Seawater Quality Research Articles

Application of a multiparameter sonde for real-time monitoring of seawater quality in Durrës Bay in Albania

Abstract Coastal areas are characterized by a high population and a wide range of industrial and agricultural activities, which puts them under high pressure and continuous pollution from anthropogenic activities. This research focuses on the application of HYDROLAB HL7 multiparameter sonde equipped with smart sensors for the measurement of physical–chemical parameters in marine waters in the Durrës Bay. The sonde is part of a transnational repository network that receives, stores, and analyzes data about seawater quality, serving as an early warning system for preventing the diffusion of marine pollution. This sophisticated instrument can thrive in demanding environmental conditions for long-term continuous monitoring. It maximizes deployment lifespan, and provides traceable data for high-quality, reliable monitoring of vital changes in water quality. Low variability on the measured parameters indicates a stable status in the water quality of the Durrës site. Time series revealed small seasonal variations on all parameters, except turbidity and water temperature. Total dissolved solids, salinity, and electrical conductivity revealed similar temporal trends over the monitoring period by indicating strong relationships between them. The obtained data for the physical–chemical parameters in this study align with the recommended values. Ensuring water quality in the Durrës Bay requires advanced monitoring, regulatory measures, and community engagement.

Assessment of the Quality of Raw Water for Salt Production in Pangarengan, Sampang, East Java

Seawater is the primary raw material for the production of sea salt. Seawater quality dramatically affects to salt production. The purpose of this study was to evaluate the seawater’s quality as a raw material for salt production in Pangarengan, Sampang, East Java, Indonesia. The assessment of water quality in this study includes physical and chemical characteristics. The location of this research was in the salt fields that close to settlements with high anthropogenic activity. Sampling points were the seawater inlet (P1), reservoir plot/bozem (P2), and evaporation plot (P3). Assessment of temperature, pH, salinity and water saturation using in-situ measurements. Determination of heavy metal parameters (Mercury, Cadmium, Lead, and Arsenic) using UV spectrometry. The physical characteristics of the highest water temperatures were in evaporated plot (40°C), while the water temperatures in the seawater entrance and reservoir ponds were respectively 33.5 °C and 36 °C. pH, one of the chemicals parameter, at the seawater entrance, reservoir plot, and evaporated plot were 8.2, 7.7, and 9. The salinity of the three points is more than 33 ‰, and the raw water saturation in the evaporated pool is 24° Be. Analysis of heavy metals in this study showed levels below seawater quality standards for consumption purposes.

Dynamic assessment of seawater quality based on semi-partial subtraction set pair potential method and game theory.

The assessment of seawater quality is a complex process as it involves the influence of several factors and is characterized by dynamic changes in these factors. Herein, a novel model coupled with the semi-partial subtraction set pair potential method (SSSPP) and game theory was discussed for the dynamic assessment of seawater quality. In the proposed model, the identity-discrepancy-contrary degrees were calculated to construct the evaluation matrix, and then the classification and the dynamic risk trends of the seawater quality were determined. A case study and comparison with the single-factor approach and Nemerow index evaluation method were carried out to confirm the accuracy and dependability of the suggested model. The results indicate that the proposed method can be used to measure trends in seawater quality evolution and also to diagnose key indicators affecting seawater quality. It provides a new and effective way to accurately identify the quality of seawater and its trends.

Study of Sea Water Quality in Malalayang Beach Walk Area

The city of Manado is famous for its fishery products, but human activities also cause problems of seawater pollution and a decrease in water quality. This study aims to examine the water quality around Malalayang Beach Walk in Manado City with a focus on physical and chemical parameters. The study was conducted at five stations with three repetitions at high and low tide. The results showed that the water temperature was relatively homogeneous, with a range of 30.02-30.29oC at high tide and 30.39-30.81oC at low tide. Turbidity is in the range of 20.1-22.5 NTU at high tide and 16.0-21.7 NTU at low tide, exceeding the quality standard. DO values conform to quality standards (5.46-8.07 mg/L at high tide and 5.69-6.32 mg/L at low tide), but TDS reaches 23900-28600 mg. L at high tide and 26600-28600 mg/L at low tide, far from the common values of 1500 mg/L. Salinity values range from 25.02-30.29 ppt at high tide and 30.35-30.50 ppt at low tide. Pollution and degradation need to be better controlled and monitored.
 Keywords: Water quality, Temperature, Turbidity, Dissolved oxygen (DO), Total dissolved solids (TDS), Salinity.
 Abstrak
 Kota Manado terkenal dengan hasil perikanannya, namun aktivitas manusia juga menyebabkan masalah pencemaran air laut dan penurunan kualitas perairan. Penelitian ini bertujuan untuk mengkaji kualitas perairan di sekitar Malalayang Beach Walk Kota Manado dengan fokus pada parameter fisika dan kimia. Penelitian dilakukan di lima stasiun dengan tiga kali pengulangan pada saat air pasang dan surut. Hasil penelitian menunjukkan bahwa suhu perairan relatif homogen, dengan rentang nilai 30,02-30,29oC saat pasang dan 30,39-30,81oC saat surut Kekeruhan berada pada rentang 20,1-22,5 NTU saat pasang dan 16,0-21,7 NTU saat surut, melebihi standar baku mutu. Nilai DO sesuai dengan standar baku mutu (5,46-8,07 mg/L saat pasang dan 5,69-6,32 mg/L saat surut), namun TDS mencapai 23900-28600 mg/L saat pasang dan 26600-28600 mg/L saat surut, jauh dari nilai umum 1500 mg/L. Nilai salinitas berkisar antara 25,02-30,29 ppt saat pasang dan 30,35-30,50 ppt saat surut. Pencemaran dan penurunan kualitas perlu dikendalikan dan dipantau secara lebih baik.
 Kata Kunci: Kualitas air, Suhu, Kekeruhan, Dissolved oxygen (DO), Total dissolved solids

The influencing factors of residents’ willingness to pay in marine ecological restoration: The integration of the theory of planned behavior and social capital theory

Public participation in marine ecological restoration is of great significance to marine environmental protection and ecological security in China. Based on the contingent valuation method, this paper evaluates residents’ preference for marine ecological restoration, and shows that residents show the strongest preference for the increase in the number of intertidal organisms, followed by the improvement in coastal environment and seawater quality. The mean willingness to pay (WTP) for a large improvement in marine environment is predicted and is 108.96 CNY/a. Additionally, a comprehensive framework, which integrates social capital theory and the theory of planned behavior, is constructed to explore the influencing factors of residents’ WTP from the social and psychological levels. The results suggest that behavioral attitude, perceived behavioral control, and social network show a significantly direct impact on residents’ WTP. Furthermore, a mechanism is constructed from pushing power and pulling power to effectively promote public participation. This paper reveals public’s preference for marine ecological restoration and its formation mechanism, which can provide theoretical basis and empirical reference for promoting the public participation in marine ecological restoration.

Multiple marine algae identification based on three-dimensional fluorescence spectroscopy and multi-label convolutional neural network

Accurate identification of algal populations plays a pivotal role in monitoring seawater quality. Fluorescence-based techniques are effective tools for quickly identifying different algae. However, multiple coexisting algae and their similar photosynthetic pigments can constrain the efficacy of fluorescence methods. This study introduces a multi-label classification model that combines a specific Excitation-Emission matric convolutional neural network (EEM-CNN) with three-dimensional (3D) fluorescence spectroscopy to detect single and mixed algal samples. Spectral data can be input directly into the model without transforming into images. Rectangular convolutional kernels and double convolutional layers are applied to enhance the extraction of balanced and comprehensive spectral features for accurate classification. A dataset comprising 3D fluorescence spectra from eight distinct algae species representing six different algal classes was obtained, preprocessed, and augmented to create input data for the classification model. The classification model was trained and validated using 4448 sets of test samples and 60 sets of test samples, resulting in an accuracy of 0.883 and an F1 score of 0.925. This model exhibited the highest recognition accuracy in both single and mixed algae samples, outperforming comparative methods such as ML-kNN and N-PLS-DA. Furthermore, the classification results were extended to three different algae species and mixed samples of skeletonema costatum to assess the impact of spectral similarity on multi-label classification performance. The developed classification models demonstrated robust performance across samples with varying concentrations and growth stages, highlighting CNN's potential as a promising tool for the precise identification of marine algae.

Effects of terrestrial input on heavy metals in Zhanjiang Bay, a typical subtropical bay in the South China Sea

Understanding the influence of terrestrial inputs on heavy metals in bays is crucial for the environmental protection of regional estuaries and coastal systems. In this study, the concentrations, temporal and regional distribution characteristics, and fluxes of heavy metals (Cr, Cu, Zn, Cd, Pb) in the surface seawater and terrestrial sewage of Zhanjiang Bay (ZJB) in four different seasons were investigated. The results identified the heavy metal concentrations in the sewage outlet around ZJB had significant seasonal variation. The heavy metals in the surface seawater of ZJB had significant spatiotemporal variations. Terrestrial input, biological activity and hydrodynamics affected the overall distribution. The heavy metal emission fluxes indicated that riverine input was the main influencing factor for heavy metals in ZJB (96.22 %). The fluxes of heavy metals into ZJB increased significantly after the typhoon (Cu: 127 %, Zn: 63 %, Pb: 136 %), it was possible to deteriorate the seawater quality.

Perhitungan Mutu Air Laut Di Perairan Sekitar Pembangkit Listrik Tenaga Uap

One of the causes of the decline in sea water quality is due to industrial activities near sea waters, one of which is Steam Power Plants where the cooling system activity process of the generating equipment becomes a problem because it is thrown into the sea at high temperatures. Based on this, it is necessary to calculate the status of sea water quality in order to find out whether sea water quality has decreased due to the PLTU's activities. The aim of this research is to determine the quality profile of sea water and determine the impact of activities in the surrounding waters at several monitoring points around the waters of the Steam Power Plant. The way to determine or status method for water quality is with a pollution index based on Decree of the Minister of Environment Number 115 of 2003. Water quality can be assessed based on the classification of pollutant indicators, the pollutant index value around the Steam Power Plant in 2020 Quarter II is 7.86 at the point 6. Meanwhile, in 2021 and 2022 there will be a decline in every quarter and at all points, for determining quality status refers to Minister of the Environment Regulation No. 2003 No. l115, in 2020 Quarter II, the quality status of sea water around the waters of the Steam Power Plant was included in the moderately polluted category and in both 2021 and 2022 the quality status of sea water around the waters of the Steam Power Plant was included in the lightly polluted category.

Geochemical partitioning of Cu and Zn in Pelabuhanratu Bay sediment

Activities such as fishing ports and power plants on the coast of Pelabuhanratu Bay have recently developed and hence, their input of metal-containing waste may influence the seawater quality of the bay as the fishing grounds. This study aimed to determine the potential sources (i.e., anthropogenic and natural) and pollution status in sediments. Sediment samples were collected once at 10 stations in the bay using a Van Veen grab. The geochemical partitioning of non-residual and residual phases of metals was used to assess the anthropogenic and natural sources, respectively. The status of metal contamination was evaluated by determining the geo-accumulation index (Igeo), contamination factor (CF), and pollution load index (PLI). Generally, Cu was dominant in residual fractions ranging 62.79-81.24%, while Zn ranged 39.56-66.02%. This suggests that Cu and Zn in Pelabuhanratu Bay are naturally sourced. Furthermore, the average geo-accumulation index of Cu was categorized as unpolluted (-0.86), and Zn was lightly polluted (0.87). The CF of Cu indicates the uncontaminated category (0.85), whereas Zn indicates a moderate contamination category (CF = 1.54). The pollution level (PLI) in Pelabuhanratu Bay is generally lightly polluted (PLI 1,135).

Effects Density and Salinity of Artificial Brackish Water on the Growth and Physiological Perfomance of Whiteleg Shrimp (Litopenaeus vannamei Boone, 1931)

The increase in shrimp culture causes problems with the quality of seawater which is a source of water for whiteleg shrimp culture it self. The use of artificial brackish water as a culture medium is an effort to increase the availability of water sources for whiteleg shrimp culture. This study aims to (1) determine the optimum stocking density of whiteleg shrimp culture using artificial brackish water salinity based on carrying capacity, (2) determine mineral content (Mg, Ca, Na and K) in artificial brackish water, (3) study the effect of salinity on the growth and blood glucose concentration of whiteleg shrimp cultivated in artificial brackish water, (4) examine the effect of salinity on hemolymph osmolarity of whiteleg shrimp cultivated in artificial brackish water. This study used an experimental method consisting of two stages. Each stage was arranged using a completely randomized design (CRD). Obtained stocking densities of SD-50% (20 shrimps/50L), SD (40 shrimps/50L) and SD+50% (60 shrimps/50L). The best growth and performance were obtained in the treatment of 20 individuals, namely survival (SR) 87%, specific growth rate (SGR) 3.26%/day and hemolymph glucose concentration of 30.73 mg/dl. In the next stage of the research, the salinity treatments tested were seawater, 10 ppt, 15 ppt, 20 ppt and 25 ppt. The best shrimp performance was obtained in treatment 20 shrimps/50 L, namely survival rate 70.00%, specific growth rate (SGR) 1.55%/day, feed conversion ratio (FCR) 1.72, glucose haemolymp 73.44 mg/dl. The optimal osmotic work level (OWL) value is obtained at a salinity of 15-20 ppt.

Analisis kondisi sanitasi pemukiman di daerah pesisir (studi kasus: Muaro Lasak, Kota Padang)

Requirements for good environmental health in a residential area are characterized by the availability of access to sanitation facilities. Muaro Lasak, Rimbo Kaluang Village, Padang City is a coastal area, as well as a tourist location in Padang City. The aim of the research was to determine the condition of sanitation facilities, healthy behavior, and the water quality in Muaro Lasak. Qualitative and quantitative data were collected to obtain complete data. The assessment indicators consist of waste disposal facilities, latrines and public facilities that support tourism, as well as water quality (pH, dissolved solids/TDS, and dissolved oxygen levels/DO) of the river that flows into Muaro Lasak.. The results of the research show that there are good latrines available in every resident's house and public latrines so that defecation is no longer in the sea. There are rubbish disposal facilities available but they are not functioning optimally. Regarding the quality of sea water, such as: the pH still meets the quality standard (6.38), the oxygen content (DO) is 3.35 ppm (moderately polluted), while the dissolved solids (TDS) still meets the quality standard at 892.75 ppm.

The Impact of Anthropogenic Pollution on Tidal Water Quality in Mangrove Wetlands

Mangrove wetlands are vulnerable coastal ecosystems that provide critical habitats for aquatic life. Tai O is a popular tourist village on Lantau Island, Hong Kong, which is surrounded by mangrove wetlands with rich biodiversity; and this village is also famous for its traditional stilt houses. However, the untreated municipal sewage from some stilt houses is directly discharged into nearby tidal channels, potentially threatening health of the adjacent mangrove wetlands. In order to evaluate the anthropogenic impact on these wetlands and identify the potential sources of their pollution, this study aimed to evaluate spatial (at the sampling points) and temporal (during weekdays and weekends) differences in the quality of their tidal water, and examine relationships between the water quality and the density of the stilt houses. The results indicated that the water quality was worse during weekends. The ammonia concentrations in most samples exceeded the limits of the Hong Kong Water Quality Objectives, China’s Sea Water Quality Standards, and even the U.S. EPA criterion for fish reproduction. This high ammonia input could potentially adversely affect the mangrove ecosystem, underscoring the need for further comprehensive studies. Moreover, some of the weekend water samples had lower dissolved oxygen levels and were polluted by phosphate. Our Principal Component Analysis revealed that water quality was correlated with stilt house density, suggesting that anthropogenic inputs of untreated sewage was the major source of pollution. These findings highlight that nutrients released from human activities, particularly ammonia and phosphate, must be controlled for a better protection of mangrove wetland ecosystems.

IDENTIFIKASI MAKROZOOBENTOS SEBAGAI BIOINDIKATOR KUALITAS PERAIRAN DI PANTAI TELUK BENOA, BADUNG

Utilization of coastal waters for aquaculture activities or for other activities provides positive value for human welfare but can also provide the potential for reducing water quality. The decline in environmental quality can be seen from changes in components such as biology, chemistry, and beach physics. Changes in chemical and physical components cause sediment to decrease, which will affect the life of marine biotas, such as the community structure, especially the slow-moving and relatively settled biota on the bottom of the waters (macrozoobenthos). Macrozoobenthos are very appropriate to be used as an indicator of changes in water quality due to their benthic nature which is relatively silent or has low mobility so it is strongly influenced by the environment. The purpose of the study was to determine the structure of the macrozoobenthos community and the condition of seawater quality. There were 25 species of gastropods and 3 other classes. The macrozoobenthos species diversity index on the Benoa Bay Coast showed a moderate level of diversity with the highest value of 2.4576. The uniformity index at each station ranges from 0.0894 – 0.5337. The value of the dominance index ranges between 0.000004-0.7656. Based on the relative abundance, the macrobenthos community is dominated by the Gastropod class. The temperature values ??at each station were relatively the same, ranging from 29.3°C– 30.8°C, and the pH was in accordance with quality standards for macrozoobenthos growth. Some indicators of water quality are still below the quality standard threshold, but the concentration of phosphate (PO4) at all locations is already above the predetermined quality standard of 0.015 mg/L?.
 Keyword: Macrozoobenthos; Bioindicator; Benoa Bay; Bali

Law Enforcement On Deforestation Forests Conservation In Indonesia

This research aims to analyze the application of multi-layered crimes in cases of environmental damage as in the case in the Malang District Court decision Number: 76/Pid.B/LH/2022/PN Mlg. with the occurrence of two criminal acts, namely not having a mining permit in a forest area and an act that intentionally caused forest damage. The formulation of the problem in this research is the qualifications of criminal acts of environmental damage and what the judge considers in imposing multiple criminal sanctions in case number: 76/Pid.B/LH/2022/PN Mlg. This research uses normative juridical research methods, as well as using a statutory approach and a case approach.Based on the results of the research and discussion, to determine whether damage to protected forests has occurred is to qualify the criminal act of environmental damage that has been carried out, that the elements of the criminal act related to the subject are defined as the party responsible, there is an element of error by knowing that the criminal act has been committed, the act that is unlawful, namely as violating the provisions in Article 89 paragraph (1) letter a jo. Article 17 paragraph (1) letter b of Law of the Republic of Indonesia Number 18 of 2013 concerning Prevention and Eradication of Forest Destruction related to carrying out mining in forest areas without the Minister's permission and Article 98 paragraph (1) of Law of the Republic of Indonesia Number 32 of 2009 concerning Environmental Protection and Management by exceeding ambient air quality standards, water quality standards, sea water quality standards, or standard criteria for environmental damage and the implementation of concurrent actions (a real collision) is closely related to this research.

Comparative Chemical Profiling and Antimicrobial/Anticancer Evaluation of Extracts from Farmed versus Wild Agelas oroides and Sarcotragus foetidus Sponges.

Marine sponges are highly efficient in removing organic pollutants and their cultivation, adjacent to fish farms, is increasingly considered as a strategy for improving seawater quality. Moreover, these invertebrates produce a plethora of bioactive metabolites, which could translate into an extra profit for the aquaculture sector. Here, we investigated the chemical profile and bioactivity of two Mediterranean species (i.e., Agelas oroides and Sarcotragus foetidus) and we assessed whether cultivated sponges differed substantially from their wild counterparts. Metabolomic analysis of crude sponge extracts revealed species-specific chemical patterns, with A. oroides and S. foetidus dominated by alkaloids and lipids, respectively. More importantly, farmed and wild explants of each species demonstrated similar chemical fingerprints, with the majority of the metabolites showing modest differences on a sponge mass-normalized basis. Furthermore, farmed sponge extracts presented similar or slightly lower antibacterial activity against methicillin-resistant Staphylococcus aureus, compared to the extracts resulting from wild sponges. Anticancer assays against human colorectal carcinoma cells (HCT-116) revealed marginally active extracts from both wild and farmed S. foetidus populations. Our study highlights that, besides mitigating organic pollution in fish aquaculture, sponge farming can serve as a valuable resource of biomolecules, with promising potential in pharmaceutical and biomedical applications.

Improving green sea urchin (Strongylocentrotus droebachiensis) hatchery production by determining effective settlement cues and post-settlement conditions

Hatchery production methodologies of Northeastern U.S. green sea urchins (Strongylocentrotus droebachiensis) have yielded low settlement success and post-settlement survival (approximately 1–5%) contributing towards high costs for producing juveniles for this emerging aquaculture species. These are likely attributed to hatchery operations needing to optimize settlement cues and post-settlement food supplies. This study examined a range of potential settlement cues using adult conspecifics or a benthic diatom biofilm (Cylindrotheca closterium or Nitzschia sp.) alone, or in combination with seawater conditioned with conspecifics or macroalga (Saccharina latissima or Ulva lactuca). This study also examined whether sea urchin post-settlement survival and growth would improve using a benthic diatom food source (C. closterium or Nitzschia sp.) alone or in combination with an additional macroalga food source (S. latissima or U. lactuca). Both trials were conducted under hatchery ambient (control 12 °C) or elevated (14 °C) temperatures to determine whether temperature elevation could enhance S. droebachiensis settlement success and post-settlement growth. This study also examined what influence biofilm age (1, 4 and 8 weeks) and seawater salinity (26, 30, 33 and 36) had on settlement success to help towards optimizing hatchery methods. This study did not improve post-settlement survival causing it to remain a significant barrier in mass producing juveniles, but it did increase juvenile growth by 30–40% and reduce growth variability when fed the benthic diatom C. closterium in combination with U. lactuca. This combination also served as an adequate settlement cue for this species. The use of a conspecific influenced biofilm substantially improved settlement success from 1 to 5% to 50–80%. Seasonal timing and age (4 weeks) of this biofilm indicated importance in yielding this success which will be location specific. The use of conspecific biofilms for improving post-settlement survival requires further investigation and is worth examining in combination with C. closterium and U. lactuca towards enhancing S. droebachiensis production in the Northeastern U.S. Elevating seawater temperature by 2 °C had no significant effect on settlement, growth, or survival in this study. Salinities of 30–33 were optimal yielding 3–7 times more settlement compared to salinities 27 and 36. This study highlights that settlement trials need to incorporate post-settlement survival measurements for at least 1–2 months to truly reflect the effectiveness of method interventions and consider extending the time before turning seawater flow back on into settlement tanks from 24 to 48 h by up to 72–96 h to facilitate greater settlement success if seawater quality parameters permit it.

Changes in mariculture and offshore seawater quality in China during the past 20 years

Mariculture can provide a large amount of food without occupying land resources, which provides important assistance for humans to achieve sustainable development. In this paper, China, where the output of mariculture exceeds half of the global output, is taken as the research area. Based on the spatial distribution data of three periods of mariculture along the coast of the Chinese Mainland in 2000, 2010, and 2020 obtained from remote sensing images and from the perspective of the mariculture center, the spatial development of mariculture in three periods in China is explored. Furthermore, by spatially overlaying mariculture data with concurrent water quality data, the relationship between the development and changes in the mariculture center and the seawater quality in different geographical environments was analyzed at the national scale.. We found that (1) Mariculture in China exhibits a noticeable geographical differentiation, with the scale and development speed of mariculture in northern regions surpassing that of the southern regions. (2) Good seawater quality is the prerequisite for the formation of mariculture centers, while water quality deterioration is detrimental to the development of mariculture. (3) The formation of large-scale high-density mariculture centers does not necessarily lead to deterioration of the seawater quality. Furthermore, we found that the water depth is an important factor leading to the spatial distribution pattern of mariculture in China, i.e., dense in the north and sparse in the south. The flow velocity is an important factor determining the water quality changes in mariculture centers.

Deriving seawater quality criteria of tris(2-chloroethyl) phosphate for ecological risk assessment in China seas through species sensitivity distributions

Tris(2-chloroethyl) phosphate (TCEP), one of the widely used organophosphorus flame retardants (OPFRs), has been frequently detected in the marine environment in the seas off China. The existing freshwater biotoxicity data are not suited to derivation of the seawater quality criteria of TCEP and evaluating the associated ecological risks. This study aimed at deriving water quality criteria (WQC) of TCEP for marine organisms based on species sensitivity distribution (SSD) approach using the acute toxicity data generated from multispecies bioassays and chronic toxicity data by converting acute data with the acute-to-chronic ratios (ACRs); the derived WQC were then used to evaluate the ecological risk for TCEP in China Seas. According to median effective concentration (EC50) and median lethal concentration (LC50), TCEP had a moderate or low toxicity to eight marine species selected, among which mysid Neomysis awatschensis (96h-LC50 of 39.65 mg/L) and green alga Platymonas subcordiformis (96-h EC50 of 395.42 mg/L) were the most sensitive and the most tolerant, respectively. The acute and chronic hazardous concentrations of TCEP for 5% of marine species (HC5) were estimated to be 29.55 and 2.68 mg/L, respectively. The short-term and long-term WQC were derived to be 9.85 and 0.89 mg/L, respectively. The risk quotient (RQ) values indicated that TECP at current levels poses a negligible risk to marine ecosystems in China. These results will provide valuable reference for the government to establish a seawater quality standard for TCEP.

Spatial distribution and pollution assessment of heavy metals in surface and bottom water along the eastern part of the Egyptian Mediterranean coast

Seawater contamination with heavy metals (HMs) as a result of anthropogenic activities is a global challenge due to its negative impacts on marine environments and coastal communities. This study investigates the distribution of HMs (Fe, Zn, Cu, Mn, Cd, Ni and Co) and assesses the quality of surface and bottom seawater. Samples were collected in winter 2020 and summer 2021 from eleven sectors along the eastern Egyptian Mediterranean Sea coast. The water quality was evaluated using Water Quality Index (WQI), Metal Index (MI), heavy metal pollution index (HMI) and Metal Pollution index (MPI). The results indicated that, Eastern Harbour, Abu-Qir and Port Said sectors were polluted with HMs. Based on Two-Way ANOVA test there was seasonal variation for dissolved HMs (Zn, Ni, Cd and Mn in bottom layer and Cu in surface layer), while, (Cd, Co, Cu, Zn and Mn (in bottom layer)) revealed spatial differences among sectors.

Underwater quantum key distribution with continuous-variable via photon additions

Quantum key distribution with continuous-variable (CVQKD) provides an alternative way for the security improvement of underwater optical communication, but facing into the awkward situation of short distance. For this reason, here we exploit photon addition operation at the emitter into enhancing the performance of underwater CVQKD. Based on numerical simulation, it is shown that applying photon-addition non-Gaussian operation between entangled resource and the sender can further enhance both the secure key rate and the transmission distance, compared to apply photon subtraction operation between entangled resource and the receiver. In addition, the influence of seawater quality factors in underwater CVQKD system is also considered, so as to provide technical support for underwater safety communication.