MODELING PREVENTION ALTERNATWES FOR NONPOINT SOURCE POLLUTION AT A WELLFIELD IN FLORIDA1

ABSTRACT: Agricultural and urban activities in the West Wellfield Interim Protection Area (WWIPA), located in West Dade County in South Florida, have the potential to impact both the environmentally sensitive Everglades and the Biscayne Aquifer. The Hydrological Simulation Program-FORTRAN (HSPF) is used to simulate surface runoff, ground water recharge, and transport of sediments, nutrients, and pesticides in the WWIPA, as a basis to quantify impacts and evaluate alternatives. Presented are four model test runs that consider current conditions, the effect of future urbanization of the agricultural land, as well as two preventive actions to minimize pollution levels. Preventive actions include application of minimum required rates of fertilizers and replacement of fertilizers by sewage sludge. Model results show that under current practices, sediments, nutrients, and pesticides are present in surface runoff and nutrients enter the ground water, and that both urbanization and preventive actions result in pollutant reductions.     

Mutatox test: a new test for monitoring environmental genotoxic agents

In this study, Yamaska River water and Milli-Q water and organically extracted sediment extracts were used to evaluate the sensitivity of a new genotoxicity screening test, the Mutatox test. Also in this study, the samples were tested for acute and chronic toxicity using the following screening test procedures: Microtox, Daphnia magna, Ceriodaphnia reticulata and ATP-TOX Systems. The Mutatox test is based on the use of a dark mutant strain of Photobacterium phosphoreum and is sensitive to chemicals which are (1) DNA damaging agents (2) DNA intercalating agents, (3) DNA synthesis inhibitors and (4) direct mutagens. In this study, the Mutatox test was found to be a simple-to-perform sensitive procedure which added greater scope to the battery of tests approach. Preliminary indications are that this procedure may prove to be one of the more responsive and valuable tests in the 'battery of tests' approach to environmental screening.     

Control of petroleum-hydrocarbon contaminated groundwater by intrinsic and enhanced bioremediation

In the first phase of this study, the e ectiveness of intrinsic bioremediation on the containment of petroleum hydrocarbons was evaluated at a gasoline spill site. Evidences of the occurrence of intrinsic bioremediation within the BTEX (benzene, toluene, ethylbenzene, and xylenes) plume included (1) decreased BTEX concentrations; (2) depletion of dissolved oxygen (DO), nitrate, and sulfate; (3) production of dissolved ferrous iron, methane, and CO2; (4) deceased pH and redox potential; and (5) increased methanogens, total heterotrophs, and total anaerobes, especially within the highly contaminated areas. In the second phase of this study, enhanced aerobic bioremediation process was applied at site to enhance the BTEX decay rates. Air was injected into the subsurface near the mid-plume area to biostimulate the naturally occurring microorganisms for BTEX biodegradation. Field results showed that enhanced bioremediation process caused the change of BTEX removal mechanisms from anaerobic biodegradation inside the plume to aerobic biodegradation. This variation could be confirmed by the following field observations inside the plume due to the enhanced aerobic bioremediation process: (1) increased in DO, CO2, redox potential, nitrate, and sulfate, (2) decreased in dissolved ferrous iron, sulfide, and methane, (3) increased total heterotrophs and decreased total anaerobes. Field results also showed that the percentage of total BTEX removal increased from 92% to 99%, and the calculated total BTEX first-order natural attenuation rates increased from 0.0092% to 0.0188% per day, respectively, after the application of enhanced bioremediation system from the spill area to the downgradient area (located approximately 300 m from the source area).     

Greenhouse gas emissions from rice based cropping systems: Economic and technologic challenges and opportunities

Recent market slump in rice, less rainfall during monsoon, high temperature and scarcity of water during dry season leads to lower grain yield and less profit from rice cultivation in India. Farmers’ grow upland crops like chickpea (Cicer arietinum), greengram (Vigna radiate), mustard (Brassica nigra), corn (Zea maize), pigeonpea (Cajanus cajan), potato (Solanum tuberosum), sunflower (Helianthus annuus) etc. along with rice (Oryza sativa) during the dry season. However, knowledge of greenhouse gas (GHG) emission from these rice based cropping systems is very limited. In the present study four rice based cropping systems was studied along with rice-rice rotation system as control in respect of GHG emission, yield potential and economic feasibility. Conventional plantation and fertilizer application methodology was followed for each crop. Methane (CH₄) and nitrous oxide (N₂O) flux from field plots were studied with conventional closed chamber method using gas chromatograph. CH₄ flux was recorded highest from rice-rice rotation plots (304.25 kg ha⁻¹). N₂O flux was recorded 1.02 kg ha⁻¹ from rice-rice rotation system during wet season. However, during wet season, higher N₂O flux (1.93 kg ha⁻¹) was recorded from rice-potato-sesame rotation plots. Annual N₂O flux was also recorded significantly low (3.42 kg ha⁻¹) from rice-rice rotation plots and high (6.19 kg ha⁻¹) from rice-chickpea-greengram rotation plots. Significantly lower annual grain yield was recorded from rice-rice rotation plots (9.25 Mg ha⁻¹) whereas it was 18.84 Mg rice eq ha⁻¹ from rice-potato-sesame rotation system. The global warming potential (GWP) of rice-rice rotation system was recorded significantly high (8.62 Mg CO₂ ha⁻¹) compare to plots with different rice based cropping systems. Computing all C-emission from cradle-to-grave, highest total C-cost was recorded from the rice-rice rotation system ($62.00 ha⁻¹). We have made an attempt to calculate the C-credit of different rice based cropping systems by considering the difference of C-cost with control. The study suggests that the rice-potato-sesame is most sustainable among different cropping system studied in terms of economic profit ($62.00 ha⁻¹). We have made an attempt to calculate the C-credit of different rice based cropping systems by considering the difference of C-cost with control. The study suggests that the rice-potato-sesame is most sustainable among different cropping system studied in terms of economic profit (1248.21 ha⁻¹) and C-credit ($38.60 ha⁻¹). The result of the study may be limited to the study region; however, the study has potential use in respect to the development of agriculture practice for adaptation to climate change.     

执行《环境空气质量标准》应注意的问题

随着《环境空气质量标准》GB30 95- 1 996(简称新标准 )取代 GB30 95- 82 (简称旧标准 ) ,大气环境质量现状监测和影响评价工作需要作出相应的修正以适应新标准的要求 ,从实际工作出发 ,总结出了执行新标准应注意的一些问题及其解决方法。     

确定卫生防护距离应注意的问题

本文总结了石化行业卫生防护距离标准编制和环境影响评价工作中的经验，对确定卫生防护距离时应注意的一些问题进行了探讨，并提出了一种新的确定石化装置废气无组织排放量的方法。     

基于非本地物种毒性数据推导出的水质基准可为本地物种提供适当保护吗？

基于非本地物种的毒性数据推导出的水质基准一直存在争议,质疑者提出应有针对不同生物区系的水质基准。而这个问题在中国尤为突出。本文作者搜集了38种污染物对本地物种和非本地物种的毒性数据,比较了这些生物的HC₅和物种敏感度分布,结果显示,基于非本地物种推导的水质基准有74%的确定性可以有效保护中国的水生态系统。如果采用评价因子(AF=5)来校正基准,那么可以获得90%的确定性。
精选自Xiaowei Jin, Zijian Wang, Yeyao Wang, Yibing Lv, Kaifeng Rao, Wei Jin, John P. Giesy and Kenneth M. Y. Leung. Do water quality criteria based on nonnative species provide appropriate protection for native species? Environmental Toxicology and Chemistry: Volume 34, Issue 8, pages 1744–1750, August 2015. DOI: 10.1002/etc.2985
详情请见http://onlinelibrary.wiley.com/doi/10.1002/etc.2985/full     

Sub-lethal effect of chlorpyrifos on protein metabolism of the food fish Clarias batrachus and monitoring of recovery

The effect of sub-lethal concentrations of chlorpyrifos on protein metabolism in physiological important tissues, namely gills, kidney, liver, and muscle of the freshwater fish, Clarias batrachus, was studied. Fish were exposed to 1/20th and 1/10th of 96?h LC₅₀ concentrations for 7, 14, 21, and 28 days. After 28 days of exposure, fish were released into fresh water and kept in the same for 21 days in order to study the recovery. Fish were sacrificed at the stipulated periods and gills, kidney, liver, and muscle tissues were used for the estimation of total protein, amino acids, ammonia, urea, glutamine, protease, transaminases, and phosphatases. Total protein, amino acid, and ammonia contents were decreased in all tissues for 28 days and recovery was observed during the recovery period. Urea and glutamine levels were elevated, except in kidneys, and recovered at the end of the recovery period. The activities of protease, alanine, and aspartate aminotransferases, and acid and alkaline phosphatases were elevated in the tissues for 28 days exposure at both concentrations. Recovery of these enzymes activities was noticed during depuration.     

Therapeutic effect of melatonin against aluminum-induced neurotoxicity in cerebellum of albino mice

The therapeutic effect of melatonin (MEL) against aluminum (Al)-induced neurotoxicity was investigated in mouse cerebellum. Two groups of male albino mice were intraperitoneally injected with Al acetate or MEL alone, at doses of 3.5 or 7?mg?kg^?1?day^?1, respectively, for 6 weeks. During this period, another group of animals received a combination of both Al and MEL (3.5?+?7?mg?kg^?1?day^?1). At the end of the treatment cerebellum was removed and processed to examine the oxidative stress markers: superoxide dismutase (SOD), catalase (CAT), and thiobarbituric acid-reactive substances (TBA-RS). Oxidative stress increased significantly with administration of Al which was estimated by increased TBA-RS and reduction in the activities of SOD and CAT. However, these alterations were significantly reversed significantly following MEL treatment which was observed in co-administered group. Protective effects of MEL were also observed at electron microscopic level. Ultrastructural studies revealed an increase in vacuolization, chromatin condensation within the nucleus, degenerated purkinje cell, degenerated axon and degenerated granule cells in the cerebellum of Al-treated mice group whereas concurrent administration of MEL with Al reduced these changes. The results of the present investigation emphasize the potential use of MEL as a supplement in therapy of free radical based neurological disorders in which oxidative stress is involved.     

Oxidative stress and changes in locomotor behavior and gill morphology of Gambusia affinis exposed to chromium

Sublethal effects of chromium trioxide on mosquito fish, Gambusia affinis, were carried out for 28 days on day 4, 8, 12, 16, 20, 24, and 28. The sublethal effects of chromium (LC₁₀, 77.62?mg?L^?1) on antioxidant enzymes, thiobarbituric acid reactive substance (TBARS), locomotor behavior, and gill morphology were studied. The antioxidant enzymes like superoxide dismutase (SOD) and catalase were induced throughout the exposure span of 28 days. Percent induction was also increase with the days of exposure. Lipid peroxidation product, malondialdehyde was enhanced in the viscera tissue of chromium-exposed fish. Perturbation of locomotor behavior like decrease in distance travelled (m?min^?1) and in swimming speed (cm?s^?1) was observed in exposed fish. Chromium toxicity caused alterations in gill morphology like hypertrophy and hyperplasia in secondary lamellae followed by detached epithelium with severe necrosis. It can be concluded from the results that Cr intoxication in Gambusia fish, caused induction in antioxidant enzymes and lipid peroxidation, plus changes in gill morphology and locomotor behavior.