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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.

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.