RAINWATER QUALITY IN PENINSULAR MALAYSIA

Transcription

1 RAINWATER QUALITY IN PENINSULAR MALAYSIA Yeap Chin Seong and Nasiman Sapari Universiti Teknologi PETRONAS ABSTRACT This paper presents rainwater quality in the tropical environment of Peninsular Malaysia. Samples of rainwater were collected monthly from 17 meteorological stations, distributed all over the country, over a period of ten years from 1990 to The locations of the stations represent both the urban and rural environment. All the samples were analyzed by the Department of Chemistry, Government of Malaysia. The water quality parameters include mineral compositions, ph, heavy metals, fluoride and ammonia. Results of the analysis indicated that heavy metal concentrations for Hg, Pb, Cu and Ni were mostly below the limits of the Malaysia and WHO drinking water standards. However, Hg and Pb occasionally exceeded the limits in 6% and 8% of the samples collected respectively. Most of concentrations that exceeded the standard for mercury and lead were found in the samples collected from 1990 to Ninety eight percent of the samples collected from 1998 onwards did not exceed the limits for the heavy metals. This is coincided with the introduction of unleaded petrol. Major elements namely K, Na, Ca and Mg were low, averaging from 0 to 0.8 mg/l. The averaged ph levels of the rainwater were above 4.4, which suggested that there were no serious acid rain problems in the country. Occasionally, 4 stations had ph values below 4.4. The low ph values were only found in rainwater samples from stations in urban environment, which has industries including oil refinery, heavy traffic, and heavy industries. Rainwater quality in the rural environment of peninsular Malaysia is generally of good quality and suitable for drinking water sources. However for the urban rainwater, prior treatments are necessary in order to be used drinking water. Alternatively the water from urban sources can only be used for other benefit purpose such as toilet flushing. Key words: Malaysia rainwater quality, urban and rural area, heavy metals, pollution, Lead, Mercury and ammonia. Introduction Malaysia is located in South-East Asia between the latitudes 1 and 7 degrees North and longitudes 100 and 119 degrees East. Malaysia comprises of West Malaysia (Peninsular Malaysia) and East Malaysia (Sabah and Sarawak). There are 11 states in the Peninsular Malaysia namely, Perlis, Kedah, Pulau Pinang, Perak, Selangor, Negeri Sembilan, Melaka, Johor, Kelantan, Terengganu and Pahang.

2 Rainwater quality in the Peninsular Malaysia is monitored by 17 stations located all over the country both the urban and rural area. The biggest state, such as Pahang, there is 4 monitoring stations covering a total land area of sq. km. The land areas coverage of the individual states and the number of monitoring stations are summarized in Figs. 1 and 2. Beside the land area coverage criteria and geographical location, industrial activities in the area were considered as important for decision on the selection of installing monitoring station. All the stations are monitored and maintained by Malaysia Meteorological Services Department (MMSD). Based on the historical data results, the rainwater quality in Malaysia has improved considerably over the past 10 years in term of lead concentration in the water. This has in lined with the introduction of unleaded petrol through out Malaysia. After the introduction of unleaded petrol, the lead concentration in rainwater were reduced by more then 3 times below the concentration recorded prior to 1997 (Yaziz et al., 1989). The lead concentration was continuously below WHO drinking standard from 1998 to This is coincided with the introduction of phase out the leaded petrol in Other heavy metal which include mercury, copper and nickel were below the WHO drinking water standard. In the past, rainwater was the main source of drinking water in Malaysia. The annual rainfall which range from 2000 to 3000mm is suitable to be harvested for household use than direct runoff. However, development in this area is affected because the cost of tap water is still very much cheaper than the cost of investment on rainwater collection system. Tap water is available almost in every household except in remote communities. A policy on rainwater harvesting was introduced in Malaysia as part of the Stormwater Management System in 1998 by Drainage and Irrigation Department (DID) of Malaysia. Considering the abundance of water, the rainwater harvesting for household use is considered a viable proposition. This paper attempts to highlight the important points of rainwater quality which include heavy metal concentrations, ph, ammonia, and chloride.

3 Material and methods This study involved collection of data from MMSD reports, statistical analysis, and assessment on the rainwater quality from 1990 to A standardized equipment were used through out all the stations for the collection of rainwater. Automatic Wet and Dry Fallout Collectors were used to collect the wet and dry deposition at the stations. The rainwater samples were accumulated weekly and sent to the Department of Chemistry, Malaysia for chemical analysis. The results presented wet fallout samples. The quality of the rainwater samples were analyzed for rainfall quantity, ph, sodium, potassium, magnesium, calcium, fluoride, chloride, ammonium, nitrate, sulphate, iron, zinc, mercury, copper, manganese, nickel, and lead. A volume weighted approach was adopted for the measurement of ph. The sample was tested in a centralized chemical laboratory using a standard method of water analysis by AWWA- APHA, Results and discussion The results of the monitoring programme for the 16 parameters are showed in Figure 3. Based on the historical data and statistical analysis, the rainwater quality in Peninsular Malaysia has achieved a statistical confident limit of 80 % on all actual measurement to meet the WHO drinking water standard. The detail of summary results can be found in Figure 3. For ph parameter, the statistical average range is where the drinking standard ph is This results showed there is no serious sign of acid-rain, but there are a few localized area where heavy industries is involved, the ph were below 4.4 such as Petaling Jaya, Senai, Seberang Prai, and Melaka. An accuracy of rainwater ph measurement is governed by local activities nearby the stations. Sodium, magnesium, fluoride, chloride, nitrate, sulphate, iron, zinc, copper, manganese and nickel, all are well below the WHO Water Drinking Standard.

4 Lead and mercury concentration in rainwater has showed a very good correlation in the replacement of leaded petrol with unleaded petrol. Lead In the early 1990, rainwater quality in Peninsular Malaysia was greatly affected by the high concentration of lead and mercury recorded in all the 17 monitoring stations. The actual lead concentration easily exceeded three times above the WHO Drinking standard of mg/l. In 1985, the initial lead content in petrol was 0.84 g/l and it was reduced to 0.15 g/l by early The commercial introduction program from leaded to unleaded petrol was between 1991 and However, the reduction of lead concentration in rainwater did not indicate any improvement. It was until August 1998, Malaysia government started to totally phase out the leaded petrol at all the petrol station, and all 17 monitoring stations recorded lead concentration dropping below the standard. This implementation had taken about approximately 13 years to achieve today s results. The outline on implementation stages are showed in Figure 4. The national consumption on leaded and unleaded petrol percentage has indicated a good correlation in the reduction of lead concentration in rainwater, as shown in Figs. 5 and 6. As the consumption of unleaded petrol increases, the reduction of lead content in rainwater develops. The trend of unleaded petrol consumption is on an upward scale, by interpolation, the 100% consumption on unleaded petrol will be successful by end of 2003 or In 1996, the unleaded petrol sales increased at an average of 5 to 6 % and the total number of cars registered in Malaysia at an average growth of 6 to 8 % (Figure 7). The difference in growth rate has no negative impact to lead concentration in rainwater. Mercury Mercury content is easily found in rainwater. This is because mercury itself can be found in natural sources and anthropogenic source. It can travel from country to country. The natural source easily travels by different natural disaster such as volcanic, forest fire and oceanic release.

5 Anthropogenic source covers a huge area of material and equipment applications. It includes thermometers, hydrometers, mercury arch lamp, switches, mercury slats, mirror, catalysts for oxidation of organic compounds, gold and silver extraction from ore, paper processing, petroleum process, and others (Jones, et al, 1996). In 1990 to 1997, results of the mercury contamination in Peninsular Malaysia were recorded at a range from to mg/l with a 50%confident limit. The recorded result has exceeded almost 400 % the acceptance level of mg/l. However, from 1998 to 2001 onward, the mercury contamination in rainwater followed the trend of lead contamination. After 1997, all 17 stations recorded the mercury contamination of mg/l at only three incidents and the rest was close to zero. (Figure 8) Hence, mercury contamination is on a diminishing trend in Malaysia rainwater based on the recorded measurement from 1990 to Conclusions The following conclusions are drawn based on the ten years (1990 to 1999) rainwater quality data: 1. Malaysia has a relatively good quality of rainwater based on the 17 parameter measured and recorded by MMSD. Out of 17 stations, only 4 stations occasionally recorded ph level below 4.5 with the lowest reading The existing level on lead concentration in the rainwater has fallen to well below the WHO drinking water standard after the introduction of unleaded petrol. 3. Rainwater is a potential alternative source for tap water. This application is suitable to landscaping, cleaning, and toilet flushing. In certain rural area where the cost of pipe water is very high, rainwater may be used for the household daily consumption. Acknowledgment The writers acknowledge Malaysian Meteorological Service for providing the historical wet an dry fallout data which made this work possible.

6 References Jones, A. B., Slotton, D.G., et al. 1996, Mercury effects, sources and control Measures Ishak, Aminuddin, Urban Air Quality Management: Motor Vehicles Emission Control Malaysia, Clear Air Regional Workshop, 2001 Malaysia Meteorological Service, , Annual Summary of Air Pollution Observations Malaysia Meteorological Service, 1995, Report on Air Quality in Malaysia 1994 Malaysia Meteorological Service, 1996, Report on Air Quality in Malaysia 1995 Malaysian Statistic Department, 2000, Compendium of Environment Statistics Malaysia Department of Environment, 2002, Malaysia Environment Quality Report 2001 Malaysia Department of Environment, 2001, Malaysia Environment Quality Report 2000 Malaysia Department of Environment, 1999, Malaysia Environment Quality Report 1998 McBean, E.A. and Rovers, F.A., 1998, Statistical Procedures For Analysis of Environmental Monitoring Data and Risk Assessment, Prentice Hall PTR. Yaziz, M.I., H. Gunting, N. Sapari, and A. W. Ghazali, Variation in Rainwater Quality from Roof Catchments, Water Research, vol.23, no.6, pp

7 Figure 1 : Location map of 17 monitoring stations in Peninsular Malaysia (O) Peninsular Malaysia State Land Area (sq km ) Monitoring Station 1 Perlis Kedah 9, Pulau Pinang 1, Perak 21, Selangor 7, Negeri Sembilan 6,643-7 Melaka 1, Johor 18, Kelantan 14, Terengganu 12, Pahang 35,965 4 Source : DOS Figure 2 : Land Area of Individual State and Monitoring Stations

8 Parameter Range (Lower-Upper) WHO Drinking Water Standard Rainfall (mm ) ph ( Average of 17 stations ) Sodium (mg/litre) <200 Potassium (mg/litre) Magnesium (mg/litre) <150 Calcium (mg/litre) Fluoride (mg/litre) <0.90 Chloride (mg/litre) <250 Ammonium (mg/litre) Nitrate (mg/litre) <10.0 Sulphate (mg/litre) <400 Iron (mg/litre) <0.30 Zinc (mg/litre) <1.5 Copper (mg/litre) <1.00 Manganese (mg/litre) <0.100 Nickel (mg/litre) Figure 3 : Summary of Rainwater Quality from for Peninsular Malaysia based on confident limit of 80 % July st Stage of Reduction January nd stage Reduction Early 1991 End 1997 Reduction of lead contents from the initial 0.84 g/l to 0.5 g/l Further reduction from 0.5 g/l to 0.15 g/l Almost all of the oil companies started to voluntarily introduced unleaded gasoline (ULG) Approximately 82 % of the nationwide gasoline was unleaded 1 st August 1998 Government announced on the total phase out of leaded gasoline Figure 4 : Implementation process stages of Unleaded Petrol ( After Ishak, et. ol 2001 )

9 Concentration ( mg/litre ) Tanah Rata Bayan Lepas Bukit Kledang Petaling Jaya Senai Perai Melaka Kuala Terengganu Alor Setar Mersing Kota Bahru Chuping Kuantan Kluang Sitiawan Batu Embun Muadzam Shah Allowable Level Figure 5 : Maximum Monthly Lead Concentration from 1990 to 2001 Percentage of Total Petrol Sales Leaded Unleaded Figure 6 : Distribution of Sales on Leaded and Unleaded Petrol from 1992 to 2000 Total Nos. of Vehicles in Peninsular Malaysia Millions Nos. of Vehicles ource : Road Transport Department, Malaysia,2003 Figure 7 : Total Nos. of Vehicles in Peninsular Malaysia 1990 to 2001 S

10 Mercury Concentration ( mg/litre ) Tanah Rata Bayan Lepas Bukit Kledang Petaling Jaya Senai Perai Melaka Kuala Terengganu Alor Setar Mersing Kota Bahru Chuping Kuantan Kluang Sitiawan Batu Embun Muadzam Shah Allowable Level Figure 8 : Maximum Monthly Mercury Concentration from 1990 to 2001 Mercury Exceeded Spec (%) Lead Exceeded Spec.(%) Tanah Rata Bayan Lepas Bukit Kledang Petaling Jaya Senai Perai Melaka Kuala Terengganu Alor Setar Mersing Kota Bahru Chuping Kuantan Kluang Sitiawan Batu Embun Muadzam Shah AVERAGE Figure 9 : Summary of Monthly Concentration For Mercury and Lead (Percentage of month ) Exceeded WHO Drinking Water Standard - ( )