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information of consumers of freshwater fish in the catchment, bioaccumulation
potential and health risks of analytes, sound sampling design, risk assessment
procedures and performing monitoring at different scales and depth (Figure 1). It is
important to note the method developed is closely linked to the protocols proposed
by the USEPA (1995a,b, 1996, 1997) for issuing fish consumption advisories for noncommercial
fish and by Heath (1999) for the monitoring of pesticides and metals in
South African rivers. The approach by Heath (1999) and the current approach are
catchment-based, making it possible to use much the data and information when
undertaking any of the proposed levels of investigation. Therefore, if projects are
carefully planned using the same methodology and principles, the data and information
can be exchanged, which would ensure the optimal utilisation of resources.
South African Methodology
The methodology developed for South African human health risks associated with
eating freshwater fish identifies ten major steps, namely:
(i) selection of scale and depth of survey,
(ii) assessment of the water-body catchment,
(iii) monitoring system design,
(iv) field collection,
(v) laboratory sample processing and analysis,
(vi) analysis of and reporting of results,
(vii) risk assessment,
(viii) risk management,
(ix) risk communication, and
(x) evaluation and review of the programme.
The application of the protocol developed, even though it has several sequential
steps, must be seen as an iterative process. For example, during the assessment of
the water body (Step 2) it is important understand the needs of the risk assessment
(Step 7) so that the relevant information is collected at the appropriate time. The
same applies to the collection of sample in the field (Step 4), which need to be
collected and preserved according to the analytical Procedures (Step 6).
The basic requirements of each step is highlighted as limited resources (financial,
infrastructure and skilled personnel) in South Africa would limit the possibility of
undertaking detailed assessments as undertaken by the United States of America
Environmental Protection Agency (USEPA). Nevertheless, by applying the proposed
protocol, sound comparable assessments, based on risk assessment methodology,
can be made regarding the human health risk associated with the consumption of
freshwater fish in South Africa.
Three monitoring levels are identified for the investigation of the chemical contaminant
concentrations in freshwater fish tissue (Figure 1). The following levels of monitoring
are considered for the South African surveys, namely Screening surveys, Intensive
surveys (Phase I) and Intensive surveys (Phase II). The intensity of the level of
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