Contaminants and heavy metals along the mangrove area of Dongzhai Harbor, China: distribution and assessment

In recent decades, higher-place shrimp ponds are prevalent in coastal areas of developing countries. However, shrimp aquaculture has a growing negative impact on mangrove wetland ecosystems. Mangroves located in Dongzhai harbor are under threat continuously of this commercialization. Therefore, a comprehensive analysis of contaminants and heavy metals is necessary for Dongzhai harbor, considering the mangrove area was declined and ecological services offered to the coastal communities with an insight for future restoration activities. In this study, pond effluents (Total Nitrogen (TN), Ammonia Nitrogen (AN), Total phosphorus (TP), Chemical Oxygen Demond (COD)) and heavy metals (Cd, Cu, Pb, Zn) were monitored in Dongzhai harbor yearly between 2013 and 2017. The results showed that the contents of Cd, Cu, Pb, and Zn were far lower than the standards. However, the main contaminants were organic matter and nitrogen. Maximum values of COD and TN were 26.10 mg·L−1 and 1.34 mg·L−1, respectively in 2017. Single factor index, Nemerow's pollution index, and Trophic level index revealed that the heavily polluted areas were Tashi and Sanjiang town.

Assessing trophic state of surface waters of Służewiecki Stream (Warsaw)

Phosphorus (P) is one of the key nutrient compounds for phytoplankton grow. In the conducted work, eutrophication indexes were used for the assessment of eutrophication level of water course (Służewiecki Stream) and the waters of nearby lakes (Bottom Berensewicz’s Pond, Wyścigi Pond, Wilanowskie Lake). Calculating eutrophication indexes were based on the most important indicators which is crucial for eutrophication process: total phosphorus (TP), total nitrogen (TN), chlorophyll a (Chl(a)) and water transparency. The research revealed that the concentration of phosphorus and nitrogen in the analysed waters determined intensity of trophic processes. The average concentration of both indicators was high: 0.81 mg/l TP and 6.8 mg/l TN. During this research, two approaches were used: trophic state index (TSI) and trophic level index (TLI). TSI (TP) in Służewiecki Stream were, respectively: 83 and 6.5 whilst for standing waters (lake and ponds) 87 and 6.6. Both indexes indicated high trophic state and confirmed that eutrophication is a serious endangerment for analysed surface waters. Calculated indexes used in the assessment were sufficient and effective for sustainable water protection and management of water quality in Służewiecki Stream and in standing waters.

Assessment of eutrophication and nitrogen and phosphorus carrying capacity before and after removing pen culture (2013–2018) in Lake Changhu, China

In this study, the eutrophication levels and nitrogen and phosphorus carrying capacities of Lake Changhu in Jingzhou city, Hubei province, China, were measured using the trophic level index (TLI) and Dillon model. The measurements were taken before (2013 and 2015) and after (2017 and 2018) the removal of pen aquaculture from the lake. The lake was divided into three districts: Lake Haizihu, Mahongtai Channel and Lake Dahu. The results showed total nitrogen (TN), chemical oxygen demand (COD), chlorophyll a (Chl-a), and total suspended solid (TSS) values were significantly higher in 2017 than in the other years. The Lake Haizihu district was predicted to be more seriously polluted than the other districts. In the sediment, the organic matter, STN (TN in sediment) and STP (TP in sediment) contents increased from 2013 to 2018. The mean TLI values ranged from 62.99 to 78.93 in the studied years, and the eutrophication level was highest in 2017. According to the Dillon model, when the target water quality was level III (GB 3838 − 2002, Ministry of Environmental Protection of China, 2002), the remaining TN and TP loading capacities were − 1470.72 t/a and − 182.74 t/a, respectively, in 2015, and 320.03 t/a and − 111.14 t/a, respectively, in 2018. The study provide valuable information about the actual water conditions of Lake Changhu, which will help to inform decision-making for the management of water environments.

Status of water quality and level of trophic in Juanda Reservoir of Purwakarta Regency, West Java, Indonesia

Juanda reservoir is one of the reservoirs located in Purwakarta Regency, West Java Province, Indonesia, whose primary function is hydropower, water resources for irrigation, industrial and drinking water, and secondary function for fisheries and tourism activities. Currently, an increase in activities around the existing reservoir has affected its water quality. In order to determine the water quality and trophic level status of the Juanda reservoir, research has been conducted within five stations during the period of August-December 2020. The water quality status includes physical, chemical, and biological parameters that compared with Store standards on Class II and III. Meanwhile, the trophic status was determined by Trophic Level Index (TLI) based on the parameters of transparency, chlorophyll-a, total nitrogen, and total phosphorus. The results show that the water quality status of Juanda reservoir has been contaminated Class III and heavily polluted Class II. The parameters that exceed include ammonia, nitrate, and BOD5. The Juanda reservoir's tropic status was in the eutrophic category, with TLI values ranging from 4.6 to 5.2.

TINGKAT KESUBURAN PERAIRAN KOLONG PASCA GALIAN TAMBANG PASIR SIDODADI, PULAU SUGI BAWAH, PROVINSI KEPULAUAN RIAU

Kolong Sidodadi merupakan genangan perairan yang terbentuk di lahan pasca tambang pasir darat di Pulau Sugi Bawah, tepatnya di Kampung Sidodadi, Kecamatan Moro, Kabupaten Karimun. Kolong ini dimanfaatkan sebagai sumber air baku oleh PDAM Tirta Karimun. Penelitian ini bertujuan untuk mengkaji kondisi parameter fisika, kimia, dan biologi serta tingkat kesuburan perairan Kolong Sidodadi, Kabupaten Karimun, Kepulauan Riau. Pengambilan sampel dilakukan secara random sampling sebanyak 30 titik sampling yang tersebar di Kolong Sidodadi. Parameter fisika, kimia, dan biologi perairan yang diukur yaitu suhu, kecerahan, pH, DO, nitrat, fosfat, dan klorofil-a. Kualitas perairan dianalisisberdasarkan kesesuaian baku mutu menurut Peraturan Pemerintah Republik Indonesia No. 82 Tahun 2001. Indeks kesuburan dihitung menggunakan metode Trophic Level Index (TLI). Hasil penelitian menunjukkan bahwa Kolong Sidodadi memiliki pH asam (rendah), konsentrasi nutrien N dan P tinggi, serta klorofil-a rendah. Nilai kesuburan berdasarkan indeks TLI berkisar 3,60-4,40 dengan rataan 4,00. Tingkat kesuburan perairan Kolong Sidodadi tergolong eutrofik (tinggi). Perlu menjadi perhatian terhadap nilai pH yang rendah karena air Kolong Sidodadi ini digunakan sebagai sumber air baku bagi PDAM Tirta Karimun. Selain itu, diperlukan kajian keanekaragaman dan kelimpahan fitoplankton sehingga dapat mengkonfrimasi konsentrasi klorofil-a yang menjadi komponen utama dalam penentuan tingkat kesuburan perairan.

Analysis and prediction of eutrophication for advanced warning of the water quality concerns in Gaoyou Lake

This paper used the trophic level index (TLI) method combined with the relevant data from 2014 to 2017 to evaluate the water quality of Gaoyou Lake. Meanwhile, based on principal component analysis (PCA) and multiple linear regression (MLR) models on chlorophyll a (Chla), this research developed predictions and an early warning scheme for eutrophication in Gaoyou Lake. The results showed the following: 1. The TLI of Gaoyou Lake showed a significant increasing trend, and the lake was in the state of light to moderate eutrophy. 2. According to the PCA eigenvalues that were greater than 1, principal components (PCs) with a cumulative contribution rate of 76.04% were obtained, and a linear model was further obtained: CChla = 6.146 + 1.209 (Score 1) + 0.583 (Score 2) + 1.095 (Score 3). 3. The credibility of the early warning system reached 75%, which met the requirements of this study. This study provides a scientific basis for the control of eutrophication and improvement of water quality.

Retrieving the Lake Trophic Level Index with Landsat-8 Image by Atmospheric Parameter and RBF: A Case Study of Lakes in Wuhan, China

The importance of atmospheric correction is pronounced for retrieving physical parameters in aquatic systems. To improve the retrieval accuracy of trophic level index (TLI), we built eight models with 43 samples in Wuhan and proposed an improved method by taking atmospheric water vapor (AWV) information and Landsat-8 (L8) remote sensing image into the input layer of radical basis function (RBF) neural network. All image information taken in RBF have been radiometrically calibrated. Except model(a), image data used in the other seven models were not atmospherically corrected. The eight models have different inputs and the same output (TLI). The models are as follows: (1) model(a), the inputs are seven single bands; (2) model(c), besides seven single bands (b1, b2, b3, b4, b5, b6, b7), we added the AWV parameter k1 to the inputs; (3) model(c1), the inputs are AWV difference coefficient k2 and the seven bands; (4) model(c2), the input layers include seven single bands, k1 and k2; (5) model(b), seven band ratios (b3/b5, b1/b2, b3/b7, b2/b5, b2/b7, b3/b6, and b3/b4) were used as input parameters; (6) model(b1), the inputs are k1 and seven band ratios; (7) model(b2), the inputs are k2 and seven band ratios; (8) model(b3), the inputs are k1, k2, and seven band ratios. We estimated models with root mean squared error (RMSE), model(a) > model(b3) > model(b1) > model(c2) > model(c) > model(b) > model(c1) > model(b2). RMSE of the eight models are 12.762, 11.274, 10.577, 8.904, 8.361, 6.396, 5.389, and 5.104, respectively. Model b2 and c1 are two best models in these experiments, which confirms both the seven single bands and band ratios with k2 are superior to other models. Results also corroborate that most lakes in Wuhan urban area are in mesotrophic and light eutrophic states.