scholarly journals Komposisi dan Kelimpahan Gastropoda Pada Ekosistem Mangrove Di Desa Tireman, Kabupaten Rembang, Jawa Tengah

2020 ◽  
Vol 9 (1) ◽  
pp. 41-48
Author(s):  
Yuli Laraswati ◽  
Nirwani Soenardjo ◽  
Wilis Ari Setyati

Ekosistem mangrove mermiliki manfaat sebagai tempat mencari makan serta habitat bagi organisme, mislanya gastropoda. Gastropoda di ekosistem mangrove berperan dalam proses dekomposisi yaitu dengan mencacah daun menjadi lebih kecil, yang kemudian dilanjutkan oleh mikroorganisme. Kepadatan  gastropoda dipengaruhi oleh kegiatan yang terdapat pada ekosistem dan dapat memberikan efek pada kelangsungan hidup gastropoda.Tujuan penelitian adalah untuk mengetahui struktur komunitas gastropoda pada ekosistem mangrove Desa Tireman Kecamatan Rembang, Jawa Tengah. Metode penentuan lokasi sampling menggunakan metode purposive sampling pada 3 lokasi dengan kerapatan mangrove yang berbeda. Pengambilan sampel gastropoda dilakukan dalam transek 5 x 5m dan sampel yang didapat kemudan disortir, diawetkan dan diidentifikasi. Hasil penelitian ditemukan 9 spesies gastropoda termasuk kedalam 3 famili yaitu Casidula nucleus, C. aurisfelis (Ellobiidae), Littoraria scabra, L. carinifera, L. Melanostama (Littorinidae), Cerithidea quadrata, C. cingulata, C. alata, Telescopium telescopium (Potamididae). Spesies yang paling sering ditemukan adalah Cassidula aurisfelis dan Cassidula nucleus. Nilai rata-rata kelimpahan berkisar antara 6,28 - 15,72 Ind/m2. Nilai indeks keanekaragaman termasuk ke dalam kategori rendah hingga sedang. Nilai rata-rata indeks keseragaman termasuk kedalam kategori rendah (0.15-0.27). Nilai rata-rata indeks dominansi menunjukkan tidak adanya dominansi dari spesies tertentu. Pola sebaran menunjukkan pola sebaran mengelompok dan acak. Nilai kesamaan komunitas gastropoda tergolong dalam kategori tinggi. Frekuensi kehadiran gastropoda kategori jarang hingga sangat sering.  The mangrove ecosystem has benefits as a place to eat and habitat for the organism, the gastropod's missile. Gastropods in the mangrove ecosystem play a role in the decomposition process, with the smaller leaves, which are then followed by microorganisms. The density of gastropods is influenced by activities found in ecosystems and can provide an effect on the viability of gastropods. The purpose of research is to know the structure of the gastropods community in the mangrove ecosystem of Tireman Village Rembang District, Central Java. Sampling method of determining location using purposive sampling method in 3 locations with different mangrove density. The gastropod sampling is done in the 5 x 5m transect and the samples obtained are then sorted, preserved and identified. The results of the study found 9 species of gastropods included in the three families, namely Casidula nucleus, C. Aurisfelis (Ellobiidae), Littoraria scabra, L. Carinifera, L. Melanostama (Littorinidae), Cerithidea quadrata, C. cingulata, C. alata, Telescopium telescopium (Potamididae). The most commonly found species are the Cassidula aurisfelis and the Cassidula nucleus. The average value of abundance ranges between 6.28-15.72 Ind/m2. The value of diversity index belongs to low to moderate category. The average value of uniformity index is included in low category (0.15-0.27). The average value of the Dominancy index indicates the absence of dominance of a particular species. The spread pattern shows both group and random distribution patterns. The value of gastropods community similarity belongs to high category. The frequency of presence of gastropods is rare until very frequent.

2016 ◽  
Vol 19 (3) ◽  
pp. 463
Author(s):  
Tiara Pandansari

<p><em>This research aims to measure the disclosure level of local governments’ financial reports in Central Java Province. More importantly, we also investigate factors associated with the disclosure level. We measure the disclosure level using the Modified LGA Index. Meanwhile we use the local government’ dependence and government complexity as the independent variables. Using purposive sampling method, this research generates 32 local governments (districts/ municipals) as the final sample. The descriptive analysis suggests that the average value of the disclosure level is 58.46%. Meanwhile, local governments’ dependence on general allocation funds (DAU) and shared revenue funds (DBH) affect the disclosure level. However, we do not find significant effect between local governments’ dependence on special allocation funds (DAK) and government complexity on the disclosure level.</em></p><p><em><br /></em></p><p align="center"><strong>Abstrak</strong></p><p align="center"><strong> </strong></p><p>Penelitian ini bertujuan untuk mengukur tingkat pengungkapan dalam laporan keuangan pemerintah daerah di Jawa Tengah, serta menguji dan menganalisis faktor-faktor yang mempengaruhinya. Tingkat pengungkapan diukur dengan menggunakan Modified LGA Index, sedangkan sebagai variabel bebas yang digunakan adalah tingkat ketergantungan daerah, dan kompleksitas pemerintahan. Sampel penelitian ini dipilih menggunakan purposive sampling method, sehingga diperoleh ukuran sampel yaitu 32 laporan keuangan pemerintah daerah. Alat analisis yang digunakan adalah regresi linear berganda. Hasil penelitian ini menunjukkan bahwa terdapat perbedaan tingkat pengungkapan pada masing-masing sampel. Rata-rata nilai pengungkapan sebesar 58,46  persen. Penelitian ini juga menunjukkan bahwa tingkat ketergantungan terhadap Dana Alokasi Umum dan tingkat ketergantungan terhadap Dana Bagi Hasil berpengaruh terhadap tingkat pengungkapan,  tingkat ketergantungan terhadap Dana Alokasi Khusus, dan kompleksitas pemerintah tidak berpengaruh terhadap tingkat pengungkapan dalam laporan keuangan pemerintah daerah.<em><br /></em></p>


2021 ◽  
Vol 4 (01) ◽  
pp. 33-46
Author(s):  
Lina Susanti ◽  
Fuad Ardiyansayh ◽  
Hasyim As'ari

The gastropods diversity have a role towards stability ecosystem in trophic level. The existence gastropods really take effect for other organism the trophic level higher than gastropods. The purpose of was to determine the value  of diverity and distribution patterns of gastropods in the mangrove forest, Jati Papak Block National Park Alas Purwo. The method used in this research is by using purposive sampling method. Sampling was divided into three stations with a range of 250 m from each station.Each station is 220 m of long and 96 m of wide with a plot measuring 2 × 2 m2. The result obtained 8 families of Gastropods with 13 genus and 19 species. Gastropods diversity ranges from H`=1.387-1.359 which indicates that the area has a moderate diversity value. The distribution pattern of gastropods between location has two distribution patterns, namely clustered and random distribution patterns


2019 ◽  
Vol 8 (1) ◽  
pp. 1
Author(s):  
Budhy Wiyarsih ◽  
Hadi Endrawati ◽  
Sri Sedjati

Segara Anakan merupakan laguna yang terletak di selatan Pulau Jawa tepatnya di perbatasan antara Jawa Barat dengan Jawa Tengah. Kawasan Segara Anakan merupakan tempat bertemunya sungai besar, sehingga mengalami perubahan penurunan kualitas perairan berupa penyempitan dan pedangkalan akibat proses sedimentasi yang tinggi. Hal ini dikhawatirkan dapat mengakibatkan menurunnya kualitas perairan yang dapat mengganggu pertumbuhan fitoplankton di perairan. Fitoplankton merupakan parameter biologi yang dapat dijadikan bioindikator untuk mengevaluasi kualitas dan tingkat kesuburan suatu perairan. Kondisi tentang lingkungan perairan diperkirakan berubah sepanjang waktu, maka perlu penelitian fitoplankton, untuk mengetahui tingkat kesuburan perairannya. Tujuan dari penelitian ini adalah untuk mengetahui komposisi dan kelimpahan fitoplankton di Laguna Segara Anakan, Cilacap. Penelitian ini menggunakan metode deskriptif eksploratif dengan pengambilan data menggunakan purposive sampling method. Hasil menunjukkan ditemukan 34 genera yaitu Kelas Bacillariophyceae (21 genera), Kelas Cyanophyceae (4 genera), Dinophyceae (6 genera), Chlorophyceae (2 genera), dan Euglenophyceae (1 genus). Kelimpahan fitoplankton berkisar antara 12.945,8-38.194,1 sel/liter. Indeks Keanekaragaman termasuk kategori sedang dengan nilai berkisar 1,60 - 2,32. Indeks keseragaman termasuk kategori sedang hingga tinggi, dengan nilai berkisar 0,59 - 0,81. Indeks dominansi berkisar antara 0,18 - 0,44. menunjukkan bahwa tidak ada genus yang mendominasi. Segara Anakan is a lagoon located in the south of Java Island precisely on the border between West Java and Central Java. Segara Anakan area is the place where the big river meets. Water quality decrease because of narrowing the lagoon due to the high sedimentation process. This may affect the presence of phytoplankton in the water. The quality and the fertility level of aquatic can be evaluated through the phytoplankton existence since phytoplankton is used as a biological indicator for the marine environment. The condition of the aquatic environment is expected to change over time, so it is necessary to study phytoplankton. The purpose of this research is to know about the composition and abundance of phytoplankton in Segara Anakan Lagoon, Cilacap. This research used the descriptive explorative method by data sampling using purposive sampling method. The study showed 34 genera of Bacillariophyceae (21 genera), Cyanophyceae (4 genera), Dinophyceae (6 genera), Chlorophyceae (2 genera), and Euglenophyceae (1 genus). The abundance of phytoplankton ranging from 12.945,8-38.194,1 cells/liter. The Diversity Index is a medium category with values ranging from 1.60 to 2.32. The evenness index is moderate to high, with values ranging from 0.59 to 0.81. The Dominant index ranges from 0.18 to 0.44. The value indicates the category of no dominating genus.


Author(s):  
Fitria Ulfa ◽  
Muhammad Ali Sarong ◽  
Abdullah Abdullah

This study aims to determine the impact of the land transfer to the diversity of mangrove benthos in the district of Banda Aceh Jaya Baru. This research was conducted in September-November 2014 in an area of mangrove Jaya Baru sub-district of Banda Aceh. The method used survey method or direct observation. Stations were divided into four stations using purposive sampling method on the basis of the existence of mangrove. Benthos diversity analyzed by formula diversity index, while the impact of the transfer was analyzed with the description. The results obtained by analysis of benthos diversity on land that has been reclaimed 1.18 and on land that is not reclaimed 1,17. The conclusion is the diversity of benthos was proving that the land transfer mangrove in the district of Banda Aceh Jaya Baru impact on the benthos diversity that needs to be disseminated and awareness-raising so that the mangrove ecosystem is maintained.


2019 ◽  
Vol 8 (1) ◽  
pp. 37
Author(s):  
Haryo Farras Raditya Hutama ◽  
Retno Hartati ◽  
Ali Djunaedi

Kerusakan hutan mangrove yang terjadi karena adanya aktivitas manusia cukup mengkhawatirkan dan berpengaruh terhadap kelangsungan hidup biota yang hidup didalamnya, salah satunya adalah Gastropoda. Penelitian ini dilakukan untuk mengetahui komposisi jenis makrozoobenthos gastropoda  dan menganalisa struktur komunitasnya. Pengambilan sampel dilaksanakan pada bulan Maret 2015 di 4 lokasi yakni Mangunharjo, Mangkang Wetan, Pantai Maron dan Trimulyo, Semarang. Penentuan lokasi sampling dengan metode purposive sampling method terbagi dari kelebatan mangrove lebat, sedang dan jarang pada setiap lokasi penelitian dengan pertimbangan pengaruh aliran sungai terhadap parameter disetiap stasiunnya.Klasifikasi kelebatan mangrove berdasarkan data sekunder kerapatan mangrove Pesisir Utara Semarang 2015. Pengambilan sampel gastropoda menggunakan metode kualitatif dengan transek 5m x 5m dan 1m x 1m dengan jumlah stasiun sebanyak 8 dan 3 kali pengulangan pada setiap stasiunnya. Hasil penelitian ditemukan 8 jenis spesies yang terdiri dari 4 famili yang berbeda.Famili Potamididae paling banyak ditemukan dengan jumlah 4 spesies. Ditemukan satu spesies Famili Neriitidae yakni Nerita sp. serta satu spesies Famili Ellobiidae yakni Cassidula sp.. Kelimpahan tertinggi terdapat pada Stasiun MR1 (25.667 ind./75m2) dan terendah distasiun MW3 (0.107 ind./75m2). Nilai Indeks Keanekaragaman masuk dalam kategori sedang, sedangkan nilai indeks keseragaman dalam kategori tinggi.Dalam penelitian ini menemukan spesies yang mendominasi pada 2 stasiun yaitu Stasiun MW1 dan MR1. The damage of the mangrove ecosystem which occur due to human activity is quite alarming and effect on the survival of biota that lived in it, one which is Gastropods. This research was conducted to find out the composition of macrozoobenthos gastropods and analyze its community structure. Sampling did on March 2015 at 4 locations, i.e., Mangunharjo, Mangkang Wetan, Maron and Trimulyo, Semarang. This study was conducted to determine and identify the community structure of gastropod macrozoobenthos in mangrove vegetation on the coast of Semarang The determination of sampling location use purposive sampling method that divide the dense mangrove luxuriance, moderate and rarely at location research. The dense mangrove classification based on secondary data from the landsat image of 8 and the data density of mangrove North Coastal Semarang 2015. Sampling use qualitative method with 5 m x 5 m transects and 12 stations with three-time repetitions for each stations. The results found gastropods 8 types of species comprising in 4 different families. Potamididae family is the most dominant where found 4 species. One species of Neriitidae family is found which Nerita sp. and one species of the Ellobidae family is also found, which Cassidula sp.. The highest abundance was found on Station MR1 (25.667 ind./75m2) and the lowest in station MW3 (0.107 ind./75m2). The value of the Diversity Index can be category as average while the Equitability Index value is high. In this study, found there is 2 dominance species on the whole research station, one at MW1 and the other at MR1.


2020 ◽  
Vol 9 (1) ◽  
pp. 81-86
Author(s):  
Siti Aminah ◽  
Ria Azizah Tri Nuraini ◽  
Ali Djunaedi

ABSTRAK : Fitoplankton merupakan dasar dari rantai makanan (primary producer) di perairan. Fitoplankton juga memiliki fungsi lain yaitu sebagai  bioindikator untuk mengevaluasi kualitas dan tingkat kesuburan perairan. Keberadaan fitoplankton sangat penting karena mendukung seluruh kehidupan biota laut lainya. Tujuan penelitian ini adalah untuk mengetahui struktur komunitas fitoplankton dan kualitas perairan di sekitar ekowisata “Dewi Mangrove sari” berdasarkan kelimpahan dan keanekargaman fitoplankton. Penelitian ini di laksanakan pada tanggal 26 Juni 2018 dan 7 November 2018. Penelitian ini dilakukan di  sekitar ekowisata mangrove “Dewi Mangrove Sari” Pandansari, Desa Kaliwlingi, Kabupaten Brebes, Jawa Tengah,  dengan 3 stasiun dan 3 pengulangan pengambilan sampel.Metode yang digunakan dalam penelitian ini adalah metode deskriptif, sedangkan dalam penentuan titik lokasi pengambilan sampel fitoplankton menggunakan metode purposive sampling. Hasil dari penelitian ini ditemukan 4 dari 22 genus yaitu,  Bacillariophycea dengan 15 genus,  Dynophyceae dengan 5 genus, Cyanophyceae dengan1 genus dan Crysophyceae ditemukan 1 genus. kelimpahan fitoplankton sebesar 42.555,67 Ind/L pada Bulan Juni 2018 dan 44.072,17 Ind/L untuk bulan November termasuk dalam kondisi kesuburan tinggi (Eutrofik). Indeks keanekaragaman (H’) berkisar antara 1,91 - 2,57, indeks keseragaman (e) berkisar antara 0,65-0,84, indeks dominasi (C) berkisar antara 0,13 – 0,18. Dapat disimpulkan  bahwa indeks keanekaragaman di perairan sekitar ekowisata “Dewi Mangrove Sari” Pandansari, Desa kaliwlingi, Kabupaten Brebes, Jawa tengah termasuk dalam kategori tinggi dan tidak ada dominasi. Perairan sekitar ekowisata “Dewi Mangrove Sari” cukup stabil dan persebaran individu pada setiap genus cukup merata dan tidak ada jenis yang mendominasi. ABSTRACT: Phytoplankton are the basis of the food chain (primary producer) in water. Phytoplankton also has another function, namely as a bio-indicator to evaluate the quality and level of water fertility. The existence of phytoplankton is very important because it supports all other marine life. The purpose of this study was to determine the structure of the phytoplankton community and the quality of the waters around the ecotourism "Dewi Mangrove sari" based on the abundance and diversity of phytoplankton. This research was carried out on 26 June 2018 and 7 November 2018. The research was conducted around the Pandansari "Dewi Mangrove Sari" mangrove ecotourism, Kaliwlingi Village, Brebes Regency, Central Java, with 3 stations and 3 sampling repeats. The method used in this research is descriptive, while in determining the location of phytoplankton sampling locations using a purposive sampling method. The results of this study found 4 out of 22 genera namely, Bacillariophycea with 15 genera, Dynophyceae with 5 genera, Cyanophyceae with 1 genus and Crysophyceae found 1 genus. Phytoplankton abundance of 42,555.67 Ind / L in June 2018 and 44,072.17 Ind / L for November included in conditions of high fertility (Eutrophic). Diversity index (H ') ranged from 1.91 to 2.57, uniformity index (e) ranged from 0.65 to 0.84, dominance index (C) ranged from 0.13 to 0.18. It can be concluded that the diversity index in the waters around Pandansari's "Dewi Mangrove Sari" ecotourism, Kaliwlingi Village, Brebes Regency, Central Java is included in the high category and there is no dominance. The waters around the ecotourism "Dewi Mangrove Sari" are quite stable and the distribution of individuals in each genus is quite evenly distributed and no species dominates. 


BIOSCIENTIAE ◽  
2021 ◽  
Vol 17 (2) ◽  
pp. 37
Author(s):  
Sukoco Sukoco ◽  
Gunawan Gunawan ◽  
Muhamat Muhamat

This study aims to determine the structure of phytoplankton communities in the pool are former coal mining Desa Kampung Baru Kecamatan Cempaka which include abundance, diversity, uniformity and dominance. Phytoplankton samples taken in two pools with a purposive sampling method with a three-point shooting at each pond. Sampling was performed three times. Phylum of phytoplankton were identified in both pools as much as 2 phylum (Chloropyta and Chrysopita) with 17 genera. Average abundance of phytoplankton in the first pool of 7174 ind / liter and 6873 ind / liter in the second pool. The average diversity index of phytoplankton in the first pool of 1.540 and 1.621 in the second pool. Average uniformity index of phytoplankton in the first pool of 0622 and 0.623 in the second pool. The average index of phytoplankton dominance in the first pool of 0271 and 0250 in the second pool. Analysis of community structure (abundance, diversity, uniformity and dominance) shows the condition of the two ponds in the state is quite stable and capable of supporting life inside the phytoplankton. Where the pool in the fertility rate is the level of contamination is, the conditions included in the category of individuals spread more evenly and there are no species that dominate other species in the extreme.


2018 ◽  
Vol 7 (3) ◽  
pp. 253-262
Author(s):  
Faudzi Ath Tho Azzam ◽  
Niniek Widyorini ◽  
Bambang Sulardiono

Sungai Lanangan merupakan bagian hulu Sungai Bengawan Solo yang terletak di Desa Daleman, Kecamatan Tulung, Kabupaten Klaten. Jenis limbah seperti limbah domestik, industri, pertanian, perikanan dan peternakan telah mencemari Sungai Lanangan. Limbah organik dari industri tepung aren dan mie soun yang dibuang di Sungai Lanangan mencapai 50 ton limbah per hari. Hal tersebut menyebabkan perubahan kualitas air dan komposisi fitoplankton di Sungai Lanangan.Penelitian ini dilakukan dari bulan Januari - Februari 2018 di Sungai Lanangan. Tujuan dari penelitian ini adalah untuk mengetahui kelimpahan dan komposisifitoplankton serta mengetahui kualitas perairan berdasarkan struktur komunitas fitoplankton di Sungai Lanangan tersebut. Penelitian ini menggunakan metode survei denganpengambilan sampel menggunakan metode purposive sampling. Frekuensi pengambilan sampel dilakukan setiap 1 minggu sekali selama 3 minggu. Sampel diambil dari 3 stasiun, dimana stasiun 1 dengan karakteristik perairan terbuka; Stasiun 2 dengan karakteristik dekat industri pengolahan tepung aren; dan stasiun 3 dengan karakteristik dekat dengan daerah budidaya air tawar.Hasil penelitian didapatkan 11 genera fitoplankton yaitu dari kelas Bacillariophyceae (4 genera), Cyanophyceae (2 genera), Chrysophyceae (1 genus), Ulvophyceae (2 genera), Zygnematophyceae (1 genus) dan Chlorophyceae (1 genus). Kelimpahan rata-rata fitoplankton tertinggi terdapat pada stasiun 2 dengan kelimpahan 1.989 ind/l yang didominasi oleh genus Oscillatoria. Indeks keanekaragaman rata-rata pada setiap stasiun adalah 1,68 pada stasiun 1; 1,63 pada stasiun 2; dan 1,52 pada stasiun 3. Dari hasil indeks keanekaragaman yang didapatkan tersebut menunjukkan kisaran nilai antara 1,52 hingga 1,68 yang berarti bahwa kualitas perairan Sungai Lanangan tercemar ringan.  Lanangan river is one upstream of Bengawan Solo river which located at Daleman, Tulung, Klaten. types of waste such as domestic waste, industrial waste, agriculture, fishery and animal husbandry polluted Lanangan river. Especially organic waste from palm starch and soun noodle industry that are dumped in the Lanangan river reaches 50 tonnes waste per day. This research was conducted from January to February 2018 in the Lanangan river. The purpose of this research is to find out the abundance and composition of phytoplankton; and to determine the water qualitybased on the structure of the phytoplankton community in Lanangan river. This research uses survey method and use purposive sampling method. The Frequency of sampling is done once a week for 3 week. The samples taken from 3 stations, where station 1 is open water; Station 2 is near palm starch and soun noodle industry; and station 3 is close to freshwater aquaculture area.The resultsof the research found 11 genus of phytoplankton in class Bacillariophyceae, Cyanophyceae, Chrysophyceae, Ulvophyceae, Zygnematophyceae and Chlorophyceae. The highest average of phytoplankton abundance found in station 2 with 1,989 ind/l which is dominated by the genus of Oscillatoria. The average diversity index each station is 1.68 at station 1; 1.63 at station 2; and 1.52 at station 3. From the results obtained the diversity index indicates the range of values between 1.52 to 1.68 which show that the water quality of Lanangan River is lightly to moderate polluted.  


2016 ◽  
Vol 7 (2) ◽  
Author(s):  
Teguh Iman Sayekti ◽  
Euis Soliha

<p><em>This study is to determine what factors influencingthe performance of SMEs. The population in this study is SMEs in the Central Java. Sample collection was conducted with a purposive sampling method. Criteriaused to take into accountis the SMEs that are already running at leastfortwo years. The sample in this study is intended as the representative of total population,67 (sixty seven). The data were processed and analyzed by computer program of SPSS 20 for Windows. Based on the results of regression analysis, it can be concluded that competitiveness has positive and significant impact on marketing performance marketing access has positive and significant impact on marketing performance. It means that the higher competitiveness and marketing access, the higher its performance. Competitiveness and marketing access have influence on SMEs’ performance through network capability.   </em></p>


2019 ◽  
Vol 18 (2) ◽  
pp. 113
Author(s):  
Murdahayu Makmur ◽  
Wahyu Retno Prihatiningsih ◽  
Mohamad Nur Yahya

Latar belakang : Radionuklida natural ditemukan hampir di semua media lingkungan, dan di lingkungan laut terdeteksi cukup tinggi karena adanya proses erosi, pelapukan dan daur ulang mineralyang mengalami perpindahan melalui badan air. Radionuklida natural tersebutdapat berpindah ke berbagai media, termasuk ke manusia melalui rantai makanan.Penelitian ini dilakukan untuk memberikan informasi dasar mengenai tingkat radioaktivitas di lingkungan perairan laut di Pesisir Pulau Bengkalis dan melakukan penilaian dampak bahaya radiologis melalui aktivitas ekuivalen radium (Raeq) dan indeks bahaya eksternal (Hex)serta laju dosis eksternal dari radionuklida natural.Metode: Metode deskriptif digunakan dalam penelitian ini dan metode pengambilan sample sedimen menggunakan metode purposive sampling. Sampelsedimen dikumpulkan dari 6 titik pengambilan sampel di pesisir Pulau Bengkalis, menggunakan sediment grab. Sampel kemudian dikeringkan dan dihomogenkan kemudian ditimbang sebanyak 1 kg. Pengukuran aktivitas radionuklida dilakukan menggunakan spektrometri gama dengan waktu cacah selama 3 hari. Aktivitas 226Ra ditentukan berdasarkan emisi sinar gamma 214Pb dan 214Bi. Aktivtias 232Th ditentukan berdasarkan emisi 212Pb dan 228Ac dan 40K ditentukan dari emisi pada 1461,8 keV. Hasil analisis akan digunakan untuk menghitung dampak radiologis di lingkungan mengunakan ekuivalen aktivitas radium dan indeks bahaya eksternal.Hasil: Aktivitas rata-rata berturut turut 56,45 ; 31,34 ; 26,04 ; 33,19 ; 30,00 dan 185,49 Bq/kg untuk radio nuklida226Ra, 212Pb, 214Pb, 214Bi, 228Ac dan 40K. Aktivitas terukur mempunyai kisaran nilai yang berdekatan dengan pengukuran di beberapa negara.Penghitungan nilai aktivitas ekuivalen radium (Raeq) berkisar dari 82,61 - 138 Bq/kg dan tidak melebihi nilai yang ditetapkan oleh ICRP (1990) dan OECD (179) yaitu sebesar 370 Bq/kg. Nilai indeks bahaya eksternal (Hex) masih dibawah 1, dengan nilai rata rata sebesar 0,31, dan laju dosis dari radionuklida natural sebesar 37,175 nGy/h.Simpulan:Aktivitas radionuklida natural di pesisirPulauBengkalismempunyai kisaran nilai yang berdekatan dengan pengukuran di beberapa Negara. Nilai aktivitas ekuivalen radium (Raeq) Yang terukur tidak melebihi nilai yang ditetapkan oleh ICRP (1990) dan OECD (179).  Nilai indeks bahaya eksternal (Hex) masih dibawah 1, dan laju dosis yang diserap lingkungan dari radionuklida natural masih dibawah nilai rata rata dunia. Dengan demikian, dapat disimpulkan bahwa parameter radiologis radionuklida natural dalam sedimen di pesisir Pulau Bengkalis berada dalam batas yang dapat diterima. AbstractTitle : --Background: Natural radionuclides are found in almost all environmental media, and in the marine compartment have been detected relative high due to the process of erosion, weathering and recycling of minerals that come trough the water bodies. Radionuclides can move to various media, including to the humans through the food chain. This research was conducted to provide baseline information about the activity of radioactivity in the marine environment of the Bengkalis Island Coast and conduct radiological hazard impact assessments through equivalent radium (Raeq) and external hazard index (Hex) and external dose rates of natural radionuclides.Method: Descriptive methods were used in this study and the sediment sampling method used a purposive sampling method. Sediment samples were collected from 6 sampling points on the coast of Bengkalis Island, using sediment grab. The samples were then dried, homogenized and weighed 1 kg. Measurement of radionuclide activity was carried out using gamma spectrometry with counting time for 3 days. The 226Ra activity is determined based on 214Pb and 214Bi gamma ray emissions. The 232Th activity was determined based on 212Pb and 228Ac and 40K emissions determined from emissions at 1461.8 keV. The results of the analysis will be used to calculate the radiological impact in the environment using equivalent radium activity and external hazard index.Results: The average activity are 56.45; 31.34; 26.04; 33.19; 30.00 and 185.49 Bq/kg for radionuclides 226Ra, 212Pb, 214Pb, 214Bi, 228Ac and 40K respectively. The value of this activity comparable withthe activities in several countries.The calculation of radium equivalent activity (Raeq) values ranges from 82.61 - 138 Bq / kg and does not exceed the value 370 Bq / kg by ICRP (1990) and OECD (179). The external hazard index value (Hex) is still below 1, with an average value of 0.31, and the dose rate of natural radionuclides is 37,175 nGy / h.Conclusion: Natural radionuclide activity on the coast of Bengkalis Island has a range of values adjacent to measurements in several countries. The measured value of radium (Raeq) activity does not exceed the value set by ICRP (1990) and OECD (179). The external hazard index value (Hex) is still below 1, and the absorbed dose rate of natural radionuclides is still below the world average value. Thus, it can be concluded that the radiological parameters of natural radionuclides in sediments on the coast of Bengkalis Island are within acceptable limits. 


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