Health Risk from Consuming POC-Contaminated Fish: Part II. Risk Analysis and Prevention Strategies Michael H. Dong, MPH, DrPA, PhD October, 2007 Readings

taken at the Epcot Center, Orlando, Florida, USA

Lecture Objectives  Appreciate the POC residue levels in fish observed in various countries.  Compare these real-time residue levels to their respective screening values that have been adopted as threshold levels.  Revisit the basic strategies used for preventing health risk from consuming fish contaminated with POCs.

Performance Objectives  Students are expected to know that worldwide levels of some POCs are still far exceeding their screening values. .. to know what the methodological issues and associated uncertainties are in the risk analysis conducted here. .. to know that the prevention strategies so discussed can be costly, yet crucial.

Advisory for High Risk Groups  A considerable number of monitoring sites were noted to have POC levels > the screening values by 30-fold+.  For these areas, no more than 1 or 2 fish meals/month should be recommended.  Fish advisories of this kind may not be all that practical to residents who rely on fish as their main diet.

Issues Inherent in the Analysis  Risk analysis of the type conducted here is far from flawless.  High consumption observed may not correlated well with high residue level detected even in the same vicinity.  Nor are all fish species in the same vicinity necessarily contaminated by the same chemical or to the same extent.

Other Related Issues (I)  The characteristics, the transport, and the fate of POCs present in the aquatic environment all can play a crucial role.  Current trends may not be indicative of the POC levels in fish in the future.  For example, some POCs have been transported to remote sites where the chemicals have never been used.

Other Related Issues (II)  There are also uncertainties with the empirical data used in the analysis.  All tolerance limits or screening values are based on the toxicity data on hand, which are ever lacking or indirect.  Residue data are vulnerable to technical errors inherent in sample collection and in the analytical procedures used.

Implications of Analysis Data  While both the tolerance levels and the POC residue data must be applied with caution, some level of conservatism could/should still be exercised to err on the side of health protection.  Certain prevention strategies are thus warranted here for fish contamination with POCs in many localities.

Concerns with Bioaccumulation  Bioaccumulation refers to cumulative and aggregate exposures during the same time interval.  Its occurrence in humans can lead to further alarming health consequences.  The main concern here is that fish and shellfish are not a person’s only source of exposure to the same/a similar POC.

Issues with Bioaccumulation  Once a lipophilic chemical (e.g., POC) is inside the human body, it will not go away any time soon.  A large enough single dose (exposure) can induce an acute adverse effect.  The ADI or RfD used might not have taken into account the extra amount of a POC coming from other sources.

A Case of Bioaccumulation  A pregnant woman was exposed to a POC daily at a constant dose of 10 units from fish consumption, and 5 units through other sources (e.g., milk, water).  Then on day 10, this woman would have as her body burden a total of 150 (not 100) units of this chemical, which would exceed the threshold of 100 units.

Risk Prevention Strategies  Certain risk prevention strategies hence should be in place to cope with the potential hazard from consuming fish contaminated with POCs.  These would involve: environmental health policy; regulatory/research activities; residue monitoring programs; and self awareness/prevention.

Environmental Health Policy  Programs/policies should be developed, with a focus on better use of POCs and on better handling of waste removal.  FQPA-like laws should be adopted to focus on children’s higher sensitivity.  Governments should have available more, as well as more effective, POC- related illness surveillance programs.

Regulatory/Research Activities  Activities should be in place to enrich risk communication resources for fish contamination with POCs.  Research is needed to refine the works done on risk assessment methodology, on toxicity studies, and on relevant exposure parameters including fish consumption pattern.

Residue Monitoring Programs  More monitoring programs for POCs in fish need to be developed around the ‘hot spot’ areas (which should be more aggressively identified).  These programs should be effective with a special focus on sampling, on the analytical technique used, and on uniform reporting of monitoring data.

Self Awareness/Prevention (I)  Awareness/prevention at the individual level is the most effective approach to minimizing the human health risk from consumption of POC-contaminated fish.  This assertion is based upon the notion that risk prevention at the individual level is much more tangible, more controllable, and thus more attainable.

Self Awareness/Prevention (II)  A fish consumer should make every effort to choose younger fish to eat.  The person should remove the fish’s guts as these are the organs where some POCs also tend to concentrate in.  The person should also trim the fish’s fat, remove the skin, and cut away the fatty dark meat.

Self Awareness/Prevention (III)  Lastly, the consumer should cook fish in a way that would allow the fat to drip away or drain off.  This can be accomplished effectively with most cooking methods.  Up to 60% or more of the POCs could be reduced by the way in which the fat is dripped or drained away.

Self Prevention with a Price  In closing, it is fair to forewarn that the type of self risk prevention measures suggested here is not without a price, unless fish can swim in or be cultivated in a cleaner aquatic environment.  Otherwise, the individual consumers would end up getting less intake of the good (i.e., the essential) fats in fish.