Environmental monitoring requirements

Binding occupational exposure limit values reflect feasibility factors related to social acceptability. When the results of environmental monitoring have to be compared with OELs, factors that influence exposure and that entail preventive policies are considered. For these values member states shall establish a corresponding national binding occupational exposure limit value based on but not exceeding the community limit value. That is, a binding limit means a minimum requirement. 

Environmental monitoring of chloroacetanilides requires methods that have the capability to distinguish between complex arrays of related residues. The two example methods detailed here for water monitoring meet this requirement, but the method for metabolites requires sophisticated mass spectral equipment for the detection of directly injected water samples. In the near term, some laboratories may need to modify this method by incorporation of an extraction/concentration step, such as SPE, that would allow for concentration of the sample, so that a less sensitive and, correspondingly, less expensive, mass spectral detector can be used. However, laboratories may want to consider purchasing a sensitive instrument rather than spending time on additional wet chemistry procedures. In the future, sensitive instrumentation may be less expensive and available to all laboratories. Work is under way to expand the existing multi-residue methods to include determination of additional chloroacetanilides and their metabolites in both water and soil samples. 

On-line SPE-LC-ISP-MS/MS (with run times of 1-3 min) is widely used in pharmaceutical, clinical, and combinatorial chemistry, as well as in environmental monitoring, whenever rapid target MS analysis in a complex matrix is required. Thermally assisted... 

On the other hand, indirect methods should be considered as an alternative when analytical measurements are not feasible. Predicting methods involve extrapolating exposure estimates from existing data, e.g., previous environmental monitoring, data about emissions and chemicals production, and questionnaires. Distribution of chemicals among the different environment compartments is also a key aspect for predicting environmental concentrations. Therefore psysicochemical properties (see Sect. 4) are required inputs in these tools. 

As mentioned before, environmental exposure is the first key aspect to develop risk characterization from a defined scenario (see Fig. 1). Experimental analysis is the most obvious and classical procedure for determining the chemical occurrence in the environment. Measuring environmental concentrations (MECs) is more accurate and reflects the reality better than any other method, but the main drawback is the large amount of resources required for these laboratory measurements. Field environmental monitoring programs have become increasingly expensive as... 

Chemical vapor sensors play an ever-increasing role in the environmental monitoring, homeland security, defense, and health care. The desirable characteristics of a chemical vapor sensor include ultrahigh sensitivity, specific and rapid response to certain vapor molecules, as well as the ability for on-the-spot chemical analysis, which usually requires the sensor to be small, portable, reusable, stable, robust, and cost effective. Toward this end, various sensing techniques have been studied... 

However, applicability of the bottom-up approach is limited primarily by cost implications to conduct ecosystem risk assessment following accurately the formal U.S. EPA procedure, an assessor must spent huge amounts of time and money on collecting necessary input data, data processing and interpreting the outputs. Of importance, very specific data are often required that cannot be easily obtained with the help of standard environmental monitoring studies. 

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