American Journal of Environmental Sciences 4 (4): 276-280, 2008 ISSN 1553-345X © 2008 Science Publications Assessing the Effect of a Dumpsite to Groundwater Quality in Payatas, Philippines Glenn L. Sia Su Department of Biology, De La Salle University, Taft, Manila, Philippines Abstract: The study assessed and compared the groundwater quality of 14 selected wells continuously used in the with (Payatas) and without dumpsite (Holy Spirit) areas at the Payatas estate, Philippines. Water quality monitoring and analyses of the bio-physico-chemical variables (pH, Total Suspended Solids (TSS), Total Dissolved Solids (TDS), total coliform, conductivity, salinity, nitrate-nitrogen, sulfate, color, total chromium, total lead and total cadmium) were carried out for six consecutive months, from April to September 2003, covering both dry and wet seasons. Results showed most of the groundwater quality variables in both the with and without dumpsite areas of the Payatas estate were within the normal Philippine water quality standards except for the observed high levels of TDS, TSS and total coliform and low pH levels. No significant differences were observed for nitrate- nitrogen, total cadmium, total lead, total chromium and total coliform in both the with and without dumpsite areas. TDS, conductivity, salinity and sulfate concentrations in the with dumpsite groundwater sources were significantly different compared to those in the without dumpsite areas. Continuous water quality monitoring is encouraged to effectively analyze the impact of dumpsites on the environment and human health. Key words: Water quality, environmental assessment INTRODUCTION concerns that the Novaliches Reservoir is now contaminated with toxic substances beyond safe The 15-ha Payatas open dumpsite is within the concentrations. Payatas estate located at the northeastern district of This study aimed to assess the quality of Quezon City, Philippines. The Payatas dumpsite is groundwater sources serving the selected communities situated half a kilometer southeast of the Novaliches situated in the with dumpsite and without dumpsite Reservoir, the main source of drinking water for Metro areas. This study also aimed to provide benchmark Manila. Garbage dumped and accumulated for several information on the extent of pollution brought about by years at the Payatas open dumpsite had been identified the open dumpsite along groundwater sources of those as a potential threat to the metropolis water supply. selected areas. Bacud et al.[1] reported that the acidification and the presence of nitrates and coliform bacteria found in the MATERIALS AND METHODS groundwater along the dump may be traced to the Payatas open dumpsite. The community of Payatas was chosen to represent A study of the Smokey Mountain dumpsite (also in the with dumpsite simply because of the dumpsite that the Philippines) showed that 90% of drinking water is situated in the area. As a control, the Holy Spirit samples obtained in its surrounding areas were found to community was chosen to represent the without be positive for bacterial contamination[2]. The presence dumpsite. These two communities are both situated and potential exposures of the community to within the Payatas estate. Prior to data collection, a groundwater contaminants may contribute to the selection criterion was established to aid in the predilection of human health impacts, from simple identification of appropriate sampling stations for the poisoning to cancer, heart diseases and teratogenic groundwater quality assessment in both the with abnormalities. Although there have been no in-depth dumpsite and without dumpsite areas. The wells were studies yet concerning groundwater quality along and selected based on the following criteria: (a) wells must within the Payatas dumpsite, many sectors, including be active and functional and continuously used for some environmentalist groups, had expressed serious drinking and domestic purposes; (b) wells must be 276 Am. J. Environ. Sci., 4 (4): 276-280, 2008 located away from toilets and piggeries; and (c) wells distributed with a 95% significance level. As the t-test must not have undergone any chemical treatment. There requires that variances be equal, Bartlett's test for were 22 wells identified, of which 14 were from the homogeneity of variance was conducted to determine with dumpsite area and eight were from the without the equality of variances, whereas Satterthwaite's test dumpsite area. Ten wells in the with dumpsite area and was done to adjust the unequal variances. The null four wells in the without dumpsite area passed the hypothesis for the t-test indicated no significant selection criteria. Water sampling was then carried out difference on water quality among the with dumpsite in the 14 wells for six consecutive months, April to and without dumpsite areas, whereas the alternate September 2003, covering both the wet and dry hypothesis presented a significant difference on the seasons. water quality among the with dumpsite and without Water samples were collected following the dumpsite areas. The test indicating p<0.05 could be a sampling procedures of Csuros[3] and were then reason to conclude that the differences between areas examined in terms of bacteria and physical and were significant. Data were analyzed using the chemical contents using the Standard Procedures of the Statistical Package for Social Sciences (SPSS) American Public Health Association (APHA), software. American Waterworks Association (AWWA) and Water Environmental Foundation (WEF)[4]. The RESULTS AND DISCUSSION variables examined included total coliform count using the Swaroop's method[4], pH using the Suntex pH/ORP The study areas are characterized as flatlands that meter SP-2200 (Suntex Instruments Co., Ltd., Taipei, rise to an elevation of about +95 mean sea level (msl) at Taiwan), Total Suspended Solids (TSS) using the the northwest margin of the Marikina River watershed. gravimetric determination[4], color determinations using The with dumpsite area is positioned along the the HACH spectrophotometer DR/2010 (HACH northeastern end of the Guadalupe Plateau Formation Company, Loveland, Colorado, USA) and Total and at the eastern edge of the Novaliches Reservoir, Dissolved Solids (TDS) and conductivity using the whereas the without dumpsite area is along the HACH Conductivity-TDS meter (HACH Company). northwestern ends of the Guadalupe Plateau Formation In addition, salinity was extrapolated from conductivity and at the western edge of the Novaliches Reservoir. measurements; nitrate-nitrogen (NO3-N) and sulfate The Guadalupe Plateau Formation is mainly composed 2- (SO4 ) determinations were tested using the HACH of clastic facies, such as tuffaceous sandstone, spectrophotometer DR/2010 (HACH Company); and conglomerate and coarse tuff. The soil type in both heavy metals, particularly total lead (Pb), total study areas is clay loam mixed with occasional layers cadmium (Cd) and total chromium (Cr), were analyzed of coarser material[7]. using the Shimadzu AA-65015 atomic absorption Groundwater quality assessment was done with 14 spectrophotometer (Shimadzu Scientific Instruments, sampling points identified in both the with dumpsite Inc., Nakagyoku, Japan). and without dumpsite areas. Table 1 shows all The groundwater quality criteria used for sampling points assessed in terms of the following interpreting results were obtained from the 1990 water quality variables: pH, TDS, TSS, color, Department of Environment and Natural Resources conductivity, salinity, total Cr, total Pb, total Cd, total 2 (DENR)-Environmental Management Bureau (EMB) coliform, SO4 and NO3-N. Administrative Order No. 34 series of 1990 for Class A Results showed that total coliform exceeded the waters[5] and the 1993 Philippine National Drinking Philippine national drinking water standards set by the [6] Water Guidelines of the Department of Health DOH and the variables NO3-N, total Cd, total Pb and (DOH)[6]. Appropriate controls and standards and total Cr were all within the prescribed limits of Class A calibration curves were prepared for each of the waters of the Administrative Order 34 series of DENR- variables that were tested. Duplicate samples were EMB[5]. The analyses have also shown that waters tested and read in triplicate. obtained from groundwater sources in both the with Results of the water samples tested for dumpsite and without dumpsite areas were slightly bacteriological, physical and chemical examinations acidic and have high TSS. Well waters in the with were analyzed for significant differences on the extent dumpsite areas showed mean concentrations that were 2 of environmental pollution in groundwater sources high in TDS, salinity, conductance, color and SO4 . among the with dumpsite and without dumpsite areas Mean concentrations of well waters in the without using the t-test for unpaired observations. The t-test dumpsite showed higher turbidity levels than those in assumed that all the variables analyzed were normally the with dumpsite area. 277 Am. J. Environ. Sci., 4 (4): 276-280, 2008 Table 1: Mean concentrations and t test results of water quality variables obtained in the with dumpsite and without dumpsite areas for the months of April to September 2003 Parameter Normal standarda With dumpsite (n = 10) Without dumpsite (n = 4) t-test −1 NS NO3-N (mg L ) 10 3.36 2.23 0.062 Total Cd (mg L−1) 0.01 <0.007 <0.007 0.928NS Total Cr (mg L−1) 0.05 <0.019 <0.013 0.114NS Total Pb (mg L−1) 0.05 <0.015 <0.015 0.900NS Total coliform (MPN 100 mL−1) 0b 16 16 0.154NS pH 6.5-8.5 6.16 6.34 0.264NS Conductivity (S cm−1) 1682.44 681.05 <0.001* TDS (mg L−1) 1000 800.70 356.28 <0.001* Salinity (mg L−1) 1084.70 435.43 <0.001* Color (Pt Co) 68.82 60.18 0.546NS TSS (mg L−1) 50 1770.71 1355.60 0.377NS −1 b SO4 (mg L ) 250 69.06 17.23 <0.001* a [5] b [6] DENR-EMB , DOH , p values: *, p<0.05; NS, not significant Significant differences were noted for TDS, oxygen in some deep well sources could have triggered 2 [14] conductivity, salinity, SO4 and turbidity in the with the denitrification of NO3-N in the water ; hence, low dumpsite and without dumpsite areas (p<0.05).