Analysis on determinants of carbon emissions from plaza ground paving during the construction stage based on life cycle assessment.

The carbon emissions of paving projects are the focus of urban managers and researchers. By introducing the life cycle assessment (LCA) method and drawing up the study time and boundary, this study analyzed the carbon emissions activities of the plaza ground paving project and established a computational model of the cast-in-place architectural concrete (CAC) and natural stone pavement's life cycle during the construction stage by comprehensively utilizing the carbon emission coefficient method and the direct source consumption statistics method of the production line. Based on the model, this study employed the ground paving of a top-notch Theme Park Plaza in Beijing as a sample to calculate the carbon emissions of two different types of building materials at various phases of their life cycle and made a comparative evaluation. It is concluded that the carbon emissions (expressed in CO2) produced by the CAC ground in the sample area is 75.46 kg CO2/m2, while that of the natural stone pavement is 110.81 kg CO2/m2. Our results demonstrate significantly linear relationship between the overall emissions of carbon and the material carbon factor. This study adds to the body of knowledge by calculating the carbon emissions and determining the trend of carbon footprint for ground paving. Furthermore, the study's findings can be used to enhance construction management options and choose green materials. The findings can also be used to provide supporting theories for the development of regulations and carbon reduction policies based on constructing energy conservation and greenhouse gas reduction.

Occurrence, trophic magnification and potential risk of short-chain chlorinated paraffins in coral reef fish from the Nansha Islands, South China Sea.

As emerging persistent organic pollutants in marine environment, short-chain chlorinated paraffins (SCCPs) have attracted increasing attentions recently. Coral reefs are important ocean ecosystems. However, data on SCCP pollution in the coral reef regions is still unavailable. In the present work, bioaccumulation of SCCPs in the coral reef ecosystems was reported for the first time. SCCP concentrations in coral reef fish from the Nansha Islands of the South China Sea were in the range of 37.9-25,400 ng/g lipid weight (lw) (average: 4400 ± 6590 ng/g lw; median: 1020 ng/g lw). C10 SCCPs were the dominating SCCP homologues, accounting for 59% to 80% of the total SCCPs (average: 70 ± 5.0%), followed by C11 SCCPs (average: 23 ± 4.5%). Regarding chlorine substitution, SCCPs were dominated by Cl7 SCCPs (average: 45 ± 2.5%) and Cl8 SCCPs (average: 30 ± 5.4%). Trophic magnification factor (TMF) of total SCCPs was 8.5, indicating trophic magnification potential of SCCPs in the coral reef ecosystems. In addition, a parabolic relationship was established between TMFs and log Kow of specific SCCP homologues. SCCP residues in the coral reef fish from the Nansha Islands of the South China Sea did not pose significant risk to human health.

Distribution characteristics of microplastics in Zhubi Reef from South China Sea.

As a new type of emerging pollutant in the ocean, microplastics have received global attention in recent years. Considering the increasing amount of human activities around the South China Sea, it is important to determine the current status of microplastic pollution in this region. In this study, we analyzed the abundance and distribution of microplastics at Zhubi Reef in the South China Sea. Microplastic abundance ranged from 1400 to 8100 items/m3 of surface water, which was much higher than the values reported from other ocean areas. About 80% of the microplastics were smaller than 0.5 mm in size. Fibers and pellets comprised the most common microplastic types. The dominant microplastics were transparent or blue in color. The main polymer types were polypropylene (25%) and polyamide (18%). In general, our results revealed Zhubi Reef was contaminated with microplastics, which were likely derived from the intensive fisheries in the area and emissions from coastal cities. This study also provides baseline data that are useful for additional studies of microplastics in the South China Sea.

Microplastic pollution in water and fish samples around Nanxun Reef in Nansha Islands, South China Sea.

Nanxun Reef is one of the typical reefs in Nansha Islands, South China Sea. As the Nansha Islands are surrounded by certain developing countries, the economic and population growth have resulted in increased surface runoff of persistent organic pollutants in offshore areas. Microplastic has been found in many freshwaters and sea areas in recent years. However, the levels of microplastics contamination in Nansha Islands are still uncharted. In this study, 15 water and 35 fish samples were collected around the Nanxun Reef. The average concentration of microplastics was 1733 items/m3 for surface water samples and 3.1 items per individual for fish samples. The majority of ingested microplastics by fish were fibers, mostly transparent or blue. In surface water samples, blue microbeads were the main types of microplastics, accounting for 76.5% of all the detected particles. The main size of microplastics was <0.5 mm both in water and fish samples. Our results demonstrated that fishery activities and human domestic sewage might be the dominant sources of microplastic pollution in the Nansha Island, South China Sea.

Persistent halogenated organic pollutants in follicular fluid of women undergoing in vitro fertilization from China: Occurrence, congener profiles, and possible sources.

Analysis of persistent halogenated organic pollutants (HOPs) in human follicular fluid is important given previous reports of their adverse effects on the reproductivity of women. In the present work, HOPs, including polybrominated diphenyl ethers (PBDEs) and polychlorinated biphenyls (PCBs), were analyzed in 127 follicular fluid samples collected from patients who were undergoing in vitro fertilization in Central China. The concentrations of ∑7BDEs (sum of BDE-28, -47, -99, -100, -153, -154, and -183) in follicular fluid ranged from not detected (n.d.) to 110 ng/g lipid weight (lw), with an average of 50 ±â€¯24 ng/g lw. BDE-100 was suggested to be an indicator of BDE congeners in follicular fluid, with the highest concentrations and showing a significantly high correlation (p < 0.01) with ∑7BDEs. Penta-BDE products were the principal source of PBDEs in follicular fluid samples. The concentrations of ∑7CBs (CB-28, -52, -101, -118, -138, -153, and -180) in follicular fluids ranged from n.d. to 250 ng/g lw, with an average of 77 ±â€¯69 ng/g lw. CB-28 and CB-52 were considered to be indicator CB congeners, with tri-CBs and tetra-CBs dominating in follicular fluid. No significant correlation was observed between patient age and PBDE or PCB concentrations in follicular fluid, indicating that age was not the controlling factor influencing the bioaccumulation of most HOPs in this study.

Microplastic abundance, distribution and composition in the Pearl River along Guangzhou city and Pearl River estuary, China.

Like many urban rivers, the Pearl River in China is contaminated with microplastics. Compared with marine environments, microplastic pollution in freshwater is less understood, especially in urban rivers. In the present study, the abundance and distribution of microplastics in water from the Pearl River was investigated, including the estuary and the urban section along Guangzhou. The average abundance of microplastics was 19,860 items/m3 and 8902 items/m3 in the urban section and estuary, respectively. Wastewater effluents from cities might be a main source of microplastics in the Pearl River, and the urban tributaries might act as retention systems for microplastics. Among these microplastics, over 80% of them were less than 0.5 mm. The main shapes of microplastics were film, fragment, and fiber, mostly blue or transparent. Moreover, the most common polymer types of these microplastics were polyamide (26.2%) and cellophane (23.1%). This study reveals the contamination and characteristics of microplastics in the Pearl River, and provides important data for further research on microplastics in freshwater ecosystems.

Occurrence and Toxicological Risk Assessment of Polycyclic Aromatic Hydrocarbons and Heavy Metals in Drinking Water Resources of Southern China.

Polycyclic aromatic hydrocarbons (PAHs) and heavy metals exposure is related to a variety of diseases and cancer development, posing a great health risk to humans. In this study, water samples were collected from nine important water sources in Guangdong, Guangxi and Hainan provinces to determine the degree of PAHs and heavy metals contamination. Overall, the total contents of 16 PAHs and heavy metals were found within the permissible levels. In human health risk assessment, the benzo(a)pyrene equivalent concentration (BaPeq) presented a much lower level than the guideline values announced by Chinese Environmental Protection Agency (CEPA) and United States Environmental Protection Agency (US EPA), demonstrating that the PAHs contamination level in drinking water was mostly acceptable. For heavy metals, the Chronic daily intake (CDI), hazard quotient (HQ) or hazard index (HI) suggested that the water quality in nine water sources was desirable and did not present a risk to human health.

The Risk of Polychlorinated Biphenyls Facilitating Tumors in Hawaiian Green Sea Turtles (Chelonia mydas).

The Hawaiian green turtle (Chelonia mydas) is on the list of threatened species protected under the U.S. Endangered Species Act in 1978 in large part due to a severe tumor-forming disease named fibropapillomatosis. Chemical pollution is a prime suspect threatening the survival of C. mydas. In this study, PCBs concentrations were determined in 43 C. mydas plasma samples archived on Tern Island. The total PCBs concentration in male C. mydas (mean 1.10 ng/mL) was two times more than that of females (mean 0.43 ng/mL). The relationship between straight carapace length and PCBs concentration in females has also been studied, which was negatively related. To figure out the possible existence of correlations between PCBs and tumor status, we measured the PCBs concentration in turtles with no tumor, moderate or severe tumor affliction. PCBs concentration of two afflicted groups was much higher than the healthy group, suggesting that PCBs may play a role in fibropapillomatosis in Hawaiian green turtle.

Tetracyclines, sulfonamides and quinolones and their corresponding resistance genes in the Three Gorges Reservoir, China.

The Three Gorges Project significantly impacted water quality and ecological balance in this area. The special engineered aquatic environment could be an important reservoir for antibiotic resistance genes (ARGs). Fifteen ARGs corresponding to three groups of antibiotics (tetracyclines, sulfonamides and quinolones) were determined in surface water, soil and sediment in this study. Total concentrations of antibiotics ranged from 21.55 to 536.86ng/L, 3.69 to 438.76ng/g, 15.78 to 213.84ng/g in water, soil and sediment, respectively. Polymerase chain reaction (PCR) of ARGs revealed the presence of two sulfonamide resistance genes (sul1, sul2), five tetracycline resistance genes (tetA, tetB, tetM, tetQ, tetG) and class 1 integron gene (intI1) in all samples. And the relative abundance of sulfonamide resistance genes was generally higher than tetracycline resistance genes in three matrices. Significant correlations (p<0.05) were found between the concentrations of intI1 and ARGs (tetA, tetB, tetM, tetQ, tetG, sul1, sul2), indicating intI1 may facilitate the proliferation and propagation of these genes. Redundancy analysis (RDA) showed distribution of ARGs was related to the certain antibiotics residues, which may exert selective pressure on bacteria and thus enrich the abundance of ARGs. The results of this study could provide useful information for both better understanding and management of the contamination caused by ARGs and related antibiotics in engineered aquatic environments.