HUBUNGAN LOGAM BERAT TIMBAL (Pb) DAN KADMIUM (Cd) TERLARUT DENGAN KELIMPAHAN FITOPLANKTON DI SUNGAI SILANDAK SEMARANG
Authors: Ardi Helmi , Rudiyanti Siti , Sulardiono Bambang 
Published: September 2020

ABSTRAK  Sungai Silandak terletak di Kota Semarang, Jawa Tengah. Sungai ini menerima limbah yang berasal dari kegiatan industri plastik yang dialirkan ke perairan, dan juga menerima aliran limbah rumah tangga serta terdapat banyak sarana transportasi air di bagian muara sungai.Limbah yang berasal dari industri tersebut mengandung logam berat timbal dan kadmium.Penelitian dilakukan pada bulan April 2016 – Mei 2016 di Sungai Silandak yang bertujuan untuk mengetahui konsentrasi kadmium dan timbal, mengetahui kelimpahan danstruktur komunitas fitoplankton, dan mengetahui hubungan kadmium dan timbal dengan kelimpahan fitoplankton. Metode penelitian yang digunakan adalah metode survei dengan teknik samplingpurposive sampling. Hasil penelitian menunjukkan konsentrasi kadmium di lokasi penelitian berkisar antara 0,0007 - 0,001 mg/l, sedangkan konsentrasi timbalberkisar antara 0,002 - 0,007 mg/l. Kelimpahan fitoplankton berkisar antara 1826 - 6730 ind/l, indeks keanekaragaman (H’) dengan angka 1.747 – 2.828, Indeks dominasi (d) diperoleh hasil dengan angka 0.077 – 0.284, dan indeks keseragaman (e) dengan angka 0.645 – 0.890. Tidak ada hubungan yang signifikan antara kadmium dengan kelimpahan fitoplankton dengan angka koefisien korelasi (r) sebesar 0.179 menunjukkan korelasi lemah.Tidak ada hubungan yang signifikan antara logam berat timbal dengan kelimpahan fitoplankton, diperoleh angka koefisien korelasi (r) sebesar 0.261 menunjukkan korelasi lemah.PCA (Principle Component Analysis) digunakan untuk mengetahui hubungan kadmium dan timbal dengan kelimpahan genera fitoplankton. Terdapat hubungan signifikan logam berat timbal dengan kelimpahan genus Dyctyocha sp dan Bacteriastrum sp di level 0.05 dari rentang kepercayaan  95 %, korelasi kuat negatif dengan koefisien korelasi -0.68. Kata Kunci  :Kadmium; Cd; Timbal; Pb; Kelimpahan Fitoplankton;Logam Berat; SungaiSilandak. ABSTRACT Silandak river is located in Semarang, Central Java. This river is suspect to receiving waste came from plastic industry activity which is streamed to the water, and also receiving household waste stream and there are plenty of water transportation in the section of the estuary. Waste from the industry is suspected contain heavy metals cadmium and lead.The study was conducted in April 2016 - May 2016 in the River of Silandak which aimed to determine the concentration of cadmium and lead, to determine the abundance and  the phytoplankton community structure, and to determine the correlation of cadmium and lead with the abundance of phytoplankton. The study used survey method with purposive sampling technique. The results showed the concentration of cadmium in the study locations was within the range of 0.0007 to 0.001 mg/l, while the concentration of lead was within the range of 0.002 to 0.007 mg/l. The abundance of phytoplankton ranged between 1826 - 6730 ind/l, the rate of diversity index (H’) was within the range of1.747 - 2.828, the dominance index (d) obtained results within the rate of 0.077 - 0.284, and evenness index (e) within the rate of 0.645 - 0.890. There was no significant correlation between cadmium with the abundance of phytoplankton with a correlation coefficient (r) of 0.179 which means weak correlations. There was no significant correlation between the heavy metals lead with the abundance of phytoplankton, the rate of the correlation coefficient (r) of 0.261 which means weak correlations. PCA (Principle Component Analysis) is used to determine the correlation cadmium and lead with the abundance of phytoplankton genus. There was a significant correlations of heavy metals lead with the abundance Dyctyocha sp and Bacteriastrum sp genus at 0.05 levels the range of 95%, a strong negative correlation with a correlation coefficient of -0.68. Keywords: Cadmium; Cd; Lead; Pb;Phytoplankton Abundance; Heavy Metal;Silandak River.