Fourth WHO-coordinated survey of human milk for persistent organic pollutants (POPs): Belgian results

Persistent organic pollutants (POPs) are chemicals that accumulate in the food chain and are toxic to humans and wildlife. The fourth World Health Organization (WHO) survey on POP levels in human milk (2006-2009) aims to provide baseline and trend information on human exposure to POPs. So far Belgium participated in all three previous rounds (1988, 1992, 2001). Whereas the first three rounds focused on determination of dioxins and PCBs in pooled (mixed) samples, the fourth survey comprised the analyses of individual milk samples for nine "basic POPs" (chlorinated pesticides and indicator PCBs) and of pooled milk samples for "basic POPs", "advanced POPs" (dioxins and dioxin-like PCBs) and "optional POPs" (polybrominated diphenylethers [PBDEs], polybrominated dioxins and dibenzofurans [PBrDD/F], mixed halogenated dioxins and dibenzofurans [PXDD/F] and hexabromocyclododecane [HBCD]). For the Belgian participation human milk samples were collected during the summer of 2006 from 197 women between 18 and 30 years old distributed over all Belgian provinces. The individual samples were analyzed in a Belgian Laboratory for "basic" POPs. A pooled sample was made from 178 individual samples and analyzed by the WHO Reference Laboratory for the "basic, advanced and optional" POPs. The results indicate that most organochlorinated pesticides banned 25-30 years ago were below or around detection limits in Belgian human milk samples although DDE was still found at low levels in all samples. Over the last five years the levels of marker PCBs and PCDD/Fs in Belgian human milk decreased, respectively, by 58% and 39%. For some of the other emerging or older compounds recent international data are needed to allow comparison. This shows the importance of international studies as run by WHO.     

Animal-related injuries: a population-based study of a five-state region in the upper Midwest: Regional Rural Injury Study II

PROBLEM: While agricultural injury has been identified among the major causes of occupational injury mortality and morbidity, data have been limited pertinent to the magnitude, consequences, and potential risk factors for animal-related injuries -- a major source of morbidity among agricultural operations. METHODS: Demographics, exposure, and injury data were collected for 1999 and 2001 among agricultural households in a five-state region. Causal models facilitated survey design, data analyses, and interpretation of results; directed acyclic graphs guided multivariate modeling. RESULTS: From 7,420 households (84% response of eligible), a total of 5,045 injury events were reported; 1,016 (20.1%) were animal-related. Multivariate analyses revealed increased risks for those <20 years; residents of all states compared to Minnesota; all age groups compared to 0-4 years; >0 hours worked; and prior agricultural injury history. For those 20+ years, increased risks were identified for: South Dakota residents; males; >0 hours worked; and prior agricultural injury history. For those cases <20 and 20+ years of age, 58% and 46%, respectively, resulted in lost work time on their agricultural operations (31% and 50%, one week or more). CONCLUSIONS: Animal-related injury has a major impact on the agricultural industry. Results serve as a basis for interventions and further research. IMPACT ON INDUSTRY: The impact of animal-related injuries on the agricultural industry appears significant; among age groups <20 and 20+, 85% and 82%, respectively, had some resulting restriction. For all events combined, 29% and 30%, respectively, involved restriction from one week to 3+ months; 12% and 15% involved restriction for one month or more. Among those <20 and 20+ years of age, 58% and 46%, respectively, lost work time on their own agricultural operation as a result of injuries associated with their own operation; 22% and 15% lost one week or more. Moreover, of the non-agriculture-related injuries, 31% and 50% resulted in lost work time on their own operation; 15% and 28%, respectively, lost one week or more. Restrictions such as these can affect the productivity of the operation, resulting in financial impacts, especially on small operations that have few people to manage the required tasks.     

Niche differentiation and fine-scale projections for Argentine ants based on remotely sensed data.

Modeling ecological niches of species is a promising approach for predicting the geographic potential of invasive species in new environments. Argentine ants (Linepithema humile) rank among the most successful invasive species: native to South America, they have invaded broad areas worldwide. Despite their widespread success, little is known about what makes an area susceptible--or not--to invasion. Here, we use a genetic algorithm approach to ecological niche modeling based on high-resolution remote-sensing data to examine the roles of niche similarity and difference in predicting invasions by this species. Our comparisons support a picture of general conservatism of the species' ecological characteristics, in spite of distinct geographic and community contexts.     

Remediation of a chlorinated aromatic hydrocarbon in water by photoelectrocatalysis

Photoelectrocatalysis driven by visible light offers a new and potentially powerful technology for the remediation of water contaminated by organo-xenobiotics. In this study, the performance of a visible light-driven photoelectrocatalytic (PEC) batch reactor, applying a tungsten trioxide (WO₃) photoelectrode, to degrade the model pollutant 2,4-dichlorophenol (2,4-DCP) was monitored both by toxicological assessment (biosensing) and chemical analysis. The bacterial biosensor used to assess the presence of toxicity of the parent molecule and its breakdown products was a multicopy plasmid lux-marked E. coli HB101 pUCD607. The bacterial biosensor traced the removal of 2,4-DCP, and in some case, its toxicity response suggests the identification of transient toxic intermediates. The loss of the parent molecule, 2,4-DCP determined by HPLC, corresponded to the recorded photocurrents. Photoelectrocatalysis offers considerable potential for the remediation of chlorinated hydrocarbons, and that the biosensor based toxicity results identified likely compatibility of this technology with conventional, biological wastewater treatment.     

Integrative approach to delineate natural attenuation of chlorinated benzenes in anoxic aquifers

Biodegradation of chlorobenzenes was assessed at an anoxic aquifer by combining hydrogeochemistry and stable isotope analyses. In situ microcosm analysis evidenced microbial assimilation of chlorobenzene (MCB) derived carbon and laboratory investigations asserted mineralization of MCB at low rates. Sequential dehalogenation of chlorinated benzenes may affect the isotope signature of single chlorobenzene species due to simultaneous depletion and enrichment of ¹³C, which complicates the evaluation of degradation. Therefore, the compound-specific isotope analysis was interpreted based on an isotope balance. The enrichment of the cumulative isotope composition of all chlorobenzenes indicated in situ biodegradation. Additionally, the relationship between hydrogeochemistry and degradation activity was investigated by principal component analysis underlining variable hydrogeochemical conditions associated with degradation activity at the plume scale. Although the complexity of the field site did not allow straightforward assessment of natural attenuation processes, the application of an integrative approach appeared relevant to characterize the in situ biodegradation potential.     

Evaluation of biotargeting and ecotoxicity of Co²⁺-containing nanoscale polymeric complex by applying multi-marker approach in bivalve mollusk Anodonta cygnea

Cobalt (Co²⁺) is present in many nanoscaled materials created for various applications. The key goal of our study was to develop sensitive approaches for assessing the bio-risks associated with using novel Co²⁺-containing nanoscaled polymeric complex (Co-NC). Freshwater bivalve mollusk Anodonta cygnea (Unionidae) was subjected to 14 d action of the developed Co-NC, as well as of Co²⁺ applied in the corresponding concentration (50 μg L⁻¹) or polymeric substance (PS). All experimental groups under study have demonstrated signs of toxic targeting, notably changes in DNA characteristics, oxidative stress (with particularities in each exposed group) and activation of anaerobiosis (Co²⁺ and Co-NC). However, the group exposed to Co-NC showed some advantages that can be related to the activation of metallothionein (MT) function (increase in the level of MT-related SH-groups (MT-SH)): low level of oxyradical formation, no increase in protein carbonylation and vitellogenin-like proteins concentration unlike in Co²⁺ and PS exposed groups. On the other hand, Co²⁺ increased metal (Co, Cu, Zn and Cd) binding to MT (MT-Me) without changes in MT-SH level jointly with activation of oxyradical formation and apoptosis and decreasing of lysosomal membrane stability. PS per se initiated unbalanced changes in activities of the biotransformation enzymes ethoxyresorufin-O-deethylase and glutathione-S-transferase. Thus, Co²⁺ complexing with the developed PS prevented bio-toxic effects of free Co²⁺ ions and PS per se, at least in the studied hydrobiont. The MT-SH was the main distinguishing index of Co-NC group selected by classification and regression tree analysis.     

Copper activity in soil solutions of calcareous soils

Copper partitioning was studied in seven calcareous soils at moisture content corresponding to 1.2 times the field moisture content (soil water potential 7.84 J kg(-1)). Copper retention was accompanied by the release in soil solution of Ca(2+), Mg(2+), Na(+), and H(+), and the total amount of these cations released was 0.8 to 1.09 times the amount of Cu sorbed (mol(c):mol(c)). The relationships between Cu activity and pH, and the balance of cations in soils correspond with the surface precipitation of CuCO(3) as the main mechanism of Cu retention. The values of ion activity product of surface precipitate were close for all studied soils with the average log(IAP(CuCO(3)))=-15.51. The relationship between copper activity in soil solutions and soil properties is well fit by a regression relating pCu (-log copper ion activity) with soil pH, total Cu, and carbonate content.