Monitoring concentrations of persistent organic pollutants in the general population: the international experience

Assessing the adverse effects on human health of persistent organic pollutants (POPs) and the impact of policies aiming to reduce human exposure to POPs warrants monitoring body concentrations of POPs in representative samples of subjects. While numerous ad hoc studies are being conducted to understand POPs effects, only a few countries are conducting nationwide surveillance programs of human concentrations of POPs, and even less countries do so in representative samples of the general population. We tried to identify all studies worldwide that analyzed the distribution of concentrations of POPs in a representative sample of the general population, and we synthesized the studies' main characteristics, as design, population, and chemicals analyzed. The most comprehensive studies are the National Reports on Human Exposure to Environmental Chemicals (USA), the German Environmental Survey, and the Arctic Monitoring and Assessment Programme. Population-wide studies exist as well in New Zealand, Australia, Japan, Flanders (Belgium) and the Canary Islands (Spain). Most such studies are linked with health surveys, which is a highly-relevant additional strength. Only the German and Flemish studies analyzed POPs by educational level, while studies in the USA offer results by ethnic group. The full distribution of POPs concentrations is unknown in many countries. Knowledge gaps include also the interplay of age, gender, period and cohort effects on the prevalence of exposures observed by cross-sectional surveys. Local and global efforts to minimize POPs contamination, like the Stockholm convention, warrant nationwide monitoring of concentrations of POPs in representative samples of the general population. Results of this review show how such studies may be developed and used.     

On the way to cyanobacterial blooms: impact of the herbicide metribuzin on the competition between a green alga (Scenedesmus) and a cyanobacterium (Microcystis)

The hypothesis that exposure to a common and widely applied photosynthesis-inhibiting herbicide, metribuzin, would alter the outcome of the competitive battle between susceptible green algae (Scenedesmus obliquus) and tolerant cyanobacteria (Microcystis aeruginosa) was tested. In a long-term (17 d) experiment, Scenedesmus and Microcystis populations as well as mixtures that started with different inoculum composition (i.e. 3:1, 1:1 and 1:3 Scenedesmus:Microcystis) were grown in the absence or presence of metribuzin (100 microg l-1). In the absence of metribuzin, Scenedesmus was competitively superior and out-competed Microcystis regardless the initial composition of the mixed communities. However, this competitive outcome was reversed completely in the presence of metribuzin, where despite growth inhibition Microcystis became dominant. Hence, photosynthesis-inhibiting herbicides may not only affect algal community structure, but also provide cyanobacteria founder populations a window for dominance and thus play an important role in promoting cyanobacteria blooms.     

Evaluation of a biomarker of Cd(II) exposure on Limnoperna fortunei

The use of organisms to monitor contamination allows the access to information that cannot be acquired by chemical methods. Limnoperna fortunei, mussel frequently found in Río de la Plata estuary, fulfils the requirements to be used as a biomonitoring organism. In this work we report that a polypeptide of 22 kDa of molecular weight (LF22) is induced when L. fortunei is exposed to Cd (II), Cu(II) and Hg(II) sublethal levels. To characterize LF22, mussels were sampled from a non-polluted region and whole soft tissue was homogenized, with and without previous exposure to 100 microg/L of Cd(II). The cytosolic proteins were evaluated by mono and bidimensional SDS-PAGE, and size exclusion chromatography. All the methods showed that LF22 triples its concentration in presence of Cd(II). Purification of LF22 was achieved by fractioned precipitation, salting-out, ionic exchange and size exclusion chromatography. We conclude that LF22 is a useful biomarker of heavy metal exposure.     

A Classification Procedure for Mapping Topo-climatic Conditions for Strategic Vegetation Planning

Environmental classification addresses issues involving the representation and analysis of continuous and variable ecological data. This study creates a methodology to define topo-climatic landscapes (TCL) in the north-west of Catalonia, which is situated in the north-east of the Iberian Peninsula. TCL provide data regarding the ecological behavior of a landscape in terms of its topography, physiognomy, and climate, which are the main drivers of an ecosystem. The variables selected are derived from a variety of different sources, such as remote sensing and climatic atlases. The methodology employed combines unsupervised iterative cluster classification with supervised fuzzy classification. Twenty eight TCL, which can be differentiated in terms of their vegetation physiognomy and vegetation altitudinal range type, were selected for the study area. Furthermore, a hierarchy among the TCL is established which permits the merging of clusters and allows for changes in thematic resolution. By using the topo-climatic landscape map, managers can identify patches with similar environmental conditions and at the same time assess the uncertainty involved in classification.     

Convergences and divergences between scientific and Indigenous and Local Knowledge contribute to inform carnivore conservation

There is increasing recognition that diverse knowledge systems can work in mutually enriching ways and that Indigenous and Local Knowledge (ILK) can enhance biodiversity conservation. However, studies using scientific knowledge and ILK in a complementary manner, and acknowledging convergent and especially divergent insights have remained limited. In this study, we contrasted proxies of abundances and trends of threatened and conflict-prone carnivores (caracal, cheetah, jackal, lion, leopard, spotted hyaena, striped hyaena) derived separately from scientific knowledge and ILK. We conducted camera trapping, track surveys and semi-structured interviews with local pastoralists from northern Kenya. We found convergences highlighting the need for conservation action and divergences suggesting scientific ecological sampling limitations or underlying socio-psychological phenomena. Overall, our study shows that complementing scientific knowledge and ILK as separate sources of information and opening up space for discrepancies can enrich our understanding of the status and trends of carnivores, as well as recognizing human-carnivore relationships.Electronic supplementary materialThe online version of this article (10.1007/s13280-020-01443-4) contains supplementary material, which is available to authorized users.     

Laboratory experiments to predict changes in radiocaesium root uptake after flooding events

Changes in soil solution composition after a flooding event were hypothesised to be one of the key factors in explaining changes in radiocaesium incorporation in the food chain in the areas affected by the Chernobyl accident. A laboratory methodology was set up to monitor changes in the soil solution composition after a sequence of flooding cycles. Experiments were performed using column and batch approaches on test soils with contrasting initial soil solution composition (high and low initial concentrations of K+). Results from column experiments indicated a potential increase in NH(4)(+) concentrations, a parameter which could lead to an increase in the radiocaesium root uptake. Batch results in the soil with high initial K+ concentration showed that after a number of flooding cycles, especially for high ratios of flooding solution/mass of soil, K+ concentration decreased sometimes below a threshold value (around 0.5-1 mmol l(-1)), a fact that could lead to an increase in radiocaesium transfer. For the soils with a low initial K+ concentration, the flooding solution increased K+ and NH(4)(+) values in the soil solution. The comparison of test soils with soils from Ukraine areas affected by flooding showed that the final stage in soil solution composition was similar in both cases, regardless of the initial composition of the soil solution. Moreover, the comparison with unflooded soils from the same area showed that potential changes in other soil parameters, such as (137)Cs activity concentration, clay content, and radiocaesium interception potential, RIP (a parameter that estimates the radiocaesium specific sorption capacity of a soil), should also be monitored for additional effects due to the flooding event. Therefore, the changes in the root uptake would depend on the resulting situation from changes in RIP, K+ and NH(4)(+) values in the soil solution.     

Polycyclic aromatic hydrocarbons study in atmospheric fine and coarse particles using diagnostic ratios and receptor model in urban/industrial region

Atmospheric fine and coarse particles were collected in Teflon filters in three cities of the region of the Lower Sinos River Basin of Rio Grande do Sul in the year 2010. The filters were Soxhlet extracted, and 14 priority PAHs were analyzed using a gas chromatograph coupled to a mass spectrometer (GC/MS). The principal emission sources of these compounds were assessed by using diagnostic ratios and receptor model: positive matrix factorization (PMF 3.0) of the US Environmental Protection Agency. The results of PAHs concentration for the studied year showed significant levels of high molecular weight (HMW) PAH, Ind, and BghiP, in PM_2.5 in the winter season, showing the influence of mobile sources. The application of receptor model PMF 3.0 revealed that the main sources of PAHs were vehicle fleet (both diesel and gasoline), followed by coal combustion, wood combustion, and resuspension of dust. The results of the receptor modeling are in agreement with the data obtained by the ratio diagnostic.