Light distribution in dynamic street lighting: Two experimental studies on its effects on perceived safety,prospect, concealment,and escape

The relationship between light and perceived safety at night is intuitively strong, yet theoretically and empirically its workings are largely unknown. Intelligent dynamic road lighting, which continuously adapts to the presence and behavior of users, can light the street only when and where it is needed. As such, it offers a solution to the energy waste and luminous pollution associated with conventional road lighting. With this innovation, however, new questions emerge about the effect of lighting on perceived safety. We need to consider not only how much lighting pedestrians need to feel safe, but also which parts of the street should be lit. In two experiments, we investigated the effect of different light distributions on perceived safety, and explored mediation by people's appraisal of three safety-related cues suggested in the literature: prospect (having an overview), escape (perceived escape possibilities), and refuge/concealment (perceived hiding places for offenders). Both experiments, one with stationary and one with walking participants, demonstrated that people prefer having light in their own immediate surroundings rather than on the road that lies ahead. This could be explained, partially, by changes in prospect, escape, and concealment. Against expectations, prospect was higher with lighting distributions in which participants' immediate surroundings, but not the more distant parts of the road, were most strongly lit.     

Controls on Coarse Wood Decay in Temperate Tree Species: Birth of the LOGLIFE Experiment

Dead wood provides a huge terrestrial carbon stock and a habitat to wide-ranging organisms during its decay. Our brief review highlights that, in order to understand environmental change impacts on these functions, we need to quantify the contributions of different interacting biotic and abiotic drivers to wood decomposition. LOGLIFE is a new long-term ‘common-garden’ experiment to disentangle the effects of species’ wood traits and site-related environmental drivers on wood decomposition dynamics and its associated diversity of microbial and invertebrate communities. This experiment is firmly rooted in pioneering experiments under the directorship of Terry Callaghan at Abisko Research Station, Sweden. LOGLIFE features two contrasting forest sites in the Netherlands, each hosting a similar set of coarse logs and branches of 10 tree species. LOGLIFE welcomes other researchers to test further questions concerning coarse wood decay that will also help to optimise forest management in view of carbon sequestration and biodiversity conservation.     

Environmental mutagenicity and toxicity caused by sodium metabisulfite in sea shrimp harvesting in Piauí, Brazil

Sodium metabisulfite is used in marine shrimp harvesting to prevent the occurrence of black spots. Shrimps are soaked in a sodium metabisulfite solution in ice, which is disposed of in sewages that run into marine canals, creating an environmental hazard. This study evaluates the toxicity and mutagenicity caused by sodium metabisulfite in sea waters and sediments collected in a shrimp farm in Cajueiro da Praia (Luis Correia), state of Piauí, Brazil, using the Allium cepa assay. Water and sediment samples were collected in the dry and in the rainy seasons, in three sites: upstream the shrimp farm (Site 1), at the point sodium metabisulfite is discharged (Site 2), and 100 m downstream the farm (Site 3). Three sample dilutions were used (50%, 25% and 10%) for all samples. A negative control (well water) and a positive control (copper sulfate 0.0006 mg mL⁻¹) were used in each experiment. At the end of the 72-h exposure period, onion roots were measured and removed. Mutagenicity analysis included the determination of mitotic index, chromosomal aberrations and the detection of micronuclei; analysis of root size and mitotic index were used as an index of toxicity. The A. cepa assay revealed that the water and sediments samples collected in the Piauí coast contaminated with sodium metabisulfite induce toxicity. The results demonstrate that the assay may be used as a regular tool in the analysis of water parameters in shrimp farms in the coast of Piauí state, and in strategies to preserve the region’s marine ecosystem.     

Genotoxic assessment on river water using different biological systems

This paper reports genotoxicity and toxicity data in water samples collected in Sinos River, an important water course in the hydrographic region of Guaíba Lake, Rio Grande do Sul State, south of Brazil. This river is exposed to intense anthropic influence by numerous shoes, leather, petrochemical, and metallurgy industries. Water samples were collected at two moments (winter 2006 and spring 2006) at five sites of Sinos River and evaluated using in vitro V79 Chinese hamster lung fibroblasts (cytotoxicity, comet assay and micronucleus test) and Allium cepa test (toxicity and micronucleus test). Comet and micronucleus tests revealed that water samples collected exerted cytotoxic, toxic, genotoxic and mutagenic effects. The results showed the toxic action of organic and inorganic agents found in the water samples in all sites of Sinos River, for both data collections. The main causes behind pollution were the domestic and industrial toxic discharges. The V79 and A. cepa tests were proved efficient to detect toxicity and genotoxicity caused by complex mixtures. This study also showed the need for constant monitoring in sites with strong environmental degradation caused by industrial discharges and urban sewages.     

Identification of new ozonation disinfection byproducts of 17β-estradiol and estrone in water

Estrogens are a class of micro-pollutants found in water at low concentrations (in the ng L⁻¹ range), but often sufficient to exert estrogenic effects due to their high estrogenic potency. Disinfection of waters containing estrogens through oxidative processes has been shown to lead to the formation of disinfection byproducts, which may also be estrogenic. The present work investigates the formation of disinfection byproducts of 17β-estradiol (E2) and estrone (E1) in the treatment of water with ozone. Experiments have been carried out at two different concentrations of the estrogens in ground water (100 ng L⁻¹ and 100 μg L⁻¹) and at varying ozone dosages (0-30 mg L⁻¹). Detection of the estrogens and their disinfection byproducts in the water samples has been performed by means of ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) with a triple quadrupole (QqQ) and a quadrupole-time of flight (QqTOF) instrument. Both E2 and E1 have been found to form two main byproducts, with molecular mass (MM) 288 and 278 in the case of E2, and 286 and 276 in the case of E1, following presumably the same reaction pathways. The E2 byproduct with MM 288 has been identified as 10epsilon-17beta-dihydroxy-1,4-estradieno-3-one (DEO), in agreement with previously published results. The molecular structures and the formation pathways of the other three newly identified byproducts have been suggested. These byproducts have been found to be formed at both high and low concentrations of the estrogens and to be persistent even after application of high ozone dosages.     

Mercury, lead and cadmium in human milk in relation to diet, lifestyle habits and sociodemographic variables in Madrid (Spain)

Background

Although breastfeeding is the ideal way of nurturing infants, it can be a source of exposure to toxicants. This study reports the concentration of Hg, Pb and Cd in breast milk from a sample of women drawn from the general population of the Madrid Region, and explores the association between metal levels and socio-demographic factors, lifestyle habits, diet and environmental exposures, including tobacco smoke, exposure at home and occupational exposures.

Methods

Breast milk was obtained from 100 women (20 mL) at around the third week postpartum. Pb, Cd and Hg levels were determined using Atomic Absorption Spectrometry. Metal levels were log-transformed due to non-normal distribution. Their association with the variables collected by questionnaire was assessed using linear regression models. Separate models were fitted for Hg, Pb and Cd, using univariate linear regression in a first step. Secondly, multivariate linear regression models were adjusted introducing potential confounders specific for each metal. Finally, a test for trend was performed in order to evaluate possible dose-response relationships between metal levels and changes in variables categories.

Results

Geometric mean Hg, Pb and Cd content in milk were 0.53 μg L⁻¹, 15.56 μg L⁻¹, and 1.31 μg L⁻¹, respectively. Decreases in Hg levels in older women and in those with a previous history of pregnancies and lactations suggested clearance of this metal over lifetime, though differences were not statistically significant, probably due to limited sample size. Lead concentrations increased with greater exposure to motor vehicle traffic and higher potato consumption. Increased Cd levels were associated with type of lactation and tended to increase with tobacco smoking.

Conclusions

Surveillance for the presence of heavy metals in human milk is needed. Smoking and dietary habits are the main factors linked to heavy metal levels in breast milk. Our results reinforce the need to strengthen national food safety programs and to further promote avoidance of unhealthy behaviors such as smoking during pregnancy.     

Effects of municipal solid waste compost and mineral fertilizer amendments on soil properties and heavy metals distribution in maize plants (Zea mays L.)

Soil amendments based on crop nutrient requirements are considered a beneficial management practice. A greenhouse experiment with maize seeds (Zea mays L.) was conducted to assess the inputs of metals to agricultural land from soil amendments. Maize seeds were exposed to a municipal solid waste (MSW) compost (50 Mg ha⁻¹) and NPK fertilizer (33 g plant⁻¹) amendments considering N plant requirement until the harvesting stage with the following objectives: (1) determine the accumulation of total and available metals in soil and (2) know the uptake and ability of translocation of metals from roots to different plant parts, and their effect on biomass production. The results showed that MSW compost increased Cu, Pb and Zn in soil, while NPK fertilizer increased Cd and Ni, but decreased Hg concentration in soil. The root system acted as a barrier for Cr, Ni, Pb and Hg, so metal uptake and translocation were lower in aerial plant parts. Biomass production was significantly enhanced in both MSW and NPK fertilizer-amended soils (17%), but also provoked slight increases of metals and their bioavailability in soil. The highest metal concentrations were observed in roots, but there were no significant differences between plants growing in amended soil and the control soil. Important differences were found for aerial plant parts as regards metal accumulation, whereas metal levels in grains were negligible in all the treatments.     

Differentiation of nitrous oxide emission factors for agricultural soils

Nitrous oxide (N₂O) direct soil emissions from agriculture are often estimated using the default IPCC emission factor (EF) of 1%. However, a large variation in EFs exists due to differences in environment, crops and management. We developed an approach to determine N₂O EFs that depend on N-input sources and environmental factors. The starting point of the method was a monitoring study in which an EF of 1% was found. The conditions of this experiment were set as the reference from which the effects of 16 sources of N input, three soil types, two land-use types and annual precipitation on the N₂O EF were estimated. The derived EF inference scheme performed on average better than the default IPCC EF. The use of differentiated EFs, including different regional conditions, allows accounting for the effects of more mitigation measures and offers European countries a possibility to use a Tier 2 approach.     

Multi-decadal changes in tundra environments and ecosystems: synthesis of the International Polar Year-Back to the Future project (IPY-BTF)

Understanding the responses of tundra systems to global change has global implications. Most tundra regions lack sustained environmental monitoring and one of the only ways to document multi-decadal change is to resample historic research sites. The International Polar Year (IPY) provided a unique opportunity for such research through the Back to the Future (BTF) project (IPY project #512). This article synthesizes the results from 13 papers within this Ambio Special Issue. Abiotic changes include glacial recession in the Altai Mountains, Russia; increased snow depth and hardness, permafrost warming, and increased growing season length in sub-arctic Sweden; drying of ponds in Greenland; increased nutrient availability in Alaskan tundra ponds, and warming at most locations studied. Biotic changes ranged from relatively minor plant community change at two sites in Greenland to moderate change in the Yukon, and to dramatic increases in shrub and tree density on Herschel Island, and in subarctic Sweden. The population of geese tripled at one site in northeast Greenland where biomass in non-grazed plots doubled. A model parameterized using results from a BTF study forecasts substantial declines in all snowbeds and increases in shrub tundra on Niwot Ridge, Colorado over the next century. In general, results support and provide improved capacities for validating experimental manipulation, remote sensing, and modeling studies.     

Dietary exposure of rainbow trout to 8:2 and 10:2 fluorotelomer alcohols and perfluorooctanesulfonamide: Uptake, transformation and elimination

The bioaccumulation of perfluorooctanesulfonamide (PFOSA) and two fluorotelomer alcohols (8:2 FTOH, 10:2 FTOH) by rainbow trout (Oncorhynchus mykiss) through dietary exposure, including depuration rates and metabolism was investigated. Concentrations in the spiked feed ranged from 10.9 μg g⁻¹ wet weight (wet wt) for PFOSA and 6.7 μg g⁻¹ wet wt for 8:2 FTOH to 5.0 μg g⁻¹ wet wt for 10:2 FTOH. Trout was fed at 1.5% body weight per day for 30 d and depuration was followed for up to 30 d following previously published dietary exposure protocols. Perfluorooctanesulfonate (PFOS) was the major perfluoroalkylsulfonate (PFSA) detected in fish following dietary exposure to PFOSA. Half-lives of PFOS and PFOSA were 16.9 ± 2.5 and 6.0 ± 0.4 d, respectively. A biomagnification factor (BMF) of 0.023 was calculated for PFOSA which indicates that dietary exposure to PFOSA does not result in biomagnification in the rainbow trout. PFOS had a BMF of 0.08. The fluorotelomer saturated acids (8:2 FTCA, 10:2 FTCA) and fluorotelomer unsaturated acids (8:2 FTUCA, 10:2 FTUCA) were the major products detected in rainbow trout following dietary exposure to 8:2 FTOH and 10:2 FTOH, respectively. Half-lives were 3.7 ± 0.4, 2.1 ± 0.5, 3.3, and 1.3 d for 10:2 FTCA, 10:2 FTUCA, 8:2 FTCA, and 8:2 FTUCA, respectively. Small amounts of perfluorooctanoate (PFOA) and perfluorodecanoate (PFDA) were also detected in the FTOH exposed fish.