Zandvlei Trust

Research Proposal.

The Funding Appeal.

• This is the research project for Margit van Heerden (2010 student at the Zandvlei Nature Reserve).

• She urgently needs R10600 for lab testing which the CSIR can do (cheapest rate and done in Stellenbosch). For the study to be viable she needs to have 10 samples analysed from each species - R530 x 20 = R10600.

• Time scale is between now June and September 2010.

• You will be contributing to conservation of species at Zandvlei, as well as helping to find out the question of mercury ingestion and accumulation.

• The appeal is to anyone or a group of people who can help financially.

Zandvlei Trust will manage and account for the money spent with a report to the donors / funders.

For more information about the project contact Margit on 021 701 7542 (o/h).
Contact David Muller for Zandvlei Trust details 072 986 5311.

photograph supplied by Margit van Heerden

A Leervis or Garrick.

photograph supplied by Margit van Heerden

Soutern Mullet.

The Proposal.

Title: Mercury levels in fish tissue of Garrick Lichia amia and Southern Mullet Liza richardsonii in the Zandvlei estuary.

Motivation: In 2009, the CSIR did a study about the mercury levels in the fish along the South African coast. Their result founded that the highest concentrations of mercury occurred in the False Bay region and it exceeded the World Health Organization’s guideline value of 0.2 µg/g.
Mercury is released into the air from industry. It falls from the air and accumulates in streams and rivers. When mercury comes into contact with water, it is converted into methylmercury (MeHg).
The bigger the size of the fish, the more mercury levels accumulate. Methylmercury also accumulates in the muscle of fish species ( Yamashita; Omura and Okazaki, 2005).
Methylmercury toxicity is associated with serious health problems such as mental retardation; cerebral palsy; deafness; blindness and dysarthria due to prenatal exposure in infants and children. Sensory impairment, motor impairment and adverse effects on the cardiovascular system in adults (Park and Johnson, 2006).

Objectives: To take a representative sample of fish tissue tested to give an indication of the mercury levels that occur in the fish and whether they exceed the World Health Organization recommended levels. If the levels are too high then management recommendations should be investigated as to how these heavy metal levels can be regulated and the effects of the mercury on the biota mitigated as well as setting guidelines or health warnings to be set for the surrounding community who eat the fish on a regular basis.

Methods: A gill net will be set out at different sections of the estuary. There will be a time limit on the gill nets and they will be regularly checked.

Budget: The lab tests will cost R 530 per sample. The equipment and staff will be supplied by the City of Cape Town. The minimum amount is 10 samples per fish species for it to be accurate.

References: Park.S and Johnson. M.A, Awareness of Fish Advisories and Mercury Exposure in Women of Childbearing Age, Nutrition Rev. Vol. 64.No.5, 2006.

www.csir.co.za/publications/pdfs/013_pdfsam_SSNovforweb_CHEMICALSAFETY.pdf.

Yamashita.Y, Omura. Y and Okazaki.E, Total Mercury and Methylmercury Levels in Commercially Important Fishes in Japan, National Research Institute of Fisheries Science, Japan, 2005.