Harbor Branch Oceanographic Institute, Florida Atlantic University, 5600 US 1, Fort Pierce, FL 34946, USA.
Lee County Division of Natural Resources, 1500 Monroe St, Fort Myers, FL 33901, USA.
Sci Total Environ. 2022 Sep 1;837:155319. doi: 10.1016/j.scitotenv.2022.155319. Epub 2022 Apr 20.
As human population growth has expanded in Southwest Florida, water quality has become degraded with an increased occurrence of harmful algal blooms (HABs). Red tide (Karenia brevis) originating offshore, intensifies in nearshore waters along Florida's Gulf Coast, and blue-green algae (Microcystis spp.) originating in Lake Okeechobee is discharged into the Caloosahatchee River. These HABs could be enhanced by anthropogenic nitrogen (N) and phosphorus (P) from adjacent watersheds. North Fort Myers is a heavily developed, low-lying city on the Caloosahatchee River Estuary serviced by septic systems with documented nutrient and bacterial pollution. To identify sources of pollution within North Fort Myers and determine connections with downstream HABs, this multiyear (2017-2020) study examined septic system- groundwater- surface water couplings through the analysis of water table depth, nutrients (N, P), fecal indicator bacteria (FIB), molecular markers (HF183, GFD, Gull2), chemical tracers (sucralose, pharmaceuticals, herbicides, pesticides), stable isotopes of groundwater (δN-NH, δN-NO) and particulate organic matter (POM; δN, δC), and POM elemental composition (C:N:P). POM samples were also collected during K. brevis and Microcystis spp. HAB events. Most (>80%) water table depth measurements were too shallow to support septic system functioning (<1.07 m). High concentrations of NH and NO, up to 1094 μM and 482 μM respectively, were found in groundwater and surface water. δN values of groundwater (+4.7‰) were similar to septic effluent (+4.9‰), POM (+4.7‰), and downstream HABs (+4.8 to 6.9‰), indicating a human waste N source. In surface water, FIB were elevated and HF183 was detected, while in groundwater and surface water sucralose, carbamazepine, primidone, and acetaminophen were detected. These data suggest that groundwater and surface water in North Fort Myers are coupled and contaminated by septic system effluent, which is negatively affecting water quality and contributing to the maintenance and intensification of downstream HABs.
随着佛罗里达州西南部人口的增长，水质已经恶化，有害藻类大量繁殖（HAB）的情况也越来越多。赤潮（Karenia brevis）从近海产生，在佛罗里达州墨西哥湾沿岸的近岸水域加剧，而蓝绿藻（Microcystis spp.）则从奥基乔比湖排出到卡卢萨哈奇河。这些 HAB 可能会因相邻流域人为产生的氮（N）和磷（P）而加剧。北迈尔斯堡是一个位于卡卢萨哈奇河河口的高度发达、地势低洼的城市，其服务系统由化粪池系统提供，该系统存在有记录的营养物和细菌污染。为了确定北迈尔斯堡的污染来源，并确定与下游 HAB 的关系，这项多年期（2017-2020 年）研究通过分析地下水位深度、营养物（N、P）、粪便指示细菌（FIB）、分子标记（HF183、GFD、Gull2）、化学示踪剂（蔗糖、药物、除草剂、杀虫剂）、地下水稳定同位素（δN-NH、δN-NO）和颗粒有机物质（POM；δN、δC）以及 POM 元素组成（C：N：P）来研究化粪池-地下水-地表水的耦合。在赤潮和蓝绿藻大量繁殖期间也采集了 POM 样本。超过 80%的地下水位深度测量值过浅，无法支持化粪池系统的正常运行（<1.07 米）。在地下水和地表水发现了高浓度的 NH 和 NO，分别高达 1094 μM 和 482 μM。地下水的 δN 值（+4.7‰）与化粪池废水（+4.9‰）、POM（+4.7‰）和下游 HAB（+4.8 至 6.9‰）相似，表明这是人类排泄物中的 N 源。在地表水，FIB 升高，HF183 被检测到，而在地下水和地表水，蔗糖、卡马西平、苯巴比妥和对乙酰氨基酚被检测到。这些数据表明，北迈尔斯堡的地下水和地表水是相互连接的，并受到化粪池系统废水的污染，这正在对水质产生负面影响，并导致下游 HAB 的维持和加剧。
