Non-point source pesticide removal by a mountainous wetland

Abstract

Non-point source (NPS) pollution is believed to be one of the major causes of impairment of water bodies. Among NPS pollution, agricultural NPS pollution is considered to be the largest single category resulting in water quality deterioration. Pesticides are some the most ubiquitous of these agricultural NPS pollutants. In this study, a mountainous wetland was selected to investigate the effects of the natural wetland system on the NPS pesticide (atrazine) removal to maintain the surface water quality. The selected wetland receives water from two unnamed creeks, which drain primarily upgradient agricultural lands. Wetland investigation and monitoring were conducted from November 1999 to March 2001. Major storm events and baseline water quality samples were analyzed. Field results indicate that the wetland was able to remove NPS atrazine flushed from the upgradient agricultural lands after the occurrence of storm events. Laboratory aerobic and anaerobic bioreactor experiments were conducted to evaluate the biodegradation of atrazine under the intrinsic conditions of the wetland system. Microbial enumeration was conducted for a quick screen of bacterial activity in the studied wetland. Results from the study suggest that the methanogenesis process was possibly the dominant biodegradation pattern, and atrazine can be degraded under reductive dechlorinating conditions when sufficient intrinsic organic matter was provided. Results from this study can provide us with further knowledge on pesticide removal mechanisms in natural wetlands and evaluate the role of wetlands in controlling pesticide pollutants from stormwater runoff.

Hydrological, Physical, and Chemical Functions and Connectivity of Non‐Floodplain Wetlands to Downstream Waters: A Review

“…Other pollutants and compounds can be mitigated by NFW sink processes (and/or transformation; see below). For example, microbial methanogenesis completely removed the pesticide atrazine from a mountainous bog in North Carolina (Kao et al 2002). The environmental contaminants cobalt (Co) and nickel (Ni) were remediated by wetland plants common in forested NFWs; plant concentrations were found to range from 1 to 530 mg Co/kg and up to 250 mg Ni/ kg (Brooks et al 1977).…”

Mitigation of agricultural nonpoint-source pesticide pollution in artificial wetland ecosystems

“…Yet, it has to be noted that almost all available studies dealt with strongly sorbing insecticides (e.g., chlorpyrifos) with a strong tendency to adsorb to macrophytes, suspended particles or bed sediment. Some studies (Kadlec and Hey 1994;Seybold and Mersie 1999;Moore et al 2000;Kao et al 2002;Stearman et al 2003;Bouldin et al 2005) investigated the fate and transport of the moderately sorbing herbicide atrazine in constructed wetlands. Moore et al (2000) found that a travel distance of 100-280 m through the wetland would be necessary to achieve an effective runoff mitigation (more precisely: an atrazine concentration in outflow corresponding to the NOEC for higher aquatic plants).…”

Mitigation of Agricultural Nonpoint-Source Pesticide Pollution in Artificial Wetland Ecosystems – A Review

“…chlorpyrifos) with a strong tendency to adsorb to macrophytes, suspended particles or bed sediment. Some studies (Kadlec and Hey, 1994;Seybold and Mersie, 1999;Moore et al, 2000;Kao et al, 2002;Stearman et al, 2003;Bouldin et al, 2005) investigated the fate and transport of the moderately sorbing herbicide atrazine in constructed wetlands. Moore et al (2000) found that a travel distance of 100-280 m through the wetland would be necessary to achieve an effective runoff mitigation (more precisely: an atrazine concentration in outflow corresponding to the NOEC for higher aquatic plants).…”