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.     

Predators use environmental cues to discriminate between prey

The cognitive processes of predators play a central role in the evolution of prey characters. Numerous studies have shown that vertebrate predators may learn to associate the characteristics of prey (e.g. color) with the cost or benefit of ingesting them, thus forming preferences and aversions for different kinds of prey. Although the distribution and quality of prey types can differ between environmental contexts, which may make it profitable to attack a prey type in some contexts but not in others, the influence of environmental cues in decisions to attack has rarely been addressed. Recent theory suggests that modification of prey preferences by environmental cues such as microhabitat or temperature may influence the evolution of prey characteristics. Here, we show that the environmental foraging context may determine prey choice in great tits (Parus major) through learned association between the prey phenotype (appearance and palatability) and a contextual background cue. The same individuals were able to learn and maintain two different sets of food preferences and aversions for use in two different environmental contexts (aviaries with red or blue wooden boards), indicating a role for contextual learning in vertebrate foraging behavior.     

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.     

Transport of Cryptosporidium parvum oocysts in sandy soil: impact of length scale

The objective of this study was to investigate the impact of length scale (travel distance) on the retention and transport of Cryptosporidium oocysts in a sandy soil. Long columns (1 and 2 meters) and an in situ lysimeter (4 m) were used to allow investigation of larger-scale transport under controlled conditions. Significant retention of oocysts was observed, with the magnitude of removal from solution ranging between 2 to 5 logs. While the removal was greater for longer travel distances (or residence times), the increase was not log-linear. This observation indicates that oocyst transport was not consistent with standard colloid filtration theory. The observed behavior is speculated to arise, at least in part, from intrapopulation variability in oocyst properties. The results of this study indicate that while Cryptosporidium oocysts may be expected to experience significant retention and removal during transport in sandy soil, the magnitude of retention may be less than that which would be predicted by applying standard colloid filtration theory to the results of typical short-column experiments. Thus, a fraction of the oocysts may be more mobile than anticipated and thereby pose a greater than expected risk to groundwater.