Process safety challenges for SMEs in China

While process safety regulations and standards have been in place in western countries for more than two decades, China has only recently started to officially embrace these issues with the adoption of its Process Safety Management (PSM) regulation AQ/T 3034-2010 (SAWS, 2010). However, compliance with this regulatory framework requires substantial resources and may therefore appear too complex to be efficiently implemented by small and medium sized enterprises (SMEs) in the chemical sector. This is of particular relevance as about 99% of chemical companies in China are SMEs, accounting for more than 80% of all chemical accidents. To address this issue, additional local regulations and planning activities related to process safety have been implemented in China, including the establishment of hundreds of chemical industry parks. Some of the process safety problems faced by chemical industry parks are identified and discussed in this paper. To help solve these problems, UNEP's “Responsible Production approach for Chemical Hazards Management along the Value-Chain” is introduced in this paper and suggested as a simplified PSM approach targeted specifically at SMEs which, regardless of handling hazardous chemicals in their daily operations, may not have the knowledge or capacity to efficiently implement PSM and may not fall in the scope of the PSM regulation AQ/T 3034-2010. By introducing PSM to SMEs in a more manageable way, relevant steps can be progressively implemented by companies towards full compliance with the current regulatory framework, contributing to increased safety in chemical industry parks in China.     

Dibenzothiophene desulfurization by Gordonia alkanivorans strain 1B using recycled paper sludge hydrolyzate

Enzymatic hydrolyzates of recycled paper sludge were tested as suitable feedstock for biological desulfurization by Gordonia alkanivorans strain 1B. Only the hydrolyzate obtained after enzymatic mixture dialysis (dialyzed hydrolyzate) allowed dibenzothiophene (DBT) desulfurization, in spite of faster bacterial growth did occur on non-dialyzed hydrolyzate. For dialyzed hydrolyzate, 250microM DBT was consumed after 96h displaying a maximum specific productivity of 2-hydroxybiphenyl of 1.1micromol g(-1)(dry cell weight) h(-1). A comparison of the kinetics of biodesulfurization was assessed according to the type of hydrolyzate supplementation. Complete consumption of DBT was observed upon the addition of only phosphates and ammonia although further addition of zinc did increase the 2-hydroxybiphenyl production by 14%. Strain 1B was able to desulfurize a model oil containing DBT, 4-methylDBT and 4,6-dimethylDBT, reducing by 63% the total sulfur content in 168h.     

Modelling the effects of eutrophication, mitigation measures and an extreme flood event on estuarine benthic food webs

Human-mediated and natural disturbances such as nutrient enrichment, habitat modification, and flood events often result in significant shifts in species composition and abundance that translate into changes in the food web structure. Six mass-balanced models were developed using the “Ecopath with Ecosim” software package to assess changes in benthic food web properties in the Mondego estuarine ecosystem (Portugal). Field, laboratory and literature information were used to construct the models. The main study objective was to assess at 2 sites (a Zostera meadow and a bare sediment area) the effects of: (1) a period of anthropogenic enrichment, which led to excessive production of organic matter in the form of algal blooms (1993/1994); (2) the implementation of mitigation measures, following a long period of eutrophication (1999/2000); and (3) a centenary flood (winter 2000/2001). Different numbers of compartments were identified at each site and in each time period. In general, the Zostera site, due to its complex community, showed a higher number of compartments and a higher level of system activity (i.e. sum of consumptions, respiration, flow to detritus, production, total system throughput, net primary production and system omnivory index). The differences at the two sites in the three time periods in the breakdown of throughput were mainly due to differences in the biomass of the primary producers (higher primary production at the Zostera site). Consumption, respiration and flow to detritus were dominated by the grazers Hydrobia ulvae and Scrobicularia plana at the Zostera and bare sediment sites respectively. At both sites, after recovery measures were implemented there was an increase in S. plana and Hediste diversicolor biomass, consumption, respiration and flows to detritus, and a decrease in H. ulvae biomass and associated flows, which increased again after the flood event. The mass-balanced models showed that the trophic structure of the benthic communities in Mondego estuary was affected differently by each disturbance event. Interestingly, in our study a high system throughput seems to be associated with higher stress levels, which contradicts the idea that higher system activity is always a sign of healthier conditions.     

Toxicity evaluation of natural samples from the vicinity of rice fields using two trophic levels

An ecotoxicological screening of environmental samples collected in the vicinity of rice fields followed a combination of physical and chemical measurements and chronic bioassays with two freshwater trophic levels (microalgae: Pseudokirchneriella subcapitata and Chlorella vulgaris; daphnids: Daphnia longispina and Daphnia magna). As so, water and sediment/soil elutriate samples were obtained from three sites: (1) in a canal reach crossing a protected wetland upstream, (2) in a canal reach surrounded by rice fields and (3) in a rice paddy. The sampling was performed before and during the rice culture. During the rice cropping, the whole system quality decreased comparatively to the situation before that period (e.g. nutrient overload, the presence of pesticides in elutriates from sites L2 and L3). This was reinforced by a significant inhibition of both microalgae growth, especially under elutriates. Contrary, the life-history traits of daphnids were significantly stimulated with increasing concentrations of water and elutriates, for both sampling periods.     

Organic matter produced by algae and cyanobacteria: Quantitative and qualitative characterization

This work aims at characterizing organic matter produced by an alga Euglena gracilis and a cyanobacteria Microcystis aeruginosa and assessing the evolution of its characteristics during growth. A culture medium was optimized. The species growth phases were monitored using both visible spectrophotometry and flow cytometry cell counting. Organic matter fractionation according to hydrophobicity and specific UV absorbance (SUVA) index were used to specifically characterize the produced algal organic matter (AOM). The AOM characteristics were both growth phase and species dependent. However, a similar evolution was observed. The hydrophilic fraction (HPI) was the major fraction whatever the growth phases and was almost the only one produced during lag and exponential phases. It represented around 75% of AOM during exponential phase and then decreased when the stationary phase appeared. It represented 46% and 60% of the AOM during late decline phase for the cyanobacteria and the alga respectively. The hydrophobic (HPO) and transphilic (TPH) fractions started to appear from the beginning of the stationary phase with more hydrophobic compounds coming from intracellular organic material of dying cells. HPO and TPH percentages still increased during the decline phase probably because of two additional processes: photo-dissolution and leaching of particulate organic matter from cells fragments. A comparison of AOM during late decline phase and natural organic matter (NOM) from Glane River (France) underlined that AOM was more hydrophilic and presented a lower SUVA for each fractions than NOM. However, the difference between NOM and AOM hydrophobicity narrowed during decline phase.     

Adsorptive and photocatalytic activity of Fe3O4-functionalized multilayer graphene oxide in the treatment of industrial textile wastewater

Environmental Science and Pollution Research - Multilayer graphene oxide (mGO) was synthesized and functionalized via co-precipitation method to produce magnetic Fe3O4-functionalized multilayer...     

Solanum nigrum grown in contaminated soil: effect of arbuscular mycorrhizal fungi on zinc accumulation and histolocalisation

Zn tissue accumulation in Solanum nigrum grown in a non-contaminated and a naturally contaminated Zn matrix and the effect of inoculation with different arbuscular mycorrhizal fungi (AMF) on metal uptake were assessed. S. nigrum grown in the contaminated soil always presented higher Zn accumulation in the tissues, accumulating up to 1622 mg Zn kg(-1). The presence of both Glomus claroideum and Glomus intraradices enhanced the uptake and accumulation of Zn by S. nigrum (up to 83 and 49% higher Zn accumulation, respectively). The main deposits of the metal were found in the intercellular spaces and in the cell walls of the root tissues, as revealed by autometallography, with the inoculation with different AMF species causing no differences in the location of Zn accumulation. These findings indicate that S. nigrum inoculated with selected heavy metal tolerant AMF presents extracting and accumulating capacities, constituting a potentially suitable remediation method for Zn polluted soils.