Michael E. Comba

Congener-specific analysis of the accumulation of polychlorinated biphenyls (PCBs) by aquatic organisms in the maximum turbidity zone of the St. Lawrence estuary, Québec, Canada☆

The polychlorinated biphenyl (PCB) contamination of the biota of the St. Lawrence estuary maximum turbidity zone (MTZ) was investigated. The species analyzed consist of zooplankton (mostly Neomysis americana), larval smelt (Osmerus mordax), juvenile smelt, juvenile tomcod (Microgadus tomcod) and adult smelt, tomcod and capelin (Mallotus villosus). A significant increase in total PCB contamination from zooplankton to all fish developmental stages indicates that the St. Lawrence MTZ is a site of significant PCB contamination. The total PCB contamination of adult smelt and tomcod sampled in the St. Lawrence MTZ was greater than the limit of 0.1 ppm set by the International Joint Commission for the protection of predators. For zooplankton, tomcod and capelin, significant correlations were found between lipid content and PCB contamination. The congener-specific analyses showed that the bioconcentration factor of the individual congeners varied with the species involved and with the molecular structure of the congener. It was found that the chlorine atoms in positions 2, 4 and 5 on at least one phenyl ring of the PCB molecule was a dominant factor causing accumulation of PCBs in aquatic organisms. The pattern of PCB congeners found in beluga (Delphinapterus leucas) whale tissues is similar to the PCB pattern found in the St. Lawrence estuary MTZ biota.

Trace Organic Contaminants in the Detroit River

Concentrations of polychlorinated biphenyls (PCBs), polynuclear aromatic hydrocarbons (PNAs), chlorobenzenes (CBs), chlorophenols (CPs), and a number of other organochlorine compounds (OCs) have been determined in the surface microlayer, subsurface water, suspended solids, sediments, and in sediment pore water at 20 sampling stations in the Detroit River. The data are discussed in terms of contaminant sources, pathways, and sinks. Spatial trends within the river and relationships of contaminant groups within and between compartments are described. The results indicate a continuing input of all contaminant groups to the river from a variety of sources, particularly from sewage treatment plant effluents and several tributaries. The contaminant distributions and intercorrelations also indicate that major sources of PCBs, PNAs, OCs, and CBs are concentrated on the westerly river shore, while CPs enter the river mainly from the easterly shore.

Distribution of Hydrocarbons and Chlorinated Hydrocarbons in Various Phases of the Detroit River

Concentrations of several chlorohydrocarbons, polychlorinated biphenyls, and polynuclear aromatic hydrocarbons in the Detroit River were measured. For purposes of this study, the river ecosystem was divided into six phases or compartments: sediments, pore water in the sediments, suspended solids, subsurface water, surface microlayer, and air. Significant amounts of the above mentioned compounds occur in all of these compartments except air (for which our detection was relatively insensitive). The sediments contained over 99% of the chlorinated compounds. The polynuclear aromatic hydrocarbons were distributed between the subsurface water and the sediments.

Volatile Halocarbon Contaminants in the Niagara River and in Lake Ontario

Water samples from 95 stations in Lake Ontario and 16 stations in the lower Niagara River Were analyzed for volatile halocarbons and carbon disulfide. The following contaminants were observed at many stations with their lake-wide means and standard deviations: trichloro-fluoromethane (Freon 11), 249 ± 882 ng · L−1; methylene chloride, 572 ± 1,826 ng · L−1; chloroform, 18 ± 92 ng · L−1; bromodichloromethane, 3 ± 9 ng · L−1; and tetrachloroethylene, 9 ± 65 ng · L−1. Eleven other compounds, including carbon disulfide, 1, 1–dichloroethylene, 1,1,1–trichloroethane, carbon tetra-chloride, and tetrachloroethylene were observed at trace levels or absent at most stations. Six compounds were observed in virtually all Niagara River samples and were traceable into the lake. As apparent from the large relative standard deviations for the above, contaminant concentrations varied strongly between stations, indicating areas of contaminant sources. Both industrialized and urban areas, such as Toronto, Hamilton, and the Niagara River, as well as comparatively small tributaries, such as Twelve Mile, Eighteen Mile, and Oak Orchard Creeks, Black River, and the Welland Canal, appear to be sources for several of the observed contaminants.

Determination of Volatile Contaminants at the ng I−1 Level in Water by Capillary Gas Chromatography with Electron Capture Detection

Abstract An improved analytical headspace method is described for the quantiative determination of volatile contaminants in water. Detection limits at the 1.0ng-1−1 levei or better can be achieved for carbon tetrachloride using a suitable capillary column gas chromatograph and electron capture detector. The method is also applicable to the analyses of haloforms and associated halomethanes and haloethanes in drinking waters or quantitation of low ppt concentrations in ground or surface waters. This headspace technique is simple, inexpensive, easily applied to field conditions and well-suited for cryogenic capillary column chromatography.

Incidence of chlorinated benzenes and chlorinated ethylenes in Lake Ontario Herring Gulls

Abstract Great Lakes Herring Gulls (Larus argentatus) and their eggs have proven to be useful integrators on a lakewide basis of high molecular weight, relatively involatile organochlorine pollutants such as PCRs. A search for relatively volatile organochlorine compounds by GC/MS also revealed the presence of tri- and tetrachloroethylene, and isomers of di-, tri-, tetra-, penta- and hexachlorobenzene in the body lipid of adult Herring Gulls from Lake Ontario. Analysis of pooled eggs from colonies throughout the Great Lakes in 1978 showed that pentachlorobenzene and hexachlorobenzene were ubiquitous contaminants at levels from 14–50 ng/kg and 90–350 ng/kg, respectively. Hexachlorobenzene levels were 2–3 times higher in Lake Ontario than the other lakes, whereas pentachlorobenzene was more evenly distributed geographically. Levels of 1,2,3,4-tetra-, 1,2,4,5-tetra- and 1,2,4-trichlorobenzene near the detection limit of 10–20 ng/kg were found in a few samples.

Volatile Halocarbons in the Detroit River and their Relationship with Contaminant Sources

Volatile halocarbon measurements show that presently active point sources for contaminants in the Detroit River are primarily sewage treatment plants (STP) and combined storm sewers. From the observed ratios of municipal and industrial type contaminants, it is deduced that the waste water processed by sewage treatment plants contains significant contaminant loadings of industrial origin. Major sources of such loadings were found along the Trenton Channel, at the confluences of several tributaries including the Ecorse River, River Rouge, Conners Creek, Little River, and Turkey Creek, and at outfalls from several industrial areas including the Detroit STP, Ford Canada, West Windsor STP, and Allied Chemical Canada.

Volatile Contaminants in the Welland River Watershed

Surveys of selected volatile contaminants in water of the Welland River, a tributary to the Niagara River, in 1980 and 1981 show high levels of carbon disulfide, methylene chloride, and chloroform immediately below two industrial outfalls. Downstream from these point sources, a rapid decline in the contaminant concentrations is noted due to dilution, degradation, and/ or volatilization of the compounds. Although toxic effects of other components of these effluents have been observed, the concentrations of the volatile contaminants are several orders of magnitude lower than those at which acute toxic effects on biota are observed.

Organic trace contaminants in St. Lawrence River water and suspended sediments, 1985–1987

The concentrations of organic trace contaminants, including chlorobenzene congeners, hexachlorocyclohexane isomers, DDT group pesticides, polychlorobiphenyls (PCB) and several other biocides, such as mirex, dieldrin and endosulfan, have been determined in water and suspended sediments of the St. Lawrence River. The data cover important areas of the river between Kingston and Quebec City for four sampling periods, i.e. May 1985, October 1985, June/July 1986 and June 1987. The results indicate: (i) low levels of suspended sediments at the head of the river (∼ 1 mgl−1) which increase towards the river mouth to ∼10 mgl−1 (up to 25 mgl−1 in October 1985); (ii) significant inputs of PCB along certain river sections; (iii) low levels of mirex in suspended sediments throughout the river; (iv) the riverine lakes in the St. Lawrence (Lakes St. Francis, St. Louis and St. Pierre) appear to be short-term contaminant sinks only.

Polychlorinated biphenyls in St. Lawrence River sediments

Abstract Sediment cores from six stations and sediment trap samples from seven stations in the riverine lakes of the St. Lawrence River have been analyzed for chlorobenzenes, organochlorine pesticides and polychlorinated biphenyls (PCBs). The sediment cores were sectioned into the top three 1 cm sections, which were analyzed individually. Three of the sediment cores were from the same sites as the sediment traps. The results indicate the presence of di-, tri-, tetra-, penta- and hexachlorobenzene isomers, γ-chlordane, DDE and DDT, and PCB residues in most of the suspended and bottom sediments. PCB in the bottom sediments made up, on average, 81 ± 11% ( n = 18) of the total organochlorine burden. PCBs had a mean concentration of 135 ± 138 ng g −1 (range 10–530 ng g −1 ; n = 18) in the core samples and were highest in Lac St. Francois and Lac St. Louis. In sediment trap samples, PCBs made up, on average, 78 ± 13% ( n = 7) of the total organochlorine burden. PCB concentrations had a mean of 53 ± 40 ng g −1 ; n = 7) in the trapped suspended particulates and were highest below Ile St. Regis and in Lac St. Pierre.