en Environmental Health, Sciences, and Engineering Environmental Health, Sciences, and Engineering پژوهشي Original Article <div style="text-align: justify;"><span style="line-height:1;"><span style="font-size:14px;"><span style="font-family:Times New Roman;"><b><span style="color:black">Background: </span></b><span class="TextChar"><span style="color:#231f20"><span style="color:black">Mercury is a dangerous biological pollutant that contaminates food chains and enters the bodies of animals. Since free-roaming dogs are omnivorous and cover a large geographical area, this study measured mercury levels in the blood of free-roaming dogs in Gorgan City.</span></span></span><b><span style="color:black"></span></b><br> <b><span style="color:black">Methods: </span></b><span class="TextChar"><span style="color:#231f20"><span style="color:black">After recording the sampled dogs</span></span></span><span class="TextChar"><span style="color:#231f20"><span style="color:black">&rsquo;</span></span></span><span class="TextChar"><span style="color:#231f20"><span style="color:black"> characteristics, blood samples were collected, and mercury concentrations were measured using Coupled Plasma Mass Spectrometry (ICP-MS).</span></span></span><b><span style="color:black"></span></b><br> <b><span style="color:black">Results: </span></b><span class="TextChar"><span style="color:#231f20"><span style="color:black">The mean mercury concentration in the blood samples was 24.9 &micro;g/L. Statistical analysis revealed no significant differences in mercury concentrations between male and female dogs (<i>P</i> = 0.669) or across different age groups (<i>P</i> = 0.486).</span></span></span><br> <b><span style="color:black">Conclusion: </span></b><span class="TextChar"><span style="color:#231f20"><span style="color:black">These findings underscore the presence of mercury pollution in Gorgan City, as blood mercury levels can indicate recent environmental contamination. The average mercury concentration in various areas of the city was below the toxic threshold of 105 &micro;g/L. However, even low levels of mercury exposure can be toxic to mammals. Since industrial and hospital waste are recognized as major sources of mercury, it is recommended that these wastes be treated before being released into the environment. The research also indicated that domestic dogs could serve as valuable bioindicators for monitoring environmental contamination by hazardous metals, such as mercury.</span></span></span></span></span></span></div> Free-roaming dogs, Mercury, Blood, Gorgan, Pollution, 88 93 http://jhehp.zums.ac.ir/browse.php?a_code=A-10-610-2&slc_lang=en&sid=1 Mahdiyeh Ghadimi Aliabadi mahdiyeh.ghadimi77@gmail.com 100319475328460015650 0009-0007-4832-2972 No Department of Environmental Sciences, Faculty of Fisheries and Environment Sciences, Gorgan University of Agricultural Sciences and Natural Resources, Gorgan, Golestan Province, Iran. Somayeh Namroodi snamroodi2000@yahoo.com 100319475328460015651 100319475328460015651 Yes Department of Environmental Sciences, Faculty of Fisheries and Environment Sciences, Gorgan University of Agricultural Sciences and Natural Resources, Gorgan, Golestan Province, Iran. Alireza Yousefi Alireza.yousefi4@yahoo.com 100319475328460015652 0009-0000-8640-2956 No Vorkan Veterinary Hospital, Gorgan, Golestan Province, Iran. Hajar Abyar hajar.abyar@yahoo.com 100319475328460015653 100319475328460015653 No Department of Environmental Sciences, Faculty of Fisheries and Environment Sciences, Gorgan University of Agricultural Sciences and Natural Resources, Gorgan, Golestan Province, Iran.