Impacts of salinity stress induced by ballast water discharge on the ecosystem of shanghai port, China.

Large quantities of marine ballast water discharged by ocean-going vessels can cause salinity increases in freshwater ports, which in turn negatively affects indigenous plankton in the ports. In this study, we investigated the impacts of marine ballast water discharge on the plankton community in a freshwater wharf through field surveys. It was found that salinity stress caused reductions in community indicators such as plankton community composition, abundance and diversity, thus threatening the structure and function of the plankton community in the wharf. In terms of the impact range, the salinity stress had a significant effect on all plankton in the waters near the discharge point and the phytoplankton in the waters 50 m from the discharge point, but had no significant effect on the plankton in the waters further away. Ballast water discharge also caused a significant decrease in the alpha diversity and richness of the plankton community but had no significant effect on the evenness of the plankton community. Moreover, phytoplankton were more tolerant of salinity changes than zooplankton in our study. This study provides an ecological reference for the scientific management of marine ballast water discharge and the risk of exogenous nutrient inputs to freshwater ecosystems.

Design and validation of a sampling skid device for collecting aquatic organisms.

As international regulations on aquatic organism discharge in ships' ballast water take effect, port state authorities will need a sampling device for compliance inspectors to potentially use for sample collection. Importantly, the device must be easily operable, quickly connectable to the main ballast water pipe, and reliable in collecting a representative sample of the ballast water flowing through the pipe. Existing sampling devices currently fall short in these aspects. Therefore, we've developed, manufactured, and validated a new sampling skid. This design enables the regulation of flow velocity and flow rate, facilitating the simultaneous, convenient collection of organisms ≥50 µm and other biological samples. In this study, we conducted a comparative analysis of sampling outcomes between traditional net sampling devices, using land-based experiments to assess the accuracy and precision of the innovative sampling skid. The findings show that, despite significant differences in <10 µm organism concentrations, the sampling skid, as an alternative to traditional net and other skid devices, has demonstrated substantial potential and feasibility.

Recommendations for representative sampling methodologies in ballast water: A case study from the land-based test.

Accurate assessment of ballast water's community composition and organism concentrations is crucial for effective management. Yet, the lack of standardized global sampling methods presents challenges to achieving this objective. Inconsistencies hinder data comparison across regions and vessels, impeding efficient ballast water treatment and discharge regulation. This study conducted land-based tests to establish suitable methodologies. For organisms ≥50 µm and ≥10 µm to <50 µm, the recommended max flow rate is 50 L/min; for <10 µm organisms, 25 L/min is advised to prevent cell damage. Sampling should cover substantial discharge durations. To ensure representation, ≥50 µm organisms require ≥1m3, while ≥10 µm to <50 µm and <10 µm organisms need 20 L. The ultimate aim is standardized methods for assessing ballast water across regions and vessel types, facilitating effective management to curb invasive species and protect aquatic ecosystems.

Comparison of heavy metal pollution and ecological risk assessment in ballast tank sediments based on two applicable reference standards.

The potential risks of ballast tank sediments have garnered global attention. This study collected sediment samples from ballast tanks of four transoceanic ships and determined 27 metal(loid) s by GB 5085.6-2007 and 9 metal(loid)s by GB 18668-2002. The pollution characteristics and ecological risk assessment of 8 typical heavy metals measured by both standards were analyzed and compared. Concentrations of Cd, Zn, and As were found to be high in the ballast tank sediments, and attention should also be directed toward Sn and Mn, which were rarely studied in ballast tank sediments. The concentration of Ni had significant differences between the two standards (P < 0.05). The results of ecological risk methods indicate that Cd, Zn, and As pose significant ecological risks. GB 5085.6-2007 demonstrated sensitivity in reflecting the ecological risks of heavy metals. Overall, this study provides valuable insights into establishing a unified standard for heavy metals for future ballast tank sediment management.

Evaluate the compliance of ballast water management system on various types of operational vessels based on the D-2 standard.

The transfer of ship ballast water poses significant risks to the aquatic ecosystem and human health. To mitigate the influences of non-native species, ballast water management systems (BWMS) have been installed on international ships to ensure proper treatment of ballast water before discharge. This study investigates whether ballast water discharges managed by BWMS meet the requirements of the D-2 standard for organisms in different size classes. Representative ballast water samples were collected from 28 ships (a total of 20 different BWMS) arriving in Shanghai during the period 2020-2022. Results have shown that two samples (7.1 %) exceeded the D-2 Standard. The compliance rates varied among different vessel types, with cargo vessels achieving a compliance rate of 81.8 %, while LNG vessels and container vessels achieved 100 % compliance. The potential to achieve higher levels of ballast water management will increase as crews improve their skills in operating BWMS and BWMS is further developed.

Bloom forming species transported by ballast water under the management of D-1 and D-2 standards-Implications for current ballast water regulations.

Ballast water (BW) is a well-known transporter for introducing non-indigenous aquatic organisms. To reduce such risks associated with BW discharge, the International Maritime Organization (IMO) adopted the International Convention for the Control and Management of Ships' Ballast Water and Sediments (BWM Convention). We examined the abundance and diversity of bloom forming species in BW under the management of Regulation D-1 Ballast Water Exchange Standard and D-2 Ballast Water Performance Standard. The abundance and richness of bloom forming species were also examined in relation to ballast water age. Our findings indicate the abundance and diversity of bloom forming species were significantly lower in BW under the management of D-2 standard than that under D-1 standard. The abundance and richness represent no statistically significant correlation with BW age (p = 0.76 and p = 0.43, respectively). Some resistant species persist in ballast water. Thereby, we further provide some advice to overcome the existing challenges for the implementation of the Regulation D-2.

Toxic effects of disinfection by-products on Pseudokirchneriella subcapitata and co-cultured algae community.

The widespread use of disinfectants in response to the COVID-19 pandemic may increase the concentration of disinfection by-products (DBPs) in surface water, posing ecological risks. This study assessed the acute toxicity of haloacetic acids and halophenols DBPs to Pseudokirchneriella subcapitata, and evaluated the impact of environmental concentrations of DBPs on co-cultured algae communities. The results showed that after exposure to disinfection by-products, the photosynthetic pigments of Pseudokirchneriella subcapitata were significantly reduced, and the MDA content and antioxidant enzyme activity were increased. The results of the ecological risk assessment showed that the RQ values of TBAA, 2,4-DBP, and 2,6-DBP were >0.1, with medium and high ecological risks. Despite this, the three DBPs with the highest risk values had little effect on the community structure of co-cultured algae. In contrast, the disinfection by-products with low ecological risk had a greater impact on the community structure and greatly promote the growth of cyanobacteria, which may cause new ecological risks. Therefore, not only high-risk disinfection by-products need to be paid attention to, but the impact of low-risk disinfection by-products cannot be ignored.

Study on the effectiveness of membrane separation + N2 deoxidation process for the treatment of bacteria in ballast water.

Effects of the membrane separation + N2 deoxidation process on the abundance and activity of bacteria were examined under two salinity conditions at Yangshan Port, Shanghai, China. Sequencing of 16S rRNA gene amplicons demonstrated a decrease in the diversity and activity of bacteria in fresh water and marine water, with a total removal rate of approximately 63 % and 69 %, respectively. Indicator bacteria decreased to 10 CFU·100 mL-1, which met the IMO D-2 standard. A total of 13 potential pathogens were detected after treatment, indicating that there is still a risk of pathogenic bacteria invasion in the discharge water, particularly marine bacteria, and that the D-2 standard may be insufficient as a preventive measure against pathogenic bacteria transfer. The results will provide reference for government supervision, and will also be important for monitoring foreign bacteria and technology development.

Polycyclic aromatic hydrocarbons in surface water and sediment from Shanghai port, China: spatial distribution, source apportionment, and potential risk assessment.

The spatial distribution, sources, and potential risk of polycyclic aromatic hydrocarbons (PAHs) were systematically investigated in Shanghai port, one of the most important hubs in international trade. The 16 priority PAHs in surface water and sediment were determined. Total concentrations of 16 PAHs (Σ16PAHs) ranged from 140.6 to 647.4 ng/L in surface water and from 12.7 to 573.2 ng/g (dry weight, dw) in sediment, respectively. The 2-ring and 3-ring PAHs with low molecular weight were main components in water, while the 3-ring and 4-ring PAHs were abundant in sediment. Flu was the main component of the Σ16PAHs in water and sediment. According to the source apportionment, the PAHs in water mostly originated from combustion of fossil fuels and petroleum and petroleum combustion were the main contributors to the PAHs in sediment. The results obtained from potential risk assessment indicate that the PAHs in surface water present a moderate ecological risk, whereas the PAHs in sediment show low ecological risk indicating a less possibility of toxic pollution.

Study on spatial distribution, potential sources and ecological risk of heavy metals in the surface water and sediments at Shanghai Port, China.

Heavy metal concentrations in surface waters and sediments of Shanghai port were measured to analyze the spatial distribution characteristics, sources and pollution degrees. The southern Shanghai port was heavily polluted by Cd, Pb, Cr and Cu in water, and the concentrations of Pb, Hg and Zn in sediments exceeded Effects Range Low. Cu, Pb, Cd and Cr in water were positively correlated in group, and they probably derived from industrial and domestic sewage, fossil fuel burning and vehicular pollution and represented 82.47 % of the contribution. Zn, Hg and As contaminations represented industrial and agricultural effluent sources and accounted for the remaining 17.53 %. Heavy metal pollution of Yangshan Port water was at high pollution, and the remaining sites were at low pollution. Most of the sampling sites were at moderate ecological risk in sediments, and the pollution of Cd, Hg and Zn were serious.

Bacterial community composition and diversity in the ballast water of container ships arriving at Yangshan Port, Shanghai, China.

Ballast water is a major vector of invasion by protozoans and metazoans. Bacterial invasion is less-well understood. We surveyed the bacterial diversity of ballast water from 26 container ships arriving at the Yangshan Deepwater Port, Shanghai, China during 2015-2016. We characterized the ballast microbiome using high-throughput sequencing (HTS) based on V4-V5 region of 16S rRNA genes. We simultaneously monitored physicochemical parameters of the ballast water, including temperature, pH, dissolved oxygen (DO), salinity, turbidity, total suspended solid (TSS), particulate organic carbon (POC), NO2, NH4, PO4. Proteobacteria was the dominant phylum, comprising more than 50% of the OTUs of almost all vessels, followed by Bacteroidetes (12.08%), Actinobacteria (4.86%) Planctomycetes (3.24%) and Cyanobacteria (1.95%). The relative abundance of Cyanobacteria differed among vessels. It was negatively correlated with temperature, NO3, pH, TSS, PO4, and turbidity and positively correlated with NH4, POC. The genus Synechococcus was the most common Cyanobacteria in our results. Escherichia coli were relatively rare; they are indicator-species of D-2 standards published by the IMO. The relative abundance of the genus Vibrio ranged from 0.003% to 24.88% among different vessels. Our results showed that HTS was able to profile the bacterial communities in ballast-waters, even when the approach was restricted by technical and other obstacles.

Effects of holding time on the diversity and composition of potential pathogenic bacteria in ship ballast water.

Ballast water is a common vector for the transport of invasive species to new marine and aquatic environments. We used a metagenomics approach to examine the diversity and composition of potential pathogens communities in ballast water from ships in the route of China- Southeast Asia (CSEA). 16 kinds of potential pathogenic genus were detected in the ballast water. Interestingly, the ballast holding time had an important effect on the distribution of potential pathogens in ballast water. The abundance of Pseudoalteromonas in the longer ballast water holding time was less than the shorter ballast water holding time. Bacteroides had completely disappeared in the long ballast holding time samples. Moreover, The Shannon index of samples with longer ballast water holding time (1.80 ± 0.07) was higher than those with shorter ballast water holding time (0.83 ± 0.13). The potential pathogenic genus (Arcobacter, Aeromonas, Enterobacter and so on) lived in the long ballast holding time vessels had more diversity. Besides, the total suspended solids (TSS), total organic carbon (TOC) and particulate organic carbon (POC) had a strong positive correlation with most potential pathogens in the ballast water, while the dissolved oxygen (DO) had a clear negative correlation with the potential pathogens in the longer ballast holding time samples. In conclusion, these results provide detailed descriptions of the characteristics of the potential pathogens present in ballast water, document significant potential pathogens diversity, and indicate the importance of ballast holding time for potential pathogens lived in ballast water.

Risk assessment of human health from exposure to the discharged ballast water after full-scale electrolysis treatment.

The presence of disinfection by-products (DBPs) releasing from ballast water management systems (BWMS) can cause a possible adverse effects on humans. The objectives of this study were to compute the Derived No Effect Levels (DNELs) for different exposure scenarios and to compare these levels with the exposure levels from the measured DBPs in treated ballast water. The risk assessment showed that when using animal toxicity data, all the DNELs values were approximately 10(3)-10(12) times higher than the exposure levels of occupational and general public exposure scenarios, indicating the level of risk was low (risk characterization ratios (RCRs) < 1). However, when using human data, the RCRs were higher than 1 for dichlorobromomethane and trichloromethane, indicating that the risk of adverse effects on human were significant. This implies that there are apparent discrepancies between risk characterization from animal and human data, which may affect the overall results. We therefore recommend that when appropriate, human data should be used in risk assessment as much as possible, although human data are very limited. Moreover, more appropriate assessment factors can be considered to be employed in estimating the DNELs for human when the animal data is selected as the dose descriptors.

[On the chitin digestive bacteria from larval gut of Eriocheir sinensis].

The foregut, mid-gut and hind gut of Eriocheir sinensis from the first Zoea to Megalopa were dissected under asepsis condition. Bacteria were separated by plate culture after liquid medium culture. A chitin digestive bacterium was separated from the first Zoea foregut. The chitin digestive bacteria weren't founded in the same experiment from the second Zoea to Megalopa. The chitin digestive bacteria showed roundness, protuberance, glassy humid, margin regular, milk-yellow, aerotolerant anaerobe, and growing intently surrounding the chitin on the plate culture medium. The chitin could promote the growth rate of some digestive bacteria in larval gut of the crab.