Dr. Evangeline C. Santiago, NPC for the Philippines

The monitoring activity in the river and coastal hydrosphere in the Philippines for the third year was a continuation of the second year activity. Surface and bottom water from the 19 sampling sites Manila Bay, Limay Bay, Subic Bay, Batangas Bay and some of their river tributaries that were monitored last year were analyzed for Organochlorine Pesticides, Phenols and Phthalates.

1. Organochlorine Pesticides (OCPs)

Different types of organochlorine pesticides were detected in the sampling sites during the two sampling periods. Concentrations detected below the Method Detection Limits (MDL indicated as Traces) and above the MDLs are reported. MDLs were estimated from analysis of spiked samples. Values in parenthesis are the highest levels found in the samples.

The highest concentrations of OCPs were found in Limay Bay. In surface waters, DDT (0.022 ppb), endosulfan (0.051 ppb) and heptachlor (0.027 ppb) and in bottom waters, gamma BHC (0.046 ppb), heptachlor (0.056 ppb), endosulfan (0.094 ppb) and DDT (0.068 ppb) were found near the Petrochemical complex. Endrin (0.148 ppb) was found in highest concentration in the bottom sample of Calumpang River in Batangas, dieldrin (0.078 ppb) in the bottom sample of Tenejeros River in Manila.

Comparing this year's results of OCPs monitoring with those obtained last year, more OCPs were detected this year and higher concentrations were recorded.

2. Phenols

The samples collected from rivers in Manila gave the highest concentrations of phenols. Most of the phenols except n-heptyl phenol were detected in the rivers of Manila. Nonyl phenol gave the highest concentration in Meycauayan River, Tenejeros Rivers and in Paranaque River (134 ppb, 5.1 ppb and 3.9 ppb respectively). Pentachlorophenol, t-butyl phenol and 4-t octyl phenols were also detected in significant amounts. The sites that gave the highest levels of phenols for this year were also the same sites that gave the highest levels of phenols last year. The excessively large phenol concentration detected in Manila Rivers can be attributed to the lack of efficient sewerage treatment facility in the city. Varying types of alkyl phenols and chlorophenols were also detected in the coastal areas of Manila, Limay, Batangas and Subic. Bisphenol A was detected in most of the sampling sites.

3. Phthalates

Di-2 ethyl hexyl phthalate (DEHP), Di-n butyl phthalate (DBP) and Di ethyl phthalate (DEP) were detected in highest concentrations in Manila Rivers (0.4-0.8 ppb, 0.1-0.7 ppb and 0.08-0.3 ppb respectively) for the first sampling and (0.02-0.62 ppb, 0.004-0.72 ppb and 0.03-0.87 ppb respectively) for the second sampling. Only DEHP was detected in Manila Bay (0.1-0.3 ppb for the first sampling and 0.1-0.57 ppb for the second sampling).

DEHP, DEP and DBP were also detected in Limay Bay and Batangas Bay and their river tributaries in the range 0.01-0.1 ppb.

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