Below detection, limit

Cumene is expected to exist almost entirely in the vapor phase in the atmosphere (13). In water, mixed cultures of microorganisms collected from various locations and depths in the Atiantic Ocean were all found to be capable of degrading cumene (14). A number of studies have examined the aerobic degradation of cumene in seawater and in groundwater (15,16). The results indicate that cumene would normally be naturally degraded to below detectable limits within a week to ten days. Cumene is tightly adsorbed by soil and is not significantly mobile in soil (17). 

Polymers. Studies to determine possible exposure of workers to residual epichl orohydrin and ethylene oxide monomers in the polymers have been done. Tests of warehouse air where Hydrin H and Hydrin C are stored showed epichl orohydrin levels below 0.5 ppm. Air samples taken above laboratory mixing equipment (Banbury mixer and 6" x 12" mill) when compounds of Hydrin H or C were mixed gave epichl orohydrin levels below detectable limits, and ethylene oxide levels less than 0.2 ppm, well below permissible exposure limits (46). A subacute vapor inhalation toxicity study in which animals were exposed to emission products from compounded Parel 58 suggests that no significant health effects would be expected in workers periodically exposed to these vapors (47). 

By using modem production methods it is possible to reduce the amounts of 1,4-dioxane to a level that is barely detectable with the best current analytical methods. Free ethylene oxide is now below detectable levels. Furthermore, volatile and nonvolatile nitrosamines ( NDELA ) both seem to be below detection limits of ppb in the alkanolamide-based sulfosuccinates. A good overview of modern analytical methods for the detection of 1,4-dioxane and ethylene oxide as well as nitrosamines and formaldehyde is given in Ref. 60. 

The pollutants characteristic of the industry wastewaters are summarized in Table 5.4 through Table 5.11, for both classical and toxic pollutants. The toxic pollutant data have been developed using a verification protocol established by U.S. EPA, with the exception of the following selenium, silver, thallium, and 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCCD). Table 5.12 presents the minimum detection limit for the toxic pollutants. Any value below the minimum limit is listed in the summary tables as below detection limit (BDL). 

Source U.S. EPA, References 1, 2, and 5. BDL, below detection limit. a Approximate value. 

BDL, below detection limits NM, not meaningful. a API, American Petroleum Institute oil-water separator. b TEB, thermal emulsion breaker. c Approximate value. 

Source U.S. EPA. Treatability Manual. Vols. 1—3. U.S. EPA, Washington, DC, 1981. Blanks indicate data not available. BDL, below detection limit. ND, not detected. NM, not meaningful. a Approximate value. ... 

BDL, below detection limit ND, not detected. a BDL was calculated in the mean concentration as equal to zero. 

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