Scenario-based urban growth allocation in a rapidly developing area: a modeling approach for sustainability analysis of an urban-coastal coupled system

Being located in an urban-coastal coupled system, the Hashtpar City is one of the most attractive areas for urban construction, tourism, agricultural activities and environmental protection in northern Iran. To resolve the issues between land developers and environmental conservation agencies, we conducted a scenario-based urban growth allocation procedure through the SLEUTH model. The scenarios consisted of ‘business as usual’, ‘managed urban growth’ and ‘environmentally sound growth’ that were introduced by modification of model parameters and exclusion layer. The resultant urban growth arrangements were compared for composition and configuration attributes of landscape patterns. According to the results, the pattern of urbanized lands under managed urban growth option demonstrated better connectivity and compactness of urban patches, while the two other scenarios generated a highly fragmented pattern. The managed urban growth can be considered as a compromised solution between other scenarios since it simultaneously takes into accounts both developers and environment protectors points’ of views. On this basis, a combination of centralized and decentralized urban land use planning is a recommended strategy for our urban-coastal environment to fulfill the purposes of a sustainable development process. The findings of the present article suggest that further expansion of the major urban core in the targeted area should be prohibited since it can lead to an urban patch with considerable physical size and noticeable ecological footprint.     

Organocopper complexes during roxarsone degradation in wastewater lagoons

Background, aim, and scope  

Organoarsenical-containing animal feeds that promote growth and resistance to parasites are mostly excreted unchanged, ending up in nearby wastewater storage lagoons. Earlier work documented the partial transformation of organoarsenicals, such as, 3-nitro-4-hydroxyphenylarsonic acid (roxarsone) to the more toxic inorganic arsenate [As(V)] and 3-amino-4-hydroxyphenylarsonic acid (3-AHPAA). Unidentified roxarsone metabolites using liquid chromatography coupled to inductively coupled plasma mass spectrometry (LC/ICP-MS) were also inferred from the corresponding As mass balance. Earlier batch experiments in our laboratory suggested the presence of organometallic (Cu) complexes during relevant roxarsone degradation experiments. We hypothesized that organocopper compounds were complexed to roxarsone, mediating its degradation in field-collected swine wastewater samples from storage lagoons. The objective of this study was to investigate the role of organometallic (Cu) complexes during roxarsone degradation under aerobic conditions in swine wastewater suspensions, using electrospray ionization mass spectrometry (ES-MS).     

Clove bud oil: an efficient, economical and widely available oil for the inhibition of wheat seed germination

Pre-harvest sprouting refers to the precocious germination of the grain in the spike prior to harvest as a result of moist weather conditions at harvest time. From the agricultural viewpoint, it is necessary to impose an exogenous dormancy to wheat seeds in order to improve the resistance of seed to pre-harvest sprouting. In this regard, we found that clove bud essential oil is a strong inhibitor for wheat seed germination. The extract obtained from clove bud by supercritical fluid extraction using CO₂ as solvent minimized the number of extracts to two compounds, eugenol and eugenyl acetate. Eugenol, as the main constituent of the oil, was responsible for its strong inhibitory activity in wheat seeds. The aqueous solution of clove bud oil was submitted to germination assay at various concentrations from 50 to 400 mg/L. Complete inhibition of seed germination was recorded when the concentration was 400 mg/L. Roots and sprouts have similar sensitivity to inhibitory effect. In an empirical study, the synergistic cooperation of eugenol and eugenyl acetate from clove bud oil in the inhibition of seed germination was found to be a 1:1 ratio. The clove bud essential oil is widely available and will broaden the horizon of applications for natural and safe inhibitors in the fields.     

Indoor Air Quality at Rural and Urban Sites in Pakistan

In the developing world, the vast majority of people rely on solid biomass fuels for cooking and heating which results in poor indoor air quality. The present study determined indoor air quality in some rural and urban areas of Pakistan. Measurements were made of particulate mass (PM10, PM2.5 and PM1), number concentration and bioaerosols in different micro environments. PM10 concentrations of up to 8,555 μg/m³ were observed inside the kitchens where biofuels were used as energy source. Cleaning and smoking was identified as a major source of indoor particulate pollution and concentrations of more than more than 2,000 μg/m³ were recorded in the living room during these activities. Indoor number concentrations in Lahore were typically greater than those observed outdoors in European cites. At a rural site the highest Colony Forming Units (CFUs) were in the 0.5 μm–2 μm size fraction, while at the urban location CFUs were dominant for 2 μm–16 μm. It was observed that CFUs(Colony Forming Units) counts were higher inside living rooms than kitchens. It is important to note that women and children were exposed to extremely high levels of particulates during cooking. Overall, indoor air quality in Pakistan was poor and there is a dire need to take a serious step to combat with it.     

Fate of arsenic in swine waste from concentrated animal feeding operations

Swine diets are often supplemented by organoarsenicals, such as 3-nitro-4-hydroxyphenylarsonic acid (roxarsone) to treat animal diseases and promote growth. Recent work reported roxarsone degradation under anaerobic conditions in poultry litter, but no such data exist for swine wastes typically stored in lagoons nearby concentrated animal feeding operations (CAFOs). The objectives of this study were to: (i) characterize a suite of swine wastes collected from 19 randomly selected CAFOs for soluble arsenate [As(V)], arsenite [As(III)], dimethylarsenic acid (DMA), monomethylarsonic acid (MMA), 3-amino-4-hydroxyphenylarsonic acid (3-HPPA), p-arsanilic acid, and roxarsone, and (ii) determine the geochemical fate of roxarsone in storage lagoons nearby CAFOs. Swine waste suspensions were spiked with roxarsone and incubated under dark/light and aerobic/anaerobic conditions to monitor roxarsone degradation kinetics. Arsenic speciation analysis using liquid chromatography and inductively coupled plasma mass spectrometry (LC-ICPMS) illustrated the prevalence of As(V) in swine waste suspensions. Roxarsone underwent degradation to either organoarsenicals (3-HPPA) or As(V) and a number of unidentified metabolites. Roxarsone degradation occurred under anaerobic conditions for suspensions low in solids content, but suspensions higher in solids content facilitated roxarsone degradation under both anaerobic and aerobic conditions. Increased solids content enhanced roxarsone degradation kinetics under aerobic conditions. According to current waste storage and sampling practices, arsenic in swine wastes stored in lagoons has been overlooked as a possible environmental health issue.     

Measurement and management of hospital waste in southern Iran: a case study

One of the requirements for development of human societies is the establishment of new healthcare centers. A variety of wastes are generated in healthcare centers depending on the type of activities. This study was conducted to identify, measure and manage different types of hospital wastes as a case study in a hospital located in southern Iran. For this purpose, a questionnaire was initially designed and distributed among the relevant experts to survey the current trend of waste management in the hospital in terms of waste collection, storage and disposal. Afterwards, the hospital waste was sampled during two seasons of fall and winter. The samples were weighted for seven consecutive days in the middle of each season. Approximately, 10 % of the total waste bags per day collected round the clock were selected for further analysis. The obtained results indicated that infectious-hazardous and pseudo-household wastes were, respectively, about 3.79 kg/day/bed, 1.36 kg/day/bed and 2.43 kg/day/bed of the total generated waste in the hospital. As the research findings suggest, proper separation of infectious and pseudo-household wastes at the source would be an essential step towards mitigating environmental and health risks and minimizing the cost of the hospital waste management.     

Health risks associated with heavy metals in the drinking water of Swat, northern Pakistan

The concentrations of heavy metals such as Cd, Cr, Cu, Mn, Ni, Pb and Zn were investigated in drinking water sources （surface and groundwater） collected from Swat valley, Khyber Pakhtunkhwa, Pakistan. The potential health risks of heavy metals to the local population and their possible source apportionment were also studied. Heavy metal concentrations were analysed using atomic absorption spectrometer and compared with permissible limits set by Pakistan Environmental Protection Agency and World Health Organization. The concentrations of Cd, Cr, Ni and Pb were higher than their respective permissible limits, while Cu, Mn and Zn concentrations were observed within their respective limits. Health risk indicators such as chronic daily intake （CDI） and health risk index （HRI） were calculated for adults and children separately. CDIs and HRIs of heavy metals were found in the order of Cr 〉 Mn 〉 Ni 〉 Zn 〉 Cd 〉 Cu 〉 Pb and Cd 〉 Ni 〉 Mn 〉 Cr 〉 Cu 〉 Pb 〉 Zn, respectively. HRIs of selected heavy metals in the drinking water were less than 1, indicating no health risk to the local people. Multivariate and univariate statistical analyses showed that geologic and anthropogenic activities were the possible sources of water contamination with heavy metals in the study area.     

Antioxidant enzymatic activities and lipid peroxidation in liver and ovary of zebrafish (Danio rerio) exposed to deltamethrin

Deltamethrin (DM) is being used as a substitute for organochlorines and organophosphates in pest control because of its low environmental persistence and toxicity. But it has become an environmental contaminant as it has been used widely. In this study, we investigated the effect of DM (technical grade) on the antioxidant system of adult zebrafish. For this, six-month-old fish were exposed to 2, 4 and 6?μg/L of DM for 96?h. The tissues selected were liver and ovary. Our data showed that exposure to DM increases CAT (catalase), SOD (superoxide dismutase), GPx (glutathione peroxidase, antioxidant enzymes), LPO (lipid peroxidation, non-enzymatic antioxidant) and GST (glutathione S-transferase, detoxifying enzyme) in liver and ovary. Increased GST could detoxify the toxicant; still there could be enough DM to cause oxidative stress. It appears from our study that zebrafish used compensatory mechanisms in eliminating reactive oxygen species. These data will be useful as oxidative stress is being used as a biomarker for aquatic pollution.     

Microbial acidification and pH effects on trace element release from sewage sludge

Leaching of sludge-borne trace elements has been observed in experimental and field studies. The role of microbial processes in the mobilization of trace elements from wastewater sludge is poorly defined. Our objectives were to determine trace element mobilization from sludge subjected to treatments representing microbial acidification, direct chemical acidification and no acidification, and to determine the readsorption potential of mobilized elements using calcareous sand. Triplicate columns (10-cm diameter) for incubation and leaching of sludge had a top layer of digested dewatered sludge (either untreated, acidified with H2SO4, or limed with CaCO3; all mixed with glass beads to prevent ponding) and a lower glass bead support bed. Glass beads in the sludge layer, support layer or both were replaced by calcareous sand in four treatments used for testing the readsorption potential of mobilized elements. Eight sequential 8-day incubation and leaching cycles were operated, each consisting of 7.6 d of incubation at 28 degrees C followed by 8 h of leaching with synthetic acid rain applied at 0.25 cm/h. Leachates were analyzed for trace elements, nitrate and pH, and sludge layer microbial respiration was measured. The largest trace element, nitrate and S losses occurred in treatments with the greatest pH depression and greatest microbial respiration rates. Cumulative leaching losses from both microbial acidification and direct acidification treatments were > 90% of Zn and 64-80% of Cu and Ni. Preventing acidification with sludge layer lime or sand restricted leaching for all trace elements except Mo. Results suggested that the primary microbial role in the rapid leaching of trace elements was acidification, with results from direct acidification being nearly identical to microbial acidification. Microbial activity in the presence of materials that prevented acidification mobilized far lower concentrations of trace elements, with the exception of Mo. Trace elements mobilized by acidification were readsorbed by calcareous sand when present.