DOI: 10.5061/dryad.b5mkkwhrn
title: Optimizing ballast water management: An evaluation of ballast water treatment system performance in challenging water conditions

description: The movement of ballast water is a major pathway for introducing aquatic
 invasive species. Ballast water management systems (BWMS) aim to reduce
 species introductions, but their performance varies under challenging
 water quality conditions. This study assessed BWMS performance in a
 freshwater port with impaired water quality by comparing harbour
 conditions to challenge water criteria for type approval testing defined
 by the International Maritime Organization and U.S. Environmental
 Protection Agency, and by analyzing paired harbour uptake and ballast
 discharge samples. Of 18 harbour samples, 67% approached or exceeded
 challenge water criteria for ≥50 μm organism abundance, while 22% and 11%
 exceeded criteria for dissolved organic carbon and total suspended solids.
 All nine discharge samples met limits for small organisms (≥10 to
 &lt;50 μm), but eight exceeded limits for larger organisms (≥50 μm)
 despite &gt;99% reduction from uptake levels. Abundance of larger
 organisms in discharge was affected by uptake water quality (ultraviolet
 transmittance and organism abundance), and BWMS treatment type/filter
 size. The findings suggest that raising challenge test criteria may
 improve BWMS reliability across environmental conditions.
description: Monitoring of environmental water quality in Hamilton Harbour,
 Lake Ontario, Canada, was conducted by long-term deployment of a YSI EXO
 multiparameter water quality sonde (YSI Incorporated, Yellow Springs,
 Ohio, USA) and semi-monthly collection of water samples for more
 comprehensive laboratory analysis. The sonde was installed at a depth of 5
 meters inside a perforated PVC housing attached to the pier wall at Pier
 25 (Agrico Canada L.P., Hamilton, Ontario, Canada, 43.272881, -79.786398)
 from April to December 2022 to take in situ measurements of temperature,
 pH, dissolved oxygen, salinity, turbidity, chlorophyll a (chl a), and
 fluorescent dissolved organic matter (fDOM) at hourly intervals.
 Discrete samples of harbour water were collected semi-monthly (18
 sample collection events) for assessment of live organism abundances and
 water chemistry. Briefly, a 4-liter Van Dorn bottle (Halltech
 Environmental and Aquatic Research Inc., Guelph, Ontario, Canada) was
 repeatedly deployed to a depth of 5 meters to collect a total of 12-15
 liters of water into a 20 L carboy. The carboy was gently inverted five
 times and split into sample bottles (1 L for live counts of organisms in
 the ≥10 to &lt;50 μm size class, 250 mL for particulate organic carbon
 (POC) and particulate organic nitrogen (PON), 125 mL for dissolved
 inorganic carbon (DIC) and dissolved organic carbon (DOC), 500 mL for
 total suspended solids (TSS) and volatile suspended solids (VSS), and 3 ×
 30 mL for measurement of Ultraviolet Transmittance (UVT)).
 For collection of organisms ≥50 µm, a 30-L Schindler-Patalas trap
 (Science First/Wildco, Yulee, FL, USA) was deployed to a depth of 5 meters
 and the collected organisms were concentrated in the 35 µm mesh cod-end
 and rinsed into a 1-L Nalgene sample bottle using ambient water that had
 been pre-filtered through a 10 µm Nitex mesh sieve (Sefar Inc., Depew, New
 York, USA). The sample was topped up to 500 mL with 10 µm filtered ambient
 water. All samples were stored in the dark in a cooler at the ambient
 temperature of the harbour water (7–26 °C ± 2 °C) until laboratory
 analysis. For the ≥10 to &lt;50 μm size class,
 samples were analyzed using epifluorescence microscopy with fluorescein
 diacetate (FDA, Sigma-Aldrich Canada, Oakville, Ontario, Canada) as a
 vital marker, following the counting protocol outlined by Adams et al.
 (2014). Briefly, a 5 mL subsample was collected from a well-mixed 1 L
 sample of unconcentrated harbour water, stained with FDA for 10 minutes,
 with 1 mL subsequently transferred to a Sedgewick-Rafter counting chamber.
 The sample was examined for 20 minutes using a Zeiss Axio Vert.A1
 microscope (Carl Zeiss Canada, Ltd, Toronto, Ontario, Canada); this
 process was repeated six times, and the mean abundance was calculated from
 the six replicate subsamples. All live organism counts were conducted
 within six hours from the time of collection. For the
 ≥50 µm size class, samples were mixed by gentle inversion prior to
 splitting in half by weight. One half sample was concentrated to 40-60 mL
 using a 35 µm mesh sieve and 10 µm filtered harbour water for analysis.
 Aliquots of 0.5-2.5 mL, depending on the number of organisms, were
 examined in a modified Bogorov chamber using a Nikon SMz800N Zoom
 stereoscope at 30 – 80x magnification, with 50 μm fluorescent microspheres
 added as a size reference. Aliquot size was determined by the analyst to
 target a coefficient of variation (CV) of 10% while spending a maximum of
 1-1.5 hours per sample (completed within 6 hours from the start time of
 collection). Analysts typically counted 17% of the half sample volume. For
 each aliquot, first, the number of dead ≥50 µm organisms were counted as
 per the ETV Protocol. Organisms were considered dead if they showed no
 movement or response to tactile stimuli. Secondly, the total number of
 organisms were counted. The number of live organisms were determined by
 subtracting the number of dead from the total (NSF International,
 2010). Water chemistry parameters, including
 particulate organic carbon (POC), particulate organic nitrogen (PON),
 dissolved inorganic carbon (DIC), dissolved organic carbon (DOC), and
 total suspended solids (TSS) were measured using standard analytical
 methods (National Laboratory for Environmental Testing in Burlington,
 Ontario, Canada), while UVT was measured using a RealUV254 Field Meter
 (Real Tech Inc., Whitby, ON, Canada). Ships were
 sampled opportunistically at terminals within Hamilton Harbour, Ontario,
 Canada between April and December 2023. Ambient harbour water was sampled
 as close as safely practicable to each ship’s sea chest intake during
 ballast water uptake and, once ballast uptake operations were completed
 and the specified BWMS hold time for treatment was met, a treated ballast
 water sample was collected during discharge. In situ
 water quality parameters (temperature, pH, dissolved oxygen, conductivity,
 salinity, turbidity, total algae, and depth) were measured using a YSI EXO
 multiparameter sonde installed prior to ballast water uptake, just outside
 each ship’s mooring lines, at a distance 31–70 m astern (mean distance: 51
 m) and a depth of 5 m. The sonde was housed within a stainless steel
 protective cage (Nexsens Technology, Inc., Fairborn, Ohio, USA), secured
 to the pier wall, and fitted with anti-fouling measures. Data were
 recorded at 5-minute intervals throughout ballast uptake operations , with
 data retrieval conducted after the completion of all ballast operations at
 berth. Grab samples were taken for live counts of organisms in the ≥10 to
 &lt;50 μm and ≥50 μm size classes, as well as for laboratory-based
 water chemistry analyses; these were collected at the start of ballast
 uptake operations and processed as described previously for harbour
 monitoring. Treated ballast water samples were
 collected during ballast discharge using the ship-supplied sample port
 installed on the main ballast pipe in the ships’ engine room, using
 in-line isokinetic continuous sampling methods, a large volume collection
 device and a plankton net collection system consistent with prior studies
 (Bailey et al., 2022). Ballast water sample flow rates and volumes were
 measured using a flow meter with digital display (Burkert S030 paddlewheel
 body and SE35 digital display, Burkert Fluid Control Systems, Germany).
 Three 1 m³ continuous samples of ballast water were collected and
 concentrated using a 35 μm mesh net (30 cm diameter; Wildco-Science First,
 USA), kept partially submerged in a 75 L sampling bin outfitted with two
 valved discharge lines to direct disposal of filtrate in accordance with
 ship crew instructions. Following sampling, each net was rinsed with 10 μm
 filtered ballast water, and the concentrate was transferred to a 1 L
 Nalgene bottle. All samples were stored in dark, insulated coolers with
 ice packs to maintain temperatures close to ambient ballast
 conditions. A continuous subsample of whole
 (unconcentrated) treated ballast water (total 20L) was collected for the
 duration of the ≥50 µm sampling for analysis of organisms ≥10 to
 &lt;50 μm using a small sample probe (Moser et al., 2018; Casas-Monroy
 and Bailey, 2021) installed within the large volume collection device.
 Samples were stored at or just below ambient water temperature in dark,
 insulated coolers with ice packs until processing. A 5 L subsample was
 removed following mixing by gentle inversion and concentrated to 125 mL
 for live counts of the ≥10 to &lt;50 µm size class using
 epifluorescence microscopy with FDA as described previously, though
 samples were concentrated to improve precision (Yardley et al.,
 2024). Live counts of the ≥50 μm size class in ballast
 discharge samples were analyzed following the methods described in Bailey
 et al. (2022). Briefly, each 1 L sample was concentrated to 20-25 mL using
 a 35 µm sieve and 10 µm filtered sample water. Aliquots of 0.5 to 2.5 mL
 were examined using a modified Bogorov chamber and a Nikon SMZ800N Zoom
 stereoscope under 30 – 80x magnification, aiming for a target of 25–50
 live organisms per aliquot, with 50 μm fluorescent microspheres added as a
 size reference. In contrast to the harbour monitoring counting method
 described previously, only ≥50 µm organisms showing movement or response
 to stimuli (NSF International, 2010) were counted since few living
 organisms were expected in samples post treatment. Samples were
 concentrated to maximize the volume assessed within 60-90 minutes (within
 six hours from the time of collection) to minimize mortality due to
 handling/containment. The abundance of live organisms was calculated
 cumulatively across the three net samples considering the volume counted
 and the concentration factor.
description: # Optimizing ballast water management: An evaluation of ballast water
 treatment system performance in challenging water conditions File Names:
 table_1.csv, table_2.csv, table_2.csv, table_4.csv, table_5.csv,
 table_6.csv, table_7.csv File Version: 1.0.0 File Format: Comma separated
 values (CSV) Data Custodians: Sean Yardley, Oscar Casas-Monroy Security
 Use Limitation: none Primary Investigator: Sarah A. Bailey;
 [sarah.bailey@dfo-mpo.gc.ca](mailto:sarah.bailey@dfo-mpo.gc.ca) Data
 Contributors: Sean Yardley, Oscar Casas-Monroy, Robin Rozon, Jocelyn Kydd,
 Dawson Ogilvie, Sarah A. Bailey ## Description of data and file structure:
 This dataset includes measurements of physical, chemical and biological
 water quality parameters collected in Hamilton Harbour, Lake Ontario
 during 2022 and 2023. Environmental water quality measurements were taken
 by long-term deployment of a YSI EXO multiparameter water quality sonde
 (YSI Incorporated, Yellow Springs, Ohio, USA) and semi-monthly collection
 of water samples for more comprehensive laboratory analysis. In addition,
 paired samples of ambient harbour water quality during ballast water
 uptake and corresponding ballast water discharge samples following use of
 a ballast water management system were collected in 2023. Ships were
 sampled opportunistically at terminals within Hamilton Harbour, Ontario,
 Canada between April and December 2023. Ambient harbour water was sampled
 as close as safely practicable to each ship’s sea chest intake during
 ballast water uptake and, once ballast uptake operations were completed
 and the specified BWMS hold time for treatment was met, a treated ballast
 water sample was collected during discharge. The dataset is comprised of
 seven tables, as follows: Table_1.csv: Daily summary of environmental
 water quality measurements collected hourly at 5 m depth at Pier 25 in
 Hamilton Harbour, Lake Ontario, Canada, using a YSI EXO multiparameter
 water quality sonde from April to December 2022. Minimum (min), Maximum
 (max), Median, Mean, Standard Deviation (sd) and Standard Error (se) are
 provided for each water quality parameter: Temperature (Temp: °C),
 Dissolved Oxygen (DO: mg/L), Salinity (ppt), pH, Turbidity (formazin
 nephelometric units, FNU), Chlorophyll a (Chl: relative fluorescence units
 (RFU)), and Fluorescent Dissolved Organic Matter (fDOM: ppb QSU).
 Table_2.csv: Seasonal summary of environmental water quality measurements
 collected at 5 m depth at Pier 25 in Hamilton Harbour, Lake Ontario,
 Canada, using a YSI EXO multiparameter water quality sonde from April to
 December 2022. Minimum (min), Maximum (max), Median, Mean, Standard
 Deviation (sd) and Standard Error (se) are provided for selected water
 quality parameters: Chlorophyll a (Chl: RFU), Dissolved Oxygen (DO: mg/L),
 Turbidity (formazin nephelometric units, FNU), Salinity (ppt), Temperature
 (Temp: °C), Fluorescent Dissolved Organic Matter (fDOM: ppb QSU) and pH.
 Table_3.csv: Bi-monthly point measurements of water chemistry parameters
 collected at 5 m depth at Pier 25 in Hamilton Harbour, Lake Ontario,
 Canada, using standard analytical methods (National Laboratory for
 Environmental Testing, Burlington Ontario), from April to December
 2022.Water chemistry parameters measured, as mg/L, included: dissolved
 inorganic carbon (DIC), dissolved organic carbon (DOC), particulate
 organic carbon (POC), particulate organic nitrogen (PON), total suspended
 solids (TSS), and volatile suspended solids (VSS). Note that TSS values
 &lt;5 mg/L (the minimum detection limit of the analysis method) are
 presented as 4.9. Table_4.csv: Seasonal summary of bi-monthly point
 measurements of water chemistry parameters collected at 5 m depth at Pier
 25 in Hamilton Harbour, Lake Ontario, Canada, using standard analytical
 methods (National Laboratory for Environmental Testing, Burlington
 Ontario), from April to December 2022. Water chemistry parameters
 measured, as mg/L, included: dissolved inorganic carbon (DIC), dissolved
 organic carbon (DOC), particulate organic carbon (POC), particulate
 organic nitrogen (PON), total suspended solids (TSS), and volatile
 suspended solids (VSS).The table shows the number of measurements (n),
 minimum (min), maximum (max), median, mean, standard deviation (sd) and
 standard error (se) for each parameter by season. Note that TSS values
 &lt;5 mg/L (the minimum detection limit of the analysis method) are
 presented as 4.9. Table_5.csv: Bi-monthly point estimates of live organism
 abundances (≥10 to &lt;50 μm and ≥50 μm size classes) collected at 5 m
 depth at Pier 25 in Hamilton Harbour, Lake Ontario, Canada, using a Van
 Dorn bottle and a 30-L Schindler-Patalas trap, respectively, and counted
 via microscopy. The table shows the date of sampling, the number of ≥50 μm
 size class organisms (ZoopCount; per cubic meter), along with 95%
 confidence limits (Lower - ZoopLL and Upper - ZoopUL) that were calculated
 from a Poisson distribution and then applied to the observed abundances;
 and the number of ≥10 to &lt;50 μm size class organisms (PhytoCount; per
 mL), as a mean of six counts with standard error (PhytoSE). Table_6.csv:
 Summary of environmental water quality measurements collected at 5 m depth
 near the stern of participating ships during nine ballast uptake events in
 Hamilton Harbour, Lake Ontario, Canada, using a YSI EXO multiparameter
 water quality sonde during April to December 2023. Maximum (max), Mean,
 Median, Minimum (min), Standard Deviation (sd) and Standard Error (se) are
 provided for selected water quality parameters: Chlorophyll a (Chl: RFU),
 Dissolved Oxygen (DO: mg/L), Turbidity (formazin nephelometric units,
 FNU), Salinity (ppt), Temperature (Temp: °C), Fluorescent Dissolved
 Organic Matter (fDOM: ppb QSU) and pH, by sampling event (E##).
 Table_7.csv. Summary of variables associated with each ballast water
 discharge sampling event (E##), including the month the discharge sample
 was collected (Sampling Month); relevant water quality parameters measured
 from the harbour during ballast water uptake (Dissolved Organic Carbon
 (DOC); Particulate Organic Carbon (POC); Total Suspended Solids (TSS));
 Treatment-Filter Type; the Age of the Ballast Water Management System at
 time of sampling (BWMS age (years)); and the percent reduction in large
 and small size class organisms observed compared to ambient levels in the
 harbour water during ballast uptake. Note that TSS values &lt;5 mg/L (the
 minimum detection limit of the analysis method) are presented as 4.9.
 Access information: Data were generated from in situ measurements and
 laboratory analyses of discrete (grab) water samples.