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Water pollution trends in Ciliwung River based on water quality parameters

Ciliwung River is one of the rivers crossing West Java and special capital region of (DKI) Jakarta provinces which plays an important role in fulfilling the needs of human activities and living things surrounding it. Designated as a national priority for management, the Ciliwung River that runs from Mount Pangrango (upper stream) to Jakarta Bay (lower stream) has received pollution from results of human activities such as household activities, agriculture, plantations, animal husbandry, industry, and recreation areas. In addition, the decreased green cover in the upstream area also adds more pressure on the quantity of water in the Ciliwung River. The purpose of this study was to determine the trend of water pollution in the Ciliwung River in the period of 2011-2014 based on physical, chemical and biological parameters. Samples were taken from 22 points starting from upstream to downstream area. From 15 water quality parameters, there were only three parameters, namely total dissolved solid (TDS), pH and nitrate (NO3-N) which still meet water quality criteria class II based on Government Regulation number 82/2001, in all observation periods and sampling sites. Other parameters invariably meet or beyond the water quality criteria. Pollution trend increased towards the downstream of Ciliwung River, however annual comparisons across the year of observations did not show significant differences. High pollution in the downstream area was caused by accumulated pollutants coming from waste disposal of densely populated area and diverse activities in the downstream. Fecal coliform bacteria and total coliform contributed the highest pollution in the Ciliwung River compared to other pollutants. Both those two parameters greatly exceed the water quality criteria at all sampling sites, except in the Ciliwung river spring. Controlling those two parameters may improve Ciliwung water quality.


Introduction
Increasing population and industrialization development commonly give rise to river water pollution. Changes in water quality are significantly affected by anthropogenic activities, and this condition eventually will influence the aquatic ecosystem. The dense population area with various activities often reduces the availability of clean river water. Various wastes originated from human activities such as household activities, agriculture, plantation, livestock, and industries could pollute the river water [1], [2]. In the hydrological cycle, the water might carries a various materials passed by, including nutrients and harmful pollutants. Besides the function of river water as a means of transportation, the river water also contributes to spread to and accumulate pollution from surrounding area [1], [3]. River water is one of the natural resources that need to be conserved because it is a habitat for many aquatic biotas and source to meet the various needs of humans and living things [1], [3]. Human activities around the rivers will greatly affect water quality changes. It decreases water quality which results in biodiversity loss [4]- [6]. At present, the quantity and quality of good river water are becoming scarce. Poor water quality will have an impact on the health of living creatures that live nearby and affect the sustainability of the ecosystem, and in turn affect both productivity and biodiversity of a given ecosystem [7], [8].
Ciliwung River is a provincial cross-border river that flows from the Pangrango Mountain and ends up in Jakarta Bay by passing Bogor Regency, Bogor City, and Depok City in West Java Province. Designated as the national priority for water quality management, the Ciliwung River received pressure from the waste of various human activities such as household, livestock, farming and industries especially in the middle and downstream areas.
The decreased green covers in the upstream area also add more pressure on the water debit of the Ciliwung River. Most of the upstream segment of Ciliwung River has been shifted from secondary forest into agricultural area which has been subsequently developed into tourism area, including pavement of infrastructure, trade and service areas [9], [10]. Land cover in the middle segment of Ciliwung River has also been converted from plantations or agriculture to settlements or other land uses [10]- [13]. The downstream, which is located in the capital city of Jakarta is dominated by settlements and densely populated area [11]. The aim of this paper is to evaluate the characteristic trend of water pollution that occurred on the Ciliwung River in the period of 2011 to 2014. Description of river characteristics can be used as input for the water resources management plan [6].

Sampling
Water quality sampling was carried out in the Ciliwung watershed in the provinces of West Java and DKI Jakarta. 320

Data Analysis
Analysis of variance (ANOVA) was used to compare the results among times (years) and locations at a confidence level of 95% or an error level of 5% (0.05). This study used data from 22 locations, collected annualy during four years. Data obtained was compared to a reference standard for class II water quality criteria (WQC), namely water for the purpose of water recreation facilities / infrastructure, cultivation of freshwater fish, livestock and irrigation. These criteria are stated in the appendix of Government Regulation number 82/2001 concerning the Management of Water Quality and Water Pollution Control [14].

Temperature, pH and TDS
Temperatures of Ciliwung River that were recorded at daytime, increased from upstream to downstream. The lowest temperature in the upstream was 19 o C and the highest temperature in the downstream was 34 o C. These temperature changes can occur directly and indirectly. Changes in water temperature might be caused by changes in land use system, backflow of agricultural irrigation, flow modification, water transfer between basins, changes in vegetation to riparian, global warming, and closure factors in riparian [15], [16]. There was no significant changes in terms of water temperature of Ciliwung river from 2011 to 2014. Low temperature in the upstream region persists due to high elevation. The average temperature in the upstream section was 23.7 o C, in the middle section was 27.1 o C and in the downstream section was 28.8 o C.
The water pH of the Ciliwung River from upstream to downstream in 2011-2014 ranged from 6.0 -8.6. The pH of the river water was still normal and in accordance with the standards of Government Regulation number 82/2001 for class II WQC of 6-9 [14].
TDS parameters in all sampling locations were still in accordance with class II WQC of 1000 mg/L, except for one sample location in Mangga Dua, which is downstream of the Ciliwung River, reaching TDS at 1,708 mg/ L. The highest value of TDS at this point could be influenced by the sea water tide that reaches those sampling locations. In most cases, TDS values tended to be the same from 2011 to 2014, and likewise, locations did not show a significant difference (P < 0.05).

BOD, COD, DO
BOD describes the content of organic matter, namely the amount of oxygen used by aerobic microorganisms to oxidize organic matter. The majority of BOD in the Ciliwung watershed did not comply with WQC class II Government Regulation number 82/2001 at 3 mg/ L (figure 2). BOD in the Ciliwung watershed from upstream to downstream ranged from 2 ~ 144 mg/ L in 2011; in 2012 were between 2 ~ 838 mg/ L; in 2013 between 2 ~ 138 mg/ L and in 2014 between 2 ~ 188 mg/ L. There were no significant differences between years of sampling (P < 0.05). However, BOD concentrations were influenced by the sampling position along the river. The highest BOD concentration was obtained in the downstream of Ciliwung River. Downstream of the Ciliwung River in DKI Jakarta is in fact, a densely populated area, where a lot of domestic wastes containing organic material might enter into the water body.  Dissolved Oxygen (DO) is very influential on aquatic life and biochemical processes. DO is necessary for aquatic biota to survive [16]- [18]. DO in waters vary and it is influenced by temperature, salinity, water turbulence, atmospheric pressure, and the presence of organic waste entering the river [19], [20]. The monitoring results indicated that DO in the downstream of Ciliwung River had decreased exceeding the standard based on the Class II WQC of 4 mg/L. Decreasing DO also occurred and even reached oxygen-unavailable conditions. Drastic decreasing DO could cause sudden death in fish. The DO from upstream to downstream of the Ciliwung river in 2011 ranged from 8. Low DO in the downstream indicated high pollution of organic waste. DO was needed for decomposition of organic matter. Domestic wastes containing low DO, high BOD, high COD, and high nutrients caused the river contains tremendous amount of pollutants [1].

NO 3 -N, NO 2 -N, NH 3 -N, TP.
High nitrates (NO 3-N) causes eutrophication of waters and encourage algae blooming [21], [22]. The existence of nitrogen in the water occurred due to fertilizer residue run off from an agricultural area and also waste disposal from industrial activities [18], [23], [24]. The level of NO 3    The presence of high phosphate and nitrogen will trigger an explosion of algae growth in the waters [21], [26], [27]. The allowable maximum level of phosphate in river waters has been reported at 0.1 mg/L [28]. The phosphate concentration of 0.025 mg/L can accelerate the eutrophication process in rivers [29]. Total phosphate (T-P) detected in the Ciliwung river water in 2011 was in the range of 0.024 -3.  7). There were no significant differences in T-P concentrations between 2011 and 2014. However, the T-P concentration tendency increased significantly from upstream to dowstream (P <0.05). T-P in the waters may be affected by utilization of fertilizers in agriculture and detergents in household washing activities [24].

Fecal Coliform and Total Coliform
Coliform is a bacterial group commonly found in the environment [30]. Coliform is not harmful to humans, but it is used as an indicator of the presence of pathogenic organisms such as bacteria, viruses and parasites. These bacteria in water can come from intestinal tracks of human and warm-blooded animals or mammals such as pets, livestock and wildlife [31]. Fecal coli and total coliform bacteria have contaminated the Ciliwung River in high numbers. The number of fecal coliforms from upstream to downstream per 100 mL in 2011 was between 0 -172,000,000; in 2012 between 100-15,700,000 ; in 2013 between 100 -1,360,000,000 and in 2014 between 0 -122,000,000. Fecal coliform has exceeded WQC Class II Government Regulation number 82/2001 of 1,000/100 mL except for Ciliwung water sources, considered as spring water, that still satisfies WQC class II standard. Fecal coliform pollution showed an increasing trend towards the downstream, however there was no significant differences among years of sampling ( figure 11). In general, total coliform observed in this study were exceeded WQC class II at 5,000/100 mL. Total coliform in 2011 was detected in the range of 10 -1,170,000,000/100 mL; in 2012 between 17,400 -119,000,000/100 mL; in 2013 between 15,000 -1,710,000,000/100 mL; in 2014 between 6,400 -197,000,000/100 mL. The total coliform trend increased significantly towards the downstream (P < 0.05), however there was no significant difference in each year of sampling (figure 12). High number of fecal coliform and total coliform in the Ciliwung River indicated high level of pollution from human and animal waste. Populated areas with high activity and livestock areas contribute high coliform pollution. The presence of coliform bacteria was originated from human and animal wastes, especially from washing, animal manure on farms, improper disposal of septic tanks, and disposal water from farms.
Based on 15 water quality parameters observed at 22 locations from 2011-2014, only three parameters, namely pH, TDS and NO 3 -N that still satisfied the standard WQC class II Government Regulation number 82/2001. Other parameters invariably meet or beyond the water quality criteria. Pollution trend increased towards the downstream of Ciliwung River and in general, annual comparisons did not show significant differences. Fecal coliform and total coliform greatly influence water quality of the Ciliwung River and significantly polluted Ciliwung River. Controlling coliform pollution needs to be done in order to get better water quality and avoid the spreading of pathogens from coliform in Ciliwung River. Pollution control in the Ciliwung River needs to be prioritized due to the fact that water quality parameters decrease as pollution increase.

Conclusion
Water pollution in the Ciliwung River tended to be increasing towards downstream. However, different observation times from 2011 to 2014 did not show significant differences of the pollution trend for majority of the parameters. Based on the Government Regulation number 82/2001, three parameters, namely TDS, pH and NO3 were still meet water quality criteria class II standard, while  11 other parameters invariably meet or beyond the water quality criteria. Fecal coliform and total coliform were dominant parameter polluted the Ciliwung River except in the spring of Ciliwung River. Water pollution control should be prioritized based on the fact where critical parameters gave high pollution contribution in Ciliwung River.