Leachates from hazardous waste sites

Occupational exposure to higher than background levels of chloroform can be expected to occur in some occupations although few quantitative exposure data were located. Populations with the highest potential exposures appear to be workers employed in or persons living near industries and facilities that manufacture or use chloroform operators and individuals who live near municipal and industrial waste water treatment plants and incinerators, and paper and pulp plants and persons who derive their drinking water from groundwater sources contaminated with leachate from hazardous waste sites. 

Even though the exact nature of the injuries to the children involved varied from site to site, these studies, and others like it, taken together make a compelling case for the teratogenic hazards posed by emissions and leachates from hazardous waste sites. All such sites release complex mixtures of toxic chemicals with varying compositions. The particular composition from a given site no doubt influences which teratogenic injuries will be sustained by those whose mothers are exposed. 

An initial solute concentration must be selected for the application of solute transport models. An initial concentration for each solvent was based on the chemical composition of leachates from hazardous-waste sites. Where available, the largest reported concentration was used in the modeling efforts (Table 17.2.1). No published data were located for some of the solvents such as cyclohexanone. In such cases, the initial concentration was arbitrarily assigned as 1,000 mg/L or it was equated to the compound s solubility in water. Hexane, decane, and tetrahydofuran were not included in fliese studies. 

Another source of acrylonitrile in water is leachate from chemical waste sites. Preliminary data from the Contact Laboratory Program (CLP) Statistical Database indicates that acrylonitrile has been detected in surface water samples collected at two of 862 hazardous-waste sites (including NPL and other sites) being investigated under Superfund. The median concentration of the positive samples was 100 pg/L (CLPSD 1988). Acrylonitrile was detected in 12 groundwater samples collected at 5 sites, also at a median concentration of 100 pg/L. 

There is also a potential for release of endrin, endrin aldehyde, and endrin ketone to water from hazardous waste sites. Endrin has been detected in surface water samples collected at 10 of the 102 NPL sites, in groundwater samples collected at 37 of the 102 NPL sites, and in leachate samples collected at 2 of the 102 NPL sites where endrin has been detected in some environmental medium (HazDat 1996). Endrin ketone has been detected in surface water samples collected at 5 of the 37 NPL sites, in groundwater samples collected at 16 of the 37 NPL sites, and in leachate samples collected at 2 of the 37 NPL sites where endrin ketone has been detected in some environmental medium (HazDat 1996). No information was found on detections of endrin aldehyde in surface water, groundwater, or leachates at any NPL hazardous waste site (HazDat 1996)... 

The only direct measurements of isophorone in soil were found for samples taken from hazardous waste sites. Ghassemi et al. (1984) found isophorone in leachates from hazardous waste landfills, and Hauser and Bromberg (1982) detected the presence of isophorone in the "sediment/soil/water" of Love Canal. These studies suggest that isophorone also was present in the soil. The Contract Laboratory Program Statistical Data Base (queried April 13, 1987) reported that isophorone has been detected at 4 of 357 hazardous waste sites at a concentration range of 1.68-6500 ppm. 

There is a potential for release of benzene to water from hazardous waste sites. Benzene has been detected in groundwater samples collected at 686 of the 816 current and former NPL sites, in surface water samples collected at 172 of the 816 sites, and in leachate samples collected at 112 of the 816 sites where benzene has been detected in some medium (HazDat 1996). 

Yasuhara, A. et al.. Determination of organic components in leachates from hazardous waste disposal sites in Japan by gas chromatography-mass spectroscopy. Journal of Chromatography A, 77, 321,1997. 

Describe and explain the best approach to managing leachate from hazardous waste disposal sites. 

The use of a drain system permits the quick construction of a collection/removal system which also serves as a barrier for leachate from large, shallow sites. At the Sylvester hazardous waste site in Nashua, New Hampshire, a groundwater interception and recirculation system was installed as a method to retard further spread of the leachate plume until a remedial cleanup action could be implemented. The system was operated for 1 year until a containment wall and cap were constructed over the 20-acre site (McAneny, 1985). 

Hexachloroethane is rarely detected in ambient water. Data reported in the STORET database indicate that the chemical was detectable in only 1 of 882 (0.1%) ambient water samples (Staples et al. 1985). The median concentration for all samples was <10 pg/L. Hexachloroethane was detected in Lake Ontario water, but not in Lake Erie (International Joint Commission 1983). The concentration of hexachloroethane in Lake Ontario was reported at 0.02 ng/L (Oliver and Niimi 1983). It was also identified in leachate from a hazardous waste site in Niagara Falls, New York (Hauser and Bromberg 1982). Hexachloroethane was not detected in 86 samples of urban runoff from 15 cities analyzed for the National Urban Runoff Program (Cole et al. 1984). 

Endrin ketone may react with photochemically generated hydroxyl radicals in the atmosphere, with an estimated half-life of 1.5 days (SRC 1995a). Available estimated physical/chemical properties of endrin ketone indicate that this compound will not volatilize from water however, significant bioconcentration in aquatic organisms may occur. In soils and sediments, endrin ketone is predicted to be virtually immobile however, detection of endrin ketone in groundwater and leachate samples at some hazardous waste sites suggests limited mobility of endrin ketone in certain soils (HazDat 1996). No other information could be found in the available literature on the environmental fate of endrin ketone in water, sediment, or soil. 

No information could be found in the available literature on the bioavailability of endrin aldehyde or endrin ketone. This information would be useful for assessing the potential for exposure to these compounds from various environmental media, particularly in the vicinity of hazardous waste sites where endrin ketone has been found in surface water, groundwater, leachate, soil, and sediment (HazDat 1996). 

Soil monitoring data in the peer reviewed literature could not be located. It can be predicted that chloroform contamination occurs at hazardous waste sites where chloroform-containing leachate moves through the soil to groundwater. An explanation of the lack of data results from the fact that any chloroform in the soil is expected to either rapidly volatilize or leach. Laboratory studies using a variety of different soil types document the effectiveness of volatilization in removing chloroform from soils (Park et al. 1988). 

Possible releases of heptachlor to soil may occur at hazardous waste sites or as a result of landfill leachate. Residues of heptachlor or heptachlor epoxide exist in soil as a result of past usage of heptachlor for both agricultural and nonagricultural purposes. Heptachlor was detected in 0.71% of the soil samples taken from the NPL sites included in the CLPSD at an estimated mean concentration of 4.07 ppb in the positive samples (CLPSD 1989). Heptachlor epoxide was not listed in the CLPSD of chemicals detected in soil samples collected at NPL sites. Note that the information from the CLPSD includes data from NPL sites only. 

Hexanone is released to water by industrial facilities and at hazardous waste sites. 2-Hexanone was detected in 2 of 3 effluents from coal gasification plants and in 1 of 2 effluents from oil shale processing plants at mean concentrations ranging from 7 to 202 ppb ( jg/L) (Pellizzarri et al. 1979). The compound has also been tentatively identified in 1 of 63 industrial effluents (Perry et al. 1979), the effluent from a chemical plant (Shackelford and Keith 1976), and in one municipal landfill leachate at 0.148 ppm (mg/L) in a study of leachates from 58 municipal and industrial landfills (Brown and Donnelly 1988). 

Recall Problem 3.1. You are the boss of an analytical laboratory and, this time, you check the numbers from the analysis of chlorobenzene in water samples of very different origins, namely (a) moderately contaminated groundwater, (b) seawater ([salt]tot 0.5 M), (c) water from a brine ([salt]tot = 5.0 M), and (d) leachate of a hazardous-waste site containing 40% (v v) methanol. For all samples, your laboratory reports the same chlorobenzene concentration of 10 ng IT1. Again the sample flasks were unfortunately not completely filled. This time, the 1 L flasks were filled with 400 mL liquid, and stored at 25°C before analysis. What were the original concentrations (in /J,g-L l) of chlorobenzene in the four samples ... 

The occurrence of acrolein in soil at one hazardous waste site in the United States and leachate from one municipal landfill in Wisconsin provides evidence that this compound has been released to soil as the result of land disposal of some organic wastes. No data were located regarding the amount of acrolein released to soil. 

Krill and Sonzogni 1986 Otson 1987). Grosjean and wright (1983) detected acrolein, in combination with acetone, at a concentration of 0.05 ppt in rainwater collected in Los Angeles, CA however, these compounds were not detected in rainwater samples collected in four less densely populated sites in California. The Contract Laboratory Statistical Database reports that acrolein has been detected in water at 3 of 357 hazardous waste sites in the United States at mean concentrations ranging from 10.3-51,000 ppb (VIAR 1987). However, this database made no distinction between groundwater and surface water monitoring data. In the only report of acrolein occurrence in municipal landfill leachate, acrolein was detected at a concentration of 170 ppb in 1 of 5 leachate samples collected from sites in Wisconsin (Sabel and Clark 1984). 

Figure 7. Anion exchange chromatogram with UV detection (230 and 254 nm) of a lyophilized extract of an aqueous leachate from the Stringfellow hazardous waste site.

Unnatural Products Chemistry. The complete identification of unknown compounds that we have successfully resolved using PB/LC/MS will clearly require additional analytical information, such as provided via liquid chromatography ICP/MS (detecting nonmetals such as chlorine and sulfur), FT-IR, UV or proton and heteroatom NMR. This situation is analogous to that of a natural products chemist faced with making a complete structural assignment of an unknown compound isolated from some matrix such as seaweed instead of a leachate from a hazardous waste site. The natural products chemist would exploit the complete array of analytical instrumentation and not attempt identification based solely upon low resolution (quadrupole) mass spectrometry. 

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