Currently used organophosphate and brominated flame retardants in the environment of China and other developing countries (2000–2016)

This review summarizes the environmental occurrence of new brominated flame retardants (NBFRs) and organophosphate compounds (OPs) in the environment of developing countries since 2000. The ban on the production and use of commercial formulations of polybrominated diphenyl ethers (PBDEs) have paved the way for the high use of NBFRs and OPs in consumer products to fulfill the fire safety regulations. Recent studies have shown that the ever increasing production volumes and extensive use of these chemicals as additive FRs and plasticizers have resulted into their ubiquitous occurrence in all environmental compartments. Although presumed to be safe for use and the environment, recent studies on their occurrence and persistence in the environment have raised questions. Due to the lack of awareness, research interest, and availability of technical facilities, limited scientific data is available on the occurrence of these chemicals in developing countries. In this study, we collected reported data and provide an overview of environmental occurrence of NBFRs and OPs in abiotic and biotic matrices of different developing countries. Finally, research gaps were identified with recommendations for future research work and would be useful towards the environmental management of these toxic chemicals.     

Damage to plants due to industrial pollution and their use as bioindicators in Egypt

Effects of industrial air pollution on growth parameters of clover and Egyptian mallow were examined at three locations in the industrial area of Shoubra Elkheima, north of Cairo. Symptoms of plant damage appeared in the form of chlorosis and necrotic patterns. The decrease in chlorophyll reached more than 60% in plants cultivated in the industrial region. Plant growth and dry weights were reduced by more than 50%. The reduction in chlorophyll and growth parameters was correlated with the concentrations of air pollutants measured in the atmosphere of the locations examined. Moreover, clover and Egyptian mallow plants cultivated in the region of Shoubra Elkheima accumulated lead and cadmium, which can pass into the human food chain. It is concluded that these plants can be used as biomonitors for industrial air pollution.     

Economics of an integrated approach to control SO2, NOX,HCl, and particulate emissions from power plants

An integrated approach for the simultaneous reduction of major combustion-generated pollutants from power plants is presented along with a simplified economic analysis. With this technology, the synergistic effects of high-temperature sorbent/coal or sorbent/natural gas injection and high-temperature flue gas filtration are exploited. Calcium-based (or Na-based, etc.) sorbents are sprayed in the post-flame zone of a furnace, where they react with S- and Cl-containing gases to form stable salts of Ca (or Na, etc.). The partially reacted sorbent is then collected in a high-temperature ceramic filter, which is placed downstream of the sorbent injection point, where it further reacts for a prolonged period of time. With this technique, both the likelihood of contact and the length of time of contact between the solid sorbent particles and the gaseous pollutants increase, because reaction takes place both in the furnace upstream of the filter and inside the filter itself. Hence, the sorbent utilization increases significantly. Several pollutants, such as SO2, H2S, HCl, and particulate (soot, ash, and tar), may be partially removed from the effluent. The organic content of the sorbents (or blends) also pyrolyzes and reduces NOx. Unburned carbon in the ash may be completely oxidized in the filter. The filter is cleaned periodically with aerodynamic regeneration (back pulsing) without interrupting furnace operation. The effectiveness of this technique has been shown in laboratory-scale experiments using either rather costly carboxylic salts of Ca or low- to moderate-cost blends of limestone, lime, or sodium bicarbonate with coal fines. Injection occurred in the furnace at 1150 degrees C, while the filter was maintained at 600 degrees C. Results showed that 65 or 40% SO2 removal was obtained with calcium formate or a limestone/coal blend, respectively, at an entering calcium-to-sulfur molar ratio of 2. A sodium bicarbonate/coal blend resulted in 78% SO2 removal at a sodium-to-sulfur molar ratio of 2. HCl removal efficiencies have been shown to be higher than those for SO2. NOx reductions of 40% have been observed with a fuel (coal)-to-air equivalence ratio, phi, around 2. The filter has been shown to be 97-99% efficient in removing PM2.5 particulates. Calculations herein show that this integrated sorbent/filter method is cost-effective, in comparison with current technologies, on both capital cost ($/kW) and levelized cost ($/ton pollutant removed) bases, if a limestone/coal mixture is used as the sorbent for fossil fuel plants. Capital costs for the filter/sorbent combination are estimated to be in the range of $61-$105/kW for a new plant. Because current technologies are designed for removing one pollutant at a time, both their cost and space requirements are higher than those of this integrated technique. At the minimum projected removal efficiencies for HCl/SO2/NOx of about 40%, the levelized costs are projected to be $203-$261/ton of combined pollutant SO2/HCl/NOx and particulates removed from coal-fired power plants.     

Effect of lead on growth and nitrate assimilation of Vigna radiata (L.) Wilczek seedlings in a salt affected environment

The inhibition of seedling growth and nitrate reductase activity in 5 d old Vigna radiata (L.) Wilczek cv. Pusa Baisakhi in the presence of 1.0 mM lead acetate increased drastically, if NaCl (6 and 12 EC) was also present in the nutrient media along with the metal salt. Correspondingly higher endogenous Na+ levels were accumulated in the roots and leaves of seedlings in presence of the two stresses. On the other hand, the levels of endogenous lead get reduced in presence of NaCl in both the roots and leaves. Roots accumulated more Pb2+ and Na+ than the leaves. The two stresses affect more drastically in the additive or even synergistic manner during the early growth phase of the seedlings.     

Distribution and abundance of fish larvae off the coast of West Pakistan

The material was collected during 4 different cruises on the shelf off the coast of W. Pakistan in November–December, 1964 and in March, 1967 and 1968. The hydrography as well as the zooplankton-biomass distribution are briefly described. A total of 5777 larval fish were taken in 33 positive vertical hauls by an Indian Ocean Standard Net. The number of larvae in positive hauls ranged from 2 to 1262 larvae haul^-1. The most productive area of the ichthyoplankton was the waters south of Karachi, covered during the Machera Cruise, where 828 to 1262 larvae haul^-1 were obtained. The larvae were identified to species, genera or family. Sardinella sindensis (specific identification uncertain) larvae dominated in abundance. The other abundant larvae belonged to Benthosema spp., Amentum commersonii, Vinciguerria spp. and Diaphus spp. Larval distributions and abundances are described. Aggregation and spawning of adult Sardinella (sindensis) in the waters off the coast of W. Pakistan in November/December, 1964, are discussed. Presumably, the waters south of Karachi represent good feeding grounds for s. (sindensis) larvae. Displacement volume, length and weight relationships of various larval size groups have been studied and a high rate of larval mortality (at a length of 5.0 to 8.5 mm) observed.     

Inhalation of concentrated ambient particulate matter near a heavily trafficked road stimulates antigen-induced airway responses in mice

The goal of this study was to test the following hypotheses: (1) exposure to mobile emissions from mobile sources close to a heavily trafficked roadway will exacerbate airway inflammation and allergic airway responses in a sensitized mouse model, and (2) the magnitude of allergic airway disease responses will decrease with increasing distance from the roadway. A particle concentrator and a mobile exposure facility were used to expose ovalbumin (OVA)-sensitized BALB/c mice to purified air and concentrated fine and concentrated ultrafine ambient particles at 50 m and 150 m downwind from a roadway that was heavily impacted by emissions from heavy duty diesel-powered vehicles. After exposure, we assessed interleukin (IL)-5, IL-13, OVA-specific immunoglobulin E, OVA-specific immunoglobulin G1, and eosinophil influx as biomarkers of allergic responses and numbers of polymorphonuclear leukocytes as a marker of inflammation. The study was performed over a two-year period, and there were differences in the concentrations and compositions of ambient particulate matter across those years that could have influenced our results. However, averaged over the two-year period, exposure to concentrated ambient particles (CAPs) increased the biomarkers associated with airway allergies (IL-5, immunoglobulin E, immunoglobulin G1 and eosinophils). In addition, mice exposed to CAPs 50 m downwind of the roadway had, on the average, greater allergic responses and showed greater indications of inflammation than did mice exposed to CAPs 150 m downwind. This study is consistent with the hypothesis that exposure to CAPs close to a heavily trafficked roadway influenced allergic airway responses.     

Cycling of metals in desert soils: effects of Tamarix nilotica and inundation by lake water

Concentrations of Ca, Mg, K, Na, Cu, Zn, Al, Fe and Mn were measured in soils and in Tamarix nilotica from Wadi Allaqi on the shore of Lake Nasser in the Eastern Desert of Egypt. All of the elements were concentrated in the leaves of Tamarix relative to the stems and roots. Leaf:soil concentration ratios, used as an indicator of metal accumulation in the plant, showed high enrichment factors for Na (67.5), K (63.0) and Mg (35.0); of the trace elements measured, Zn had the highest enrichment factor (7.64). Comparison with other desert species suggested that Tamarix was exceptional only in the accumulation of sodium. Periodic inundation of the soil by Lake Nasser caused dilution and dispersion of the accumulated salts.