Occurrence of Organic Chemicals in Two Rivers Inhabited by Ozark Hellbenders (Cryptobranchus alleganiensis bishopi)

Abstract

Ozark Hellbender (Cryptobranchus alleganiensis bishopi) populations are in decrease throughout their native range with rare recruitment of young. Increased estrogenic chemical levels and alterations of physicochemical properties in their habitat may play a significant role in this phenomenon. We report here the first systematic, comprehensive study of organic chemical concentrations and physical and nutrient parameters in two rivers containing Ozark hellbender populations. Water samples were collected monthly from August 2003 to November 2004. Concentrations of 21 organic chemicals were determined using gas chromatography-mass spectrometry. Nine organic chemicals were detected. Benzyl butyl phthalate, dibutyl phthalate, bisphenol A, and beta-sitosterol were all detected >85% of the time, with median concentrations of 18 to 234 ng/L and maximum concentrations of 198 to 4141 ng/L. Individually, concentrations of nutrients and organic chemicals were much lower than those shown previously in laboratory and field experiments to have reproductive effects on amphibians. Nevertheless, hellbenders are exposed to a variety of chemicals with potential estrogenic effects. Our study establishes the basis to examine the specific effects of the detected concentrations, alone and in combination, on the Ozark hellbenders.

A Comparison of Sperm Health in Declining and Stable Populations of Hellbenders (Cryptobranchus alleganiensis alleganiensis and C.a. bishopi)

“…Interestingly, Swan, et al (2003) conducted a similar comparison of geographic differences in sperm concentrations in humans and found that males from Missouri had relatively low sperm counts, which they suggested were due to the close proximity of this population to pesticides associated with industrial agriculture. Hellbenders in Missouri at our sample locations are exposed to a variety of potentially estrogenic chemicals, but exposure levels appear to be relatively low (Solis et al, 2007). However, due to the limited scope of our study we were unable to quantify this relationship.…”

Evaluation of Microorganisms Cultured from Injured and Repressed Tissue Regeneration Sites in Endangered Giant Aquatic Ozark Hellbender Salamanders

“…Previous studies investigating the impact of human activities on NFWR water quality revealed relatively high concentrations of total phosphorus (6–52 µg L− 1 ) and total nitrogen (0.35–3.06 mg L− 1 ) in the 4.6 km research site originally investigated by Nickerson and Mays [80], [81]. The impact of this type of increased nutrient level on the hellbenders was investigated by Solis et al, which focused on a historically populated area, located 11.3 km downstream of the Nickerson and Mays site [80], [82]. Not unexpectedly, the site studied by Solis et al indicated that nutrient concentrations (including total phosphorous and nitrogen) exceeded the EPA recommended criteria in two thirds of the samples [80].…”

“…Environmental factors that have been considered to affect regeneration include temperature, diet, photoperiod, parasitism, infection, and quality of terrestrial and aquatic microhabitats [79]. Human-induced alterations to the NFWR and surrounding landscape have resulted in changes to the physical-chemical properties of the NFWR, including nutrient-loading, introduction of estrogenic chemical levels, algal blooms, and a microbial content deemed unsafe for full body contact by state and federal agencies [43], [80], [81]. Previous studies investigating the impact of human activities on NFWR water quality revealed relatively high concentrations of total phosphorus (6–52 µg L− 1 ) and total nitrogen (0.35–3.06 mg L− 1 ) in the 4.6 km research site originally investigated by Nickerson and Mays [80], [81].…”

“…Human-induced alterations to the NFWR and surrounding landscape have resulted in changes to the physical-chemical properties of the NFWR, including nutrient-loading, introduction of estrogenic chemical levels, algal blooms, and a microbial content deemed unsafe for full body contact by state and federal agencies [43], [80], [81]. Previous studies investigating the impact of human activities on NFWR water quality revealed relatively high concentrations of total phosphorus (6–52 µg L− 1 ) and total nitrogen (0.35–3.06 mg L− 1 ) in the 4.6 km research site originally investigated by Nickerson and Mays [80], [81]. The impact of this type of increased nutrient level on the hellbenders was investigated by Solis et al, which focused on a historically populated area, located 11.3 km downstream of the Nickerson and Mays site [80], [82].…”

Relating resource use to body condition and survival of Ozark hellbenders Cryptobranchus alleganiensis bishopi

“…Examples of extrinsic factors suggested to potentially affect Ozark hellbender populations include impoundments affecting flow and temperature of water, sedimentation, water contamination, predation, disease, and disturbance (Briggler et al 2007, Solís et al 2007, Bodinof et al 2011, Gould 2011. Perhaps measures of energetics and extrinsic factors can be simultaneously related to an accurate index of fitness such as lifetime reproductive success to gain a clearer understanding of causes of variation in individual hellbender biological outcome.…”