Year-Round Monitoring of Contaminants in Neal and Rogers Creeks, Hood River Basin, Oregon, 2011-12, and Assessment of Risks to Salmonids

Abstract

Pesticide presence in streams is a potential threat to Endangered Species Act listed salmonids in the Hood River basin, Oregon, a primarily forested and agricultural basin. Two types of passive samplers, polar organic chemical integrative samplers (POCIS) and semipermeable membrane devices (SPMDs), were simultaneously deployed at four sites in the basin during Mar. 2011–Mar. 2012 to measure the presence of pesticides, polybrominated diphenyl ethers (PBDEs), and polychlorinated biphenyls (PCBs). The year-round use of passive samplers is a novel approach and offers several new insights. Currently used pesticides and legacy contaminants, including many chlorinated pesticides and PBDEs, were present throughout the year in the basin’s streams. PCBs were not detected. Time-weighted average water concentrations for the 2-month deployment periods were estimated from concentrations of chemicals measured in the passive samplers. Currently used pesticide concentrations peaked during spring and were detected beyond their seasons of expected use. Summed concentrations of legacy contaminants in Neal Creek were highest during July–Sept., the period with the lowest streamflows. Endosulfan was the only pesticide detected in passive samplers at concentrations exceeding Oregon or U.S. Environmental Protection Agency water-quality thresholds. A Sensitive Pesticide Toxicity Index (SPTI) was used to estimate the relative acute potential toxicity among sample mixtures. The acute potential toxicity of the detected mixtures was likely greater for invertebrates than for fish and for all samples in Neal Creek compared to Rogers Creek, but the indices appear to be low overall (<0.1). Endosulfans and pyrethroid insecticides were the largest contributors to the SPTIs for both sites. SPTIs of some discrete (grab) samples from the basin that were used for comparison exceeded 0.1 when some insecticides (azinphos methyl, chlorpyrifos, malathion) were detected at concentrations near or exceeding acute water-quality thresholds. Early life stages and adults of several sensitive fish species, including salmonids, are present in surface waters of the basin throughout the year, including during periods of peak estimated potential toxicity. Based on these data, direct toxicity to salmonids from in-stream pesticide exposure is unlikely, but indirect impacts (reduced fitness due to cumulative exposures or negative impacts to invertebrate prey populations) are unknown.

Salinity Alters Toxicity of Commonly Used Pesticides in a Model Euryhaline Fish Species (Menidia beryllina)

“…Once they enter the watershed, pesticides travel throughout the aquatic ecosystem, where they can be ultimately deposited in estuarine and marine environments. Many pesticides are used in agricultural, residential, and industrial (non-agricultural) applications within close proximity to estuaries and coastal regions due to the larger number of crops and high human population along coastlines, further increasing pesticide pollution in these ecosystems [15,16]. Estuaries can serve as a sink for many pollutants that enter through stormwater runoff, wastewater discharge, and pesticide drift, where they are frequently detected in surface water [16,17].…”

Exploring Biophysical Linkages between Coastal Forestry Management Practices and Aquatic Bivalve Contaminant Exposure

“…Pesticide contaminants were more frequently detected in bivalve tissues during the summer of 2017 during low runoff conditions, and higher concentrations were detected in the spring of 2018 during high runoff conditions ( Table 3 ). Elevated contaminant levels in spring are expected due to the timing of spring pesticide applications to commercial forestlands and resultant high flow downstream [ 53 , 61 ]. Bivalve tissues frequently exhibit seasonal variability in lipid content due to gametogenesis and reproduction, which can influence the composition and concentration of stored contaminants [ 62 ].…”

Effects of Environmentally Relevant Concentration Exposure Profiles on Polar Organic Chemical Integrative Sampler (POCIS) Sampling Rates

“…Passive sampling devices, such as the polar organic chemical integrative sampler (POCIS), are being adopted as an alternative to conventional discrete grab sampling for the monitoring of chemicals in agricultural and urban streams. − POCIS devices provide several advantages over traditional grab water sampling, including analyte preconcentration and the capability to capture short spikes and time-weighted average (TWA) concentrations for subchronic and chronic exposure evaluations. POCIS devices are typically made of Oasis HLB resin or other sorbent uniformly distributed and sandwiched between two PES membranes, which are held together by two stainless steel rings.…”