PESTICIDES, AGRICULTURAL chemicals, POLLUTANTS, SURFACE active agents, and ORGANIC chemistry
Abstract
Two predominant perfluorinated compounds (PFCs), Perfluorooctane sulfonate (PFOS) and perfluorooctanoate (PFOA), in surface water (SW, 0-20 cm), subsurface water (SSW, >30 cm depth), and sea surface microlayer (SML 50 μm thickness) were measured from Dalian Coastal waters in China. The SML samples were collected using glass-plate dipping method. Analysis of the PFCs was conducted through solid-phase extraction, followed by LC/MS-SIM. The PFC's concentrations in SW samples were consistent with previously reported data in this region. Significantly higher concentrations of PFCs were found in SML samples than corresponding SSW samples. The enrichment factors (EF = CSML/CSSW) for PFOS were as high as 24-109 at three near-shore sites. The concentration in SW was also generally higher than corresponding SSW samples, giving Csw/Cssw mean ratios of 1.5 and 1.4 for PFOS and PFOA, respectively. This apparent enrichment of PFCs in surface water, especially in the microlayer, has implications for designing measurement techniques, understanding their distributions, and sea spray-mediated transport in the environment [ABSTRACT FROM AUTHOR]
INDUSTRIAL wastes, HEAVY metals, ORGANIC chemistry, BIOCONCENTRATION, and CHEMICAL reactions
Abstract
Heavy metals and arsenic contamination in municipal solid waste (MSW) and its treatment products has garnered increasing attention. This study investigated the heavy metals and arsenic flows in organic fractions of MSW (OFMSW) in Shanghai, China, through a one-year monitoring program. The OFMSW separated directly from the source (source- separated, pure organic waste), obtained from the treatment facilities were sampled and compared with pure foodstuffs. The heavy metals and arsenic contents in the source-separated OFMSW resembled those in foodstuffs, whereas the OFMSW from the treatment facilities was significantly contaminated with heavy metals and arsenic and failed to meet the government standards for land use. Using flow analysis, >80% of heavy metals and arsenic were from extrinsic inorganic waste with high ash content that was combined with OFMSW during MSW collection, transfer, transportation, and storage stages. Based on source analysis of heavy metals and arsenic, suggestions for reducing heavy metals and arsenic contents in the current MSW management system in Shanghai are presented. [ABSTRACT FROM AUTHOR]
The atmospheric outflow of polycyclic aromatic hydrocarbons (PAHs) from Guangdong, China, a region of high PAH emission, was modeled using a potential receptor influence function (PRIF) probabilistic model which was based on a spatially resolved PAH inventory and air mass forward-trajectory calculations. Photochemical degradation and deposition (dry and wet) of PAHs during atmospheric transport were taken into consideration. On average, 48% of the PAHs (by mass) remained in the atmosphere for a transport period of 5 days, staying within the boundary of the source region. The medium molecular weight PAHs (four rings) were predicted to travel longer distances in the atmosphere than the low (three rings) or high molecular weight PAHs (five rings) because they are less photodegradable than the lower molecular weight, gas-phase PAHs and less likely to undergo wet and dry depositions than the higher molecular weight, particulate phase PAHs. Under the strong influence of the East Asian monsoons in winter, the predominant outflow pattern of PAHs from Guangdong was to the South China Sea and Southeast Asian countries. In summer, PAHs were transported primarily to northern mainland China. Under particular weather conditions in winter, the PAH-containing air masses were lifted by cold fronts or convection and transported toward the Pacific Ocean by westerly winds. In addition to the distinct seasonality in PAH dispersion and outflow, inter annual long-term variation in the outflow is likely influenced by El Niño and southern oscillation. [ABSTRACT FROM AUTHOR]