Corrosion-induced release of Cu and Zn into rainwater from brass, bronze and their pure metals. A 2-year field study

A 2-year field study has been conducted in an urban environment to provide annual release rates of copper and zinc from brass (20 wt% Zn) and copper and tin from bronze (6 wt% Sn) compared to sheets of their pure alloy constituents, copper and zinc. Despite relatively low nominal bulk alloy content, substantially more zinc was released from brass compared to copper. Both metals were released at a significantly slower rate from the brass alloy, compared to the pure metals. The proportion of release rates of copper and zinc from the alloy differed significantly from their proportions in the bulk alloy. Bronze showed relatively constant release rates of copper, being similar to that of pure copper sheet. The release of tin from bronze was negligible. The results clearly show that alloys and the pure metals behave very differently when exposed to rainwater. Accordingly, release rates from pure metals cannot be used to predict release rates of individual constituents from their alloys. Generated data are of importance within REACH, the new chemical policy of the European commission, where metal alloys erroneously are being treated as mixtures of chemical substances.     

Chlorination and water quality monitoring within a public drinking water supply in Rawalpindi Cantt (Westridge and Tench) area, Pakistan

Concern over the presence of fecal coliform in public drinking water supplies has been expressed in recent years in Pakistan since it has been regarded as pathogenic organism of prime importance in gastroenteritis. Two major drinking water distribution systems in the Cantt area of Rawalpindi district covering the Westridge and Tench areas was monitored over a 2-month period to determine the prevalence of fecal coliform and chlorine residual. The collected samples were examined for total chlorine, free chlorine residual, chloramines, total coliforms, fecal coliforms, and turbidity. The drinking water quality monitoring in the distribution network was performed by collecting samples from water source, overhead reservoir, and residential taps. In the Westridge area, total chlorine varied from the lowest value of 0.27 mg/L at Station # W-5 to the highest value of 0.42 mg/L at Station # W-2, total coliforms varied from 1.1 to 3.6 most probable number (MPN)/100 mL with presence of Escherichia coli in all samples, total dissolved solids (TDS) ranged from 199.5 to 205 mg/L, conductivity fluctuated between 399 and 411 microS/cm, and turbidity varied from 0.43 to 0.73 NTU. In the Tench area, the value of total chlorine ranged from 0.14 mg/L at Station # T-7 to 0.55 mg/L at Station # T-1. Total coliform varied from 3.6 to 5.1 MPN/100 mL and fecal coliform were detected at all the stations except at Station # T-1. TDS ranged from 201.4 to 257 mg/L, conductivity varied from 343 to 513 microS/cm, and turbidity ranged between 0.66 and 1.55 NTU. It is recommended to the respective agencies to ensure that the chlorine residual is available at consumer end.     

An Examination of Governance Arrangements at Kisakasaka Mangrove Reserve in Zanzibar

This study employs insights largely derived from critical reflections on the common pool resources (CPR) theory to examine the current governance arrangements in place to manage the mangrove forest at Kisakasaka, in Zanzibar, Tanzania. Kisakasaka was used as a site for a community-based management pilot project of forest resources in Zanzibar. After some initial success in setting up a local management structure and regulating access to the mangrove for mainly charcoal production, there are now clear indications that forest conditions have deteriorated dramatically with concomitant ongoing resource use problems for local villagers who have relied heavily on forest resources as a source of cash income. Extra-local factors, such as urban population increases and associated market pressures for charcoal, are also conjectured to overlay and interact with the institutional problems at Kisakasaka. As a result, over concern about the deterioration in the condition of the mangrove forest, the responsible government authority decided not to renew the community-based governance arrangements after an initial five-year pilot period. While revealing the inadequacies of existing governance arrangements and of its relationship to deteriorating forest conditions at Kisakasaka, this study concludes by suggesting an approach to more fully understand forces driving local resource management and use.     

Results of the monitoring program of pesticide residues in organic food of plant origin in Lombardy (Italy)

Organic agriculture, with its restrictions on the use of synthetic chemical inputs, seems to offer a low-residue alternative to conventional methods. In Europe, the Council Regulation n. 2092/91/EEC regulates the production and trade of organic products and foodstuffs; national and regional legislation in Italy gives specific guidance on the surveillance of organic agriculture. However, monitoring of specific chemical residues in organic foodstuffs is part of the regular controls on food, aiming to safeguard consumer's health. Monitoring programs are coordinated at the national level by the Ministry of Health and at local level by Regional authorities. In Lombardy, in accordance with the provisions of the General Directorate of Health of the Region and under the supervision of the 15 Local Health Units, a monitoring program of pesticide residues in food of plant origin is undertaken every year. The International Centre for Pesticides and Health Risk Prevention (ICPS), on behalf of the General Directorate of Health of the Region of Lombardy, has been collecting and elaborating the data resulting from the analysis of food samples, carried out by the local laboratories. During the period 2002-2005, a total of 3508 samples food of plant origin were analyzed for pesticide residues, among which were 266 samples of organic farming products. Commodities were classified into groups (citrus fruits, legumes, vegetables, potatoes, processed products, cereals, and fruit other than citrus) and the outcomes of the analyses were reported by year, origin of the sample and presence/absence of pesticide residues. Results showed that the vast majority of organic farming products were in conformity with the relevant legislation and did not contain detectable pesticide residues. A limited amount of samples had residues at concentration below the Maximum Residue Limit (MRL). Only in one sample the residue level was above the MRL, however it did not pose a concern for public health, as demonstrated by the outcomes of dietary risk assessment. Organic fruits and vegetables can be expected to contain fewer agrochemical residues than conventionally grown alternatives. There is a widespread belief that organic agriculture products are safer and healthier than conventional foods. It is difficult to come to conclusions, but what should be made clear to the consumer is that "organic" does not automatically equal "safe". In the absence of adequate comparative data, additional studies in this area of research are required.     

Plasma PBDE and thyroxine levels in rats exposed to Bromkal or BDE-47

In experimental models, polybrominated diphenyl ethers (PBDEs), a group of brominated flame retardants, have caused effects in a number of biological end-points, including neurobehavioural effects, disturbances in thyroid and steroid hormone homeostasis, and other steroid-related effects. Almost exclusively, only external dose metrics (dose per body weight basis) have been studied in connection to the observed effects. In this study we report on new analyses of plasma PBDE levels in surplus samples from earlier studies on thyroid hormones (TH) in exposed rodents. Female, 7-week old Sprague-Dawley rats were given either Bromkal 70-5 DE (Study I; 18 or 36 mg/kg bw/day) or BDE-47 (Study II; 1, 6 or 18 mg/kg bw/day) daily by gavage for two weeks. At an external dose of 18 mg/kg bw/day significant TH effects (decreased plasma free thyroxin levels) were observed in both studies, corresponding to an internal (plasma) dose of 463 microg sumPBDE/g lipid (Study I) or 421 microg BDE-47/g lipid (Study II). If we compare the contribution of different BDE congeners to the total BDE level in rat plasma after Bromkal exposure (Study II), and in the Bromkal mixture itself, the most important congener in the Bromkal mixture were also found in plasma. However, the relative concentration of BDE-99 was lower, and that of BDE-153 was higher, than that of the mixture, indicating selectivity in uptake, metabolism and/or excretion of the individual BDE congeners. Explicitly, the possible in vivo conversion of BDE-99 to BDE-47, and of BDE-154 to BDE-153 could not be excluded. The internal dose in the present rat study could be compared to reported human serum doses of PBDE. Human serum/blood levels have a wide range, from 3 to 6 ng sumPBDE/g lipid in background samples from Europe, about 10 times higher in US sample, and up to 100 times higher (300-600 ng/g lipid) in upper-end levels in collected samples from USA. As a consequence, the margin between effects levels in the rat and exposure levels in man varies widely, with a quotient roughly from 1000 to 100,000. Generally, it could be expected that this margin is lower than if external dose metrics would be used. An even lower margin could be expected as recent studies have shown effects in offspring at lower doses than those giving effects in our studies. Lastly, it should be noted that humans are already exposed to a mixture of chemicals in daily life, a fact that complicates this kind of comparison.     

From food aid to livelihoods support: rethinking the role of WFP in eastern Sudan

Despite more than 20 years of distribution of free emergency food in eastern Sudan (38 years in the case of refugees) Global Acute Malnutrition rates are currently the highest in the country. There has been no real improvement in the chronic livelihoods vulnerability that affects people in the region—particularly pastoralists. Food security must be seen from an informed livelihoods perspective. While food aid may still be required as part of transition, WFP must rethink its assistance strategy and advocate for complementarity in the efforts by development actors working across a range of sectors. Alternative models and interventions focused on the rehabilitation of markets and the development of' cargo nets' for the destitute, including cash transfers, must be developed and tested. Land tenure issues should be given particular attention. Food aid will probably remain an important element in the overall response, but its significance relative to other less developed forms of interventions should be reassessed.     

Global-scale vs. regional-scale scenario assumptions: implications for estimating future water withdrawals in the Elbe River basin

In this paper, we explore how scenarios of future water withdrawals in a river basin are influenced by scale-dependent quantifications of the driving forces for two global-scale storylines. Either global-scale information or region-specific information is used to do the quantifications. In addition, we analyze the impact of including or not some restricted regional-scale information in the employed water use model. To develop scenarios of water withdrawals in the German part of the Elbe River basin, we applied the modules for domestic, thermoelectric power and manufacturing water use of the global water model WaterGAP, using scale-dependent driving forces scenarios and other scale-dependent model input. In the global-scale quantitative interpretations of the storylines of the IPCC SRES scenarios A1 and B2, all major driving forces of water withdrawals in the basin—population, thermoelectric power production and industrial gross domestic product—show vigorous increases between 2000 and 2025, while from the regional perspective, smaller increases but mostly decreases appear to be plausible. These discrepancies are partly due to the fact that for the global-scale interpretations only the historic developments until 1990 were taken into account, and not until 2000 as in the regional case. The resulting scenarios of sectoral water withdrawals in 2025 differ strongly between the two scale-dependent interpretations of the storylines, with the global one leading to much higher absolute water withdrawals and much lower withdrawal decreases between 2000 and 2025. Therefore, for regional assessments of water withdrawals, we recommend to embed the scenario analysis in global-scale storylines by performing regional-scale quantifications of the global qualitative driving forces scenarios, based on a limited amount of region-specific information.     

Rhythmic vertical migration of the gastropod Cerithidea decollata in a Kenyan mangrove forest

In Mida Creek, Kenya (3°20′S, 40°5′E), at high water, the snail Cerithidea decollata dwells on the trunks of mangrove trees (Avicennia marina), while during low water it migrates to the ground, foraging at various distances from the trunk, where it aggregates again well before the incoming tide. Snails from the upper shore level are 150–200 m distant from those living at the lower shore level and they cluster at lower heights on trunks. In any case, sufficient height is usually attained to avoid being submersed. An experiment was designed (February and October 2005), exchanging individuals from different shore levels subject to different tide regimes, in order to test whether snails rely on internal information or on external, direct cues, to adapt their behaviour to local conditions. Results show that C. decollata mostly rely on internal information, presumably based on an internal clock. When individuals from upper and lower shore levels were exchanged, their internal clocks continued to govern when to ascend the home trunk and how high to climb for five to six successive tides, after which the behaviour was reset to the new local conditions.     

Regulation of intertidal food webs by avian predators on New England rocky shores

Although there is a large body of research on food webs in rocky intertidal communities, most of the emphasis has been on the marine benthic components. Effects of avian predation on highly mobile predators such as crabs, remains practically unstudied in rocky shore ecosystems. The crab, Cancer borealis, is an important component of the diet of gulls (Larus marinus, L. argentatus) at the Isles of Shoals, Maine, USA. C. borealis prey include the predatory gastropod Nucella lapillus L., the herbivore Littorina littorea, and mussels Mytilus edulis L. We hypothesized that gulls reduce abundance of C. borealis in the low intertidal and shallow subtidal, thereby allowing C. borealis prey to persist in high numbers. A study of crab tidal migration showed that C. borealis density nearly doubled at high tide compared to low tide; thus, crabs from a large subtidal source population migrate into the intertidal zone during high tides and either emigrate or are removed by gulls during low tides. Results from a small-scale (1 m2) predator caging experiment in the low intertidal zone indicated that enclosed crabs significantly reduced L. littorea abundance when protected from gull predation. In a much larger-scale gull exclusion experiment, densities of C. borealis increased significantly during low and high tides in exclosures relative to the controls. C. borealis density was inversely correlated with changes in the abundance of two mesopredators Carcinus maenas and Nucella lapillus, and with the space-occupier M. edulis. There was a similar negative correlation between abundance of C. borealis and the change in abundance of the herbivore L. littorea, but the trend was not significant. Mortality of tethered L. littorea was associated with C. borealis density across sites. However, preferred algae did not change in response to L. littorea density during the experiment. Thus, we found suggestive, but not conclusive, evidence for a three-level cascade involving gulls, crabs, and L. littorea. Our studies strongly suggest that gulls, as apex predators, generate three-level trophic cascades in rocky intertidal food webs by preventing the highly mobile subtidal predator, C. borealis, from establishing substantial populations in the low-mid intertidal zone thereby indirectly enhancing densities of two key mesopredators (N. lapillus, Carcinus) and blue mussels (M. edulis).     

Capacity of transportation and spread of COVID-19—an ironical fact for developed countries

Environmental Science and Pollution Research - The widespread epidemic of the COVID-19 in developed countries such as Europe and the USA has sparked many speculations. What factors caused the rapid...