Contaminants management, methods

Rulkens, W.H. and Assink, J.W., Extraction as a Method for Cleaning Contaminated Soil Possibilities, Problems and Research, 5th National Conference on Management of Uncontrolled Hazardous Waste Sites, Washington, DC, 1984, pp. 576-583. 

A permeable reactive barrier (PRB) is defined as an in situ method for remediating contaminated groundwater that combines a passive chemical or biological treatment zone with subsurface fluid flow management. Treatment media may include zero-valent iron, chelators, sorbents, and microbes to address a wide variety of groundwater contaminants, such as chlorinated solvents, other organics,... 

Abstract Many hazardous substances of today had been looked at as valuable chemicals some decades ago. At present, management especially in the case of scarce, non-renewable resources is of growing importance. The experiences collected with the management of contaminants might be helpful also for valuable resources. This is demonstrated using two well-documented examples, Cd and PCBs. Pt serves as a counterexample to prove if the DPSIR method can be applied to contaminants and resources without fundamental changes. Some of the countermeasures introduced to control environmental contaminants may also be applied to save non-renewable resources. 

The sustainable management of sediments, in addition to water, soil and sludge environmental matrices, in relation to surfactant regulations, is also an important and relevant issue. The US EPA has recently shown concern regarding the levels of surfactants in sediments and has thus released a Draft Contaminated Sediment Science Plan. In this draft, recommendations for the development of analytical methods and evaluations of the toxicity and risk assessment of Emerging endocrine disrupters like APEOs and their metabolites in sediment samples are outlined. 

Due to the capacity of deep wells to store injected waste for a long period of time, if the correct measures are taken in design, construction and operation, deep well injection can provide an effective and environmentally safe method of concentrate management. The major environmental concern for deep well injection is the potential for contamination of nearby aquifers, which may be used as a source of drinking water. Six pathways have been defined that describe the potential migration of concentrate that can cause contamination of aquifers (Shammas et al. 2009 United States Environmental Protection Agency 2002) ... 

Komatsu, F., Sawada, Y., Ohtsuka, K. OHUCHI, J. 1981. Development of a new solidification method for wastes contaminated by plutonium oxides. In Management of Alpha-Contaminated Wastes. IAEA, Vienna, 325-337. 

Advice of the type noted above on avoiding adventitious contamination of food needs to be made both nationally and by management in companies involved with food. The control of pesticide residues in food could include HACCP (Chapter 11) to provide an important element of prevention. Other preventative methods include testing of incoming supplies of raw and other materials, and direction by retailers to suppliers that they must use only a defined list of pesticides in specified ways. 

The outputs from risk assessment will normally include information about the relationship between dose and risk and estimates of levels of doses and thus risks in the population. For contaminants that have a toxicological threshold the Provisional Tolerable Weekly Intake (PTWI) might be defined and the number of consumers who have the potential to exceed this level of intake quantified. If a PTWI cannot be established (such as for genotoxic carcinogens) then it may be possible to quantify the proportion of a population exposed to a given level of risk by using QRA methods. If QRA methods cannot be applied then a qualitative assessment can be made such as to reduce intake levels to as low as is reasonably practicable. In either case it is the function of risk management to identify an optimal course of action to minimise the risk to consumers. 

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