Damage due to the effects of the Mt. Pinatubo eruption was observed but more importantly the effects of man made destruction were reported. Although much of the forest is still is old-growth, a large fraction of the area is secondary forest and cogon-talahib dominated grassland. The grassland resulted from logging, burning, and cultivation.
Reforestation of degraded lands is recommended, as well as increased patrols to stop further destruction.
Much of the mangrove habitat has been destroyed by reclamation activities of the US Navy and the remaining mangrove is under severe stress. Some of this stress may be due to Mt. Pinatubo, but likely much of the stress is due to changes in hydrology and sedimentation resulting from land development in the area. Chemical contamination may also be a factor but no evidence was obtained to determine possible chemical factors that might contribute to degradation.
If the natural diversity and beauty of the area is to be part of what SBMA offers to tourists the SBMA must do more to determine how to restore the mangroves to health as well as initiate activities to rehabilitate degraded forests and preserve the existing old-growth forests.
Ecological and human heath risks due to contamination of the sediments in the bay.
In the background statements, the authors of the report state contamination of the sediments should not be a problem because sediments are periodically dredged and taken out to sea and dumped. However, many of the 41 samples of sediments contained inorganic elements at concentrations above the screening criteria for and many had very high concentrations. For arsenic, barium, and lead about 20% of the samples were above the screening criteria. For zinc 32% were above the screening criteria. For mercury and zinc about 40% of the samples were above the screening criteria. Tributyl tin, the toxin added to paint used on military ships was detected at levels of concern but not at levels that would trigger remediation in the Netherlands. The organo-tin breakdown products of tributyl tin were detected at much higher concentrations than the tributyl tin.
The possible effects of these organo-tin compounds was not discussed. Unfortunately, total tin was not determined.
There was no attempt to assess risk to the health of the biotic communities in the bay. No samples of biota were taken.
Petroleum residues were found in all of the samples but at levels that are less than would be of concern in the Netherlands. PCBs were only detected in one sample , at very low levels. Unfortunately the sediments were not analyzed for chlorinated solvents. Chlorinated pesticides analyzed but were not detected.
The discussion of health effects of sediment assumed:
a) no dermal contact or ingestion during swimming, and
The report states that because there is no commercial fishing in the harbor the exposure due to fish consumption in not a problem. However, we have observed non commercial fishing in the inner harbor. We are most concerned with the problem of mercury which is at very high levels in some of the sediment samples.
b) no ingestion of contaminated fish.
In sediments mercury is converted to methyl mercury, a powerful neurotoxin that is biomagnified and accumulates in predator fish. Mercury is especially problematic for pregnant women and young children. Fishing in the harbor should be prohibited and fish and other seafood consumed from the harbor and nearby areas should be sampled for Hg and other inorganic contaminants.
Stream water quality and landfill leachate.
Only 8 sites were samples and 6 of these were upstream control sites Only 2 sites were sampled in areas of concern. Both of these sites were on the Binictican River , one just down stream of the landfill and the other further downstream near the golf course. It is unfortunate that the Kalaklan River, the drainage channel, and other down stream areas of concern (e.g. the Boton River) were not sampled. At the downstream sites on the Binictican River, contamination was indicated by elevated chemical oxygen demand and reduced dissolved oxygen. The report suggests the river may be receiving landfill leachate.
The problem of leachate is further indicated by wellwater sampling near the landfill The groundwater at this area contained arsenic, lead, and selenium at levels above drinking water standards Phenols, PAHs, chlorobenzene, phenols, and endosulfan were also detected in the wells and chromium lead and mercury were detected in the soil. Unfortunately, no chemical or biological oxygen demand analyses were made on the well water. These data would help determine the extent of landfill leachate problems. The level of contamination is evidence that leachate from the landfill is moving into the shallow groundwater which then can seep into he river. This is leachate movement suggests remediation, with the installation of a leachate control system, (as recommended in the report) should be a very high priority for SBMA.
Comment on the old dump site and the landfill.
Both of these sites are in the Port Industrial Area. Both contaminate the groundwater, which is not an immediate problem because the groundwater is not used for drinking or irrigation, but the dumpsite leachate can seep directly into the harbor and the landfill leachate appears to be seeping in to the Binictican River. Both of these sites are very problematic for development . Without remediation, construction should not take place on these sites. Remediation must be a high priority for SBMA.
Unexploded ordnance in test ranges across the bay from SBMA developments.
As shown in "Toxic Sunset" these areas pose an immediate hazard to human health and warrant immediate attention.