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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.

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.

Ballast Water Managements Systems (BWMS) installed on vessels may use Active Substances (AS) to inactivate organisms. This paper provides new insights in the global issue of noxious Disinfection By-Products (DBP) produced with primarily oxidant-based BWMS, and the risk assessment for workers, including port State control officers, while performing tasks on a vessel that involve exposure to treated ballast water. The Joint Group of Experts on the Scientific Aspects of Marine Environmental Protection - Ballast Water Working Group (GESAMP-BWWG) plays a role in the certification process of BWMS that make use of AS evaluating potential negative effects. All BWMS that passed GESAMP-BWWG Final Approval until mid 2019 were analyzed providing an overview of chemicals in the treated ballast water before and after neutralization. The ballast tank cleaning scenario, the sampling scenario, and the ballast tank inspection scenario all showed elevated human health risks using the Derived Minimal Effect Levels approach. The most critical exposure occurs in the ballast tank cleaning scenario through the inhalation of volatile DBP, such as tribromomethane. This substance may cause acute effects such as headache, dizziness and also has carcinogenic properties. The two risk reducing options available in the GESAMP-BWWG Tier 2 calculations were compared, one being mitigation measures such as protective gloves and coveralls, the other option is taking into account a time correction factor. The results showed that thetrihalomethanes in air are most problematic, however, there is a possibility that the calculated values may be overestimated as generally worst case assumptions were used. (C) 2020 Elsevier Ltd. All rights reserved.

In Chesapeake Bay, Maryland, USA, some of the most contaminated sediments are found in the highly industrialized Baltimore Harbor-Patapsco River area. As part of a comprehensive assessment of sediment quality in this system, sediment toxicity was assessed in 10-d acute tests with the estuarine amphipod Leptocheirus plumulosus. Mean amphipod survival was significantly reduced in 7 of the 25 samples tested despite the occurrence of minor experimental artifacts. The most toxic sediments were collected from Bear Creek; other areas exhibiting toxicity included the Inner Harbor and Colgate Creek. Marginal toxicity was observed in samples from Curtis Creek, Lazeretto Point, and Back River. Negative relationships were detected between survival and concentrations of select sediment-associated contaminants, whereas a very strong positive association existed between survival in laboratory exposures and density of L. plumulosus at the test sites. A weight of evidence approach, including correlation analyses, a model of polycyclic aromatic hydrocarbon bioavailability, and comparisons to benchmark sediment levels, was used to tentatively identify classes of contaminants that contributed to the observed toxicity. Analysis of results suggested that toxicity at stations in Bear Creek and Colgate Creek may have been driven by sediment-associated metals, whereas toxicity at stations in the Inner Harbor was likely due to both metal and organic contaminants. The observed relationships among toxicity test results, concentrations of sediment-associated contaminants, and abundance of L. plumulosus at the test sites suggests that acute toxicity tests with this species are indicative of adverse biological effects in the field.

Sodium bromide can be used to convert hypochlorous acid into hypobromous acid. An alternative strategy to biofouling control uses the simultaneous addition of sodium bromide and chlorine to water used for power plant condenser cooling. This approach can significantly reduce the total disinfectant and halogen application rates because the bromine oxidants that are generated are more effective for controlling biofouling than their chlorine counterparts, especially at higher pHs. Since such a change in biofouling control strategy could adversely impact the environment, the acute toxicity of bromine oxidants were evaluated in both continuous and intermittent exposure scenarios. Decay properties of bromine oxidants were compared to those of chlorine oxidants. In addition, two tests were conducted to investigate the relative toxicities of chloramines and bromamines. For the six species tested, bromine oxidants were two to five times more toxic than chlorine oxidants. For continuous exposure to bromine oxidants, LC50 values for daphnids (Dapnia magna) and amphipods (Hyalella azteca) could not be calculated because significant mortality occurred at the oxidant quantitation limit. Both chlorine and bromine proved to be more toxic to daphnids and mysids (Mysidopsis bahia) in the presence of ammonia. While the toxicity data show that bromine oxidants are more toxic than chlorine oxidants, bromine oxidants decayed two to five times faster than chlorine oxidants in freshwater and saltwater, respectively. With regard to potential environmental impact, it is important that one consider the more efficacious biocidal characteristics of bromine (i.e. higher pHs) in the context of more rapid decay relative to chlorine. The strategy of using simultaneous addition of sodium bromide and chlorine could reduce environmental impact potential, although insufficient data exists to prove this.

Since 1987, an effluent biomonitoring program of major and selected minor industrial and municipal point source dischargers has been conducted for Maryland's Department of the Environment. Acute and chronic toxicity test procedures were developed and implemented for testing freshwater (Pimephales promelas, Daphnia magna, and Ceriodaphnia dubia) and estuarine (Cyprinodon variegatus and Mysidopsis bahia) invertebrates and fish. Results from the laboratory bioassays were used by Maryland to identify toxic discharges to state waters. Beginning in 1987, totals of 488 and 89 effluent samples were tested for acute and chronic toxicity, respectively. Both the frequency of acute and chronic toxicity and the severity of the toxicity of the remaining toxic effluents have decreased dramatically since the inception of the program. Examples are presented concerning the use of these data by Maryland to regulate toxic discharges. These results indicate the important role whole-effluent toxicity testing plays in controlling the point source discharge of toxic substances to surface waters.

Ballast water treatment has become a major issue in the last decade due to the problem of invasive species transported and released by the uptake and discharge of ballast water for shipping operations. One of the important issues considering ballast water treatment is to determine whether treated ballast water, once discharged, is safe to the aquatic environment. The International Maritime Organization (IMO) Marine Environmental Protection Committee (MEPC) has determined that prior to approval of a ballast water management system, aquatic toxicity data must be available for both the active substance and relevant byproducts. Many proposed ballast water treatment systems use chlorine as the active ingredient. Although there are sufficient toxicity data concerning active substances such as chlorine, there are limited toxicity data concerning disinfection (halogenated) byproducts including dibromochloromethane, four haloacetic acids and sodium bromate. Acute and chronic toxicity were determined for these disinfection byproducts (DBPs). Acute toxicity values ranged from 96-h LC50s of 46.8 mg/l for Daphnia magna for both dibromochloromethane and sodium bromate to a 96-h LC50 of 376.4 mg/l for Cyprinodon variegatus for tribromoacetic acid. Acute Isochrysis galbana population growth effect values ranged from a 72-h EC10 of 39.9 mg/l for dichloroacetic acid to a 72-h EC50 of 15,954 mg/l for sodium bromate. Chronic toxicity mortality/reproduction effects values for D. magna ranged from a 21-d IC25 of 160.9 mg/l for tribromoacetic acid to a 21-d LOEC of 493.0 mg/l for trichloroacetic acid. Chronic toxicity mortality/growth values for C. variegatus ranged from a 32-d IC25 of 246.8 mg/l for trichloroacetic acid to a 32-d LOEC of 908.1 mg/l for tribromoacetic acid. I. galbana 96-h chronic population growth effects values ranged from an EC10 of 38.5 mg/l for trichloroacetic acid to an LOEC of 500.0 mg/l for tribromoacetic acid. Acute to chronic ratios for all of these DBPs ranged from 0.8 to 3.0. Based on toxicity/ecorisk categories generated by the U.S. Environmental Protection Agency, these disinfection byproducts would be considered either slightly toxic or practically nontoxic to the aquatic organisms tested.

In October 1990, the US Environmental Protection Agency promulgated application requirements with deadlines for storm-water discharges associated with industrial activity and certain municipal systems. Major airports have a number of hydrocarbon-based contaminants that could appear in storm-water runoff. In addition, ethylene, diethylene, and propylene glycol deicing and anti-icing mixtures are used during freezing and near-freezing weather. The objective of this study was to characterize the potential acute impact on aquatic life from industrial storm-water discharges from an international airport. Samples from winter storm events caused acute toxicity to both the fathead minnow (Pimephales promelas) and the daphnid (Daphnia magna), with LC50 values for both species as low as 1.0 and 2.0% effluent. The toxicity of the samples was due to the various glycol-based deicer/anti-icer mixtures used during these events. High oxygen demands and elevated total nitrogen levels are other potential problems during anti-icing/deicing activities. Samples from rain events during the nonwinter months at the airport did not cause acute toxicity unless associated with fuel spills. As a result of this study, a new discharge permit has been issued for this airport, requiring the implementation of plans for the collection and recycling and/or disposal of the deicer/anti-icer mixtures.

Intermittent chlorination to inhibit biofouling in condensers is a widespread practice in the power generation industry. Because the U.S. Environmental Protection Agency's water quality criteria for chlorine were based on continuous chlorine exposure of test organisms, it is possible that effluent discharge limits derived from these criteria are overprotective to aquatic organisms exposed only intermittently. The toxicity of 96-h acute and 7-d short-term chronic exposures under continuous and intermittent chlorination (2-, 4-, 6-, and 8-h daily exposures) to two saltwater species was determined. Mysids (Mysidopsis bahia) were found to be more sensitive to chlorine than inland silversides (Menidia beryllina) when exposed continuously under acute and short-term chronic conditions. No difference was found between the acute toxicity responses of mysids and silversides exposed to intermittent chlorination. In contrast, a difference in short-term chronic toxicity was found between the two species exposed to intermittent chlorination. All intermittent chlorine exposures were less toxic to both species than the continuous exposures. The acute-to-chronic ratios (ACR) for silversides exposed to both continuous and intermittent chlorination indicate that ACRs of approximately 1.5 can be used with acute data to estimate chronic toxicity of chlorine. The ACRs for mysids exposed to both continuous and intermittent chlorine range from 3.1 to 6.1.

In 1998, we conducted a field-validation study of the chronic 28-day whole-sediment toxicity test with Leptocheirus plumulosus in Baltimore Harbor, MD, an area where this amphipod is indigenous. This study included an evaluation of the effect of sieving on sediment chemical concentrations and the use of field replicates, or separate grabs from the same site, which provided an estimation of within-site chemical and toxicologic variability. Six stations in Baltimore Harbor, MD, were included in this evaluation. Chemical analysis of two separate unsieved field replicates from the six sites indicated that, overall, the chemical concentrations of replicates within each site were similar, especially for metals. Organic contaminants particularly total PCBs, had the highest variability between replicates. Chemical variability did not appear to be related to differences in organic carbon content or grain size or to variability in toxicologic end points. Results supported the use of composite samples in sediment toxicity tests. In addition, in most cases, sieving had little effect on sediment chemistry. For the metals and trace elements, only selenium showed a substantial change after sieving, with some samples increasing after sieving and others decreasing. Concentrations of acid-volatile sulfide (AVS) increased 194.6% at one station after sieving, although in most other cases, AVS and simultaneously extracted metals remained relatively unchanged. As expected, concentrations of organics generally decreased after sieving, but in the majority of cases this decrease was small (i.e., coefficient of variationor = 25%). Total benzene hexachloride and total chlordanes had the greatest changes, whereas polychlorinated biphenyl concentrations decreased at only two stations after sieving. Concentrations of polyaromatic hydrocarbons showed little change after sieving. These changes in sediment chemistry due to sieving must be viewed in the larger context of the potentially confounding effects that indigenous organisms may have on the interpretation of test results from whole-sediment toxicity tests.

Chlorine dioxide has been proposed as an alternative to chlorine because it is a powerful disinfection agent that does not react with ammonia or chlorinated organics to form chloramines or trihalomethanes. The major reduction product formed when chlorine dioxide is added to water is the chlorite ion. Chlorite has been shown to be less toxic than free or combined chlorine. However, previous studies with eight freshwater families produced a US Environmental Protection Agency (USEPA) acute water quality criteria (WQC) lower than the WQC for chlorine. In the current study, an additional 12 families were added to the toxicological database to determine ecological risk criteria (ERC) using both the standard USEPA WQC methodology and the USEPA Office of Pesticide Programs (OPP) probabilistic approach. Chlorite LC50 values for the 20 family database ranged from 0.27 mg/L for the Daphnidae to 208.76 mg/L for the Salmonidae. The Daphnidae were by far the most sensitive family tested, with an LC50 44 times lower than the next most sensitive family tested, the Hyalellidae (LC50=1.19 mg/L) and 214 times lower than the most sensitive fish family tested, the Ictaluridae (LC50=5.79 mg/L). The Criteria Maximum Concentration calculated using the USEPA WQC methodology was 0.025 mg/L while the 95% ERC calculated using the USEPA OPP probabilistic methodology was 0.135 mg/L. The USEPA OPP probabilistic approach yields a criterion more consistent with the overall species sensitivity distribution and is not overly skewed by the low Daphnidae LC50 as is the USEPA WQC approach.

A 28-d partial life-cycle test with the estuarine amphipod Leptocheirus plumulosus was developed in response to the need for an assay to mimic chronic exposure to sediment-associated contaminants. To ensure that toxicity tests have environmental relevance, it is essential to evaluate the relationship between laboratory responses and field measures of contamination. Consequently, one objective of the study was to compare the results of the chronic sediment toxicity test with L. plumulosus to gradients of sediment contamination and the in situ benthic community in its native Chesapeake Bay. Chronic tests were conducted by two laboratories, the Army Corps of Engineers Waterways Experiment Station ([WES]; Vicksburg, MS, USA) and the University of Maryland ([UM] College Park, MD, USA) using different feeding regimes, providing the opportunity to evaluate the effect of this variable on response sensitivity. A second objective was to compare the relative sensitivity of acute and chronic tests with L. plumulosus with field-collected sediments. Overall, there was good agreement between the toxicological response of acute and chronic tests with L. plumulosus and field measures of contamination. Survival in the acute test and chronic test conducted by WES was negatively correlated with concentrations of sediment-associated contaminants. Survival in acute exposures was significantly reduced in sediments from 8 of 11 stations. Indigenous L. plumulosus were found only at two of the three stations that did not exhibit acute toxicity. An unexpected finding was the difference in responsiveness of the two chronic tests. Survival in tests conducted by UM and WES was significantly reduced in sediments from 4 and 6 of 11 stations, respectively. No additional sublethal toxicity was detected in the UM chronic test, but the WES test detected reproductive effects at two additional stations. We believe the observed differences were related to the test diet used. Partly as a result of our findings, the recommended diet for the L. plumulosus chronic test was changed in the final methods document.