山阴地区高砷饮用水处理技术

通过对山西省山阴县高砷地下水分布和污染程度的实地调查,对高砷水环境中砷的形态及富集转化规律进行了研究,并在此基础上形成一套以曝气氧化和加药(加入FeCl2和FeCl3的混合物作为混凝剂)过滤工艺为基础的联合水处理方法.结果表明,在山阴县砷污染严重的地段,地下水的氧化还原电位Eh为-50～142 mV,pH值为8.28～8.73,这种Eh下降、pH升高的地下环境给高砷地下水的形成创造了条件.当地下水中ρ(硫化氢)<140μg·L-1时,用功率为5 W的松宝SB-648双头氧气泵连续曝气1.5 h即可达到基本去除的效果.以25 m深处地下水为例,其ρ(As)为275 μg·L-1,待硫化氢去除后在水中加入摩尔比n(FeCl2):n(FeCl3)=1:1的混合物,连续曝气5 h,水体中60%以上的As(Ⅲ)可转变为As(V).经投加药品和曝气氧化处理后的地下水若能及时通过简易过滤装置,过滤后的水体中ρ(As)仅为5～8 μg·L-1,达到GB 5749-2006<活饮用水卫生标准>,且过滤后的水体中ρ(Fe)为0.03 mg·L-1,远小于GB/T 14848-93<地下水水质标准>规定的Ⅰ类标准.该水处理方法可快速有效地将As(Ⅲ)转化为As(V),并使As(V)与混凝剂发生吸附共沉淀反应,从而达到高效除砷的效果.过滤过程则可以防止氢氧化物胶体与砷酸盐形成的絮体二次进入环境,同时进一步降低水体中铁离子含量.该方法适用于我国广大高砷水地区家庭分散式供水的处理.     

Likelihood Ratio Analysis of Skin Cancer Prevalence Associated with Arsenic in Drinking Water in the USA

Several published studies have examined skin-cancer prevalence in regions of the USA that have concentrations of arsenic above the USA drinking-water standard. Those studies with adequate exposure and health outcome data did not report any skin cancer cases. Because the USA's arsenic concentrations are relatively low compared to some other countries and the study populations are small, the absence of reported skin-cancer cases could be due to an absence of risk in USA populations or random variability from a predicted risk. We used the current EPA arsenic cancer slope factor (CSF) model, which is derived from Taiwanese populations exposed to high levels of arsenic, to predict the expected number of skin cancers. We then conducted a likelihood ratio analysis, which showed that a null hypothesis (no additional skin cancer risk from arsenic) was approximately 2.2 times more likely than the hypothesis that ingested arsenic causes the predicted rate of skin cancers. Although based on small numbers, our analysis of USA populations indicates that the CSF derived from arsenic exposure in Taiwanese populations may be an overestimate when applied to USA populations.     

The Relationship Between Exposure to Arsenic Concentrations in Drinking Water and the Development of Skin Lesions in Farmers from Inner Mongolia, China

Associations between the concentration of arsenic naturally occurring in drinking water and the development of skin lesions in people have been documented for some years at various locations around the world. Data on the exposure-response relationship between concentrations of arsenic in drinking water and prevalence of skin lesions in farmers from five locations in Inner Mongolia, China have been collected from the original publications and re-analysed together as a meta-study. The calculated data show a positive linear exposure-response relationship without a threshold. The reasons for this linear correlation are discussed and compared with the data from Xinjiang, another arsenism area located in a different geographical area of China. Here a different relationship was recorded that involved a threshold concentration before skin lesions developed. The significance of these two different exposure-response scenarios is discussed.     

Evaluation of the validity of the US EPA's cancer risk assessment of arsenic for low-level exposures: a likelihood ratio approach

Skin cancers associated with ingesting of arsenic have been documented since the 19th century. A study in the southwestern coastal area of Taiwan where people drank well water containing arsenic is generally recognised as providing the best data available for quantifying the risk, and the US Environmental Protection Agency (EPA) used these data to conduct a risk assessment of arsenic ingestion. However, the lowest exposure category in the Taiwan study included arsenic levels up to 290 µg L^–1, which is nearly six times higher than the current EPA maximum contaminant level (MCL), 50 µg L^–1. Therefore, the EPA risk assessment model extrapolated data on high-level exposures to generate risk estimates for low-level exposures. To evaluate the validity of this model, we conducted a quantitative review of epidemiological studies observing arsenic exposures below 290 µg L^–1. A ratio of the likelihood of the EPA model being inappropriate to that of it being appropriate was calculated for each study population as a measurement of the validity of the EPA model. Although existing human data on low-level exposures are limited, the review suggested that the EPA model is unlikely to be able to predict the risk of skin cancer accurately when the arsenic exposure level is between 170 and 270 µg L^–1.     

我国水污染及饮用水源中有机污染物的危害

本文阐述了我国水污染环境的状况和危害,以及微污染饮用水源的水质特征和饮用水源中的有机污染物及其危害。     

Fluoride Concentration in Drinking Water in The Province of Soria (Central Spain) and Caries in Children

The fluoride content in the water supply of the Soria province is not normally above 0.2mg L^–1 and its geographical distribution is related to the lithological and geological features of the zone, the highest concentration being associated with the Miocene clay formation of the Almazán Basin.A statistical analysis confirms a connection between this fluoride content and tooth decay among children in rural areas. However, other factors such as oral hygiene and diet have been found to affect tooth decay.     

紫外分光光度法同时测定生活饮用水中的硝酸盐氮和亚硝酸盐氮

提出了紫外分光光度法同时测定生活饮用水中的硝酸盐氮和亚硝酸盐氮的含量。方法操作简便快速,精密度和准确度都是令人满意,大大提高分析效率。     

Distribution and Risk Assessment of Fluoride in Drinking Water in the West Plain Region of Jilin Province, China

The west plain region of Jilin province of northeast China is one of the typical endemic fluorosis areas caused by drinking water for many years. Investigations of hydrogeological and ecoenvironmental conditions as well as endemic fluorosis were conducted in 1998. Results show that the ground water, especially, the water in the unconfined aquifer is the main source of drinking water for local residents. The fluoride concentration in groundwater in the unconfined aquifers is higher than that in the confined aquifer in the west plain of Jilin province. The fluoride concentration in the unconfined aquifer can be used to classify the plain into fluoride deficient area, optimum area and excess area, which trend from west to east. High fluoride (>1.0 mg L(-1)) in drinking water resulted in dental and skeletal fluorosis in local residents (children and pregnant women). There exists a positive correlation between fluoride concentration in the drinking water and the morbidities of endemic fluorosis disease (r1 = 0.781, r2 = 0.872). Health risks associated with fluoride concentration in drinking water are assessed. It has been determined that fluoride concentration in excess of 1.0 mg L(-1) exposes residents to high health risks based on risk identification. The study area is classified into five health risk classes as shown in Figure 4. The risk indexes of this area more than 1.0 are accounted for 68% of the total west plain region.     

Health Impact Evaluation of Boron in Drinking Water: A Geographical Risk Assessment in Northern France

Objective: To evaluate health impact of boron in drinking water. Methods: A regional scale geographical study in Northern France was conducted. Assessment of boron blood levels in a group of 180 healthy individuals and correlation with boron content in drinking water were followed by an assessment of health indicators such as birth rates, mortality rates, and sex ratios in zones of different boron content in drinking water. Results: After necessary adjustments, men living in municipalities with more than 0.30 mg/L of boron in drinking water had elevated but not significant boron blood levels compared with those living in municipalities with boron water levels of less than 0.30 mg/L (159.1 versus 123.0 ng/g; p > 0.05). The standardized birth ratio adjusted for the reference geographic zone and calendar time period was 1.07 and 1.28 in the low and high (>0.3 mg/L) boron content municipalities, respectively. The birth rate in municipalities with high boron content in drinking water was higher than that of the reference geographic zone and of the French general population (p < 10^-4). The standardized mortality ratio adjusted for the reference geographic zone and calendar time period was 0.94 and 0.92 in the low and high boron content municipalities, respectively. The mortality rate in municipalities with high boron content in drinking water was less than that of the reference geographic zone and of the French general population (p < 10^-3). No statistical difference was noted in the male–female sex ratios between the different municipality zones (p = 0.45). Conclusions: The results of this study do not support the idea of a deleterious effect of boron on human health, at the boron water level contents found in this specific region. In fact, there is a tendency toward a beneficial effect with low-dose environmental exposure (less than 1 mg/L of boron) in drinking water.     

Arsenic in freshwater ecosystems of the Bengal delta: status,sources and seasonal variability

The study aimed to examine the contamination status of arsenic (As) in excavated small water bodies, commonly known as ponds – the integral part of daily life in the arsenic-affected rural areas of West Bengal, India in comparison to the unaffected areas. The ponds of the contaminated area had higher levels of As: water 2–174 µg L^?1 (mean 31 ± 2 µg L^?1) and sediment 1.3–37.3 mg kg^?1 (mean 10.3 ± 0.4 mg kg^?1), than those from the unaffected area: water 1–8 µg L^?1 (mean 4 ± 0 µg L^?1) and sediment 1.4–5.3 mg kg^?1 (mean 3.0 ± 0.1 mg kg^?1). A moderate positive correlation was observed between the water and sediment arsenic content of the ponds of the arsenic-affected region (r = 0.688, n = 277, p < 0.0001). Contaminated ground water, either as direct input or through agricultural washings, was found to be the major contributor of arsenic pollution to these ecosystems. Seasonal variations were not prominent. This study emphasized the beneficial role of using the studied ecosystems over the highly contaminated ground water for various livelihood activities in the Gangetic delta region.     

Heavy Metals and Arsenic in Sediments, Mussels and Marine Water from Murano (Venice, Italy)

This paper describes a study of the trace element distribution in sediments, marine water and mussel Mytilus galloprovincialis of the Venetian Lagoon around the Island of Murano, an island with a long tradition of glassmaking. Trace elements analysed include Fe, Mn, Zn, Cu, Cr, Pb, Ni, Ag and As. Sediments are contaminated with Zn, Cu, Ag, As and Pb, with levels in the <2m fraction that are likely to cause adverse biological effects to marine organisms. The pelite (<63m) is the main carrier of heavy metals at most sites. However, the fine-grained and coarse sand on the southern coast of Murano accounts for a significant proportion of Fe, Mn, Zn, Cr, Ag, Ni and Pb. Most trace element concentrations found in soft tissue of mussels appear to be within recommended Italian and international guidelines for shellfish for human consumption, the only exception being relatively high As levels. The bioaccumulation of Ag and Cr is more pronounced in the shell of these organisms. In the marine water of the lagoon, trace elements are more enriched than in other areas of the Mediterranean, with particular reference to the dissolved labile species of Zn, Mn, As, Cu, Ni and Cr.     

Arsenic contamination in the Kanker district of central-east India: geology and health effects

This paper identifies newer areas of arsenic contamination in the District Kanker, which adjoins the District Rajnandgaon where high contamination has been reported earlier. A correlation with the mobile phase episodes of arsenic contamination has been identified, which further hinges on the complex geology of the area. Arsenic concentrations in both surface and groundwater, aquatic organisms (snail and water weeds) soil and vegetation of Kanker district and its adjoining area have been reported here. The region has been found to contain an elevated level of arsenic. All segments of the ecoysystem are contaminated with arsenic at varying degrees. The levels of arsenic vary constantly depending on the season and location. An analysis of groundwater from 89 locations in the Kanker district has shown high values of arsenic, iron and manganese (mean: 144, 914 and 371 μg L⁻¹, respectively). The surface water of the region shows elevated levels of arsenic, which is influenced by the geological mineralised zonation. The most prevalent species in the groundwater is As(III), whereas the surface water of the rivers shows a significant contamination with the As(V) species. The analysis shows a bio-concentration of the toxic metals arsenic, nickel, copper and chromium. Higher arsenic concentrations (groundwater concentrations greater than 50 μg L⁻¹) are associated with sedimentary deposits derived from volcanic rocks, hence mineral leaching appears to be the source of arsenic contamination. Higher levels of arsenic and manganese in the Kanker district have been found to cause impacts on the flora and fauna. A case study of episodic arsenical diarrhoea is presented.     

Preliminary Report on Radon Concentration in Drinking Water and Indoor Air in Kenya

A screening survey has been carried out to determine activity concentrations of radon (²²²Rn) in drinking water and indoor air in various locations in Kenya. The concentration of ²²²Rn in water was measured using a liquid scintillation counter (LSC). Three different passive integrating devices were used in the measurements of ²²²Rn in air. In the short-term measurements, radon is absorbed in activated charcoal and the analyses were carried out using either LSC or gamma ray spectrometry. The long-term measurements were carried out using solid-state nuclear track detectors (SSNTD). The mean and maximum values of ²²²Rn concentrations in water are 37 and 410 Bq L^–1 and 100 and 1160 Bq m^–3, respectively, in air. The highest values were obtained from groundwater sources and in the basements of buildings. When these values are compared with the internationally recommended reference levels, there are indications of existence of radon problems in some of the water sources and the dwellings tested in this survey.     

Arsenic, Cadmium, Lead, and Mercury in surface soils, Pueblo, Colorado: implications for population health risk

Decades of intensive industrial and agricultural practices as well as rapid urbanization have left communities like Pueblo, Colorado facing potential health threats from pollution of its soils, air, water and food supply. To address such concerns about environmental contamination, we conducted an urban geochemical study of the city of Pueblo to offer insights into the potential chemical hazards in soil and inform priorities for future health studies and population interventions aimed at reducing exposures to inorganic substances. The current study characterizes the environmental landscape of Pueblo in terms of heavy metals, and relates this to population distributions. Soil was sampled within the city along transects and analyzed for arsenic (As), cadmium (Cd), mercury (Hg) and lead (Pb). We also profiled Pueblo’s communities in terms of their socioeconomic status and demographics. ArcGIS 9.0 was used to perform exploratory spatial data analysis and generate community profiles and prediction maps. The topsoil in Pueblo contains more As, Cd, Hg and Pb than national soil averages, although average Hg content in Pueblo was within reported baseline ranges. The highest levels of As concentrations ranged between 56.6 and 66.5 ppm. Lead concentrations exceeded 300 ppm in several of Pueblo’s residential communities. Elevated levels of lead are concentrated in low-income Hispanic and African-American communities. Areas of excessively high Cd concentration exist around Pueblo, including low income and minority communities, raising additional health and environmental justice concerns. Although the distribution patterns vary by element and may reflect both industrial and non-industrial sources, the study confirms that there is environmental contamination around Pueblo and underscores the need for a comprehensive public health approach to address environmental threats in urban communities.     

基于主成分分析和水质标识指数的天津地区主要河流水质评价

于2009年5月(枯水期)、8月(丰水期)、11月(平水期)对天津地区蓟运河、潮白新河、永定新河、金钟河、北塘排污河、黑猪河、海河、大沽排污河、独流减河、青静黄排水渠、子牙新河和北排水河12条主要河流的水质进行监测,并对监测数据进行主成分分析,构建水质评价指标体系,采用水质标识指数进行水质评价。结果表明,主成分分析与水质标识指数相结合的评价方法客观可靠。从时间分布来看,枯水期水质最差,58.3%的河流为劣Ⅴ类水质,部分河流已经黑臭,8月水质较好。从综合水质标识指数来看,海河以南河流污染较为严重。该地区河流NH3-N污染最为严重,其次是BOD5、CODMn和TP,属于有机型及富营养化污染。     

蒙古栎林生态系统的辐射能量与水分关系的研究

本文把水分循环与辐射能量转换两个功能过程结合起来,研究蒙古栎林生态系统中的辐射能量与水分的关系。结果表明,森林作用层与林地作用层由于获得不同待征的辐射能量,导致水分交换的数量与方向不同。约74.5％的净辐射用于森林的水分蒸发散,而蒸发散又占降雨量77.45％。可见,辐射能量的大部分用于水分循环。本文还研究了辐射能量对融雪过程的影响,发现针阔混交林在冬季由于具有获得适度辐射能量的特点,使得它是一种较理想的融雪径流产流模式,为合理经营森林提供了依据。     

工业发展与环境污染关系的区域差异分析--基于江苏省的实证研究

利用格兰杰因果关系检验（Granger causality tests）方法分析了江苏省处在不同发展阶段的三大区域的工业经济增长和环境污染之间双向作用关系。研究结果表明：经济发展水平越高,工业经济增长对环境污染的影响越明显,并且持续时间长,在某种程度上环境污染已经成为受工业经济增长影响的内生变量;江苏省三大区域环境污染都不是工业经济增长的原因,环境污染的加重并不能带来工业经济的增长,因此,在实践中靠牺牲环境来换取经济增长的理念是不可取的,＂先污染后治理＂的发展思路是不可行的。     

基于MODIS时序数据北回归线(云南段)地区植被物候时空变化及其对气候响应分析

植被物候作为自然界规律性、周期性事件,对开展全球气候变化、植被长势观测等研究具有重要价值。以北回归线(云南段)穿过的县域为研究区,基于长时间序列MODIS EVI(Enhanced Vegetation Index,EVI)、土地利用类型和气候因子数据,采用S-G滤波、动态阈值、相关分析等方法分析19 a(2001—2019年)间植被物候的时空分布特征及其对水热因子的响应。结果表明,(1)海拔和地势起伏在物候地域分异中作用显著,植被物候存在明显的垂直地带性分布特征。山地与河谷、坝子、低海拔区的物候值差异较大,山地地区的植被生长季开始期(Start of Season,SOS)在192—240 d,生长季结束期(End of Season,EOS)在次年144—192 d,生长季长度(Length of Season,LOS)为272—304 d;河谷、坝子、东部低海拔地区的植被SOS在80—112 d,EOS在337至次年17 d,LOS在224—256 d。(2)19 a间植被物候年际变化总体特征为SOS显著提前(R²=0.51,P=0.001<0.05),平均提前1.14 d·(10 a)^?1;EOS推迟(R²=0.01,P=0.756>0.05),平均推迟0.07 d·(10 a)^?1;LOS显著延长(R²=0.47,P=0.001<0.05),平均延长1.07 d·(10 a)^?1。(3)不同植被类型的物候期及其变化趋势不同,研究区森林植被生长期最长,草地次之,耕地最短;19 a间SOS、EOS、LOS变化最大的分别是常绿阔叶林(?1.68 d·(10 a)^?1)、耕地(1.25 d·(10 a)^?1)、木本热带稀树草原(1.28 d·(10 a)^?1)。(4)水热组合对植被生长影响显著,河谷、坝子、东部低海拔地区的植被SOS、EOS分别主要受2月降水(负相关)和4月气温(正相关)、9月降水和气温(正相关)影响,山地地区植被SOS、EOS分别主要受6月降水(正相关)和5月气温(正相关)、5月降水(正相关)和4月气温(正相关)影响。