Analysis of the Impact of Perchlorate: Thyroid Health and Water Environment
In recent years, perchlorate pollutants has aroused widespread concern in society. In March 2022, National Health Commission of the People’s Republic of China released Standard for Drinking Water Quality (GB 5749-2022). This document introduced perchlorate as a newly regulated parameter for the first time, establishing a standard limit of 70㎍/L. Relevant testing indicates that partial surface water has relatively high content of perchlorate and that these regions show obvious characteristics of pollution. Actions should be taken to investigate the sources of pollution and to reduce the concentrations.
Perchlorate pollution mainly stems from human activities. The primary anthropogenic sources of perchlorate pollution originate from its utilization in rocket propellants, fireworks manufacturing, military munitions industries, demolition operation, lubricant production and so on. These manufacturing and production activities discharge perchlorate through multiple channels, resulting in a close connection between the distribution of polluted areas and the industrial layout. Furthermore, fertilizers produced using raw materials such as nitrates from Chile’s Atacamca Desert introduce perchlorate into the environment during agricultural application.
The major harm of perchlorate lies in its interference with the normal function of human thyroid gland. Due to the nearly identical charge and ionic radius between perchlorate and iodide ions, perchlorate competitively inhibits iodide uptake into the thyroid gland. The interference disrupts iodine absorption, potentially leading to iodine deficiency disorders and thyroid hypertrophy. Additionally, perchlorate dust may irritate mucous membranes and eyes. Upon entering the respiratory system or being absorbed systemically, it can induce respiratory distress, persistent coughing, and potentially cause hepatic and renal impairment.
Perchlorate detection can be performed with relatively simple analytical equipment, enabling rapid assessment of contamination levels. In soil environments, perchlorate primarily originates from two anthropogenic sources: landfill solid waste and legacy contamination. In the past, relevant enterprises did not have enough environmentally friendly awareness, they directly discharge wastewater to lakes and rivers, which is the fundamental cause of perchlorate pollution.
Perchlorate’s high mobility, poor adsorbability, and exceptional chemical stability render it resistant to traditional remediation approaches such as chemical precipitation and physical adsorption. By far, domestic and international researchers have successfully developed multiple effective treatment technologies for perchlorate contaminated wastewater, including: ion exchange resin adsorption, chemical reduction, biological reduction. In Hunan Province, several technical teams have developed and successfully demonstrated two industrialized perchlorate treatment processes in compliance with regulatory requirements: Targeted High-Efficiency Adsorption and Nano Zero-Valent Reduction. For wastewater generated by fireworks and related industries, an integrated mobile treatment system employing the “Pretreatment-Sand Filtration-Targeted Adsorption” process has been developed, achieving a large treatment capacity (50 t/d) and high removal efficiency (up to 99%). The treated water can be directly discharged or recycled. The nano zero-valent iron reduction process can effectively covert perchlorate into chloride ions under controlled conditions, achieving removal efficiencies of 50%-95%. Current research focuses on enhancing the technology’s stability for broader application.
To meet the pollution control requirements, relevant authorities are positively formulating the Industrial Wastewater Perchlorate Pollutant Discharge Standard. Preliminary discharge limits have been proposed, and the technical review has been completed. Control measures have been proposed for perchlorate-producing enterprises, as well as fireworks and fuse manufacturing enterprises, with the draft regulation soon to be released for public consultation. Once the discharge standard is formulated, enterprises which are affected by the latest standard may either construct dedicated wastewater treatment facilities or opt for centralized treatment by professional wastewater treatment providers. This approach will reduce perchlorate emissions at the origin and enhance water environmental safety.
