Additive manufacturing (AM), commonly named 3D printing, is a promising technology for many applications. It is the most viable option for widespread use in automated construction processes, especially for harsh environments such as underwater. Some contemporary applications of this technology have been tested in underwater environments, but there are still a number of problems to be solved. This study focuses on the current development of 3D printing technology for underwater applications, including the required improvements in the technology itself, as well as new materials. Information about underwater applications involving part fabrication via AM is also provided. The article is based on a literature review that is supplemented by case studies of practical applications. The main findings show that the usage of additive manufacturing in underwater applications can bring a number of advantages—for instance, increasing work safety, limiting the environmental burden, and high efficiency. Currently, only a few prototype applications for this technology have been developed. However, underwater additive manufacturing is a promising tool to develop new, effective applications on a larger scale. The technology itself, as well as the materials used, still require development and optimization.

Eutrophication is one of the major threats to the quality of water in high mountain lakes. The inflow of elements having biological origin may significantly aggravate the ecological status of those ecosystems. For this reason, the aim of this study was to map and assess the impact of anthropogenic pressure on alpine lakes in the valley of Dolina Pięciu Stawów Polskich (known in English as the Valley of Five Polish Lakes) in the Tatra National Park in Poland. The effects of tourism and easy access to alpine lakes on changes in their ecological status were determined. Tourist trails were evaluated based on the difficulty of access to the water surface of analyzed alpine lakes, with a method developed for assessing anthropogenic pressure on aquatic ecosystems. The method, deployed for the first time in 2019, was modified and adapted to the local environmental conditions in the research area. The results of this study indicate that tourism pressure contributes to the growth of submerged vegetation in alpine lakes. The presence of aquatic plants (including vascular plants) shows ecosystem response to water enrichment with biogenic substances. The present findings were used to formulate practical recommendations and propose modifications to the evaluated hiking trails. The research method developed in the study can support analysis and control of tourist traffic, thus reducing anthropogenic pressure on alpine lakes in national parks located in mountain areas.

Tourism pressure on protected areas with attractive landscapes leads to environmental modifications. Eutrophication poses the main threat to the quality of water in alpine lakes. Even small inflows of biogenic elements can disrupt the ecological balance of these ecosystems. The aim of this study was to verify the hypothesis that recreational activities and easy access to alpine lakes contribute to changes in their ecological status. This hypothesis was verified by analyzing the presence of hydromacrophytes in two lakes of the Tatra National Park (Poland). The analysis was carried out along segments of hiking trails which were evaluated for accessibility to the studied lakes. Underwater surveys were carried out during scuba diving expeditions in 2012–2016. Submerged vegetation was evaluated in both lakes. This is the first study in Poland and one of the few projects in the world to have relied on such extensive support from scuba divers to generate highly accurate measurements. The study demonstrated that lake bottoms were extensively covered by Potamogeton friesii in the vicinity of trail segments with easy access to lakes. Our results show that tourism pressure contributes to the growth of aquatic vegetation in some areas of alpine lakes. We relied on our findings to propose several modifications to the routes of the evaluated tourist trails to minimize the impact of anthropogenic pressure on the studied lakes.

In recent years, additive manufacturing technologies have been employed for ecological projects, especially those connected with artificial reefs. This approach brings a lot of advantages, including the design of more complex structures, with surfaces fitted to the needs of water organisms. This technology can effectively support ecological design and engineering, especially in restoration efforts. The main aim of this article is to demonstrate the state of the art and further perspectives for the development of artificial coral reefs. This article is based on a critical analysis of the literature, supported by selected case studies. This article describes current technologies used in the creation of artificial reefs, putting emphasis on additive manufacturing, evaluates currently used materials, and summarizes the influence of this technology on ecosystems through the analysis of selected case studies. It also discusses the challenges and limitations of current technologies used in 3D printing artificial reefs as well as presents current trends and further directions. The most important findings show that the analyzed field is a promising interdisciplinary research area and practical implementations require collaboration between specialists from different branches.

Water from road drainage systems shed into ditches and infiltration reservoirs may pose a hazard to the natural environment due to the possibility of being introduced into groundwater and surface water. The paper presents the results of chemical analyses of samples collected from selected points of the Warsaw agglomeration road drainage system. The samples were tested for the content of the following parameters: pH, EC (multimeter-electrode), Cl⁻ (Mohr method), SO₄²⁻, PO₄³⁻, NH₄⁺, NO₃⁻, TOC, COD (UV-VIS), Cu, Zn, Ni, and Pb (ASA). The analysed points differed significantly in the variability of the tested parameters in the measurement period. The highest values of EC and Cl⁻ were noted in three tested points, in which the EC content exceeded the permissible values for the second class of water quality. The contents of sulphates in all but one point were within the range for water of very good quality. Water pH was slightly alkaline. Low concentrations of nitrogen forms, nitrate and ammonium ions were observed. The concentrations of Ni, Pb and Zn did not exceed the boundary values for industrial sewage shed into the water or ground. The concentration of Cu exceeded the permissible concentrations determined in the Regulation of the Minister of the Environment almost three times.