Parks and Recreational Areas as Sinks of Plastic Debris in Urban Sites: The Case of Light-Density Microplastics in the City of Amsterdam, The Netherlands

Soils of parks and recreational areas are potential sinks of microplastics because they are under multifunctional use. The aims of this research were to quantify and determine the types and abundance of light-density microplastics in one of the most cosmopolitan cities of the world: Amsterdam, the Netherlands. Therefore, potential differences between the city districts were explored through the assessment of light-density microplastics’ concentrations in soils together with the soil properties. Microplastics were extracted from 74 soil samples. Predictions of microplastic concentrations and soil characteristics were made for the entire city by using ordinary kriging; 97% of the samples contained microplastic particles (MPPs), and on average, there were 4825.31 ± 6513.85 MPP/kg soil. A total of 21 hotspot samples were identified, and all of them contained LDPE, which represented 40.82% of the plastic types, in addition to 35.06% PAC and 15.58% natural polyamide. Other types of plastics were PP (0.19%), PS (1.30%), bioplastic (0.19%), PA (0.37%), PU (0.56), PVC (0.19%), and unidentified plastics (0.19%). There were no significant differences in MPP concentration between city districts. Our results showed that MPPs are abundant in urban soils, which represents a high risk for soil life. Further studies are required for identifying the sources of this pollution.

Photodynamic therapy in tuberculous pleural empyema

as a lethal outcome predictor. To enhance treatment efficacy, TPE local sanitation method utilizing antimicrobial photodynamic therapy (PDT) has been developed. This technique is based on the generation of oxygen radicals by the interaction of photosensitizers and light quanta which inactivate Mycobacterium tuberculosis and pyogenic flora. To assess the sanitizing and antimicrobial efficacy of PDT, 96 procedures were performed in 16 patients (in 14 cases, TPE was complicated by bronchopleural fistula, in 10 cases it developed after surgical treatment of pulmonary tuberculosis). After intrapleural instillation of phthalocyanine aluminum 0.5 mg, all walls of the empyema cavity were irradiated by laser radiation with the wavelength of 662 nm and light density of 30-100 J/cm2. The response to PDT of tuberculous pleural empyema was reported in 93.75% of cases (n = 15), with complete response observed in 75% of cases (n = 12).

Sources of Light Density Microplastic Related to Two Agricultural Practices: The Use of Compost and Plastic Mulch

Microplastics (MPs) constitute a known, undesirable contaminant of the ecosystems. Land-based pollution is considered to be an important contributor, but microplastics in the terrestrial environment remains largely unquantified. Some agriculture practices, such as plastic mulch and compost application, are suspected to be major sources of microplastics as plastics are exposed to weathering or are present in organic fertilizers. The overall aim of this research is to bridge the terrestrial plastic contamination information gap, focusing on light density microplastics in two vegetable production systems in Southeast Spain and in the Netherlands. The selected farmer in Spain used plastic mulch for more than 12 years whereas the two farmers in the Netherlands annually applied 10 t ha−1 compost for the past 7 and 20 years. Samples from two different depths were collected: 0–10 cm and 10–30 cm. High quality compost samples originating from municipal organic waste and from garden and greenhouse waste were obtained from two Dutch compost plants. All samples from both Spanish (n = 29) and Dutch (n = 40) soils were contaminated by microplastics, containing 2242 ± 984 MPs kg−1 and 888 ± 500 MPs kg−1, respectively. Compost samples from municipal organic waste (n = 9) were more contaminated than the ones from garden and green house wastes (n = 19), with, respectively, 2800 ± 616 MPs kg−1 and 1253 ± 561 MPs kg−1. These results highlight the need for studies focusing on the effects of microplastics in the environment and the need for monitoring campaigns and the implementation of thresholds to regulate the microplastic contamination.

Utilization of the light density to reduce the development of Lyngbya sp. and their growth on Caulerpa lentillifera J. Agardh in a recirculating aquature system

The release of pollutants is endangering ecosystems, biodiversity and seafood. Therefore, it is of the requirement to create innovative methods in seafood production. Caulerpa lentillifera J. Agardh is a well-known seaweed for its properties and edible. We cultured C. lentillifera in a recirculating aquaculture system under laboratory conditions. However, after 7 days the culture was invaded by epiphyte algae Lyngbya sp. This experiment was designed to remove those algae by using light density as a treatment. Two irradiances were tested including 20 μmol photons m-2.s-1 (low light density) and 40 μmol photons m-2.s-1 (initial light density). Every week we measured the stolon length, thallus weight, and calculated the specific growth rate. Results showed that after 30 days C. lentillifera under low light density regained their healthy green color and Lyngbya sp. was no longer present. Meanwhile, in the initial light density (40 μmol photons m-2.s-1) Lyngbya sp. covered almost all thalli of C. lentillifera, and half of them were dead. The measured results of specific growth rate (%d-1) and weight (g) of C. lentillifera in low light density conditions were better than those of C. lentillifera in the initial condition. The light density, therefore, might be used as a treatment to remove Lyngbya sp. from Caulerpa lentillifera in aquaculture.

Robot for Under Water Monitoring

Unmanned underwater vehicle is the branch of robotics which comes under the autonomous underwater vehicle. These robots have the wide applications like research, collection of the samples and observation of underwater bodies. The proposed work involves underwater robot for measuring the parameters of water and surveillances for inspecting underwater structure. The contamination of the water bodies can be found out by using the light density method. The evaporation level of water bodies can be studied through temperature measurements and also the acidic and alkaline nature of the water can be seen through pH measurement. To move easily through any standard inspection doors, the robot is designed with the length of 240 mm, breadth 94.68mm and height of 130mm by considering the mass to length calculation method based on floating theory. In addition, this robot is fitted with air tubes of dimension 81.5mm which is a standard size for 5kg robot. This work makes use of Arduino UNO commands to control the motors, light density measurement and water sample collection and communication through Bluetooth communication between the user and the float which floats on the surface of water. The customized mobile application makes the robot user friendly and easily controllable. In this work, an underwater 4K ultra HD camera is fitted to the hardware. This camera is used to record the underwater view. The recorded sequences of images stored in micro SD card are used to analyze surrounding objects in the target area. All the elements connected to the Arduino are controlled by the user. The robot is designed for monitoring the under water.