PENENTUAN GIARDIA DAN CRYTOSPORIDIUM DARIPADA LOJI AIR MINUMAN
Satu kajian awal telah dijalankan di Loji Pembersihan Air Cheras, Sg. Langat, Sg. Batu dan Bukit Nanas bagi mengesan kehadiran sista Giardia sp. dan oosista Cryptosporidium sp. dalam sampel air mentah dan juga air yang telah dirawat. Sebanyak 100 liter sampel air mentah dan 200 liter sampel air yang dirawat telah ditapis dengan penapis polipropilena dan diproses mengikut kaedah yang disyorkan oleh ‘British Standing Committee of Analysis, Drinking Water Inspectorate’. Monoklonal antibodi berfluoresen (Cellabs) digunakan bagi pengesanan dan pengiraan sista dan oosista. Koliform fekal dikesan melalui teknik penurasan membran dengan menggunakan membran penuras bersaiz liang 0.1 um. Parameter fizikal air seperti kepekatan klorin bebas, suhu, pH dan turbiditi (kekeruhan) juga diukur. Persampelan dilakukan sebanyak 12 kali di antara bulan Julai, 1995 hingga Februari, 1996. Keputusan mendapati sista Giardia sp. dan oosista Cryptosporidium sp. boleh dikesan dalam sampel air mentah tetapi tidak dapat dikesan dalam sampel air yang dirawat di keempat-empat loji kajian. Kepekatan bagi sista adalah diantara 0-1.50 sista per liter manakala bagi oosista adalah di antara 0-2.50 oosista per liter. Kepekatan sista dan oosista yang tinggi didapati berhubungkait dengan sumber air yang menerima effluen dari industri dan kumbahan. Bilangan koliform fekal didapati berada dalam julat 0.1 X 101-5.3 X 104 koloni per 100 ml. Analisis korelasi dan regresi linear mendapati tiada korelasi yang bererti bagi bilangan koliform tinja dengan bilangan sista dan oosista di kesemua loji kajian. Analisis regresi linear antara sista dengan oosista hanya menunjukkan korelasi yang bererti bagi L.P.A. Cheras. Parameter fizikal seperti klorin bebas, suhu, pH dan turbiditi juga tidak menunjukkan kolerasi yang bererti antara sista, oosista dan bilangan koliform fekal kecuali bagi bilangan sista dengan suhu dan bagi bilangan oosista dengan kepekatan klorin pada L.P.A. Cheras. Kesimpulannya, koliform fekal didapati boleh bertindak sebagai indikator pencemaran air oleh feses tetapi tidak boleh digunakan sebagai penunjuk kepada pencemaran air oleh sista Giardia sp. dan oosista Cryptosporidium sp.. Dengan ini parasit bawaan air seperti Giardia dan Cryptosporidium patut juga dicadangkan sebagai indikator mikrobial kualiti air.
ABSTRACT
DETECTION OF GIARDIA AND CRYPTOSPORIDIUM
FROM WATER TREATMENT PLANT
Attempts to detect the presence of Giardia cysts and Cryptosporidium oocysts in raw water and treated water was carried out at the Cheras, Sg. Langat, Sg. Batu and Bukit Nanas water treatment plants. Approximately 100 litres of raw water and 200 litres of treated water were filtered using polypropylene cartridge filter and processed following the method recommended by the British Standing Committee of Analysis, Drinking Water Inspectorate. Flourescein labelled monoclonal antibody were used for detection and enumeration cysts and oocysts. Fecal coliform was determined by membrane filtration technique, using membrane filter with pore size 0.1 um. Other physical parameters, such as free chlorine, temperature, pH and turbidity were also measured. The samplings were carried out for 12 times between July, 1995 to February, 1996. The present result indicated that Giardia sp. cysts and Cryptosporidium sp. oocysts were detected in the raw water but no cysts or oocysts were found in treated water in all water treatment plants. Concentrations ranged between 0-1.50 cysts per litre for Giardia cyst and between 0-2.50 oocysts per litre for Cryptosporidium oocyst. Higher cysts and oocysts densities were associated with source water receiving industrial or sewage effluents. The fecal coliform counts were found ranging from 0.1 X 101-5.3 X 104 counts per 100 ml. No significant correlations were found between the number of Giardia cysts and the number of Cryptosporidium oocysts with fecal coliform counts in all the plants studied except for the Cheras water treatment plant. The other physical parameters such as free chlorine, temperature, pH and turbidity also did not show any significant correlations with the number of cysts, oocysts and fecal coliform count present in the raw water samples except for temperature and cysts, and also level of free chlorine and oocysts at Cheras water treatment plant. Fecal coliform is a good indicator for water contamination by feces but unsuitable as an indicator for water contamination by cysts and oocysts. The presant study suggested that parasites such as Giardia and Cryptosporidium should be considered as microbial indicator for water quality as well.