Investigation of organic chemicals potentially responsible for mortality and intersex in fish of the North Fork of the Shenandoah River, Virginia, during Spring of 2007

Abstract

Declining fish health, fish exhibiting external lesions, incidences of intersex, and death, have been observed recently within the Potomac River basin. The basin receives surface runoff and direct inputs from agricultural, industrial, and other human activities. Two locations on the North Fork of the Shenandoah River were selected for study in an attempt to identify chemicals that may have contributed to the declining fish health. Two passive sampling devices, semipermeable membrane devices (SPMDs) and polar organic chemical integrative samplers (POCIS), were deployed during consecutive two-month periods during the spring and early summer of 2007 to measure select organic contaminants to which fish may have been exposed. This study determined that concentrations of persistent hydrophobic contaminants, such as polycyclic aromatic hydrocarbons (<760 picograms per liter), legacy pesticides (<10 picograms per liter), and polychlorinated biphenyls (<280 picograms per liter) were low and indicative of a largely agricultural area. Atrazine and simazine were the most commonly detected pesticides. Atrazine concentrations ranged from 68 to 170 nanograms per liter for the March to April study period and 320 to 650 nanograms per liter for the April to June study period. Few chemicals characteristic of wastewater treatment plant effluent or septic tank discharges were identified. In contrast, para-cresol, N,N-diethyltoluamide, and caffeine commonly were detected. Prescription pharmaceuticals including carbamazepine, venlafaxine, and 17α-ethynylestradiol were at low concentrations. Extracts from the passive samplers also were screened for the presence of estrogenic chemicals using the yeast estrogen screen. An estrogenic response was observed in POCIS samples from both sites, whereas SPMD samples exhibited little to no estrogenicity. This indicates that the chemicals producing the estrogenic response have a greater water solubility and are, therefore, less likely to bioaccumulate in fatty tissues of organisms.

Reproductive health of bass in the Potomac, USA, drainage: Part 2. Seasonal occurrence of persistent and emerging organic contaminants

“…The estimated water concentrations were similar to those reported by Alvarez et al [20] from a sampling on the nearby North Fork of the Shenandoah River in northern Virginia during the spring and early summer of 2007. For both chemicals, the concentrations were 3.1-to 91-fold greater in the spring sampling, which was expected because of increased pesticide application corresponding to spring crop planting in the largely agricultural reaches of the watershed.…”

“…Considering that the mean stream flow only increased twofold between the fall and spring (flow was measured at the downstream sites only), any variation in the POCIS R s was considered to be negligible. The estimated water concentrations were similar to those reported by Alvarez et al [20] from a sampling on the nearby North Fork of the Shenandoah River in northern Virginia during the spring and early summer of 2007.…”

“…Processing methods for selected hormones from POCIS have been reported previously [20]. Processing methods for selected hormones from POCIS have been reported previously [20].…”

“…Hormones. Processing methods for selected hormones from POCIS have been reported previously [20]. Briefly, the extracts were fractionated by SEC, with the collect window initiated at 5% of the time between the apexes of the chromatographic reference peaks diethylhexylphthalate and biphenyl [19].…”

Mortality of Centrarchid Fishes in the Potomac Drainage: Survey Results and Overview of Potential Contributing Factors

“…Hence, a number of studies were conducted using passive sampler devices. Two types of device, semipermeable membrane devices and polar organic chemical integrative samplers, have been deployed at numerous sites within the Potomac drainage (Alvarez et al 2008b(Alvarez et al , 2008c). These devices provide a means of integratively sampling a variety of bioavailable waterborne nonpolar and polar organic contaminants.…”