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Dissolved organic matter (DOM) assists in the phytoremediation of heavy-metal-contaminated soils, but the effect of synergistic remediation of DOM on plants is unclear. This study investigated the effect of two DOM sources (cotton straw (CM) DOM and farmyard manure (FM) DOM) on cadmium (Cd) accumulation in Cd-contaminated soil by cotton and evaluated the phytoremediation effect of DOM. The results showed that adding DOM reduced the available nitrogen and increased organic matter, available phosphorus and available potassium. Applying DOM increased the proportions of Cd acid soluble fractions and reduced the proportions of Cd residual fractions by 1–7%. DOM application increased root length, root surface area and root volume compared to the control and had a promoting or inhibiting effect on cotton biomass, depending on the soil Cd concentration. Furthermore, applying DOM improved the Cd content and bioconcentration factor of cotton. The lower the molecular weight, hydrophilic components and aromaticity of DOM, the more conducive to Cd accumulation is in cotton. The correlation and random forest analyses also showed that CM showed high remediation potential. According to our study, DOM can improve the phytoremediation efficiency of cotton, especially in low-concentration contaminated soils. This study provides a basis for applying DOM in the phytoremediation of Cd-contaminated soils.

Studies in human and non-human primates have confirmed the compensatory enlargement or positive remodeling (Glagov phenomenon) of coronary vessels in the presence of focal stenosis. To our knowledge, this is the first study to document arterial enlargement in a metabolic syndrome animal model with diffuse coronary artery disease (DCAD) in the absence of severe focal stenosis. Two different groups of Ossabaw miniature pigs were fed a high fat atherogenic diet for 4 months (Group I) and 12 months (Group II), respectively. Group I (6 pigs) underwent contrast enhanced computed tomographic angiography (CCTA) and intravascular ultrasound (IVUS) at baseline and after 4 months of high fat diet, whereas Group II (7 pigs) underwent only IVUS at 12 months of high fat diet. IVUS measurements of the left anterior descending (LAD), left circumflex (LCX) and right coronary (RCA) arteries in Group I showed an average increase in their lumen cross-sectional areas (CSA) of 25.8%, 11.4%, and 43.4%, respectively, as compared to baseline. The lumen CSA values of LAD in Group II were found to be between the baseline and 4 month values in Group I. IVUS and CCTA measurements showed a similar trend and positive correlation. Fractional flow reserve (FFR) was 0.91 ± 0.07 at baseline and 0.93 ± 0.05 at 4 months with only 2.2%, 1.6% and 1% stenosis in the LAD, LCX and RCA, respectively. The relation between percent stenosis and lumen CSA shows a classical Glagov phenomenon in this animal model of DCAD.

Microbial biosurfactants are surface-active agents synthesized by microbial cultures. Biosurfactants consist of hydrophilic and hydrophobic molecules, just as other chemical surfactants. Thus, biosurfactants can reduce surface tension (air-water), and interfacial tension (IFT) in liquid-liquid and liquid-solid systems (e.g. wetting phenomena). Tests of five biosurfactants showed that the surface tension of rhamnollpids and sophorolipids/trehalolipids is 27.0 and 26.9 mN/M, respectively, and the critical micelle concentration is 0.0016 and 0.0015 wt%, respectively. Experiments show that interfacial tension between solutions of trehalolipids and rhamnolipids and Daqing degassed oil at the Daqing oil field (temperature 45°C, average salinity of formation water 4456 ppm) is 0.4 and 0.6 mN/m, respectively. Better systems, with mixtures of trehalolipids and rhamnolipids, or trehalolipids and synthetic sulfonates 3A were obtained, and interfacial tension between the system and the Daqing degassed oil reached 0.1 mN/m. The interfacial tension between alkaline solutions (NaOH) with trehalolipids and Daqing dressed oil is 0.03 mN/m when the alkalinity is 0.8 wt%. Mixtures of trehalolipids and petroleum sulfonates show efficient synergism; the IFT between the mixtures and Daqing degassed oil of low acidity reached very low values of 0.006 mN/m when the concentration of total surfactants was 0.4 wt% and alkalinity was 0.5 wt%. When alkaline concentration was 1.0 wt%, the interfacial tension fell to 0.002 mN/m. The salinity requirement diagram (SRD) shows that ultralow IFTs can be reached with the total surfactant concentration between 0.2–0.6 wt% and salinity below 15000 ppm. The results in the flooded core show that tertiary recovery can be increased by 11.3% and water cut can be reduced from 98% to 74%.

Since many of the main oil fields in China such as Daqing, Shengli, Karamai, etc., have been waterflooded for more than twenty years, the water content of the producing fluids runs as high as 75–80%. Consequently, tertiary recovery is urgently needed to improve the producing conditions and to increase the ultimate yields of these oil fields. Microbiological tertiary recovery, among other tertiary methods has been receiving considerable attention by our oil industry. Hence, we present an overview of the activities in this field in China that was introduced at the First International MEOR Conference in 1982.