ABSTRAKPenelitian ini bertujuan untuk mengetahui konsentrasi amonia, nitrat, nitrit dan fosfat di Perairan Pesisir Desa Lontar, Kabupaten Serang. Peneliti menggunakan metode deskriptif kuantitatif. Pengumpulan data dilakukan dengan pengambilan sampel pada 3 titik stasiun. Analisis data dilakukan secara deskriptif. Hasil pengukuran konsentrasi amonia pada stasiun 1 berkisar antara 0,07-0,23 mg/l dengan rata-rata 0,15 mg/l, stasiun 2 berkisar antara 0,087-0,444 mg/l dengan rata-rata 0,272 mg/l dan stasiun 3 berkisar antara 0,115-0,409 mg/l dengan rata-rata 0,223 mg/l. Hasil pengukuran konsentrasi fosfat pada stasiun 1 berkisar antara 0,02-0,05 mg/l dengan rata-rata 0,033 mg/l, stasiun 2 berkisar antara 0,04-0,05 mg/l dengan rata-rata 0,046 mg/l dan stasiun 3 berkisar antara 0,05-0,1 mg/l dengan rata-rata 0,066 mg/l. Hasil pengukuran konsentrasi nitrat pada stasiun 1 memiliki nilai rata- rata 1 mg/l, stasiun 2 berkisar antara 0,6-2,5 mg/l dengan rata-rata 1,3 mg/l dan stasiun 3 berkisar antara 0,9-2,8 mg/l dengan rata-rata 1,5 mg/l. Hasil pengukuran konsentrasi nitrit pada stasiun 1 berkisar antara 0,01-0,03 mg/l dengan rata-rata 0,02 mg/l, stasiun 2 memiliki nilai rata-rata 0,016 mg/l dan stasiun 3 dengan rata-rata 0,023 mg/l. Berdasarkan Peraturan Pemerintah Nomor 22 Tahnun 2021 dan ANZECC (Australian and New Zealand Environment and Conservation Council) ARMCANZ (Agriculture and Resource Management Council of Australia and New Zealand) Chapter 9 (2000) Perairan pesisir utara Desa Lontar belum bisa sepenuhnya dikategorikan perairan baik karena beberapa nutrien seperti nitrat dan fosfat memiliki konsentrasi yang melebihi ambang baku mutu. Kata Kunci: Konsentrasi Fosfat, Nitrat, Nitrit, Amonia, Desa Lontar ABSTRACTThis study aims to determine the concentration of ammonia, nitrate, nitrite and phosphate in the Coastal Waters of Lontar Village, Serang Regency. Researchers used a quantitative descriptive method. Data collection was done by sampling at 3 station points. Data analysis was done descriptively. The results of ammonia concentration measurements at station 1 ranged from 0.07-0.23 mg/l with an average of 0.15 mg/l, station 2 ranged from 0.087-0.444 mg/l with an average of 0.272 mg/l and station 3 ranged from 0.115-0.409 mg/l with an average of 0.223 mg/l. The results of phosphate concentration measurements at station 1 ranged from 0.02-0.05 mg/l with an average of 0.033 mg/l, station 2 ranged from 0.04-0.05 mg/l with an average of 0.046 mg/l and station 3 ranged from 0.05-0.1 mg/l with an average of 0.066 mg/l. The results of nitrate concentration measurements at station 1 have an average value of 1 mg/l, station 2 ranges from 0.6-2.5 mg/l with an average of 1.3 mg/l and station 3 ranges from 0.9-2.8 mg/l with an average of 1.5 mg/l. The measurement results of nitrite concentration at station 1 ranged from 0.01-0.03 mg/l with an average of 0.02 mg/l, station 2 had an average value of 0.016 mg/l and station 3 with an average of 0.023 mg/l. Based on Government Regulation No. 22 of 2021 and ANZECC (Australian and New Zealand Environment and Conservation Council) ARMCANZ (Agriculture and Resource Management Council of Australia and New Zealand) Chapter 9 (2000) the north coastal waters of Lontar Village cannot be fully categorized as good waters because some nutrients such as nitrates and phosphates have concentrations that exceed the quality standard threshold.Key Words: Concentration of Phosphate, Nitrate, Nitrite, Ammonia, Lontar Village