Akumulasi Mikroplastik Pada Ikan Dengan Level Trofik Berbeda di Pulau Barranglompo, Kepulauan Spermonde, Sulawesi Selatan

Abstract

Pengelolaan sampah plastik yang tidak terkontrol di Pulau Barranglompo menimbulkan berbagai permasalahan di perairan laut, salah satunya pencemaran mikroplastik. Mikroplastik (MP) dengan bioavailabilitasnya yang tinggi di laut memungkinkan untuk dikonsumsi oleh ikan baik secara sengaja maupun tidak sengaja. Mekanisme akumulasi dan translokasi mikroplastik dapat terjadi di berbagai organ ikan seperti insang, saluran pencernaan, dan daging. Selain itu, adanya perbedaan level trofik dari ikan diduga memberikan pengaruh terhadap perbedaan akumulasi mikroplastik. Akumulasi mikroplastik pada saluran pencernaan ikan telah banyak diteliti, namun penelitian terkait akumulasi mikroplastik di di organ ikan lainnya seperti insang dan daging pada ikan dengan level trofik berbeda masih sangat terbatas. Penelitian ini bertujuan untuk membuktikan keberadaan mikroplastik pada air laut dan organ-organ ikan meliputi insang, saluran pencernaan, dan daging pada ikan dengan level trofik berbeda (herbivora dan karnivora) yang dikumpulkan dari perairan Pulau Barranglompo pada Juli – November 2020. Sampel ikan dikumpulkan secara acak di area padang lamun menggunakan metode neuston net volume reduced. Sebanyak 100 individu ikan meliputi Hemiramphus far (julung-julung) (N= 25), Siganus virgatus (baronang) (N= 25), dan Lethrinus lentjan (katamba) (N= 50) diamati setiap organnya yang terdiri dari insang, saluran pencernaan, dan daging, kemudian diekstraksi menggunakan KOH 20%. Sampel air laut disaring menggunakan kertas saring Whatman 47 mm dengan pori 0,45 µm pada pompa vakum. Pengamatan karakteristik MP dilakukan secara visual menggunakan mikroskop stereo dan dilanjutkan dengan analisis menggunakan Fourier Transform Infrared (FTIR) untuk mengidentifikasi jenis-jenis polimer mikroplastik. Analisis histopatologi pada hati ikan dilakukan menggunakan metode standar. Selain itu, indeks hepatosomatik (IHS) dan faktor kondisi relatif (Kn) dianalisis untuk menilai status kesehatan ikan. Hasil penelitian menunjukkan tingkat deteksi MP di insang pada masing-masing ikan herbivora dan karnivora yaitu 76% dan 52%. Tingkat deteksi MP di saluran pencernaan pada masing-masing ikan herbivora dan karnivora yaitu 86% dan 60%. Tingkat deteksi MP di daging pada masing-masing ikan herbivora dan karnivora yaitu 50% dan 24%. Pada sampel air laut, tidak terdapat perbedaan kelimpahan mikroplastik secara spasial, sedangkan peningkatan kelimpahan mikroplastik terjadi secara temporal baik di zona dalam (3800 – 10040 MP/m3), maupun di zona luar (3540 – 11260 MP/m3). Karakteristik mikroplastik yang ditemukan pada kompartemen ikan dan air laut didominasi oleh warna biru dan bentuk line, ukuran MP dengan kisaran 1 – 5 mm mendominasi pada kompartemen ikan, sedangkan ukuran MP dengan kisaran 0,1 – 0,5 mm mendominasi pada kompartemen air laut. Terdapat enam jenis polimer mikroplastik yang teridentifkasi meliputi polyester (PES), polypropylene (PP), polyethylene (PE), polyurethane (PU), polystyrene (PS) dan rayon. Terdapat tiga jenis pola reaksi yang teridentifikasi pada pengujian histopatologi organ hati yaitu gangguan peredaran darah (hiperemia dan kongesti), perubahan regresif (melanomakrofag dan nekrosis), dan perubahan progresif (hiperplasia). Hasil perbandingan ikan yang terdeteksi MP dan yang tidak terdeteksi MP pada ikan H. far menunjukkan hasil yang signifikan baik pada indeks hepatosomatik (IHS) maupun faktor kondisi relatif (Kn), sedangkan fenomena yang sama tidak ditemukan pada kedua spesies lainnya.

Microplastic pollution is one of the various problems at Barranglompo Island Waters. It is caused by the uncontrolled management of plastic debris on this island. Microplastics (MPs) with its high bioavailability in marine waters allow it to be consumed by fish either intentionally or unintentionally. The mechanism of microplastic accumulation and translocation can occur in various fish organs such as gills, gastrointestinal tract, and flesh. Also, the difference in trophic levels of fish is assumed to affect differences in microplastic accumulation. The accumulation of microplastics in the digestive tract of fish has been widely studied, but research on the accumulation of microplastics in other fish organs such as gills and flesh in fish with different trophic levels is still very limited. This study aimed to investigate the presence of microplastics in seawater and fish organs including gills, gastrointestinal tract, and flesh in fish with different trophic levels (herbivorous and carnivorous) collected from Barranglompo Island Waters on July – November 2020. Fish samples were collected randomly in the seagrass area using the seine net and the sampling of seawater was using the neuston net volume reduced method. A total of 100 individual fish including Hemiramphus far (halfbeak) (N = 25), Siganus virgatus (rabbitfish) (N = 25), and Lethrinus lentjan (pink ear emperor) (N = 50) were observed for each organ including gills, gastrointestinal tract, and flesh, then extracted using KOH 20% solution. Seawater samples were filtered using filter paper Whatman 47 mm with a pore size of 0.45 µm on a vacuum pump. The MPs characteristics were identified visually using a stereomicroscope and continued using Fourier Transform Infrare (FTIR) to identify the polymer types of microplastics. Histopathological analysis of fish liver was performed using standard methods. Furthermore, hepatosomatic index (IHS) and relative condition factors (Kn) were analyzed to assess the health status of fish. The results showed that the detection rate of MP in the gills of herbivorous and carnivorous fish was 76% and 52%, respectively. The detection rate of MP in the gastrointestinal tract of herbivorous and carnivorous fish was 86% and 60%, respectively. The detection rate of MP in the flesh of herbivorous and carnivorous fish was 50% and 24%, respectively. In seawater samples, there is indifferences in MP abundance spatially, while an increase in MP abundance occurred temporally both in the inner zone (3800 - 10040 MP/m3) and the outer zone (3540 - 11260 MP/m3). The characteristics of microplastic found in fish and seawater were predominantly by blue color and line shape, the MP size with a range of 1 – 5 mm was dominated in fish, while the MP size with a range of 0,1 – 0,5 mm was dominated in seawater. There were six types of microplastic polymers identified including polyester (PES), polypropylene (PP), polyethylene (PE), polyurethane (PU), polystyrene (PS), and rayon. Three types of reaction patterns identified in the histopathological examination of the liver were circulatory disturbances (hyperemia and congestion), regressive changes (melanomacrophage and necrosis), and progressive changes (hyperplasia). The comparison of fish detected with MP and none MP in H. far showed significant results both of the hepatosomatic index (HSI) and the relative condition factor (Kn), while the same indication was not found in other species.