The impact of heavy metals exposure on male fertility: a scoping review of human studies

Introduction: Male infertility is a critical global health issue, with environmental and occupational exposure to heavy metals, such as lead (Pb), cadmium (Cd), mercury (Hg), and arsenic (As), impacting male reproductive health. This scoping review aims to evaluate the effects of heavy metal exposure on semen parameters. Content: This study adhered to the 2020 PRISMA framework. A broad literature search was performed on January 2025, using Embase, PUBMED, and Scopus. A comprehensive literature search was performed using PubMed, Embase, and Scopus on January 12, 2025, using a combination of Medical Subject terms and keywords. Summary: Of the 1,709 identified studies, 21 met the inclusion criteria and were analyzed. Findings indicate that lead exposure negatively impacts sperm concentration, motility, and morphology, primarily through oxidative stress and enzymatic inhibition. Cadmium disrupts the blood-testis barrier and acrosomal function, leading to sperm abnormalities. Arsenic exposure is linked to oxidative stress, apoptosis, and impaired sperm motility. Outlook: The cumulative evidence supports a strong association between heavy metal exposure and male infertility. This review underscores the need for stricter occupational safety regulations and environmental policies to mitigate heavy metal exposure.