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1.
Microplastics (MPs) are frequently regarded as environmental and biota contaminants. Yet, research on the accumulation of MPs in living entities, particularly aquatic insects that serve as food resources in the aquatic food chain, is limited. This study to investigate the accumulation of MPs in aquatic insects from water and sediment in an Egyptian wastewater basin. Four typical freshwater insect groups were used. The highest MP load per gram wet weight was reported by collector-gatherers (Chironomus sp. and Hydrophilus sp.), followed by collector-filterers (Culex sp.) with the second highest MP load. However, Predators (Aeshna sp.) had the lowest values. Also, the present results showed a reduction in the number of MPs in all insect taxa tested after a 24 h depuration time, with differences in the observed egestion ability. The mean number of MPs per individual significantly reduced after 24 h in both Chironomus sp. and Culex sp. larvae, where 53% and 40% of MPs particles were ejected from them, respectively. However, the ability of MP egestion decreases in Aeshna sp. nymph (25%), and the lowest proportion of ejection was observed in Hydrophilus sp. adults (9%). Polyethylene terephthalate fibers were the most abundant type of MP in both sediment and water, followed by fragments (polyethylene and polypropylene). Yet, only polyester fibers were detected in the various insect species. The average length of fibers in the various insects was somewhat shorter than in the surrounding environment. The current study reveals that MP ingestion by aquatic insects is not always related to levels of pollution in the environment, since other factors such as feeding strategies may play a role in MP ingestion. Based on these observations, further studies should be carried out on studies on toxicological impacts of MPs on freshwater/aquatic biota. 相似文献
2.
While factors influencing perceptions of drinking water have been well studied, those of aquatic ecosystems have been to lesser extent. We conducted a review to improve awareness of these factors. Environmental factors found to influence public perceptions of aquatic ecosystems were presence/absence of water plants and algae, presence/absence of floating debris, the odor, movement (for flowing waters) and clarity/turbidity of the water, and the type, condition, setting, naturalness, and overall aesthetic appeal of the ecosystem. Sociocultural factors found to influence public perceptions of aquatic ecosystems included age, education, gender, and place-based knowledge. We provide perspectives of how managers can better meet the diverse social demands placed on aquatic ecosystems. The importance and benefits of considering these perspectives may be especially beneficial where significant multi-generational and culturally relevant place-based knowledge exist. 相似文献
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依据2017年5、7、9月对三江平原19处沼泽湿地(参照湿地6处,受损湿地13处)的水生无脊椎动物采样结果,应用生物完整性理论和方法,构建水生无脊椎动物完整性指数,评价三江平原沼泽湿地健康状况。通过对27个候选指标的分布范围、判别能力和相关性分析,筛选出总分类单元数、扁卷螺科百分比、龙虱科百分比、刮食者百分比4个指标构成水生无脊椎动物完整性指数核心指标。采用比值法计算各指标参数值,将各参数值加和得到水生无脊椎动物完整性指数值。根据参照湿地水生无脊椎动物完整性指数值的25%分位数值确定评价标准,对小于25%分位数的值进行三等分,确定三江平原沼泽湿地健康评价标准:≥2.58,无干扰;1.72~2.58,轻度干扰;0.86~1.72,中度干扰;0~0.86,重度干扰。结果表明:所调查的三江平原沼泽湿地有78.95%受到不同程度的干扰(其中47.37%受到了中重度干扰),21.05%属于无干扰。 相似文献
4.
新的《火电厂大气污染物排放标准》和新《环境保护法》实施后,燃煤火电企业的依法治企自觉性不断提高,但由于不同的环保管理文件对超标处罚依据和处罚手段不同,造成政府对企业处罚的自由裁量权加大,对企业造成一定的压力与困惑。结合企业实际运行情况对燃煤电厂大气污染物排放考核时间间隔提出建议。 相似文献
5.
为了研究化工厂选址的合理性,以山东省某化工厂为例,采用ALOHA(有害大气空中定位软件)模拟软件定量确定厂区内环氧乙烷毒气扩散事故的影响区域和敏感点毒气浓度,结合GoogleEarth地图对影响范围进行实地拟合。结果表明化工厂的环氧乙烷储罐泄漏后,毒气扩散到厂区范围之外,毒气浓度在50~500ppm之间的重伤区(ERPG-2)扩散距离可达1.7km,对周围居民的人身安全构成严重威胁;厂区应根据拟合结果重新规划工厂中环氧乙烷储罐的位置;ALOHA软件对化工厂选址评价提供了新的手段。 相似文献
6.
Petrochemical plants are continuously turning into large-size corporations, the installations of facilities show a developing trend from ground to underground because of the difference in land using rate. In this regard, the safety distance of petrochemical equipment buried in both ground and underground cases were investigated based on risk assessment. As a case study, gasoline tank and LPG tank set on the ground and underground are singled out to compare the risks involved. The research showed that the setting case of installation had a great influence on safety distance. Two cases have 80% reduction of equivalent safety distance compared with the rest of the cases. It was found that when the gasoline storage tank was placed underground alone, the PLL value decreased by 36.7%. Only LPG tank was placed underground, and the PLL decreased by 6.33%, and the gasoline and LPG storage tanks were placed underground simultaneously, the PLL value declined by 42.3%. Thus, the layout of plants could be further optimized, which can greatly improve the performances of land use efficiency and safety. In addition, this paper, the selection of embedding methods and the sensitivity of underground case to overpressure was resumed from two aspects: soil properties and burial depth. For the soil properties, it was found that the water saturated sandy soil with high air content and the low density unsaturated sandy soil had better effects on weakening overpressure. Such properties are particularly beneficial to reducing the occurrence rate of accidents. In terms of burial depth, it can be observed that as the burial depth was changed from 0.5m to 1.1m, the value of overpressure has dropped dramatically. When the burial depth was 2m, the damage to personnel and buildings has been greatly reduced beyond 2m from the explosion center. 相似文献
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水库底层低温低氧水从坝体下泄或渗漏,可能对下游生态产生不利影响。通过对湖北温峡水库下游温峡河225 km河段的野外试验,测量溶解氧、水温等指标的日变化和沿程变化,开展复氧试验研究阶梯深潭结构和沙洲对溶解氧的影响,并取样分析大型底栖无脊椎动物的沿程分布。结果表明,流速对水温与溶解氧日变化规律无明显影响。试验河段水温和溶解氧恢复很快,经过17 km的河段,水温从123℃升高至300℃,且溶解氧饱和度基本达到饱和。河宽对水温恢复起重要作用,对溶解氧影响较小,对复氧速度基本无影响。流量通过改变淹没程度影响阶梯深潭的复氧能力。溶解氧在沙洲下游存在横向分布,滞水区溶解氧高于左右汊道。溶解氧是水库下游水生态的控制因素,物种多样性随溶解氧的升高而增加 相似文献