene), dacthal (DAC), endosulfans and metabolite endosulfan sulfate (ENDO-I, ENDO-II, ENDO SUL), chlorothalonil (CHT), chlorpyrifos (CPF) and trifluralin (TFN). Pentachloronitrobenzene (PCNB, quintozene) and its soil metabolite pentachlorothianisole (PCTA) were also found in air. Concentrations of most OCPs declined in surface water, whereas some CUPs increased (ENDO-I, CHT and TFN) or showed no significant change (CPF, DAC), while most compounds declined in air. Chlordane compound fractions TC/(TC+CC) and TC...
Environmental pollution (Barking, Essex : 1987), Jan 18, 2015
Microplastics are a source of environmental pollution resulting from degradation of plastic produ... more Microplastics are a source of environmental pollution resulting from degradation of plastic products and spillage of resin pellets. We report the amounts of microplastics from various sites of Lake Ontario and evaluate their potential for preservation in the sediment record. A total of 4635 pellets were sampled from the Humber Bay shoreline on three sampling dates. Pellet colours were similar to those from the Humber River bank, suggesting that the river is a pathway for plastics transport into Lake Ontario. Once in the lake, high density microplastics, including mineral-polyethylene and mineral-polypropylene mixtures, sink to the bottom. The minerals may be fillers that were combined with plastics during production, or may have adsorbed to the surfaces of the polymers in the water column or on the lake bottom. Based on sediment depths and accumulation rates, microplastics have accumulated in the offshore region for less than 38 years. Their burial increases the chance of microplast...
The Science of the total environment, Jan 15, 2005
Two annually laminated cores collected from Lake DV09 on Devon Island in May 1999 were dated usin... more Two annually laminated cores collected from Lake DV09 on Devon Island in May 1999 were dated using 210Pb and 137Cs, and analyzed for a variety of halogenated organic contaminants (HOCs), including polychlorinated biphenyls (PCBs), organochlorine pesticides, short-chain polychlorinated n-alkanes (sPCAs), polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs), and polybrominated diphenyl ethers (PBDEs). Dry weight HOC concentrations in Lake DV09 sediments were generally similar to other remote Arctic lakes. Maximum HOC fluxes often agreed well with production maxima, although many compound groups exhibited maxima at or near the sediment surface, much later than peak production. The lower than expected HOC concentrations in older sediment slices may be due to anaerobic degradation and possibly to dilution resulting from a temporary increase in sedimentation rate observed between the mid-1960s and 1970s. Indeed, temporal trends were more readily apparent for those compound classe...
The Science of the total environment, Jan 15, 2005
Gas-particle partitioning relationships were developed for partitioning of polychlorinated naphth... more Gas-particle partitioning relationships were developed for partitioning of polychlorinated naphthalenes (PCNs) and non- and mono-ortho PCBs in arctic air by regressing observed gas-particle partition coefficients, K(P), at Alert and Dunai in the high Arctic with temperature-adjusted experimental vapor pressures (p(L) degrees ) and octanol-air partition coefficients (K(OA)). Slopes were near -0.5 and 0.5 for log p(L) degrees and log K(OA), respectively, at both sites, indicating that aerosol characteristics and partitioning processes were similar at the two sites. The K(OA) absorption model provided an adequate estimate of the percentage of PCNs and non-/mono-ortho PCBs associated with particulate matter, based on fraction of organic matter (f(OM)) ranging from 0.074 to 0.12, compared to the Junge-Pankow adsorption model, which slightly over-estimated the distribution on particles. There were no indications that partitioning to soot carbon influences the observed gas-particle distrib...
In this paper, a microscopic system for cell physiological research is presented. The setup which... more In this paper, a microscopic system for cell physiological research is presented. The setup which is to a large extent based on commercially available products was designed to establish a platform for time-coordinated electrophysiological and fluorescence optical compound experiments on living neurons in brain slices. Instruments for infrared differential interference contrast video microscopy ~IRDICM!, confocal scanning laser microscopy ~CSLM!, and for patch clamp studies have been assembled into one unit. Using the IRDICM equipment, a neuron can be patched somatically and dendritically. Loading the neuron with a Ca21 indicating dye substance can be examined epifluorescence optically using the Hg lamp or Xe lamp of the microscope. A stimulus initiating the propagation of an action potential through a dendrite can be synchronized to the electronic control unit of the CSLM, and changes in the concentration of Ca21 in the dendrite can be recorded in a time-coordinated way. The setup h...
Elevated concentrations of some persistent organic pollutants (POPs) in fish from arctic and suba... more Elevated concentrations of some persistent organic pollutants (POPs) in fish from arctic and subarctic lakes have been hypothesized to be due to processes within food webs and fish physiology. We investigated limnological processes and contaminant chemistry as explanations of these elevated concentrations by developing and applying fugacity-based mass balance models to a relatively small lake in the high arctic and a series of larger lakes in the southern Yukon River basin. The results indicate that high arctic lakes are transient and inefficient sinks for POPs. The mobility of POPs in high arctic lakes is conferred by their hydrologic regime (i.e. partial through flow of melt water loadings) and minimal scavenging and retention in sediments due to extremely low organic carbon in settling and sediment particles. Contaminant dynamics in lakes of the south Yukon River basin are governed by hydrology (i.e., water residence time), because, similarly to high arctic lakes, most of the contaminant inventory resides in the water column due to inefficient scavenging by settling particles. For the less persistent compounds, long water residence time shifts the major loss process from export to degradation. Model results also suggest relatively short degradative half-lives of the hexachlorocyclohexanes (sum of HCHs) and endosulfan, particularly in high arctic Amituk Lake.
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