Mangroves Sediment Ability as a Traps of Heavy Metal Chrome in Tukad Mati Estuary, Bali – Republic of Indonesia

Tukad Mati is one of the ten rivers has decreased due to the development of water quality screen printing and textile industries. Monitoring of the waters of the Tukad Mati has so far been confined to the Biological Oxygen Demand (BOD) and Chemical Oxygen Demand (COD) only. Whereas monitoring should be carried out thoroughly considering the heavy metal content is also harmful to users of water resources in Tukad Mati. One of the natural buffer of heavy metals in sediments of mangrove waters is a final media gathering all kinds of heavy metals waters, while mangrove itself is a natural sediment trap. Therefore, the heavy metals in the waters will experience the highest accumulation in mangrove sediments. The purpose of this study is as early monitoring to detect the chromium metal in waters and sediments in Tukad Mati estuary. In this study conducted in on-site data measurements in the form of data pH, temperature, salinity, disolved oxygen (DO) and discharge water. measurement of chromium content in the water and sediment of Tukad Mati estuary using AAS method. The study showed that from the results of on-site data measurements in estuary of Tukad Mati showed that the average value of salinity, pH, temperature and Dissolved Oxygen still meet quality ministerial decree of the environment of Indonesian Republic no 51 in 2004 for biota and marine tourism. The measurement results also showed that chromium content in water an average of 0.19 (mg/l) and exceed the ministerial decree of the environment of Indonesian Republic no 51 in 2004. Mangrove and non-mangrove sediments in Tukad Mati estuary have been exceed the Lowest Effect Level for organism and some sediment contaminated with chromium and passed the quality standards According to Canadian Council of Ministers of Environmental in 2000. Chromium concentration in sediment higer than water allegedly caused by heavy metals that tends to bind and fall to the bottom waters along the process of sedimentation.

are generally used as material consumption.
Although it has been known to cause pollution, so far controlling and monitoring is performed only on the water quality in terms of BOD and COD, even though pollutants screen printing industry coming from the dyeing process to the production of film and plate processor that uses ink, solvent, diluent and dryer. These materials contain heavy metals such as chromium. Chromium is a heavy metal that forms the basis of pigments which are generally used in textile and screen printing. Waste that is directly discharged into the river, sooner or later will result in the addition of chrome metal ions in water. Khairani et al. (2007) explains that the waters of the excessive amount of chromium metal ion generally can not be consumed as drinking water. This is because the content of chromium in the water can cause health effects for humans.
One of the natural buffer of heavy metals in the water are mangrove sediments. Sediment is the final media gathering all kinds of heavy metals waters, while mangrove itself is a trap natural sediment quality. Therefore, the heavy metals in the waters will experience the highest accumulation in mangrove sediments. The existence of mangrove which is still quite heavy on the flow along Tukad Mati, especially on the estuary would be very helpful in reducing the metal chromium in natural waters. However, until now unknown degree of reduction of heavy metal chromium in water by mangrove sediments, especially in estuaries.
The existence of industrial waste textile and screen printing are the center of attention Tukad Mati management must be done thoroughly. The existence of pristine mangrove has great potential to help solve the waste problem. This research is important as early detection rate of absorption of heavy metals chromium in water by mangrove sediments. So that more research can provide policy advice enter or change legislation on science-based collaborative management that although the mangrove resource can be used by the general public around, but its management should also pay attention to the ecological benefits of mangrove. Therefore, the purpose of this study was to determine the water quality, heavy metals chromium in waters and sediments of mangrove in Tukad Matiestuary.

Research Methodology
Location of the research conducted at estuary of Tukad Mati, District of South Kuta, Badung, Bali Province, Republic of Indonesia. Location of the study and distribution of sampling points (Figure 1) is set with the following distribution: 5 sampling points in waters taken during the ups and downs, a 5 point sampling sediment in the water and sediment sampling mangrove 5 points right and left sides. Measurement of chromium in water and sediment done in Analytical Laboratories of Udayana University.
Sampling was done in 2 stages, the samples of water and sediment samples. Water sampling is done at high tide (flood) and low tide (ebb). Water sampling conducted in accordance with Andarani and Roosmini (2010), ie at half the total depth is 0,5d, as shown in Figure 2. The sediment samples carried out only in estuarine areas. Water sampling is done by using a water sampler 250 ml and preserved by adding HNO3. Then the sample bottle stored in a coolbox filled ice cubes. jsd.ccsenet.

Figure
The sedim side of ekm of each sta In additio environme are perform salinity, an calculating width and org e 2. The cross s ment samples w man grab to av ation. Then the on to conduct ental paramete med using por nd the DO-m g the cross sec depth of the ri   Based on the picture above the river sectional area measurements using the formula trapezoidal area with the following formula:

Remarks:
A: trapezoidal area (m ) d: side-by-side parallel (m) x: height (m) Calculation of the wet cross-sectional area (A) was performed using the interval method middle (mid section) by the following equation (Chow, 1989in Surbakti, 2010: Remarks: i: number of segments (sub) cross-section; i = 1,2,3, ..., n; n: number of cross-sectional segments Thus obtained the total cross-sectional area wet by using the equation: (4) Remarks: : sub-sectional area of the river or canal to-i (m ) : speed average river flow cross section into sub-i(m/det).
In order to obtain the value of river discharge runoff water can be obtained through the equation: .. + (5) Analysis of heavy metals chromium in water and sediment samples using Inductively Coupled Plasma Emission (ICPE) 9000 Spectroscopy and detection limit is 0.001. ICPE spectrophotometry produces high-temperature plasma by high ionization argon with high frequency (27.12 MHz). The sample is sucked and atomized by a nebulizer which is then streamed to the plasma to stimulate the elements in the sample, thus causing the Cr element in the sample to emit plasma light. Preparation of water samples is done by referring to American Public Healt Association (APHA) (2012). For the sediment sample was done wet spraying first, by adding HNO 3 and H 2 SO 4 (Yenrina, 2015). After that, the sediment sample is treated the same as the water sample.
The data were analyzed descriptively and compared to ministerial decree of the environment of Indonesian Republic no 51 in 2004 for marine biota and maritime tourism .

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