Marine litter pollution along sandy beaches of Can Gio coast, Ho Chi Minh City, Vietnam

Marine debris is a significant threat to the marine environment, human health and the economy in Can Gio island, Vietnam. In this study, we conducted beach litter surveys to quantify and characterize marine litter from six beach transects in this region for the first time using the OSPAR beach litter monitoring guideline. A total of 29,456 items weighting 529,432 g was recorded from 12 surveys in two monitoring campaigns in December 2019 (dry season) and in June 2020 (rainy season). Plastic was the most abundant type of litter in terms of quantity (a total of 26,662 items) and weight (325,606 g), followed by paper and cardboard, cloth, wood, metal, glass and ceramics, rubber and other items. Meanwhile, ropes (less than 1 cm in diameter) and plastic bags accounted for the major parts of sampled plastic items, i.e., 20.18% and 14.46%, respectively. In general, a higher percentage of marine litter, particularly the fishing related items, was found in the rainy season than in the dry season, possibly due to increased fishing and aquaculture activities. In contrast, a reduction pattern of the single use plastics in the rainy season might be due to the decreased tourism activities during the Covid pandemic period. This study not only showed the magnitude of litter pollution, but also provided valuable information that could help decision making to better control and reduce marine litter in the region. In addition, insights from this study indicate that there is an urgent need to design collection, reuse and recycling programs in the area. The collected recyclables, specially plastics, will be a great source of materials for recyclers in a circular economy achieving sustainable development goals.

Qualitative and Quantitative Beach Cleanliness Assessment to Support Marine Litter Management in Tropical Destinations

In addition to its ecological and recreational relevance, beach cleanliness is also one of the five most important aspects (i.e., the “Big Five”) for beach visitors around the world. Nonetheless, few efforts have been carried out to guide the sound management of this rising issue. This paper presents a quantitative and qualitative method to assess the level of beach cleanliness, in order to allow managers to focus their attention on the environmental management of the most frequent and relevant types of litter in tropical areas. In a first step, a survey on users’ perception was applied to 361 beachgoers in eight beaches in Colombia to identify the most relevant types of beach litter and the weighting factors to obtain quantitative calculations. In a second step, the thirteen categories of litter identified were analyzed in relation to beach cleanliness, origin of litter, and environmental impact, to define its individual weighting importance. Some categories were also selected according to particularities of tropical countries, such as the presence of abundant natural vegetation debris and gross polystyrene items, largely transported by rivers in great quantities. In a third step, the method was then tested at eight beaches in the Caribbean coast of Colombia through a period of four months, during which 192 transect samplings were carried out. The qualitative module of the proposed technique, named Beach Litter Assessment Technique—Qualitative and Quantitative (BLAT-QQ), identified the main types of beach litter and the quantitative module gave an overview on the state of beach cleanliness. The method is demonstrated to be quick and effective in diagnosing beach cleanliness, providing a simple instrument to carry out sound environmental management actions in coastal destinations.

Quantifying Marine Plastic Debris in a Beach Environment Using Spectral Analysis

Marine plastic debris (MPD) is a globally relevant environmental challenge, with an estimated 8 million tons of synthetic debris entering the marine environment each year. Plastic has been found in all parts of the marine environment, including the surface layers of the ocean, within the water column, in coastal waters, on the benthic layer and on beaches. While research on detecting MPD using remote sensing is increasing, most of it focuses on detecting floating debris in open waters, rather than detecting MPD on beaches. However, beaches present challenges that are unique from other parts of the marine environment. In order to better understand the spectral properties of beached MPD, we present the SWIR reflectance of weathered MPD and virgin plastics over a sandy substrate. We conducted spectral feature analysis on the different plastic groups to better understand the impact that polymers have on our ability to detect synthetic debris at sub-pixel surface covers that occur on beaches. Our results show that the minimum surface cover required to detect MPD on a sandy surface varies between 2–8% for different polymer types. Furthermore, plastic composition affects the magnitude of spectral absorption. This suggests that variation in both surface cover and polymer type will inform the efficacy of beach litter detection methods.