Secondary containment disadvantage

The principal disadvantage of this procedure is that the olefin must be used in at least three- to fourfold excess in order to obtain reasonable yields. In case of rare olefins, or of olefins containing groups such as the carbonyl group which add organolithium compounds, other methods might be more advantageous. The method is also limited to the preparation of secondary cyclopropanols. 

Traditional landfill presents several disadvantages since the space available for landfill has become scarce. In addition, municipal waste has to be transported over increasing distances with associated wastage of energy [3]. Leachates from unprepared landfills may contain hazardous levels of substances such as ammonium salts, heavy metals and organic chemical waste that may contaminate the air, soil and ground water [4] and thus may affect crops and secondary animals and man [3, 4, 5, 6, 7]. 

Toxicity tests using artificially contained communities have long been a resource in environmental toxicology. The nature and design criteria for these types of tests are discussed in Chapter 3. Many different methodologies have been developed (Table 4.12). Each has particular advantages and disadvantages and none have been demonstrated to faithfully reproduce an entire ecosystem. However, as a research tool to look at secondary effects, bioaccumulation and fate, the various multispecies toxicity tests have been demonstrated to be useful. 

---