Paints For Ships Research Articles

Research on path generation and stability control method for UAV‐based intelligent spray painting of ships

AbstractThis paper presents an intelligent path planning method with multiple constraints to solve the problem of instability of unmanned aerial vehicle (UAV) intelligent spray painting (UAV‐ISP) systems for spray painting the outer panels of ships. Spray‐painting path planning is realized using the multiobjective particle swarm algorithm and ant colony algorithm. In addition, a stability control method for the UAV based on the linear active disturbance rejection control (LADRC) algorithm is proposed and controlled by Mission Planner ground station software to solve the stability control problem of UAVs during spray painting. Through the above two key technologies, the painting quality of the UAV‐ISP system is guaranteed. First, a three‐dimensional (3D) model of the ship was obtained in a 3D modeling environment. Then the paint paths were optimized using the multiobjective particle swarm algorithm. The optimized path planning results were then combined using the ant colony algorithm to obtain the final spray painting path. Force analysis of the UAV during spray painting was carried out using the Newton–Euler equation and catenary theory, and a mathematical model of the UAV spray‐painting system with multiload coupling was established. Finally, a stability control system for the spray‐painting UAV based on LADRC was designed. The experimental and simulation results show that the proposed painting path is accurate, the spray‐painting UAV has good stability, and the spray‐painting quality of the UAV‐ISP system meets the standards for the outer panels of ships.

Coating matching recommendation based on improved fuzzy comprehensive evaluation and collaborative filtering algorithm

Coating matching design is one of the important parts of ship coating process design. The selection of coating matching is influenced by various factors such as marine corrosive environment, anti-corrosion period and working conditions. There are also differences in the coating performance requirements for different ship types and different coating parts. At present, the design of coating matching in shipyards depends on the experience of technologist, which is not conducive to the scientific management of ship painting process and the macro control of ship construction cost. Therefore, this paper proposes a hybrid algorithm of fuzzy comprehensive evaluation and collaborative filtering based on user label improvement (IFCE-CF). Based on the analytic hierarchy process (AHP), the evaluation index system of coating matching is constructed, and the weight calculation process of fuzzy comprehensive evaluation is optimized by introducing the user label weight. The collaborative filtering algorithm based on matrix decomposition is used to realize the accurate recommendation of coating matching. Historical coating process data of a shipyard between 2010 and 2020 are selected to verify the recommendation ability of the method in the paper. The results show that using the coating matching intelligent recommendation algorithm proposed in this paper, the root mean square error is < 1.02 and the mean absolute error is < 0.75, the prediction accuracy is significantly better than other research methods, which proves the effectiveness of the method.

ADHESIVE COATING VALUE BASED ON THE MAIN INGREDIENT OF SHIP PAINT

Coatings are important instruments in inhibiting the corrosion rate. Field facts in various Indonesian shipping industries show that the choice of organic materials as coating for ship paint uses epoxy, vinyl and polyurethane. Therefore an experimental study is needed on the adhesion ability of paint as a coating for ship armor with these three types of organic materials. The preparation of steel specimens with type ASTM A36 is carried out by blasting, visual inspection standard ISO 8501-1, and roughness test standard ISO 8503-4. Painting of specimens by measuring the thickness of the paint in the wet conditions ASTM D4414 standard and ASTM D4138 standard dry conditions. Treatment of specimens in two conditions, are: tropichal weather condition and salt spray conditon. Observation of specimens by scanning electron microscope and adhesion test standard ASTM D4541-02. The final result shows that the best adhesion ability of the main paint coating in tropical weather conditions was a polyurethane coating with no blister characteristics, but there are fractures on the surface of the material. While the main material for the best coating in salt spray conditions was epoxy coating with characteristics that are resistant to blisters and blends with the surface of the material.

Speciation and quantification of organotin compounds in Lagos harbour, Nigeria

ABSTRACT The application of organotin-based antifouling compounds in the harbour during repairing and painting of ships in Nigeria harbour is a common practice in the maintenance wing of the dockyard. These antifouling chemicals are extremely toxic to aquatic life. As a result of dearth of data on the levels of organotin compounds in the West African coast including Lagos harbour, a study was undertaken to profile organotin compounds, in Lagos Dockyard harbour, Nigeria. The sediment and water samples were collected for two years (2016–2018) covering both the dry and wet seasons. A cold extraction technique by ultrasonication was used for sediments collected and a liquid-liquid separation technique was applied to water samples and later cleaned up by the use of silica gel-based packed column. The six organotin compounds considered in this work are Monobutyltin (MBT), Dibutyltin (DBT), Tributyltin (TBT), Monophenyltin (MPhT), Diphenyltin (DPhT), Triphenyltin (TPhT) were analysed by using an optimised high-performance liquid chromatography (HPLC). The result of the analysis on the sediment showed that the concentration of the organotin compounds (OTCs) ranges from 0.008 ± 0.00 to 272.710 ± 100.2 (ng/g) in MBT, 0.001 ± 0.00 to 69.780 ± 42.01 (ng/g) in DBT, 0.002 ± 0.00 to 7.110 ± 0.45 (ng/g) in TBT, 0.046 ± 0.01 to 76.210 ± 4.00 (ng/g) in MPhT, 0.070 ± 0.01 to 11.520 ± 0.62 (ng/g) in DPhT and 0.006 ± 0.00 to 2.330 ± 0.04 (ng/g) in TPhT. Higher values of OTCs were recorded during the wet season than the dry season and this was attributed to the dredging of harbour and remobilisation of organotin compounds from sediments into the water compartment. Principal Component Analysis (PCAs), Cluster Analysis (CA) and correlation analysis provided evidence for the interaction among these contaminants and possible sources of the contaminants. More so, the study showed that the degradation of these organotin compounds into their metabolites was governed by the influence of specific microorganisms. Therefore, regular monitoring of harbour was recommended for public safety.

Calculation of coating consumption quota for ship painting: a CS-GBRT approach

This paper focuses on the prediction of the coating amount before the construction of ship painting, i.e., the calculation of coating consumption quota. At present, each shipyard uses a larger coating loss coefficient to calculate the coating consumption quota; after the construction, there is often a lot of inventory left, which is not conducive to the scientific management of the ship coating process and the cost control of shipbuilding. Therefore, this paper proposes a coating consumption prediction method based on ensemble learning, using cosine similarity and gradient boosting regression tree hybrid algorithm (CS-GBRT) to calculate the coating loss coefficient under different working conditions. Cosine similarity is used to select similar data with less difference from the target to be predicted as the training set, and the loss function in GBRT is improved based on similarity weight to improve the prediction performance and calculation accuracy of GBRT. The coating data recorded by a shipyard from 2014 to 2019 are randomly selected to evaluate the prediction ability of the model established in the paper. The results show that when the proposed CS-GBRT algorithm is used to calculate the coating loss coefficient, the mean absolute error of training set and test set are both < 1.4, and the mean absolute error percentages are both < 4%. Compared with other research methods, the prediction accuracy is obviously improved, and the output feature importance is also consistent with the trend calculated by Spearman method, which proves the validity of the model again.

Sedimentary butyltin compounds and sediment transport model at the Shuwaikh Port, Kuwait Bay

Organotin compounds are highly toxic and have a direct impact on the marine environment. The leaching rate of tributyltin (TBT) was estimated to be 1.6 μg cm−2 per day, and the freshly painted leaching rate can be as high as 6 μg cm−2 per day. The present work is carried out at the Shuwaikh Port located at the Kuwait Bay. The major aim of the present work is to point out the presence of organotin compounds in the sediments along with the 10 stations of the Shuwaikh Port including the reference point at the outside of the port. The observations of basic hydrographic parameters which include salinity (42.4–44.5 ppt), temperature (17–33 °C, minimum at winter and maximum at summer), pH (7.7–9.79), and dissolved oxygen (6.2–7.8 mg/L) were noted in this study. The basic sediment texture analysis has been carried out from the previous studies as well. The amount of TBT leaching from the industries’, ship paints (antifouling) will spread to water; as the residence time of TBT in water is very small (3–15 days), it will end up to sediments (4–5 months; and in anaerobic sediment, it will extend up to 8–10 years) or affect the direct uptake of organisms. Depths in the main basin of the Shuwaikh Port ranges between 6.7–10 m. Evaluations of the annual longshore transport quantities are carried out based on the Coastal Engineering Research Center (CERC). The waves were classified based on their predominant direction, and the longshore sediment transport rate has been estimated. The analyzed results reflect the presence of TBT compounds in the locations nearby the shipyard. The observed range was 0.8–1.16 μg/g. The present results are showing lesser values of TBT compared with the same study of different regions.

Distribution, sources and ecological risks of organochlorine compounds (DDTs, HCHs and PCBs) in surface sediments from the Pearl River Estuary, China

The Pearl River Estuary is an important sink of organochlorine compounds (OCs), and OC pollution levels in surface sediments remain largely unknown at present. We collected and analysed residual DDTs, HCHs and PCBs of 45 surface sediments from the Pearl River Estuary in 2017. The values of DDTs (1.83 to 6.98 ng·g−1) and HCHs (0.43 to 2.14 ng·g−1) were higher in the Humen outlet, and the values of PCBs (4.6 to 187.4 ng·g−1) were higher in the coastal areas of Shenzhen. The DDTs and HCHs have generally decreased while the PCBs have been rapidly increasing in recent decades. The DDTs might originate from technical DDT and dicofol. The major source of HCHs was lindane. The main potential sources of PCBs were increased industrial products, ship painting, E-waste disassembly, maricultural and agricultural pollution. The total PCBs and DDTs had medium ecological risks according to the sediment quality guidelines.

Use of Methods of Electronic Microscopy, Mass-Spectrometry and Roentgenospectral Electronic Probe Micro-Analyzer in Ecological and Analytical Studies. Elemental Composition of Blue Micro-Particles of Unknown Nature Observed in Suspended Substance of Lake Baikal

During the period from April till June, 2018, suspended substance of Baikal Lake water from depths up to 25 meters in various distance from the shore (up to 4,000 m) showed presence of hard particles of blue color in size up to 900 mkm of unknown nature with maximum numbers at the nearshore zone, resistant to mineral acids and combustion. The analysis using methods of electronic microscopy with spray application of conducting golden coating, field desorption with inductively connected plasma (mass-spectroscopy) roentgenospectral electronic probe micro-analyzer, along with investigation of the surfaces of the objects studied and the components distributed in them, showed a set of 68 elements entering the composition of the particles. The major composition is marked for Ti, Ca and Si. Comparatively high composition is found for high-density metals: Zn, Pb, Sb, Nb, Cu, As. Suppositions are made about the anthropogenic nature of the blue particles — in forms of products of agglomerating titanium with fuliginous phase, as well as in composition of sorbents on the basis of compounding of titanium and ship paints.

Environmental risk assessment on ship repair work at cilegon national shipyard company

The main objective of this study is to develop an Environmental Risk Assessment at PT. X shipyard in the ship repair process by developing a risk matrix and identifying potential that can be caused when repairing the ship. Ship is an important and vital facility particularly as transportation mode and as part of inter-regional Community’s Economic Development Infrastructure Data obtained from national shipbuilding companies in the Cilegon area. Data collection and analysis is carried out following the ship repair process. Environmental risks that are classified as heavy are sandblasting dust and the ship painting process which is classified as heavy in the category of environmental pollution standards from other activities.

Experimental Design and Spray Technology Research of Ship Paint Spraying Robot

A wall climbing robot for ship painting is designed. The robot is the separation of the paint output device and the main machine of the painting equipment to realize the painting operation of the wall climbing robot. The test environment and test method design of the robot are introduced in detail, and the painting process of the robot is verified. On this basis, the thickness of paint film and the related aspects of spraying process are studied, so as to eliminate the random error caused by experience and technical techniques, and to achieve the established film thickness and the stability of paint film coating. Improve automatic spraying process and labor productivity.

Characterization of BaM and PaNi-Based Radar Absorbency (RAM) Behavior with Multilayer Geometry Structure for X-Band Absorption

Behavioral characterization of radar absorbent material consisting of Polyaniline (PaNi) and Barium M-Hexaferrite (BaM) has been successfully synthesized by solid state method. Polyaniline conductive material was synthesized using the polymerization method with DBSA dopant. A Radar Absorbing Materials (RAM) is characterized by X-Ray Fluorescence (XRF), X-Ray Diffraction (XRD), Fourier Transform Infrared (FTIR), Four Point Probe (FPP), Scanning Electron Microscope (SEM) and Vector Network Analyzer (VNA). The ion Zn 2+ is dopping into the BAM structure, where Zn 2+ ions replace Fe2+ ions in Hexaferrite barium so that the phase becomes soft magnetic materials . RAM and PANi particles are combined with ship paint to form radar wave absorbent coatings. The layer is coated with multilayer geometry on AH 36 type A steel, with thicknesses of 2.4 mm, 3.6 mm, 4.8 mm and 6 mm respectively. The X-band wave absorption was identified by VNA testing, where the maximum reflection loss value was found at 6mm thickness with a reflection loss value - 32.6 dB at 8.4 GHz frequency. Reflection loss values of multilayer variations with a thickness of 2.4 mm, 3.6mm and 4.8mm each have reflection loss values of -8.02 dB, -19.13 dB and -28.9 dB respectively in the x band frequency range.

Pencegahan Korosi Kapal Dengan Metode Pengecatan

Salah satu sumber kerusakan terbesar pada kapal laut dan alat-alat apung lainya adalahkorosi yang disebabkan kendaraan/alat apung tersebut berada di lingkungan air laut. Kelalaian atau kekurang sempurnaan perlindungan terhadap serangan korosi air laut akan sangat merugikan. Salah satu cara untuk mengurangi kerugian yang lebih besar akibat serangan korosi tersebut adalah dengan cara pencegahan pasif. Pencegahan pasif tersebut adalah dengan cara pengecatan. Pengecatan kapal/alatapung ini bertujuan untuk menyulitkan atau menghambat terjadinya gejala-gejala tumbuh dan berkembangnya terjadinya korosi.&#x0D; Pelaksaan pengecatan kapal dilakukan dalam dua (2) tahap kegiatan yaitu pembersihan badan kapal dan dilanjutkan pengecatan. Baik buruknya hasil pengecatan tergantung dari kualitas material bahan kapal, kualitas cat, jenis dan cara pembersihan kontruksi, jenis dan cara pengecatan serta ketrampilan dan pengalaman tukang cat.&#x0D; Hasil pengecatan akan berpengaruh terhadap kemampuan cat dalam melindungi kontruksi kapal terhadap serangan korosi air laut.

Occurrence, source, and partition of PAHs, PCBs, and OCPs in the multiphase system of an urban lake, Shanghai

Dianshan Lake (DSL) as an important water source protection area in Shanghai is facing serious water quality deterioration. A detailed investigation of persistent organic pollutants (POPs) including polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), and organochlorine pesticides (OCPs) in the multiphase system of DSL is very important for understanding their occurrence, sources, partition, and health risks. Total 11 sampling sites were selected including 3 inflowing rivers, 6 lake body sites, and 2 outflowing rivers. Total OCPs (Σ20OCPs) showed the highest concentration in water dissolved phase with a range of 47.8–143 ng/L. Total PAHs (Σ16PAHs) were the dominant compounds for suspended particle matter (SPM) and sediment phase, with a range of 2805–4130 and 206–4262 ng/g, respectively. The nonparametric test revealed the significantly higher concentrations of Σ16PAHs in sediment, Σ18PCBs in SPM, and Σ20OCPs in dissolved water from inflowing rivers than lake body (p < 0.05), indicating the strong effect of riverine pollution input. The different seasonal distribution between Σ16PAHs with Σ18PCBs/Σ20OCPs in SPM phase of lake body was closely attributed to their source disparities and the changes of rainfall and hydrodynamic conditions. Homologue compositions and isomer ratios analysis showed in DSL watershed PAHs were mainly derived from pyrogenic sources, PCBs from the leakage of capacitor equipment, sewage drainage of industries, and exfoliation of ship paints, and DDT from historical and recent application. The bioaccumulations of POPs in six fish species (n = 20) of DSL had high detection frequencies and a descending concentration order: Σ16PAHs (353 ± 106 ng/g) > Σ20OCPs (67.4 ± 27.0 ng/g) > Σ18PCBs (32.0 ± 13.7 ng/g), with obvious species-specific characteristics. The partitioning behaviors of PAH congeners in the water-SPM-sediment-fish system of DSL were greatly influenced by logKow values. However, the feeding habits (e.g., sediment-feeding behavior) of fish species played a predominant role in the bioaccumulation of PCB and OCP congeners compared to two-phase partition. Health risk assessments of POPs in dissolved water and fish samples revealed that only Σ16PAHs in dissolved phase have potential carcinogenic risk.

Distribution and source appointment of rare earth elements in offshore sediments of Western Xiamen Bay, Southeast China

The REEs concentrations in offshore sediments (surface sediments and core sediments) of Western Xiamen Bay and some potential sources (parent materials, Pb-Zn deposit, vehicle exhaust, atmospheric dust, ship paint, coal combustion and domestic sewage sludge) were determined to investigate the geochemical characteristics and major sources of REEs in the sediments of Western Xiamen Bay. The results showed that the mean concentrations of REEs in surface sediments and core sediments were 245.9 mg·kg−1 and 220.0 mg·kg−1, respectively, which were close to the background value of topsoil in Xiamen City. There were negative Eu anomaly and no Ce anomaly in general and LREEs had a significant enrichment relative to HREEs. The results of enrichment factor showed that REEs were slightly enriched in surface sediments. The patterns of chondrite-normalized REE exhibited a negative slope, indicating that the REEs in surface sediments were mainly from the continental crust. Parameters and normalized patterns of REEs suggested that the sediments in Western Xiamen Bay were mainly from terrestrial sources and also affected by anthropogenic activities such as domestic sewage sludge and coal combustion. The results of Pearson's correlations, chondrite-normalized REEs distribution patterns and ternary plot of (La/Yb)N-(La/Sm)N-(Gd/Yb)N for the surface sediments and some potential sources indicated that the REEs accumulated in the surface sediments might be related to natural sources (parent materials and Pb-Zn deposit) and anthropogenic activities (coal combustion and domestic sewage sludge).

Investigation and Source Apportionment of Air Pollutants in a Large Oceangoing Ship during Voyage.

The aims of this study were to determine compartmental air pollution during navigation of a large oceangoing ship and to identify preliminarily the major pollution sources. During the voyage of a bulk carrier ship, air samples were collected at 18 selected sites using a stratified sampling method. The concentrations of 15 pollutants were determined using gas chromatography. Results showed the concentrations of these pollutants varied significantly among the sampling sites, indicating major pollution sources at or nearby those locations. Five common factors extracted using factor analysis explained 89.092% of the total variance. Multivariate linear regression analysis showed the contributions to air pollution of these five common factors, i.e., the volatilization of ship paint, volatilization of ship-based oil, cooking activities, high-temperature release of rubber components on the ship and daily use of chemical products, and the application of deodorant and insecticide, were 41.07%, 25.14%, 14.37%, 11.78%, and 7.63%, respectively. Three significant groups were determined using cluster analysis based on their similarity, i.e., high, medium, and low pollution of sampling sites. This study established that the air of the bulk carrier ship was heavily polluted, and that effective identification of pollution sources could provide a scientific basis for its control.

Field Optimation of Durio zibethinus as Macro-Antifouling at PT Dok and Shipping, Surabaya, Indonesia

The use of TBT (Tributyltin) as a mixture of antifouling compounds in ship paint has been banned since 2001, and the use of Natural Product Antifoulant (NPA) as a substitute continues to be made by utilizing many resources. Durio zibethinus is one of the plants suspected of having antifouling compounds, so it needs to be explored its potential as an NPA with field test mechanism on ship plates for 28 days. The result of phytochemical screening test showed that extract of the skin of D. zibethinus positive contains secondary metabolite compound Alkaloid, Terpenoid, Tannin, Flavonoid, and Saponin. Field test results show that D. zibethinus extract has an effect on the area of adhesion and biomass biofouling. In the fourth week of the experiment, the biofouling attachment was recorded at concentrations of 0, 25, 50, 75, and 100 ppm respectively 66.1%, 62.1%, 60.9%, 54.2%, and 47.8 %. As for biomass biofouling recorded 36.6 g, 30.3 g, 20.4 g, 9.6 g and 8.9 g. The identified species of biofouling are only one species of Balanus amphitrite.

Sailing across Duniyāv: Sufi Ship–Body Symbolism from the Malabar Coast, South India

The paper examines Sufi ship–body symbolism in a painting on the wall of an eighteenth-century mosque from the riverine hinterland of the Malabar coast as well as in two poems, one in Arabic and the other in Arabi-Malayalam, produced in the region. Focusing on the intricate details of the painting and poems, the paper shows how the ship’s semantic field (sea, storm, pirates, pearls, shore, and so on) is connected to everyday Islamic rituals and mystical ideas and beliefs. In discussion, the paper draws attention to the creative hermeneutics of the local Muslim scholars and the use of an imagery which has a deep resonance in the intellectual history of Islam as well as in the littoral–cultural context of Malabar. The paper highlights the need to include imageries and motifs from inside the mosque when looking at artistic agency in the mosque architecture of the region. The paper argues that the ship painting in the spatiality of the mosque and in the Arabi-Malayalam poems is intended to induce wonderment among its audience, and thereby to inculcate ethical and pietistic dispositions among them.

Концепция экологически безопасной защиты от морского обрастания и её разработка с использованием каучук-эпоксидных покрытий

Развиты положения авторской концепции экологически безопасной защиты от морского обрастания. Изучены три направления её практической реализации: небиоцидная противоадгезионная защита с использованием оксидов некоторых металлов и органических соединений, а также покрытия с пониженной экологической опасностью за счёт частичного замещения меди противоадгезионным компонентом. В качестве базового использовано покрытие КЭЛТ-2, разработанное в ФГУП «НИИСК». Для лабораторных исследований противообрастающих веществ и покрытий использованы методы экспериментальной биологии, для морских испытаний покрытий — нестационарные стенды (гидрофлюгеры). Представлены результаты технических и биологических испытаний каучук-эпоксидных покрытий. При испытаниях в Белом и Чёрном морях разработанные покрытия показали более высокую эффективность, чем судовые краски. Обсуждается перспективность дальнейшей разработки экологически безопасных противоадгезионных покрытий и медных покрытий с пониженной экологической опасностью.

Growth Kinetics Modelling of Tributytin-Resistant Klebsiella SP. FIRD 2 In Cadmium Media

Tributyltin (TBT) has been generally used as component of antifouling biocide in boat and ship paints to prevent the attachment of marine organism on the hull surface. TBT has been classified to be a very toxic compound, and poses significant danger to a broad diversity of organisms in the polluted environments due to the high concentrations. The growth kinetic of TBT-Resistant Bacterium containing cadmium was studied. In this study various cadmium concentrations ranging from 1 to 100 mg/L were used. Seven kinetic models (Haldane, Teissier, Monod, Yano, Luong, Aiba and Webb) were investigatedand the accuracy of the fitted model were evaluated using statistical analysis such as coefficient of determination, adjusted coefficient of determination (R2) and root mean square (RMSE). Luong model were fitted to the experimental growth kinetics data and gave a very good fit. The calculated value for the Luong constants such as maximal growth rate, half saturation constant and half inhibition constant rate symbolized by umax, ks, and ki, were 0.03405 hr-1, 0.3 mg/L and 0 mg/L, respectively. Luong model also predicted the significant substrate concentration (Sm) value, at which specific substrate degradation rate falls to zero (98.93 mg/L). This is the first report of growth kinetics of TBT-Resistant bacterium by Klebsiella sp. FIRD 2 Containing Cadmium

New promising antifouling agent based on polymeric biocide polyhexamethylene guanidine molybdate.

A new polymeric biocide polyhexamethylene guanidine (PHMG) molybdate has been synthesized. The obtained cationic polymer has limited water solubility of 0.015 g/100 mL and is insoluble in paint solvents. The results of acute toxicity studies indicate moderate toxicity of PHMG molybdate, which has a median lethal dose at 48 h of 0.7 mg/L for Daphnia magna and at 96 h of 17 mg/L for Danio rerio (zebrafish) freshwater model organisms. Commercial ship paint was then modified by the addition of a low concentration of polymeric biocide 5% (w/w). The painted steel panels were kept in Dnipro River water for the evaluation of the dynamics of fouling biomass. After 129-d exposure, Bryozoa dominated in biofouling of tested substrates, forming 86% (649 g/m2 ) of the total biomass on control panel surfaces. However, considerably lower Bryozoa fouling biomass (15 g/m2 ) was detected for coatings containing PHMG molybdate. Dreissenidae mollusks were found to form 88% (2182 g/m2 ) of the fouling biomass on the control substrates after 228 d of exposure, whereas coatings containing PHMG molybdate showed a much lower biomass value of 23.6 g/m2 . The leaching rate of PHMG molybdate in water was found to be similar to rates for conventional booster biocides ranging from 5.7 μg/cm2 /d at the initial stage to 2.2 μg/cm2 /d at steady state. Environ Toxicol Chem 2017;36:2543-2551. © 2017 SETAC.