Drinking Water Criteria for Arsenic in High-Income, Low-Dose Countries: The Effect of Legislation on Public Health.

Due to the potential health risks at very low concentrations, the criterion for arsenic in drinking water has been debated. High-income, low-dose countries are uniquely positioned to follow WHO's recommendation of keeping concentrations "as low as reasonably possible." In this policy analysis, 47646 arsenic analyses from Denmark are used to follow the effect of lowering the national criterion from 50 to 5 µg/L. The first 3 years (2002-2004) following the criterion change, 106 waterworks were identified as noncompliant. An additional 64 waterworks were identified as noncompliant in the next 12 years (2005-2016). Of the 106 waterworks initially (2002-2004) aware of the violation, an average concentration drop from 6 to 3 µg/L was observed during a 6 year period following a lag time of 1 year. After this point, no further improvements were observed. Thirteen years after regulation was imposed, 25 of 170 waterworks were still in violation. The results suggest that legislation alone is insufficient to ensure better drinking water quality at some waterworks and that stakeholders' drivers and barriers to change also play an important role. In an exploration of five legislation scenarios, this study showed that a criterion of 1 µg/L would require action by more than 500 Danish waterworks, with treatment costs from 0.06 to 0.70 €/m3. These scenarios illustrate that it can be technically feasible and affordable to lower the arsenic criterion below 5 µg/L in low-dose, high-income countries. However, more information is needed to apply a cost-benefit model, and comparative studies from other counties are warranted.

Lithium in drinking water and the incidence of bipolar disorder: A nation-wide population-based study.

OBJECTIVE: Animal data suggest that subtherapeutic doses, including micro doses, of lithium may influence mood, and lithium levels in drinking water have been found to correlate with the rate of suicide. It has never been investigated whether consumption of lithium may prevent the development of bipolar disorder (primary prophylaxis). In a nation-wide population-based study, we investigated whether long-term exposure to micro levels of lithium in drinking water correlates with the incidence of bipolar disorder in the general population, hypothesizing an inverse association in which higher long-term lithium exposure is associated with lower incidences of bipolar disorder. METHODS: We included longitudinal individual geographical data on municipality of residence, data from drinking water lithium measurements and time-specific data from all cases with a hospital contact with a diagnosis of mania/bipolar disorder from 1995 to 2013 (N=14 820) and 10 age- and gender-matched controls from the Danish population (N= 140 311). Average drinking water lithium exposure was estimated for all study individuals. RESULTS: The median of the average lithium exposure did not differ between cases with a diagnosis of mania/bipolar disorder (12.7 µg/L; interquartile range [IQR]: 7.9-15.5 µg/L) and controls (12.5 µg/L; IQR: 7.6-15.7 µg/L; P=.2). Further, the incidence rate ratio of mania/bipolar disorder did not decrease with higher long-term lithium exposure, overall, or within age categories (0-40, 41-60 and 61-100 years of age). CONCLUSION: Higher long-term lithium exposure from drinking water was not associated with a lower incidence of bipolar disorder. The association should be investigated in areas with higher lithium levels than in Denmark.

A Roman provincial city and its contamination legacy from artisanal and daily-life activities.

Roman metal use and related extraction activities resulted in heavy metal pollution and contamination, in particular of Pb near ancient mines and harbors, as well as producing a global atmospheric impact. New evidence from ancient Gerasa (Jerash), Jordan, suggests that small-scale but intense Roman, Byzantine and Umayyad period urban, artisanal, and everyday site activities contributed to substantial heavy metal contamination of the city and its hinterland wadi, even though no metal mining took place and hardly any lead water pipes were used. Distribution of heavy metal contaminants, especially Pb, observed in the urban soils and sediments within this ancient city and its hinterland wadi resulted from aeolian, fluvial, cultural and post-depositional processes. These represent the contamination pathways of an ancient city-hinterland setting and reflect long-term anthropogenic legacies at local and regional scales beginning in the Roman period. Thus, urban use and re-use of heavy metal sources should be factored into understanding historical global-scale contaminant distributions.

Palm community transects and soil properties in western Amazonia.

Western Amazonia is a global biodiversity hotspot that encompasses extensive variation in geologic, climatic, and biotic features. Palms (Arecaceae) are among the most diverse and iconic groups of plants in the region with more than 150 species that exhibit extraordinary variation of geographical distributions, regional abundance patterns, and life history strategies and growth forms, and provide myriad ecosystem services. Understanding the ecological and evolutionary drivers that underpin palm distribution and abundance patterns may shed light on the evolution and ecology of the tropical forest biomes more generally. Edaphic conditions, in particular, are increasingly recognized as critical drivers of tropical plant diversity and distributions but data deficiencies inhibit our understanding of plant-soil relationships at broad scales, especially in the tropics. We present data from 546, 0.25-ha (5 × 500 m) georeferenced transects located throughout western Amazonia where all individual palms were identified, counted, and assigned to a life-history stage. Several environmental covariates were recorded along each transect and surface soil samples were collected from multiple points in N = 464 of transects. Altogether, the transects include 532,602 individuals belonging to 135 species. Variation among transects in terms of palm species richness and abundance is associated with major habitat types and soil properties. The soil properties including pH, acidity, all macronutrients for all samples, and texture, carbon, nitrogen, and micronutrients for some transects vary substantially across the study area, providing insight to broad-scale variation of tropical surface soils. The data provided here will help advance our understanding of plant distributions and abundance patterns, and associations with soil conditions. No copyright restrictions are associated with this data set but please cite this paper if data are used for publication.

Lithium in Drinking Water and Incidence of Suicide: A Nationwide Individual-Level Cohort Study with 22 Years of Follow-Up.

Suicide is a major public health concern. High-dose lithium is used to stabilize mood and prevent suicide in patients with affective disorders. Lithium occurs naturally in drinking water worldwide in much lower doses, but with large geographical variation. Several studies conducted at an aggregate level have suggested an association between lithium in drinking water and a reduced risk of suicide; however, a causal relation is uncertain. Individual-level register-based data on the entire Danish adult population (3.7 million individuals) from 1991 to 2012 were linked with a moving five-year time-weighted average (TWA) lithium exposure level from drinking water hypothesizing an inverse relationship. The mean lithium level was 11.6 µg/L ranging from 0.6 to 30.7 µg/L. The suicide rate decreased from 29.7 per 100,000 person-years at risk in 1991 to 18.4 per 100,000 person-years in 2012. We found no significant indication of an association between increasing five-year TWA lithium exposure level and decreasing suicide rate. The comprehensiveness of using individual-level data and spatial analyses with 22 years of follow-up makes a pronounced contribution to previous findings. Our findings demonstrate that there does not seem to be a protective effect of exposure to lithium on the incidence of suicide with levels below 31 µg/L in drinking water.

Cu-nanoparticles ecotoxicity--explored and explained?

The nano-form of copper (Cu-NPs) is already extensively used. In this paper the toxic effect of Cu in the worm Enchytraeus crypticus (Oligochaeta: Enchytraeidae) was assessed following exposure to (1) Cu-salt: freshly spiked soil with copper-nitrate, (2) Cu-NPs: freshly spiked soil with Cu nanoparticles (80nm), and (3) Cu-field: historically Cu contaminated soil (80years ago). Our main aims were to compare the three different exposure regimes and respective toxicity, and to determine how the oxidation state of the Cu and dissolution state of the particles differed. Characterization of in situ-exposure included identification of oxidation states with synchrotron generated X-ray absorption near-edge spectroscopy (XANES) analysis, activity of free Cu(2+) in soil-solution (Ion Selective Electrode), and the relative distribution of the labile Cu-fractions (Sequential Extraction). Freshly spiked Cu-salt was the most toxic for reproductive output of the worms, followed by Cu-NPs and then Cu-field. XANES indicated only one oxidation state (II) in Cu-salt and Cu-field soil, whereas in Cu-NPs soil it was present in all oxidation states (0, I and II). The partial oxidation of the Cu-NPs (in soil) was evident and with limited dissolution.

Ocean lead at the termination of the Younger Dryas cold spell.

The Younger Dryas (YD) cold interval is one of the most abrupt climate events of Earth's recent history. The origin of this rapid, severe cooling episode is still widely debated, but it was probably triggered by a large freshwater influx to the North Atlantic resulting in disruption of the Atlantic Meridional Overturning Circulation. The YD termination, despite having been even more abrupt than the onset has, however, received significantly less attention. Here using multi-proxy data from a high-resolution marine sediment record, we present evidence for a gradual decrease of the Labrador Current influence, northward migration of the Gulf Stream oceanic front and a rapid decline of sea-ice cover at the YD termination. Our data indicate a stepwise sequence of events with changes in ocean circulation clearly preceding those in atmospheric conditions, in contrast to the hitherto commonly assumed single-event rapid climatic shift at the YD-Holocene transition.