这项研究检查了图拉格河的水质,达卡的一条重要支流河,孟加拉国在物理化学特征和重金属污染方面评估对生态系统和人类健康的潜在风险。大多数水样符合世界卫生组织(WHO)为各种参数(包括pH值)规定的可接受限值。电导率(EC),总溶解固体(TDS),溶解氧(DO),化学需氧量(COD),钠吸附比(SAR),和镁吸附比(MAR),除了总硬度(TH)。钠(Na),钾(K),钙(Ca),镁(Mg),氯化物(Cl-),氟化物(F-),硝酸盐(NO3-),在大多数情况下,发现水样中的硫酸盐(SO42-)水平在可接受的范围内。此外,重金属,包括铅(Pb),镉(Cd),铬(Cr),镍(Ni),铁(Fe),锰(Mn),锌(Zn),铜(Cu),砷(As),硒(Se),和汞(Hg)进行了分析,发现它们的平均浓度(μg/L)在Fe(244.72±214.35)>Mn(28.93±29.64)>Zn(22.97±10.93)>Cu(8.28±5.99)>Hg(8.23±6.58)>As(1.34±0.39)>Ni(1.20±0.38)>Cr(0.67±0.48)中的可接受范围为除了Hg。通过重金属污染指数(HPI)评估了所有重金属的累积效应,污染程度(Cd),和内梅罗污染指数(PN)。HPI的平均值(682.38±525.68)超过了临界指数值100,表明污染水平升高。Cd的平均值(8.763±6.48)表明由于汞含量升高而造成的低-中-显着污染水平,对于PN,发现的是174.27±146.66,表明由于高含量的铁而造成的污染水平很高。生态风险指数(ERI)表明铅的风险水平较低,Cd,Cr,Ni,Fe,Mn,As,Se,Cu,和锌,但汞的风险很高。根据其物理化学性质(pH,EC,TDS,COD,CODDO,F-,Cl-,NO3-,和SO42-),而根据水质指数(WQI),它被认为不适合重金属。在致癌成分中,作为最大的致癌风险,特别是对于儿童。Cr的平均值,Mn,就像在HQingestion对成人和儿童一样,还有Cd,儿童的汞含量超过了美国环境保护局(USEPA)设定的阈值,而HQderal值仍低于所有重金属的最大限值。所有位置的HI值都超过了USEPA规定的阈值1。主成分分析(PCA)和聚类分析表明,图拉格河中重金属的存在主要归因于人为来源,包括邻近工业的工业废水排放,生活污水,以及来自周围土地的含有农用化学品的农业径流。
This study examined the water quality of the Turag River, an important tributary river in Dhaka, Bangladesh in terms of physicochemical characteristics and heavy metal contamination to assess the potential risks to both ecological systems and human health. The majority of the water samples complied with the acceptable limits established by the World Health Organization (WHO) for various parameters including pH, electrical conductivity (EC), total dissolved solids (TDS), dissolved oxygen (DO), chemical oxygen demand (COD), sodium adsorption ratio (SAR), and magnesium adsorption ratio (MAR), except total hardness (TH). The sodium (Na), potassium (K), calcium (Ca), magnesium (Mg), chloride (Cl-), fluoride (F-), nitrate (NO3 -), and sulfate (SO4 2-) levels in the water samples were found to be within acceptable ranges for most cases. Moreover, heavy metals including lead (Pb), cadmium (Cd), chromium (Cr), nickel (Ni), iron (Fe), manganese (Mn), zinc (Zn), copper (Cu), arsenic (As), selenium (Se), and mercury (Hg) were analyzed and their mean concentrations (μg/L) were found in the order of Fe (244.72 ± 214.35) > Mn (28.93 ± 29.64) > Zn (22.97 ± 10.93) > Cu (8.28 ± 5.99) > Hg (8.23 ± 6.58) > As (1.34 ± 0.39) > Ni (1.20 ± 0.38) > Cr (0.67 ± 0.85) > Pb (0.61 ± 0.72) > Se (0.42 ± 0.48) > Cd (0.13 ± 0.09) which were within the acceptable limit, except Hg. The cumulative effect of all heavy metals was assessed through the heavy metal pollution index (HPI), contamination degree (Cd), and nemerow pollution index (PN). The mean value of HPI (682.38 ± 525.68) crossed the critical index value of 100, indicating an elevated level of pollution. The mean value of Cd (8.763 ± 6.48) indicates a low-moderate-significant level of contamination due to an elevated level of Hg, and for the PN it was found 174.27 ± 146.66, indicating a high level of pollution due to high level of Fe. Ecological risk index (ERI) indicated low levels of risk for Pb, Cd, Cr, Ni, Fe, Mn, As, Se, Cu, and Zn but a significantly high risk for Hg. The water was classified as good to excellent based on its physicochemical properties (pH, EC, TDS, COD, DO, F-, Cl-, NO3 -, and SO4 2-) while it was deemed poor to unsuitable for heavy metals according to the water quality index (WQI). Among the carcinogenic constituents, As poses the greatest carcinogenic risk, particularly for children. The mean value of Cr, Mn, and As in the HQingestion for adult and child, and Cd, Hg for child exceeded the threshold value established by the United States Environmental Protection Agency (USEPA), while the HQdermal values remained below the maximum limit for all heavy metals. The value of HI at all locations exceeds the threshold of 1, as specified by USEPA. Principal component analysis (PCA) and cluster analysis revealed that the presence of heavy metals in the Turag River was mainly attributed to anthropogenic sources, including industrial effluent discharge from neighboring industries, domestic wastewater, and agricultural runoff containing agrochemicals from the surrounding lands.