Negative impact of introductions of invasive species by ship vectors in Arctic ecosystem has been identified as risk. Concerns have arisen that especially BWMSs using active substances may not operate as expected in cold environments. Electrochemical chlorine production for instance, is not only strongly dependent on salinity, but also on temperature. Both can be limiting in Arctic waters. Technical adaptations (e.g. separate treatment loops and injection into the main stream) are possible to overcome this, but the toxic potential of chlorine and other active substances at low temperatures is hardly known.
Currently, information on toxicity of chemicals under Arctic conditions is more or less limited to persistent organic pollutants, heavy metals, oil and production water chemicals used in the offshore oil & gas industry. These chemicals exert their effect on organisms when critical body burdens are exceeded after uptake of the substance. In contrast to these chemicals, biocides used as active substance in BWMSs are very rapidly neutralised by natural degradation processes, sometimes assisted by chemical neutralisers. Their effect on (micro-) organisms is very direct, by disrupting cell membranes. At very low temperatures, the degradation process may be much slower, resulting in a higher potential environmental risk. Alternatively, micro-organisms may be less susceptible at temperatures close to freezing. This will reduce the efficacy of the treatment, implying an increased risk for transfer of NIS within the Arctic. For this reason more insight is necessary in the efficiency and environmental safety of BWMS in these low temperatures.