Dynamic extreme values modeling and monitoring by means of sea shores water quality biomarkers and valvometry

Water quality can be evaluated using biomarkers such as tissular enzymatic activities of endemic species. Measurement of molluscs bivalves activity at high frequency (e.g., valvometry) during a long time period is another way to record the animal behavior and to evaluate perturbations of the water quality in real time. As the pollution affects the activity of oysters, we consider the valves opening and closing velocities to monitor the water quality assessment. We propose to model the huge volume of velocity data collected in the framework of valvometry using a new nonparametric extreme values statistical model. The objective is to estimate the tail probabilities and the extreme quantiles of the distribution of valve closing velocity. The tail of the distribution function of valve closing velocity is modeled by a Pareto distribution with parameter ??_t,τ, beyond a threshold τ according to the time t of the experiment. Our modeling approach reveals the dependence between the specific activity of two enzymatic biomarkers (Glutathione-S-transferase and acetylcholinesterase) and the continuous recording of oyster valve velocity, proving the suitability of this tool for water quality assessment. Thus, valvometry allows in real-time in situ analysis of the bivalves behavior and appears as an effective early warning tool in ecological risk assessment and marine environment monitoring.     

Radiosynthesis of perfluorooctanesulfonate (PFOS) and perfluorobutanesulfonate (PFBS), including solubility, partition and adhesion studies

Here, we describe for the first time the synthesis of [³⁵S] PFOS and [³⁵S] PFBS with sulfur-35 enriched sulfur dioxide as the radiolabelled reagent, resulting in 2.5 and 2.3 mCi of product, respectively. Basic information concerning the physicochemical properties of perfluorooctanesulfonate (PFOS), perfluorobutanesulfonate (PFBS) and perfluorooctanoic acid (PFOA) are still limited. Hence, we utilized these radiolabelled perfluoroalkanesulfonates (PFSAs), as well as carbon-14 labelled perfluorooctanoic acid ([¹⁴C] PFOA) to determine some basic characteristics of physiological and experimental significance.The solubility of PFOS in buffered aqueous solutions at pH 7.4 was found to be severely reduced in the presence of potassium and sodium ions, which, however, did not reduce the solubility of PFOA or PFBS. PFOS was found to adhere to a small extent to polypropylene and polystyrene, whereas no such adhesion of PFOA or PFBS was detected. The extents of adhesion of PFOS and PFOA to glass were found to be 20% and 10%, respectively. For the first time, the partition coefficients for PFOS, PFBS and PFOA between n-octanol and water were determined experimentally, to be −0.7, −0.3, and 1.4, respectively, reflecting the difference in the amphiphilic natures of these molecules.     

Solid waste management associated with the development of 3R initiatives: case study in major urban areas of Vietnam

The purpose of this article is to describe the application and progress of the Reduce-Reuse-Recycle (3R) initiative and its gradual implementation and development in solid waste management in Vietnam through the study of the municipal solid waste management (MSWM) systems of eight major urban cities and provinces. The resulting survey and studies showed that there are big challenges for MSWM in the study areas due to the absence of an appropriate master plan for MSWM; there is a clear need to set up indicators for waste reduction and greenhouse gas emission reduction from waste generators and enterprises involved in MSWM, especially in terms of using 3R activities in the management of industrial waste. The strength and organic combination of institutional frameworks, support measures, and technologies for 3R promotion need to be applied as soon as possible in order to implement MSWM practices using more effective measures; in particular, a reduction in the amount of hazardous substances discarded and improvements in the handling of hazardous waste are required.     

Contamination of drinking water resources in the Mekong delta floodplains: arsenic and other trace metals pose serious health risks to population

This study presents a transnational groundwater survey of the 62,000 km(2) Mekong delta floodplain (Southern Vietnam and bordering Cambodia) and assesses human health risks associated with elevated concentrations of dissolved toxic elements. The lower Mekong delta generally features saline groundwater. However, where groundwater salinity is <1 g L(-)(1) Total Dissolved Solids (TDS), the rural population started exploiting shallow groundwater as drinking water in replacement of microbially contaminated surface water. In groundwater used as drinking water, arsenic concentrations ranged from 0.1-1340 microg L(-)(1), with 37% of the studied wells exceeding the WHO guidelines of 10 microg L(-)(1) arsenic. In addition, 50% exceeded the manganese WHO guideline of 0.4 mg L(-)(1), with concentrations being particularly high in Vietnam (range 1.0-34 mg L(-)(1)). Other elements of (minor) concern are Ba, Cd, Ni, Se, Pb and U. Our measurements imply that groundwater contamination is of geogenic origin and caused by natural anoxic conditions in the aquifers. Chronic arsenic poisoning is the most serious health risk for the ~2 million people drinking this groundwater without treatment, followed by malfunction in children's development through excessive manganese uptake. Government agencies, water specialists and scientists must get aware of the serious situation. Mitigation measures are urgently needed to protect the unaware people from such health problems.     

Towards eco-agro industrial clusters in aquatic production: the case of shrimp processing industry in Vietnam

The concept of industrial ecology has been applied in this research to study possibilities to develop an eco-industrial cluster model for fishery production industry in Vietnam. By learning from experiments of other developed countries, we apply the principles of Industrial Ecology and of Ecological Modernization in the context of Vietnam. We design a physical-technological conceptual model for minimizing waste in agro-industries, with a case study of frozen shrimp production. The results indicate that it is possible and feasible to develop an eco-industrial cluster including aquaculture, fishery processing companies, by-product plants, and wastewater treatment units. By doing so, aquaculture and industry can cooperate for environmentally sound development. Actors and institutions that may govern the proposed eco-industrial cluster of shrimp processing industry are also analysed in this paper. The economic feasibility of the designed eco-agro industrial cluster for fish production in Vietnam depends on the energy savings and effective revenues gained from selling the produced valuable materials, such as Chitosan and animal feed.     

Prediction of groundwater nitrate concentration in a semiarid region using hybrid Bayesian artificial intelligence approaches

Environmental Science and Pollution Research - Nitrate is a major pollutant in groundwater whose main source is municipal wastewater and agricultural activities. In the present study, Bayesian...     

Ionomics and metabolomics analysis reveal the molecular mechanism of metal tolerance of Pteris vittata L. dominating in a mining site in Thai Nguyen province,Vietnam

Environmental Science and Pollution Research - This study aims to find the interaction between ionome and metabolome profiles of Pteris vittata L., an arsenic hyperaccumulator plant, to reveal its...     

Market governance for safe food in developing countries: The case of low-pesticide vegetables in Vietnam

In many developed countries private arrangements have emerged in food governance. Following limited successes of state regulation, market actors and mechanisms are increasingly included in the environmental and safety governance of domestic and global food chains and networks. But do such private governance arrangements also work in domestic markets in developing countries? Pesticide use in vegetable supply is taken as a case to explore the role of market actors and dynamics in food safety governance in Vietnam. The so-called safe vegetable production system in the Red River Delta, introduced 10 years ago as a domestic alternative to conventional vegetable production, is analyzed through detailed monitoring of farmers, surveys of retailers and consumers, and in-depth interviews with state officials and vegetable traders. The paper finds limited success of this low-pesticide vegetable production, distribution and consumption system. This private arrangement in food governance lacked trust from market actors (especially consumers), and was short of an active state that organized transparency and got market actors involved. As such, market governance in food safety needs to be strong.     

Environmental performance improvement for small and medium-sized slaughterhouses in Vietnam

Slaughtering cattle and pigs is good business nowadays in Vietnam and in Ho Chi Minh City alone there are already 42 slaughter units. Though slaughtering has for a long time been considered a low-technology operation and thus not the sort of subject to be taken seriously by researchers, the recent increase of public awareness on environmental problems caused by this activity however attracts more attention. This article provides an analysis of the environmental impacts caused by the small- and medium-sized slaughterhouses in the Ho Chi Minh City and describes the shortcomings and causes of its present poor environmental performance and management. The main environmental problems caused by the small- and medium-sized slaughterhouses are the uncontrolled use of ground water and the discharge of untreated wastewater with high concentrations of organics including animal feces and blood, parasite eggs and pathogenic bacteria that might easily contaminate the receiving environment and endanger human health. The article concludes that the application of a pollution-prevention concept is crucial to improve the environmental performance of small- and medium-sized slaughterhouses in Vietnam.     

Software for Sustainability Assessment: a Case Study in Quang Tri Province,Vietnam

Sustainable development is a widespread concept. Indicator selection and sustainability assessment are basic methods to analyse the sustainable development process. This study aims to develop a software application to select indicators and to allocate weightings to the indicators and the sub-indexes, so that they can be listed in a sustainability assessment. The Visual Basic software is used to develop a software package based on Delphi, analytic hierarchy, normalization and combination processes. Software for sustainability assessment was developed. Thirty-five indicators are selected as a first step of which eight health indicators and eight environmental ones and their sub-indexes are given weightings. The indicators are normalized. Sub-indexes are combined into a composite sustainable development index. The model is validated showing the ‘main features’ of the sustainability situation on health and environmental aspects in the Quang Tri province during the period 2000–2005. The results support the decision-making process of the competent authorities.