川东华蓥山废弃矿井水化学特征及影响因素分析

对废弃煤矿酸性矿井水(AMD)、地表水、地下水的水化学特征及影响因素进行分析,可为保护华蓥山水环境提供理论支撑。以广安市华蓥山废弃煤矿群为研究对象,基于水化学参数统计,运用水化学、相关性分析和离子比等方法对水样进行了综合分析研究。结果表明：岩溶水化学类型大多为HCO₃-Ca型;非酸性矿井水主要为HCO₃-Ca型为主;酸性矿井水主要主要为SO₄-Ca和SO₄-Na;受酸性矿井水影响的地表水化学类型以SO₄-Ca和SO₄-Na型为主;酸性矿井水的形成演化除了受溶滤、浓缩、混合及阳离子交换作用外,主要受黄铁矿(FeS₂)的氧化还原反应影响。研究该区废弃矿井水化学特征及控制因素,将为酸性矿井水治理方案提供理论基础,从而削减入江污染负荷,从“源头”上保护长江生态环境。     

辽阳市典型重污染过程特征及成因分析

2021年1月22—27日,辽阳市经历一次重度及以上污染过程,此次污染过程呈现持续时间长、污染物浓度高、污染范围广等特点,总体程度为轻—严重污染。截至27日,辽阳市出现4 d重度及以上污染(严重污染1 d),全市PM2.5浓度均值由污染过程前的40μg/m³上升至71μg/m³,直至27日上午污染过程结束。此次污染过程较重且较为典型,对辽阳市污染特征分析具有代表性意义。     

西南地区石漠化发生、演变时空特征及成因分析

采用GIS技术对我国西南喀斯特地区石漠化数据进行空间叠加分析,研究了石漠化发生及演变分布、岩性、地貌、区域经济等时空特征,并对我国西南喀斯特地区石漠化成因机理作了初步探讨。研究发现,石漠化发生、演变与碳酸盐岩岩性密切相关;其发生及加剧区域主要分布在较适宜人类活动的峰丛洼地、峰林洼地中;石漠化发生和演变程度与农民人均纯收入水平呈反相关。因此,石漠化治理必须根据石漠化发生和演变的区域、岩性和地貌特点、区域经济发展以及石漠化的程度等条件因地制宜地开展。     

四川省游客流时间分布特征及成因分析

将四川省作为旅游目的地,以旅游人数为指标,运用季节性强度指数、季节指数以及数理统计方法比较分析了四川省入境游客流与国内游客流的时间分布特征,主要从年际变化特征与月变化特征两个方面进行研究。依据四川省主要旅游景点季节性强度指数的时间变化特征,从旅游主体、旅游客体和旅游媒体三方面分别探讨了游客流时间变化的成因,重点研究了旅游客体类型、知名度、区位等因素对游客流时间分布特征的影响。     

成都市区酸雨变化及降雨化学组成分析

依据成都市1995～2003年城区酸雨监测统计资料,本文对成都市城区酸雨的变化特征、离子化学组成进行了分析。结果表明:城区降水酸度变化呈现出一定的波动性,酸雨频变化表现出较大的波动性;1999年和2000年酸雨年均酸度及频率情况都较好,之后出现反弹;降水中离子含量高,雨水污染严重;降水中CSO2-的比值正在逐步缩小,酸雨状况转变为硫/CNO-34酸型和硝酸型并重的局面,大气污染物中NOx的贡献率正在升高。灰色关联分析表明:降水pH值与雨水中碱性阳离子的关联序为NH+4>Ca2+>Mg2+>K+>Na+;降水pH′值与雨水中酸性阴离子的关联序为Cl->F->SO2-3。4>NO-     

Response of Fish and Macroinvertebrate Bioassessment Indices to Water Chemistry in a Mined Appalachian Watershed

Multimetric indices based on fish and benthic macroinvertebrate assemblages are commonly used to assess the biological integrity of aquatic ecosystems. However, their response to specific stressors is rarely known. We quantified the response of a fish-based index (Mid-Atlantic Highlands Index of Biotic Integrity, MAH-IBI) and a benthic invertebrate-based index (West Virginia Stream Condition Index, WV-SCI) to acid mine drainage (AMD)-related stressors in 46 stream sites within the Cheat River watershed, West Virginia. We also identified specific stressor concentrations at which biological impairment was always or never observed. Water chemistry was extremely variable among tributaries of the Cheat River, and the WV-SCI was highly responsive across a range of AMD stressor levels. Furthermore, impairment to macroinvertebrate communities was observed at relatively low stressor concentrations, especially when compared to state water quality standards. In contrast to the WV-SCI, we found that the MAH-IBI was significantly less responsive to local water quality conditions. Low fish diversity was observed in several streams that possessed relatively good water quality. This pattern was especially pronounced in highly degraded subwatersheds, suggesting that regional conditions may have a strong influence on fish assemblages in this system. Our results indicate that biomonitoring programs in mined watersheds should include both benthic invertebrates, which are consistent indicators of local conditions, and fishes, which may be indicators of regional conditions. In addition, remediation programs must address the full suite of chemical constituents in AMD and focus on improving linkages among streams within drainage networks to ensure recovery of invertebrate and fish assemblages. Future research should identify the precise chemical conditions necessary to maintain biological integrity in mined Appalachian watersheds.     

啤酒厂排放废水中COD与BOD5的相关性分析

本文针对ＢＯＤ５测定时间长，对突发性污染事故无法及时提供监测数据的缺点，采用最小二乘法，找出ＣＯＤ与ＢＯＤ５之间的回归方程式，应易测的ＣＯＤ值，较快地估测废水中的ＢＯＤ５值。     

Recent Changes in Stream Flashiness and Flooding,and Effects of Flood Management in North Carolina and Virginia

The southeastern United States has undergone anthropogenic changes in landscape structure, with the potential to increase (e.g., urbanization) and decrease (e.g., reservoir construction) stream flashiness and flooding. Assessment of the outcome of such change can provide insight into the efficacy of current strategies and policies to manage water resources. We (1) examined trends in precipitation, floods, and stream flashiness and (2) assessed the relative influence of land cover and flow‐regulating features (e.g., best management practices and artificial water bodies) on stream flashiness from 1991 to 2013. We found mean annual precipitation decreased, which coincided with decreasing trends in floods. In contrast, stream flashiness, overall, showed an increasing trend during the period of study. However, upon closer examination, 20 watersheds showed stable stream flashiness, whereas 5 increased and 6 decreased in flashiness. Urban watersheds were among those that increased or decreased in flashiness. Watersheds that increased in stream flashiness gained more urban cover, lost more forested cover and had fewer best management practices installed than urban watersheds that decreased in stream flashiness. We found best management practices are more effective than artificial water bodies in regulating flashy floods. Flashiness index is a valuable and straightforward metric to characterize changes in streamflow and help to assess the efficacy of management interventions.