In this study we report the concentration levels of heavy metals (including Pb, Cd, Hg, Cr, Ni, Fe, Mn, Cu) in ballast water of commercial ships, entering Bushehr port for the first time in the region of the Persian Gulf. The concentration levels of Cu and Fe in all samples of the ballast water were higher compared with the coastal waters of Bushehr port. In the case of Cd, 76.47% of samples had higher concentration level compared with the coastal waters of Bushehr port. Results showed that in a long term the ballast water has the potential to change the chemical quality in marine environments and also may affect the human health and marine ecosystem where ships discharge their ballast water. Therefore, permanent monitoring as well as treatment of ballast water before discharging is crucial to keep the marine environment health.

Ballast water is used to safely stabilize and operate shipping vessels worldwide, in a multitude of aquatic settings, including inland, coastal and open oceans. However, ballast water may pose ecological, public health, and/or economic problems as it may serve as vehicles of transmission of microorganisms. Current ballast water regulations include limits of Escherichia coli, Enterococcus spp. and toxigenic Vibrio cholerae. Several United States Environmental Protection Agency approved standard operating protocols (SOPs) exist for detection of E. coli and Enterococci, yet none exists for V. cholerae. Current V. cholerae detection methods include colony blot hybridization, direct fluorescent antibody test (DFA), and/or polymerase chain reaction (PCR), which can be time consuming and difficult to perform. This study utilizes Cholera SMART II to determine its potential use in detection of V. cholerae. Validation of this method would help provide quick and accurate analysis for V. cholerae in ballast discharge waters in the field.

Effects of heating, ultraviolet (UV), ultrasound (US), hydrogen peroxide (H2O2) and freshwater, and the combined treatments on inactivation of cysts of Scrippsiella trochoidea and cysts in sediment suspension were studied. Heating was the most efficient way to inactivate cyst germination, and cysts were completely inactivated at 38°C for 5h. UV, US, and freshwater efficiently inhibited but could not completely inactivate cyst germination. Effects of heating, UV, and US on cyst germination decreased for cysts in sediment, and germination rates increased by 6.7–48% compared to the same treatment for cysts without sediment. H2O2 significantly inhibited cyst germination, but complete inactivation occurred at high concentration for long duration (100mg/L, 6d). The combined treatments were more effective, especially the combinations of heating and UV. The results suggested that heating might be a feasible way for ballast water treatment especially after combined with filtration and UV.

Maritime shipping transports over 90% of global goods. Ballast water, used to provide vessel stability, has been associated with the introduction of marine invasive species. Thus, understanding ballasting trends is imperative to protecting human and environmental health. This paper examines data from the National Ballast Information Clearinghouse to assess ballasting behavior and shipping trends in the United States. From 2005 to 2017, vessel arrivals have remained relatively constant (annual growth rate of 1.2% per year) while total ballast discharge per vessel has grown at an annual rate of 7.6%. Furthermore, from 2014 to 2016, alternative ballast water management methods have been on the rise, and these treatment options are likely to continue increasing in response to the International Maritime Organization Ballast Water Management Convention that entered into force in September 2017. It is critical that the shipping industry monitors potential cascading impacts on other ballasting behaviors stemming from this shift.

The objective of this study is to propose the use of specific synthetic lipid as an active substance (biocide) in the control of harmful aquatic microorganisms, such as pathogens and non-indigenous species, transported in ships' ballast water. The biocide candidate, without metal or halogen components, was produced from a sub-product of the edible oil industry, the lecithin. Laboratory assays were conducted with phytoplankton, zooplankton, and marine bacteria to evaluate the efficiency of the biocide. The study also considers specific biocide's characteristics related to environmental risks, such as chemical composition, persistence, bioaccumulation, and toxicity. Results showed that, in the first 24 h of treatment, the biocide effectively reduced the concentration of the planktonic micro-organisms to very low levels. Additionally, a preliminary risk evaluation pointed that biocide candidate has a low residual toxicity, also a low potential for persistence and bioaccumulation in the environment.

This study investigates the extra UV fluence needed to meet the International Maritime Organisation's ballast water discharge standards for the 10–50 μm size-class using the approved vital stain (VS) method compared to the Most Probable Number (MPN) method for organism viability assessment. Low- and medium pressure UV collimated beam treatments were applied to natural algae collected in temperate and tropical water environments and analysed using both methods. About 10 times higher UV fluence was required to meet discharge standards when using VS compared to MPN. Implementing a dark-hold period after UV treatments decreased algal viability. Length of dark-hold period to meet discharge standards decreased with increasing UV fluence. No significant differences between temperate and tropical samples were observed. The results showed that UV treated algae assessed using the VS method could meet discharge standards by increasing fluence and/or introducing a dark-hold period.

Ballast water is essential for maintaining the balance and integrity of a ship. However, exchanging ballast water resulted in discharging water of different origins in vessel recipient ports, and this may have caused ecosystem disturbance or aquatic pollution. The ballast water management (BWM) system is essential for the purification and disinfection of the ballast water that is taken up. Because current BWM systems widely use biocides for the treatment of aquatic organisms, the biocides may result in unintended toxicity of the discharged ballast water. In this study, we suggested thymol and carvacrol as chemical biocides for BWM systems and investigated their effectiveness using Artemia salina and Escherichia coli. Thymol and carvacrol showed biocidal effects in our study. A combination of these substances showed a synergistic increase in the biocidal effects. Moreover, carvacrol naturally degrades after disinfection, which indicates that natural substances may be promising candidates to increase the efficacy and reduce unwanted side effects of the BWM system.

Shipping is recognised as an unintentional efficient pathway for spreading non-native species, harmful organisms and pathogens. In 2004, a unique IMO Convention was adopted to control and minimize this transfer in ship's ballast water. This Convention entered into force on 8th September 2017. However, unlikely the majority of IMO Conventions, the Ballast Water Management Convention requires ships to comply with biological standards (e.g. concentration of organisms per unit of volume in ballast water discharges). This study aimed to apply different techniques developed to measure concentrations of viable phytoplankton in natural and treated ballast water samples and compare them with the established flow cytometry method and vital staining microscopy. Samples were collected in the English Channel over one year and on-board during ballast water shipboard efficacy tests. Natural abundance of live phytoplankton varied from 23% to 89% of the total, while for cells larger than 10 μm (a size defined by the BWM Convention) the percentage varied from 3% to 60%. An overall good correlation was seen between the measurements taken with the two fluorometers and in comparison with the flow cytometry analysis, as found in previous studies. Analysis of treated ballast water samples showed a large variation in the number of viable cells, however indicating a low level of risk on all occasions for regulatory purposes. One of the key aspects to bear in mind when sampling and analysing for compliance is to be aware of the limitations of each technique.

While introduced marine species have been arriving in Australia for centuries, it was the advent of container shipping and the discharge of ballast water into Australian ports that highlighted the problem. A summary is provided of how Australia responded to this challenge and continues to. More recently there has been an acceptance that hull fouling is also an important vector of introductions. A major problem in Australia is distinguishing introduced species from as yet undescribed native species. This is a particular problem in northern Australia where the native fauna is poorly documented. Despite the economic and environmental threats posed by introduced species, the impetus to undertake expensive comprehensive surveys has declined and attention is now focusing on targeted surveys especially of known marine pest species and molecular data to identify introductions. Ongoing research is still needed to monitor other species identified as being introduced and their potential to become pests.

National and international regulations require that ships' ballast water is treated to minimize the risk of introducing potentially invasive species. A common approach employed by commercial ballast water management systems is chlorination. This study presents the algal toxicity findings for three chlorination-based BWMS and their implications to environmental safety of port waters receiving treated ballast water from ships. Discharged treated ballast water from all three BWMS was toxic to algae with IC25s (25% growth inhibition) ranging from 9.9% to 17.9%, despite having total residual oxidant concentrations below 0.02 mg/l, based on Whole Effluent Toxicity assays. When held at 4 °C, some of the ballast water samples continued to exhibit toxic effects with no observed effect concentrations as low as 18% after a 134 day holding time. Thirteen individual disinfection by-products were measured above the detected limit at the time of discharge. No correlation between DBPs and algal toxicity was observed.