Anthropocene microplastic stratigraphy of Xiamen Bay, China: A history of plastic production and waste management.

Microplastics (MPs) are considered one of the significant stratigraphic markers of the onset of the Anthropocene Epoch; however, the interconnections between historic plastic production, waste management as well as social-economic and timing of MP accumulation are not well understood. Here, stratigraphic data of MPs from a sediment core from Xiamen Bay, China, was used to reconstruct the history of plastic pollution. Generalized Additive Modeling indicates a complex temporal evolution of MP accumulation. The oldest MPs deposited in 1952 was 30,332 ± 31,457 items/kg•dw, coincide with the infancy of the plastic industry and onset of the Anthropocene. The Cultural Revolution (1966-1976) curtailed these initial increases. Subsequent rapid growth in MPs during the late 1970s was peaked at 189,241 ± 29,495 items/kg•dw in 1988 and was followed by a drastic decline in the late 1980s to a low value in 1996 (16,626 ± 26,371 items/kg•dw), coinciding with proliferation of MP sources, coupled with evolution of plastic production, consumption, and regulation. Increasing MPs over the past decades implies that previous mitigation measures have been compromised by the escalated influx of MPs from increasing plastics production, legacy MPs remaining in circulation and insufficient waste management for a growing population. The present methodology and results represent a conceptual advance in understanding how changes in policy and economics over time correlate to changes in MP records in Anthropocene strata, which may help make decisions on plastic pollution mitigation strategies worldwide.

Study of marine debris around a tourist city in East China: Implication for waste management.

Marine debris characterization is fundamental for developing policies aiming at ending the flow of marine debris at the source. China has the largest coastal population in the world. For this emerging economy, the sources of debris might be different from those in regions at different developmental stages. As a typical coastal tourist city and a special economic zone in East China, there are multiple sources of marine debris continuously produced around Xiamen. Marine debris characterization here could provide insights into regulatory measures. Therefore, the abundance and composition of marine debris around Xiamen were investigated. Average densities of floating, beached, benthic macro-debris and floating microplastics (0.5 mm - 5 mm) were 3963 ±â€¯2027 items km-2, 0.13 ±â€¯0.08 items m-2, 20,274 ±â€¯15,873 items km-2 and 36,455 ±â€¯33,935 items km-2, respectively. Based on the Clean Coast Indexes, the beaches investigated were supposed to be "very clean" most of the time (73.2% ±â€¯34.9%). Wastes with low value for recycling/reuse, such as grocery bags, ropes, and foams, were the main items of marine debris in the study area. Both domestic sources from the upstream and local fishing/aquaculture activities significantly contributed to marine debris. Obvious regional differences in benthic debris categories could be explained by both natural factors and the rural-urban gap in economic levels, waste-management strategies and infrastructure. These might be common features in this emerging market and densely populated economy. The findings provide insights into the sources of mismanaged waste around this tourist city and some neglected deficiencies in China's current solid waste management system.

Microplastic abundance, characteristics, and removal in wastewater treatment plants in a coastal city of China.

Studying the abundance, characteristics, and removal of microplastics (MPs) in wastewater treatment plants (WWTPs) in coastal cities is of great significance for understanding the impacts of human activities on the marine environment, but currently, little information on this topic is available in China. Therefore, the abundance, characteristics, and removal of MPs in seven WWTPs of Xiamen, a typical coastal city in China, are studied. Sixty samples were collected using an improved sampling method involving an electromagnetic flowmeter and a fast digital camera. The influent MPs concentration is 1.57-13.69 items/L, and it is reduced to 0.20-1.73 items/L in the effluent, indicating that 79.3-97.8% MPs is removed. Based on the daily effluent discharge and MPs removal rate, it is estimated that ∼6.5 × 108 MPs are released from the seven WWTPs into the Xiamen Bay each day. The light microscopic and micro-Raman spectroscopic analysis indicates that ∼62.68% of particles are plastic polymers, including polypropylene (31.6%), polyethylene (21.9%), polystyrene (10.1%), propylene/ethylene copolymer (9.2%), and polyethylene terephthalate (7.5%). The color of MPs is mainly composed of white (27.3%) and clears (25.8%). Our results show that granules (41.1%) are the dominant shape of MPs, followed by fragments (31.3%), fibers (23.7%), and pellet (3.9%). The characteristics of MPs such as sizes, shapes, and types affect the MPs removal in WWTPs. Our findings show that MPs concentration in the influent is positively correlated with the suspended solids (SS), however, in the effluent, it is associated with the WWTPs operating load, as reflected by obviously higher MP abundance in overloaded ones.