Narayanan M Seeththa Sankar, Pitchaimani V Stephen, Sivakumar M, Dinesh Kumar T, Abishek S Richard, Karuppannan Shankar
Manonmaniam Sundaranar University, Tirunelveli, Tamil Nadu, 627012, India.
PG and Research Department of Geology, V. O. Chidambaram College, Thoothukudi, Tamil Nadu, 628008, India.
Sci Rep. 2025 Jul 29;15(1):27704. doi: 10.1038/s41598-025-12120-5.
Groundwater quality in Kadaladi is a critical concern due to contamination from natural and human activities. This study assesses heavy metal concentrations across pre-monsoon and post-monsoon seasons at 44 sampling sites, using the Heavy Metal Pollution Index (HPI), Metal Index (MI), and non-carcinogenic risk (HQ) assessments. Key heavy metals analysed include Cu, Pb, Zn, Ni, Cd, Mn, and Fe, in Pre-monsoon and Post-monsoon with comparisons to WHO (2017) standards using atomic absorption spectrometry. The Heavy Metal Pollution Index (HPI) and Metal Index (MI) were computed to assess contamination levels, and health risks were evaluated through non-carcinogenic hazard quotient (HQ) models for adults and children. Results revealed that Mn and Fe concentrations exceeded WHO permissible limits in 20% of the samples, with Site 33 showing the highest pollution in HPI (99.1) and MI (17.89). Post-monsoon samples showed notably higher contamination, attributed to monsoonal leaching and runoff from agricultural and saltpan activities. GIS-based spatial analysis identified persistent hotspots at Sites 6, 24, and 33. Children were particularly vulnerable, with HQ values exceeding 2.0 in affected zones, especially due to Mn exposure. HQ values indicated that children face higher health risks, particularly from Mn, exceeding permissible limits in 4.55% of samples. Pearson correlation revealed strong Mn-Fe geogenic associations, while Cd-Mn correlations post-monsoon pointed to anthropogenic sources. The integration of spatial mapping using GIS and statistical methods provides insight into contamination hotspots, emphasizing the critical role of monsoonal hydrology in mobilizing pollutants. These findings underscore the need for region-specific mitigation strategies and regular water quality monitoring. The study fills a regional knowledge gap and contributes globally relevant insights on managing groundwater quality in vulnerable coastal systems.
由于自然和人类活动造成的污染，卡达拉迪的地下水质量成为一个关键问题。本研究利用重金属污染指数（HPI）、金属指数（MI）和非致癌风险（HQ）评估，对44个采样点在季风前和季风后季节的重金属浓度进行了评估。分析的主要重金属包括铜、铅、锌、镍、镉、锰和铁，在季风前和季风后通过原子吸收光谱法与世界卫生组织（2017年）标准进行比较。计算了重金属污染指数（HPI）和金属指数（MI）以评估污染水平，并通过成人和儿童的非致癌风险商（HQ）模型评估健康风险。结果显示，20%的样本中锰和铁的浓度超过了世界卫生组织的允许限值，33号采样点的HPI（99.1）和MI（17.89）污染程度最高。季风后样本的污染明显更高，这归因于季风淋溶以及农业和盐田活动产生的径流。基于地理信息系统（GIS）的空间分析确定了6号、24号和33号采样点为持续热点区域。儿童尤其脆弱，在受影响区域HQ值超过2.0，特别是由于锰的暴露。HQ值表明儿童面临更高的健康风险, 尤其是锰，在4.55%的样本中超过了允许限值。皮尔逊相关性显示锰与铁有很强的地质成因关联，而季风后镉与锰的相关性则表明存在人为来源。利用GIS进行空间绘图与统计方法的结合，有助于深入了解污染热点，强调了季风水文在污染物迁移中的关键作用。这些发现强调了制定区域特定缓解策略和定期进行水质监测的必要性。该研究填补了区域知识空白，并为管理脆弱沿海系统中的地下水质量提供了具有全球相关性的见解。
